Compliance, peritoneal dialysis and chronic kidney disease: lessons from the literature.
Abstract: Poor patient compliance with peritoneal dialysis (PD) has significant adverse effects on morbidity and mortality rates in individuals with chronic kidney disease (CKD). It also adds to the resource burdens of healthcare services and providers. This paper explores the notion of PD compliance in patients with CKD with reference to the relevant published literature. The analysis of the literature reveals that 'PD compliance' is a complex and challenging construct for both patients and health professionals. There is no universal definition of compliance that is widely adopted in practice and research, and therefore a lack of consensus on how to determine 'compliant' patient outcomes. There are also multiple and interconnected determinants of PD compliance that are context-bound, which healthcare professionals must be aware of, and which makes producing consensus of measuring PD compliance difficult. The complexity of the interventions required to produce even a modest improvement in PD compliance, which are described in this paper, are significant. Compliance with PD and other treatments for CKD is a multidimensional, context-bound concept, that to date has tended to efface the role and needs of the renal patient. We conclude the paper with the implications for contemporary practice.

Key Words

Compliance, adherence, peritoneal dialysis, chronic kidney disease
Article Type: Clinical report
Subject: Chronic kidney failure (Care and treatment)
Chronic kidney failure (Patient outcomes)
Patient compliance (Health aspects)
Continuous ambulatory peritoneal dialysis (Methods)
Continuous ambulatory peritoneal dialysis (Health aspects)
Peritoneal dialysis (Methods)
Peritoneal dialysis (Health aspects)
Authors: McCarthy, Alexandra
Shaban, Ramon Z.
Fairweather, Carrie
Pub Date: 07/01/2010
Publication: Name: Renal Society of Australasia Journal Publisher: Renal Society of Australasia Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2010 Renal Society of Australasia ISSN: 1832-3804
Issue: Date: July, 2010 Source Volume: 6 Source Issue: 2
Geographic: Geographic Scope: Australia Geographic Code: 8AUST Australia
Accession Number: 264921867
Full Text: Introduction

Peritoneal dialysis (PD) is a home-based treatment for chronic kidney disease (CKD), which comprises a complex technical and lifestyle prescription. Health professionals often argue that successful dialysis outcomes hinge upon the renal patient following that prescription. They also note that the personal consequences of unsuccessful outcomes for the PD client, which include sepsis, cardiovascular morbidity, transfer to haemodialysis and death, also have implications for renal care providers and health insurers in terms of increased costs of care (Kutner, Zhang, McClellan, & Cole, 2002; Raj, 2002; Simpson et al., 2006). Yet PD is an intricate regimen with multiple aspects--compliance in this context does not relate to the dialysis procedure alone. Patients are asked to adhere to instructions regarding numerous adjuvant medications such as antihypertensives, phosphate binders, vitamins, iron replacement and subcutaneously-administered erythropoietin and antiglycaemics. They must also adhere to the recommended aseptic technique, PD prescription and timing, blood glucose and blood pressure monitoring, diet, exercise, and attend follow-up appointments.

There is good reason to believe that patient compliance with many aspects of this complicated regimen is poor, and can significantly undermine treatment benefits (Kutner, 2001; McDonald, Garg, & Haynes, 2002; Raj, 2002). This is reflected in the considerable time and energy that clinicians have expended in the last four decades in developing interventions to enhance the capacity of patients to comply with PD and the other regimens inseparable from it. In this paper, we review the literature to examine the concept of compliance in the context of CKD. The review, which first examines compliance theoretically and then moves to the phenomenon of PD compliance in practice, is organised into five key themes. These are defining compliance, measuring compliance, the factors influencing compliance, improving compliance, and the implications for nephrology nurisng practice and research.

Methods and Search Strategy

This review examined literature published in English between 1979 and 2009. Search parameters comprised the combination of the following terms: 'compliance', 'non-compliance', 'adherence', 'concordance', 'peritoneal dialysis', 'chronic kidney disease', 'home dialysis', 'end-stage kidney disease'; 'end-stage renal disease'; 'end-stage renal failure' and 'medication' and 'chronic illness'. The search focused initially on articles published in peer-reviewed journals that were relevant to patient compliance in PD. However, sentinel articles that examined the phenomenon of compliance with medical treatment more broadly were also included where relevant. These provided a valuable theoretical lens with which to examine the phenomenon. Databases searched included the Cumulative Index of Nursing and Allied Health Literature (CINAHL), Proquest, MEDLINE, OVID, PsycINFO, and Cochrane Collaboration. Meta-analyses, systematic reviews and randomised controlled trials (evidence Level I and II) were sought in the first instance. However, Level I and II evidence concerning compliance with specific dialysis procedures was limited, and because PD involves not just compliance with the dialysis technique but also with its many adjuvant regimens, the search necessarily extended to qualitative and quantitative compliance studies and literature reviews undertaken in these areas. A manual search of references in the identified articles was also conducted. In total 41 of the articles identified during the search were included in this review. These were assessed by the authors as meeting the inclusion criteria and of direct relevance to the review PD compliance in patients with CKD (see Table 1).

Findings

Defining compliance

The notion of compliance is one of the most researched, yet least understood phenomena in the body of health knowledge, mostly because of its elusive nature (Denhaerynck, Manhaeve, Nolte, & de Geest, 2007; Evangelista, 1999; Kyngas, Duffy, & Kroll, 1999; Murphy & Canales, 2001). Several authors report that up to fifty percent of papers describing compliance interventions fail to articulate a definition of compliance on which their study is based (Murphy & Canales, 2001; Vermeire, Hearnshaw, Van Royen, & Denekens, 2001). Adding to this problem is that the terms 'compliance' and 'non-compliance' are frequently used interchangeably, despite being quite different constructs (Kyngas et al., 1999; MacLaughlin et al., 2005; Murphy & Canales, 2001). Broadly speaking, non-compliance is the choice or ability not to do something, compliance is the choice or ability to do it. Many authors suggest that noncompliance is often used as a synonym for compliance (for example, see Leggat, 2005; Leggat et al., 1998; Raj, 2002). Defining the positive action of compliance in terms of its negative, equally elusive concept in this way is an understandable, but ultimately unhelpful strategy on which to base rigorous research. Moreover, compliance can be intentional or unintentional (Vermeire et al., 2001), but it is not often differentiated in studies as to whether intentional or unintentional compliance has been investigated.

Prior to 2000, most articulated definitions of compliance were congruent with dictionary definitions that emphasised ceding to the desires and demands of others; of conformity in deference to the social order of things (Evangelista, 1999). Given biomedicine's pervasive influence throughout all of the health professions, early and subsequent definitions of compliance are frequently centred in this worldview, conceiving it as the extent to which the patient's behaviour coincides with medical advice (for example, see Friberg & Scherman, 2005; Haynes, Taylor, & Sackett, 1979; MacLaughlin et al., 2005; McDonald et al., 2002; Rietveld & Koomen, 2002). Haynes et al's influential definition emphasised the need for patients "to yield [their emphasis] to the advice of health professionals ... whether declared by an autocrat, authoritarian clinician or developed as a consenual regimen through negotiation between a health professional and a citizen" (Haynes et al., 1979:1-2). To this day, many definitions of compliance concentrate on the biomedical rather than the behavioural or psychosocial processes involved. They define compliance, for example, as the amount of drug taken versus the amount not taken (Rietveld & Koomen, 2002; Schaffer & Yoon, 2001); the level of renal biochemical markers such as serum phosphate and creatinine (Kutner et al., 2002); or the lowering of blood pressure (Vermeire et al., 2001).

Reflecting more recent debates about the patient's role in their health care, the term 'adherence' is now commonly used by those who object to the "negative and authoritative" (Evangelista, 1999:9) connotations of the term compliance, or to the inference that compliance is the sole responsibility of a passive patient who has no input into the decision (Evangelista, 1999; MacLaughlin et al., 2005; Schaffer & Yoon, 2001). After initial resistance, the pioneers of compliance study, Haynes and colleagues, eventually embraced the term 'adherence' in recognition of its apparently less judgemental overtones (Haynes, McDonald, & Garg, 2002; McDonald et al., 2002). Hence, their formal definition was amended to "adherence may be defined as the extent to which a patient's behaviour (in terms of taking medication, following a diet, modifying habits, or attending clinics) coincides with medical or health advice" (McDonald et al., 2002:1) Their amended definition, however, differs little from their original, except in terms of semantics; and they continue to discuss adherence synonymously with compliance. Furthermore, there is little consensus about the new term. 'Adherence' is criticised for its perpetuation of paternalism; while its supporters argue that although the patient should be given more responsibility in their health care actions, those actions should nonetheless still be prescribed by those in a position to know better (Friberg & Scherman, 2005).

Hence, another discipline, pharmacy, has developed a further alternative--'concordance'. It has been adopted by the Royal Pharmaceutical Society of Great Britain, who believe it emphasises the ultimate ethical goal of treatment rather than the processes implied in 'compliance'. They also prefer its overtones of agreement and harmony between an empathetic professional and the patient as decision-maker (Vermeire et al., 2001). Concordance implies that the patient and the prescriber collaborate actively to create and implement a therapeutic regimen recommended, rather than prescribed by the health expert (Friberg & Scherman, 2005). It has not, however, been widely embraced among pharmacists or the other health disciplines (Loghman-Adham, 2003), for irrespective of disciplinary affiliattion, 'compliance' remains the most commonly used term in the health literature (Carpenter, 2005).

Nephrology nurses' views of compliance, adherence and concordance tend to reflect nursing's general discomfort with the reductionist, moralistic implications of all of these terms and definitions (Murphy & Canales, 2001; Costammm 2006; Russell, Daly, Hughes, & op't Hoog, 2003). More recently, nephrology nurses have moved away from such definitions altogether, preferring the notions of self-care or self-management (Burrows-Hudson & Prowant, 2005). While these concepts are still evolving, and continue to recognise that something called 'compliance' may exist, such notions emphasise the patient as an active partner in their treatment, possessing the "knowledge and skills to care for themselves, making decisions about their care; identifying problems; setting goals; and monitoring and managing symptoms" (White, 2004:388). It is argued that the notion of self-management is more useful than compliance because it is the client, after all, who self-manages the required PD regimen in their home, not the clinician (White, 2004).

The literature nonetheless demonstrates that irrespective of the notion of patient inclusiveness embedded in these alternative notions of adherence and self-management, focus must be placed on the patient-health professional relationship; and that furthermore, attention needs to be paid to the health care system issues that can compromise a patient's adherence (Kammerer, Garry, Hartigan, Carter & Elrich, 2007; Orr et al., 2007; Sussman, 2001). As will be examined further in this paper, nurses have an important role to play in supporting patients, identifying system barriers, and implementing strategies to help patients understand the rationale and practice of adherence.

Measuring compliance

There is currently no widely or universally-accepted standard for the measurement of compliance in any area of chronic disease, much less in PD compliance, mainly because the lack of a consensus definition makes it difficult to operationalise and then quantify compliance in a standardised way (Denhaerynck et al., 2007; Mattke et al., 2007). As a result, the heterogenous outcome measures in the myriad studies undertaken to date are not amenable to the pooling and meta-analysis that would allow comparison of their efficacy (Bennett & Glazsiou, 2003; Connor, Rafter, & Rodgers, 2004; Higgins & Regan, 2004; Murphy & Canales, 2001; Schroeder, Fahey, & Ebrahim. S., 2004; Takiya, Peterson, & Finley, 2004). Nonetheless, in the PD context it is possible to categorise two broad areas that are often measured: 1) compliance with adjuvant medications and 2) compliance with specific dialysis techniques.

Compliance with adjuvant medications

Measurements of general patient medication compliance can be direct or indirect. Indirect measures are often biochemical metabolites or markers detected in a body fluid. For example serum low density lipoprotein cholesterol (Lee, Grace, & Taylor, 2006) or urine drug levels (Vermeire et al., 2001) are measured as surrogate markers of compliance. Other indirect biophysiological measures include blood pressure monitoring (Lee et al., 2006). These measures have been criticised, however, as they are not available for all of the relevant medications and cannot account for the individual pharmacokinetic variances of drugs and of the people who take them; particularly people with CKD (Vermeire et al., 2001). Nor can they account for the time of day at which the sample was drawn or measured (MacLaughlin et al., 2005) or the methods patients have developed to avoid the detection of undesirable biophysiological markers (McCarthy & Martin-McDonald, 2007; McCarthy, Cook, Fairweather & Shaban, 2009).

Direct measures of medication compliance by patients are also varied, and not many are related to the PD regimen. It is necessary in this instance to look for studies measuring compliance with medications that may be prescribed for PD patients. For example, Mattke et al measured the quantity of prescriptions filled, the time elapsed between obtaining prescriptions, and the amount of medication possessed by the patient over a prescribed length of time (Mattke et al., 2007); although this study did not include people with CKD. Similarly, the main outcome measure in assessing medication adherence in one recent prospective randomised controlled trial was a change in the proportion of pills taken by patients compared to baseline (Lee et al., 2006). The limitation of these measures is that they may overestimate true rates of compliance, because obtaining medications and taking medications are two different things (MacLaughlin et al., 2005). Other researchers quantify apparent pill ingestion and express it as a percentage to measure compliance rates. Hence in one study, if a patient was prescribed an antibiotic to be taken as 1 tablet 4 times per day, but they took only 2 tablets per day for 5 days, the adherence rate was calculated at 36% (10/28) (McDonald et al., 2002). In a similar vein, one randomised controlled trial calculated drug compliance scores as the number of drugs that the patient was fully compliant with, divided by the total number of prescribed drugs, expressed as a percentage (Wu et al., 2007). None of these 'objective' methods for assessing medication compliance are considered completely reliable (MacLaughlin et al., 2005; Vermeire et al., 2001). They are criticised because direct questioning of patients may provide unreliable data, particularly if close-ended questions or those with judgemental overtones are used (MacLaughlin et al., 2005).

In addition, recent research reports that people with CKD and health professionals' perspectives of compliance with medications can be quite different (Orr, Orr, Willis, Holmes & Britton, 2007). In their qualitative study of consumers' and health professionals' perspectives to adherence to multiple, prescribed medications in diabetic kidney disease, Williams, Manias and Walker (2008) found that consumers were not convinced of the need, effectiveness, or safety of their medications. The authors also reported that health professionals considered medication-taking essential and believed that consumers over-rated concerns about medication-related adverse effects. Importantly, their study highlighted healthcare system issues that adversely affected relationships between consumers with diabetic kidney disease and health professionals, which have the potential to impede adherence. Other authors (Kammerer, Garry, Hartigan, Carter & Elrich, 2007; Orr et al., 2007; Sussman, 2001) have also argued the influence of health system barriers such.

Compliance with PD

With respect to the measurement of other aspects of the PD regimen, compliance with aseptic technique; dialysate dose, timing and frequency; catheter exit site care; and diet and fluid restrictions are all considered important indicators. Again a variety of direct and indirect measures have been used to assess these. These include patient self reports, observational checklists, observer subjective reports, attendance rates at clinics, hospitalisation rates, quality of life surveys, interdialytic weight gains; and shortening or skipping of dialysis sessions. These have all been utilised with varying degrees of success (Chow et al., 2007; Vlammck et al., 2001; White, 2004). Similarly, electronic monitoring systems using computer chips in home dialysis machines (Sevick et al., 1999); and quantifying the supply of dialysate ordered by the patient (Bernardini, Nagy, & Piraino, 2000; Figueiredo, Santos, & Cruetzberg, 2005) have enabled the frequency and quantity of dialysate use to be determined--but not who is actually using it or how they are doing so. Moreover, none of these benchmarks can account for the intention to comply in situations where confounding factors beyond the patient's control, such as technical problems with the PD machine, thwart their efforts (McCarthy et al, 2009).

Factors affecting PD compliance

Just as there is no adequate definition of PD compliance, there is little understanding of the factors that might contribute to it. Several authors note that predictors of compliance may be different for people over the age of 65, as they may have age-specific barriers to compliance (such as co-morbidities that impair cognition, sight and hearing) that consequently make them more vulnerable to the incorrect use of renal medication (Higgins & Regan, 2004; MacLaughlin et al., 2005; van Eijken, Tsang, Wensing, de Smet, & Grol, 2003). Demographics have also been investigated, but have demonstrated only a tenuous relationship between medication adherence and factors such as socioeconomic status, gender or marital status (Schaffer & Yoon, 2001; Vermeire et al., 2001). PD and its associated regimens are costly, life-long treatments. It is known that compliance rates are lower in similarly chronic illnesses if the treatment is longstanding, inconvenient to lifestyle, entails a high number and cost of medications, or it attempts to manage concurrent asymptomatic conditions such as hypertension (Holley & De Vore, 2006; Lee et al., 2006; Loghman-Adham, 2003; Vermeire et al., 2001). Conversely, good rates of compliance are reported in patients who are disabled or incarcerated, or whose costs are contained, due to higher incidences of community responsibility and supervision (McCarthy et al, 2009).

Complex social determinants may be the most influential of all the factors related to compliance. For example, one study (Orr et al., 2005) identified that patients' personal loyalty to health professionals was an important influence on compliance to regimen, and that their non-adherence was unintentional, being largely due to forgetfulness and medication side effects. Patients' own knowledge, coping styles and experiences, as well as those of family members and friends, are among the few other variables demonstrated as associated with compliance in chronic diseases such as CKD (Christensen, 2000; Vermeire et al., 2001). In this context, it is unfortunate that many renal patients are prejudged by clinicians as unable to comply by the very nature of their perceived neglect of the conditions (such as diabetes and hypertension) that led to their CKD. White (2004:1), for example, argues that by the time "a typical patient reaches end-stage renal disease ... an individual pattern of nonadherence has been developed and refined for over 50 years".

It is increasingly recognised that compliance behaviour cannot be understood by taking any of these variables in isolation, as they are usually mutually influential, socially-mediated, and can perhaps only be understood from a complex systems perspective (Rietveld & Koomen, 2002).

Interventions to improve compliance

The literature offers a variety of methods and interventions to improve compliance. The interventions tested to enhance compliance are as various as the indicators used to measure it. These interventions fall into four broad categories: educational strategies; practical aids; simplifying the regimen; and a combination of one or more of these.

The first type of intervention to improve compliance that is most commonly reported in the literature is education. For example, one recent randomised controlled trial involving 502 people with chronic illnesses (but not CKD) investigated the effect on medication compliance of periodic telephone education by a pharmacist, with a resulting reported improvement in medication compliance (Wu et al., 2007). Similarly, Mattke et al (2007) undertook a pre-post test intervention with 24,943 patients to improve medication compliance. After first identifying the patients' potential for compliance through predictive modelling, those less likely to comply received regular personalised education and advice from a call-centre based nurse. The lowest risk patients were given access to information from a range of internet, call centre and print resources regarding their disease (Mattke et al., 2007). However, unlike Wu et al's (2007) study and despite the considerable resources expended, the investigators concluded that the intervention had only a modest effect that was neither clinically or statistically significant (Mattke et al., 2007). It is unclear if similar strategies in patients receiving PD would improve medication compliance.

In addition to education, providing practical aids appears to enhance compliance. People receiving PD may have peripheral neuropathies, digital amputations and decreased visual acuity as a result of the diabetes. Making it easier for them to visualise, locate and open medication bottles may readily improve compliance. In addition, simplifying patient instructions for medications, particularly those that require multiple daily doses, appears to reduce the risk of patient misinterpretation (MacLaughlin et al., 2005). For patients, the meaning they ascribe to phrases like 'every 6 hours' and 'three times daily' vary. In their study, MacLaughlin et al. suggested that using 'every 6 hours' rather than 'three times daily' minimises incorrect self-administration. Fixed-dose combination pills and unit-of-use packaging designed to simplify medication regimens and by implication, enhance medication compliance in chronic illnesses, have been tried repeatedly. A systematic review of these strategies concluded that the limitations of the available evidence meant that their clinical efficacy was not able to be determined (Connor et al., 2004)

Another common strategy to improve compliance is to to simplify the treatment regimen. In a systematic review of antihypertensive medication compliance Schroeder et al. (2004) concluded that a reduction in the number of daily doses appeared to be effective in increasing adherence as a first time strategy. An earlier meta-analysis of studies investigating the relationship between patient adherence and antihypertensive drug dosing frequency similarly concluded that compliance with a once-daily dose was significantly higher than for multiple-daily or twice-daily dosing (Iskedjian et al., 2002). A review of interventions to enhance clinic attendance noted that simplifying procedures such as patient-initiated appointments, shorter intervals between referral and appointment, shorter clinic waiting times and prepayment were all effective in improving patient compliance with appointments (Vermeire et al., 2001). Hence for patients undergoing PD for CKD, a thorough review of treatment plans could improve patient compliance with appointments. For example, the review could provide opportunities to schedule concurrent specialist appointments or procedures, or to co-locate their provision.

It has been argued that the most successful strategies comprise a combination of these three categories of intervention, because multifaceted approaches are posited as addressing a more comprehensive range of compliance barriers (Ogedegbe & Schoenthaler, 2006; Schroeder et al., 2004; Takiya et al., 2004; van Eijken et al., 2003). However, the present examination elicited little evidence to support complex multimodal interventions. For example, Higgins and Regan systematically reviewed the effectiveness of interventions to enhance the compliance of older people with their medication regimens, most of which involved a combination of external cognitive supports and educational interventions (Higgins & Regan, 2004). Few of these had clinically significant effects and their findings support other meta-analyses that concluded there is little evidence to support one type of compliance intervention over another (Haynes et al., 2002; Higgins & Regan, 2004; MacLaughlin et al., 2005; McDonald et al., 2002). A systematic review of all randomised controlled studies to enhance medication adherence in chronic conditions, undertaken between 1967 and 2004, found that informational, behavourial and social interventions undertaken alone or in combination may improve medication adherence, but were not likely to affect clinical outcomes (Kripilani, Yao, & Haynes, 2007).

One of the significant deficits in all intervention studies, no matter how successful, is that they provide limited information about their apparently considerable human, financial and material resource implications (Beswick et al., 2005). In the Australian context, the establishment of nephrology nurse practitioners provides a valuable opprtunity to re-examine health service delivery to people treated for CKD. Nephrology nurse practitioners have considerable potential to create synergies in education, providing practical aids and simplifying treatment regimens for improved patient compliance.

Implications for nephrology nursing practice and research

Four main issues arise from this review. First, there is currently little consensus on how to define compliance, particularly as it relates to PD, which makes it difficult to operationalise the concept in a rigorous or meaningful way. This contributes to the second challenge apparent in the literature: in the absence of a standard working definition, it is difficult to develop valid and reliable measures of compliance with any aspect of PD regimen. Third, despite these challenges, numerous interventions based on the vaguest notion of PD compliance have been developed to improve it, with varying success. Fourth, compliance appears to be a result of multiple determinants in all domains of health; hence some approaches to this issue have tried to account for these by developing complex 'bundled' interventions. Again, these have reported mixed outcomes with generally only modest improvements in compliance. They are not likely to enhance it in the PD context.

In addition, the literature review has made it apparent that compliance is a multidimensional, context-bound concept, involving numerous perspectives, procedures and levels of measurement. It is the synergy of these factors that probably influences whether a person wants to comply with all or part of their PD regimen; or indeed, if they are able to. People generally seek treatment approaches that are manageable, tolerable and effective for their situation; hence, they may not necessarily view all of the treatments recommended as in their best interests (Friberg & Scherman, 2005; Vermeire et al., 2001).

The review also highlights the importance of understanding just how messy and dynamic the concept of 'compliance' really is, and how laden it is with a range of moral assumptions. In the context of PD, these judgements are concerned with measuring and correcting acceptable ways to care for the self, standards of personal cleanliness, levels of intelligence, frugal use of material and economic resources, and other criteria that determine who should and should not be allowed to self manage their CKD with this home-based therapy. As a consequence, renal compliance incorporates a range of factors which, from the client perspective, may not be the concern of the health professions at all and which they may believe renal clinicians have no business in promoting.

This review has illustrated how treatment regimens such as PD "fulfill theoretical, physiological, and empirical considerations about optimal care, while ignoring practical patient-centred concerns, such as the nature, nurture, culture, and stereotyping of the patient, and the inconvenience, cost, and adverse effects of the treatment" (McDonald et al., 2002:1). We really know very little about how important adherence to an inflexible, medically-oriented treatment regimen is to people receiving PD, or whether there are other outcomes that are more desirable for them. As some authors have argued, efforts to enhance adherence must focus on patient-health professional relationships and the health care system that surrounds the patient, rather than just patient factors alone (Kammerer, Garry, Hartigan, Carter & Elrich, 2007; Orr et al., 2007; Sussman, 2001). We know that patients do not blindly follow professional advice but negotiate their PD therapy into their lifestyle to enable them to live with their CKD in the way that best suits them (McCarthy et al., 2007; Polaschek, 2007). What we may need to facilitate is a better understanding of how to enhance the patient-health care provider relationship and ameloriate the effects of the health care system within which patients are situated.

Finally, with respect to improving compliance, of the four broad interventions offered in the literature--educational strategies; practical aids; simplifying the regimen; and a combination of these--it is the last, the combination of them, that is most likely to be effective in maximising opportunities for PD adherence and compliance in CKD. Nephrology nurses, who specialise in PD, are well positioned to maximise patient-health care provider relationships, and integrate education, practical aids, and treatment regimens to improve patient compliance.

Conclusion

The implications of this review for research into PD compliance or for those who practise PD nursing are two-fold. First, robust research into PD compliance means revisiting the basics. It would be useful if each investigation established an unambiguous definition and a sound theoretical basis for its use of the term 'compliance' and its variants. Without these tools, there are very few options with respect to operationalising or measuring the concept in a practical or meaningful way. Because PD compliance is a dynamic construct, involving an array of medication, procedure and lifestyle choices, it is unreasonable to expect that every researcher arrive at the same definition or employ the same theoretical framework across diverse contexts. However, a definition and theoretical framework suitable to the context should be articulated in each investigation from the outset, and remain a constant guide for action within that project. It can be reasonably argued that this consistent lack of conceptual clarity on which to base research has contributed to the current paucity of Level I and II evidence with respect to PD compliance.

Second, PD compliance is complex. It means different things to different people, particularly to different patients. Moreover, most successful compliance strategies in areas other than PD are those that make life easier and simpler for patients. It is therefore essential for researchers and practitioners to make every effort to understand how patients understand compliance, and how it might complicate their specific situation. Given the inherent complexity and flexibility of the notion of PD compliance, we should hesitate to apply the concept to patients in a blanket fashion, and without awareness of the moral judgements implicit in the term. Patients should not be burdened with the unconscious value judgements of health professionals. It is relatively easy to dichotomise patients as 'compliant', 'non-compliant', 'adherent' or 'non-adherent'; but it is not so easy for patients to carry these labels, particularly when they have not been self-determined.

Submitted December 2009 Accepted May 2010

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Leggat, J. E. (2005). Adherence with dialysis: A focus on mortality risk. Seminars in Dialysis, 18(2), 137-141.

Leggat, J. E., Orzol, S. M., Hulbert-Shearon, T. E., Golper, T. A., Jones, C. A., Held, P. J., et al. (1998). Noncompliance in hemodialysis: Predictors and survival analysis. American Journal of Kidney Disease, 32, 139-145.

Loghman-Adham, M. (2003). Medication noncompliance in patients with chronic disease: Issues in dialysis and transplantation. The American Journal of Managed Care, 9(2), 155-171.

MacLaughlin, E. J., Raehl, C. L., Treadway, A. K., Sterling, T. L., Zoller, D. P., & Bond, C. A. (2005). Assessing medication adherence in the elderly. Which tools to use in clinical practice? Drugs & Aging, 22(3), 231-255.

Mattke, S., Jain, A. K., Sloss, E. M., Hirscher, R., Bergamo, G., & O'Leary, J. F. (2007). Effect of disease management on prescription drug treatment: What is the right quality measure? Disease Management 10(2), 91-100.

McCarthy A. & Martin-McDonald K. (2007). A 'politics of what": the enactment of peritoneal dialysis in Indigenous Australians. Sociology of Health and Illness. 29(1) 82-99.

McCarthy, A., Cook, P., Fairweather, C., Shaban R. Z. & Martin-McDonald, K. (2009). Compliance in peritoneal dialysis: A qualitative study of renal nurses. International Journal of Nursing Practice, 15, 219-226.

McDonald, H. P., Garg, A. X., & Haynes, R. B. (2002). Interventions to enhance patient adherence to medication prescriptions: Scientific review. Journal of the American Medical Association, 288(22), 2868-2879.

Murphy, N., & Canales, M. (2001). A critical analysis of compliance. Nursing Inquiry, 8, 173-181.

Ogedegbe, G., & Schoenthaler, A. (2006). A systematic review of the effects of home blood pressure monitoring on medication adherence. Journal of Clinical Hypertension, 8(3), 174-180.

Orr, A., Orr, D., Willis, S., Holmes, M., & Britton, P. (2007). Patient perceptions of factors influencing adherence to medication following kidney transplant. Psychology, Health & Medicine, 12(4), 509-517.

Polaschek, N. (2007). Client attitudes towards home dialysis therapy. Journal of Renal Care, 33(1), 20-24.

Raj, D. S. (2002). Role of APD in compliance with therapy. Seminars in Dialysis, 15(6), 434-436.

Rietveld, S., & Koomen, J. M. (2002). A complex system perspective on medication compliance: Information for healthcare providers. Disease Management and Health Outcomes, 10(10), 621-630.

Russell, S., Daly, J., Hughes, E., & op't Hoog, C. (2003). Nurses and 'difficult' patients: Negotiating non-compliance. Journal of Advanced Nursing, 43(3), 281-287.

Schaffer, S. D., & Yoon, S. L. (2001). Evidence-based methods to enhance medication adherence. The Nurse Practitioner, 26(12), 44-54.

Schroeder, K., Fahey, T., & Ebrahim. S. (2004). How can we improve adherence to blood pressure-lowering medication in ambulatory care? Systematic review of randomised controlled trials. Archives of Internal Medicine, 164(7), 722-732.

Sevick, M. A., Levine, D. W, Burkart, J. M., Rocco, M. V., Keith, J., & Cohen, S. J. (1999). Measurement of continuous ambulatory peritoneal dialysis prescription adherence using a novel approach. Peritoneal Dialysis International, 19(1), 23-30.

Simpson, S. H., Eurich, D. T., Majumdar, S. R., Padwal, R. S., Tsuyuki, R. T., Varney, J., et al. (2006). A meta-analysis of the association between adherence to drug therapy and mortality. British Journal of Medicine, 333(7557), 15-20.

Takiya, L. N., Peterson, A. M., & Finley, R. S. (2004). Meta-analysis of interventions for medication adherence to antihypertensives. Annals of Pharmacotherapy, 38(10), 1617-1624.

van Eijken, M., Tsang, S., Wensing, M., de Smet, P. A., & Grol, R. P. (2003). Interventions to improve medication compliance in older patients living in the community: A systematic review of the literature. Drugs & Aging, 20(3), 229-240.

Vermeire, E., Hearnshaw, H., Van Royen, P., & Denekens, J. (2001). Patient adherence to treatment: Three decades of research. A comprehensive review. Journal of Clinical Pharmacy and Therapeutics, 26, 331-342.

Vlaminck, H., Maes, B., Jacobs, A., Ryntjens, S., & Evers, G. (2001). The dialysis diet and fluid non-adherence questionnaire: Validity testing of a self-report instrument for clinical practice. Journal of Clinical Nursing, 10, 707-715.

Williams, A., Manias, E., & Walker, R. (2008). Adherence to multiple, prescribed medications in diabetic kidney disease: a qualitative study of consumers' and health professionals' perspectives. International Journal of Nursing Studies, 45(12), 1742-1756.

White, R. B. (2004). Adherence to the dialysis prescription: Partnering with patients for improved outcomes. Nephrology Nursing Journal, 31(4), 432-435.

Wu, J. Y., Leung, W.Y., Chang, S., Lee, B., Zee, B., Tong, P. C., et al. (2007). Effectiveness of telephone counselling by a pharmacist in reducing mortality in patients receiving polypharmacy: Randomised controlled trial. British Journal of Medicine, 333(7567), 552-556.

Dr Alexandra McCarthy RN BN MN PhD is a Senior Research Fellow, Princess Alexandra Hospital and Senior Lecturer, School of Nursing and Midwifery, Queensland University of Technology. Mr Ramon Z. Shaban RN CICP EMT-P BSc(Med) BN GCertInfCon PGDipPH&TM MEd MCHlth (Hons) PhD (Cand) FRCNA is a Senior Research Fellow, Princess Alexandra Hospital and Senior Lecturer, School of Nursing and Midwifery, Research Centre for Clinical and Community Practice Innovation, Griffith Institute for Health and Medical Research. Ms Carrie Fairweather RN, BN (Hons), PhD (Cand) is Deputy Head of School, School of Nursing El Ain Campus Griffith University United Arab Emirates.

Correspondance to: Mr Ramon Z. Shaban, School of Nursing and Midwifery, Research Centre for Clinical and Community Practice Innovation, Griffith Institute for Health and Medical Research. University Drive, Meadowbrook, Queensland Australia 4131 Email: r.shaban@griffith.edu.au
Table 1 Compliance in peritoneal dialysis articles

Author/s      Date     Type of         Outcome of       Conclusions
                        study/          interest
                        paper

Bernadini     2000  Longitudinal,   Noncompliance     72%
et al               prospective,    with PD,          consistently
                    observational,  defined as        compliant, 2%
                    descriptive     performance of    consistently
                                    less than 90%     noncompliant,
                                    of prescribed     15%
                                    PD exchanges (n   noncompliant at
                                    = 92)             beginning of PD
                                                      but became
                                                      compliant at
                                                      follow up, 11%
                                                      intermittently
                                                      noncompliant.
                                                      Recommend a
                                                      home visit
                                                      during 1st 6
                                                      months to
                                                      determine
                                                      compliance.

Carpenter     2005  Literature      Relationship of   Little
                    review of       concept of        consistency in
                    concept         perceived         operationalising
                                    threat to         perceived
                                    treatment         threat'
                                    adherence         relating to
                                                      treatment
                                                      adherence, nor
                                                      incorporation
                                                      of personal and
                                                      contextual
                                                      patient factors

Chow et al    2007  Prospective     Adherence with    Late arrival in
                    observational   PD, measured by   >20% of PD
                                    late arrival      training
                                    for PD training   sessions
                                    and subsequent    associated with
                                    peritonitis (n    >50% increased
                                    = 159)            likelihood of
                                                      subsequent
                                                      peritonitis. RR
                                                      1.56 (95% CI;
                                                      1.02-2.39; p =
                                                      0.04).

Connor et     2004  Systematic      Studied 15        Note a trend
al                  review          trials            towards
                                    investigating     improved
                                    role of fixed     adherence that
                                    dose              was
                                    combination       statistically
                                    pills and unit    or clinically
                                    of use            significant;
                                    packaging in      however outcome
                                    promoting         measures were
                                    medication        heterogenous
                                    adherence         and studies
                                                      limited by
                                                      small sample
                                                      sizes.

Costanini     2006  Discussion      Compliance,       Compliance and
                    paper           adherence and     adherence
                                    self management   poorly
                                    in CKD patients   understood in
                                                      this
                                                      population.
                                                      Patient
                                                      perspectives
                                                      need to be
                                                      accounted for,
                                                      and self-
                                                      management' is
                                                      promising as a
                                                      conceptual
                                                      basis for
                                                      improving
                                                      outcomes

Denhaerynck   2007  Literature      Prevalence and    Inconsistencies
et al               review          consequences of   in definitions
                                    non-adherence     and invalid
                                    to                measurement
                                    haemodialysis     methods hamper
                                    prescriptions     research.

Evangelista   1999  Concept         Compliance        Patient should
                    analysis                          be viewed as
                                                      active
                                                      participants in
                                                      health care and
                                                      more
                                                      understanding
                                                      of patient
                                                      perspective of
                                                      compliance
                                                      required

Figeuiredo    2005  Descriptive,    Compliance        Patients who
et al               telephone       measured by PD    first treatment
                    self-           supply            choice was PD
                    report by       inventories.      were more
                    patients        Patients          likely to be
                                    performing at     compliant than
                                    least 90% of      patients for
                                    prescribed        whom PD was not
                                    exchanges         the first
                                    considered        choice (74% vs
                                    compliant (n =    64%
                                    30).              compliance),
                                                      hence
                                                      participation
                                                      in the
                                                      decision-making
                                                      process
                                                      improves
                                                      compliance

Friberg       2005  Discussion      Compliance        Understanding
and                 paper                             of the teaching
Scherman                                              and learning
                                                      components of
                                                      compliance, and
                                                      understanding
                                                      patients'
                                                      perspectives,
                                                      is essential

Higgins       2004  Systematic      Review of RCTs    Studies too
and Regan           review          between           heterogenous to
                                    1966-2002         compare; used
                                    studying          variety of
                                    effectiveness     behavioural and
                                    of                social
                                    interventions     interventions
                                    for improving     that had little
                                    medication        statistical or
                                    compliance in     clinical
                                    the elderly.      effects. No
                                    7 studies         strong evidence
                                    assessed.         to support any
                                                      one
                                                      intervention
                                                      type.

Holly and     2006  Descriptive     Medication        Inadequate
DeVore              survey          compliance        prescription
                                    dialysis          coverage, lack
                                    patients (PD      of
                                    and haemo: n =    transportation,
                                    54)               medication cost
                                                      are primary
                                                      contributors to
                                                      medication
                                                      noncompliance.

Iskedjian     2002  Meta            Relationship      With
et al               analysis        between daily     antihypertensive
                                    dose frequency    regimens,
                                    and adherence     once-daily
                                    to                dosing
                                    antihypertensive  schedules are
                                    medication, 8     associated with
                                    studies pooled    higher rates of
                                                      adherence than
                                                      twice daily or
                                                      multiple dosing
                                                      schedules.

Kammerer      2007  Discussion      Strategies for    Interventions
et al               paper           success           need to focus
                                    Adherence in      on
                                    patients on       patient-health
                                    dialysis:         care provider
                                                      relationships
                                                      and the health
                                                      care system
                                                      that surrounds
                                                      the patient
                                                      that compromise
                                                      the patient's
                                                      adherence,
                                                      rather than
                                                      just patient
                                                      factors alone.
                                                      Nurses have an
                                                      important role
                                                      to play in
                                                      supporting
                                                      patients,
                                                      identifying
                                                      barriers, and
                                                      enabling
                                                      strategies to
                                                      help patients
                                                      improve
                                                      adherence.

Kripalani     2007  Systematic      RCTs published    Adherence
et al               review          between Jan       increased with
                                    1967 and Sept     behavioural
                                    2004 reporting    interventions
                                    unconfounded      that reduced
                                    interventions     dosing demands
                                    intended to       or involved
                                    enhance           monitoring and
                                    medication        feedback;
                                    adherence with    involved
                                    self-             multisession
                                    administered      information or
                                    medications in    combined
                                    chronic medical   intervention.
                                    conditions, 39    Several
                                    studies           interventions
                                    assessed          may be
                                                      effective in
                                                      improving
                                                      adherence in
                                                      chronic medical
                                                      conditions, but
                                                      few
                                                      significantly
                                                      affect clinical
                                                      outcomes.

Kutner        2001  Literature      Compliance with   Further study
                    review          dialysis          required into
                                                      psychosocial
                                                      determinants,
                                                      compliance
                                                      behaviour
                                                      patterns over
                                                      time, and
                                                      parameters in
                                                      which
                                                      compliance can
                                                      vary and still
                                                      remain safe

Kyngas et     2000  Literature      Compliance        No agreement on
al                  review of                         definition or
                    concept                           measurement

Lee et al     2006  Randomised      Effect of         Intervention
                    controlled      pharmacy care     increased
                    trial           program on        medication
                                    medication        adherence to
                                    adherence (n=     96.9% (5.2%;p <
                                    200)              0.001) 6 months
                                                      post
                                                      intervention

Loghman-      2003  Literature      Compliance in     Suggests
Adham               review          renal disease     simplifying
                                                      treatment
                                                      regimen,
                                                      establishing a
                                                      partnership
                                                      with client and
                                                      increasing
                                                      patient
                                                      awareness
                                                      through
                                                      education and
                                                      feedback to
                                                      improve
                                                      compliance

MacLaughlin   2005  Literature      Assessing         Personal and
et al               review          medication        contextual
                                    adherence in      factors
                                    the elderly       influence
                                                      medication
                                                      adherence.
                                                      Traditional
                                                      methods for
                                                      measuring
                                                      adherence are
                                                      unreliable.

Mattke et     2007  Non-            Effect of         Different ways
al                  randomised,     disease           to
                    pre-test/       management        operationalise
                    post-test       program on        compliance can
                    intervention    medication        lead to
                    study           compliance,       fundamentally
                                    measured by       different
                                    prescription      conclusions' in
                                    fill rates,       measurement
                                    medication        methods
                                    possession
                                    ratio and
                                    length of gap
                                    between refills
                                    (n = 24,943)

McCarthy      2007  Original        Qualitative       Historically,
et al.              research        study of renal    the notion of
                                    nurses            compliance is
                                    constructs of     poorly
                                    compliance in     conceptualized
                                    PD                or defined.
                                                      Renal nurses
                                                      consider it
                                                      complex and
                                                      difficult to
                                                      manage, so much
                                                      so that it may
                                                      be pointless to
                                                      tame
                                                      compliance'
                                                      through rigid
                                                      definitions and
                                                      measurement, or
                                                      to rigidly
                                                      enforce it in
                                                      PD patients.

McCarthy      2009  Original        Enactment of      PD for
et al.              research        roles for PD in   Indigenous
                                    Indigenous        Australians is
                                    Australians       bound by
                                                      complex and
                                                      contested
                                                      networks which
                                                      makes
                                                      translating
                                                      renal
                                                      healthcare
                                                      networks across
                                                      cultural
                                                      contexts
                                                      difficult, and
                                                      are inexorably
                                                      linked to
                                                      notions of
                                                      compliance.

McDonald      2008  Systematic      Patient           Studies too
et al               review          adherence to      disparate to
                                    medication        warrant meta-
                                    prescriptions.    analysis.
                                    All RCTs          Current methods
                                    published         for improving
                                    between 1967      medication
                                    and               adherence are
                                    2001 reporting    complex, labor-
                                    interventions     intensive, and
                                    to improve        not predictably
                                    medication        'effective'.
                                    adherence in
                                    the elderly.
                                    33 studies
                                    assessed

Murphy and    2001  Discussion      Definition of     Advocate an
Beanland            paper           compliance from   'emancipatory'
                                    nursing           definition on
                                    perspective       which to base
                                                      further nursing
                                                      research

Ogedegbe      2006  Systematic      11 RCTs           Complex
and                 review          reviewed for      interventions
Schoenthaler                        effects of home   report more
                                    blood pressure    statistically
                                    monitoring on     significant
                                    medication        improvements in
                                    adherence         adherence;
                                                      interventions
                                                      conducted in
                                                      hospital and
                                                      home settings
                                                      more successful
                                                      than those in
                                                      primary care
                                                      settings.

Orr et al.    2007  Original        Patients          Motivators for
                    research        perceptions of    adherence were
                                    factors           to avoid kidney
                                    influencing       failure and
                                    adherence to      loyalty to the
                                    medication        renal team and
                                    following         donors.
                                    kidney            Non-adherence
                                    transplant        was largely due
                                                      to forgetting
                                                      and medication
                                                      side effects.

Polaschek     2007  Critical        Attitude of       Many variables
                    interpretive    home dialysis     affect
                                    patients to       compliance, and
                                    therapy and       understanding
                                    adherence (n =    these variables
                                    20)               may help
                                                      improve
                                                      outcomes

Raj           2002  Literature      Compliance with   Reviews
                    review          PD                predictors,
                                                      consequences,
                                                      methods to
                                                      identify and
                                                      monitor.
                                                      Concludes
                                                      noncompliance
                                                      should be
                                                      managed by
                                                      patient
                                                      education and
                                                      therapy
                                                      modification.

Rietveld      2002  Literature      The effect of     Knowledge,
and Koomen          review          complex systems   illness
                                    on medication     beliefs,
                                    compliance        symptom
                                                      perception,
                                                      anxiety,
                                                      symptom
                                                      self-efficacy,
                                                      medication
                                                      self-efficacy,
                                                      social support
                                                      and
                                                      patient/health
                                                      professional
                                                      congruence are
                                                      variables that
                                                      mutually
                                                      influence
                                                      medication
                                                      compliance.

Russell et    2003  Discussion      Non compliance    A
al                  paper                             patient-centred
                                                      approach
                                                      necessary to
                                                      enhance
                                                      compliance

Schaffer      2001  Literature      Medication        Classifies
and Yoon            review          adherence         adherence
                                                      interventions
                                                      into affective,
                                                      behavioural and
                                                      cognitive
                                                      domains.

Schroeder     2004  Systematic      Improvement of    Results not
et al               review          adherence to      pooled due to
                                    anti-             heterogeneity
                                    hypertensive      of studies.
                                    medication in     More successful
                                    ambulatory        strategies are
                                    care, 38 RCTs     reducing the
                                    undertaken        number of daily
                                    between 1975      doses, with
                                    and 2000          motivational
                                    assessed          and complex
                                                      strategies more
                                                      promising.

Sevick et     1999  Descriptive,    PD adherence,     Significant
al                  observation     measured by       disparities
                    of              self-reported     found between
                    behaviours      daily logs and    self- and
                                    electronic        computer
                                    monitoring of     monitored
                                    dialysis fluid    reports
                                    use (n = 20)

Takiya et     2004  Meta-           Pooled 16 RCTs    Interventions
al                  analysis        using             varied and
                                    interventions     study groups
                                    to enhance        non-homogenous.
                                    adherence to      No single
                                    anti-             intervention
                                    hypertensives     improves
                                    from 1970-2000.   adherence over
                                                      others. Suggest
                                                      a patient-
                                                      specific
                                                      intervention
                                                      approach be
                                                      modelled.

Van Eijken    2003  Systematic      Improving         Telephone-
et al               review          medication        linked
                                    compliance        interventions
                                    amongst older     achieved 'the
                                    community         most striking
                                    dwellers, 14      effect', with
                                    RCTs reviewed     multifaceted
                                                      and tailored
                                                      interventions
                                                      resulting in
                                                      more favourable
                                                      compliance
                                                      rates

Vermeire      2001  Literature      Patient           Research
et al               review          adherence to      hampered by
                                    treatment         failure to
                                                      define
                                                      'adherence'.
                                                      Further
                                                      research
                                                      required.

Vlaminck      2001  Multicentre,    Construct and     Suggest that
et al               cross-          criterion         DDFQ is valid
                    sectional,      validity of       self-report
                    self- report    Dialysis Diet     instrument to
                    survey          and Fluid         assess
                                    Non-Adherence     non-adherence
                                    Questionnaire     behaviour
                                    (DDFQ) in         haemodialysis
                                    Flanders (n =     patients in
                                    564)              Flanders

White         2004  Discussion      Adherence to      Patient-centred
                    paper           dialysis          approaches that
                                    prescription      removal
                                                      barriers to
                                                      adherence and
                                                      provide
                                                      education and
                                                      cognitive
                                                      behavioural
                                                      strategies my
                                                      improve
                                                      adherence
                                                      outcomes.

Williams,     2008  Original        Adherence to      Different
Manias              research        multiple,         perspectives
and Walker                          prescribed        between
                                    medications in    consumers, who
                                    diabetic kidney   were not
                                    disease           convinced of
                                                      the need,
                                                      effectiveness
                                                      and safety of
                                                      all of their
                                                      medications,
                                                      and health
                                                      professionals
                                                      who considered
                                                      consumer
                                                      concerns about
                                                      medication-
                                                      related adverse
                                                      effects were
                                                      over-rated.

Wu et al      2007  Randomised      Telephone         Drug compliance
                    controlled      intervention to   defined as
                    trial           enhance           taking 80-120%
                                    compliance (n =   of prescribed
                                    506)              daily dose.
                                                      Main outcome
                                                      measure = all
                                                      cause
                                                      mortality.
                                                      Telephone
                                                      counselling
                                                      associated with
                                                      41% reduction
                                                      in the risk of
                                                      death (RR 0.59;
                                                      95% CI; 0.35-
                                                      0.97; p =
                                                      0.0039);
                                                      patients
                                                      receiving
                                                      polypharmacy,
                                                      poor compliance
                                                      associated with
                                                      increased
                                                      mortality.
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