Do we have enough information? How ICD-10-AM Activity codes measure up.
Abstract: This research explored the usage of activity codes introduced into the International Statistical Classification of Diseases and Related Health Problems, Tenth revision, Australian Modification (ICD-10-AM) Third Edition and examined the data quality of activity coding, explicitly, completeness and specificity. Injury separations for years 2001/02 to 2005/06 specifying a 'true injury' were extracted for descriptive analyses. Part A investigated the usage of activity codes and compared the usage of the 236 activity codes available in the Activity block (U50-U73) present in the ICD-10-AM Third Edition against the 16 codes present in the second edition. Part B examined the level of completeness of external cause coding and the degree of activity coding specificity in the 2005/06 dataset. It was found that the additional activity codes were used extensively with only 46 codes seldom assigned. Codes present in the second edition were extensively used in the third and fourth editions and the new additional activity codes represent 10% of all activity codes assigned per year. All five datasets demonstrated high levels of completeness, recording completeness levels greater than 97%, where missing activity codes attributed to the majority of missing codes. Fourteen out of the 24 activity categories demonstrated a strong reliance on non-specific codes and Team ball sports and Wheeled non-motor sports illustrated that activity codes assigned lacked detail in the code. Clinicians and coders need to acknowledge the importance of quality clinical documentation for research and policy-making purposes so that circumstances surrounding injury events can be coded to the highest level of specificity to improve injury prevention and control activities. Missing activity codes and the abundance of non-specific coding hinders the usefulness of the data.

Keywords (MeSH): Clinical Coding; International Classification of Diseases; ICD-10-AM; Hospital Administration Data; Data Quality; Morbidity.
Article Type: Report
Subject: Information management (Methods)
Wounds and injuries (Statistics)
Diseases (Australia)
Diseases (Identification and classification)
Medical records (Evaluation)
Authors: Soo, Irene Hoi-Yen
Lam, Mary K.
Rust, Julie
Madden, Richard
Pub Date: 02/01/2009
Publication: Name: Health Information Management Journal Publisher: Health Information Management Association of Australia Ltd. Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2009 Health Information Management Association of Australia Ltd. ISSN: 1833-3583
Issue: Date: Feb, 2009 Source Volume: 38 Source Issue: 1
Topic: NamedWork: International Classification of Deaths (Standard) Event Code: 680 Labor Distribution by Employer Computer Subject: Information accessibility
Geographic: Geographic Scope: Australia Geographic Code: 8AUST Australia
Accession Number: 216488659
Full Text: Introduction

Globally, injuries result in over five million injury-related deaths annually and have been shown to contribute significantly to the health burden on all populations, irrespective of age, sex, income or geographical location (Krug, Sharma & Lozano 2000). Injury is an important public health problem and is increasingly being acknowledged as a major but often preventable cause of morbidity worldwide (Australian Institute of Health and Welfare 2008). In Australia, injury is a leading cause of death, illness and disability, costing the health system approximately $3.4 billion for the year 2004/05 (Australian Institute of Health and Welfare 2008). In 2004/05, injuries accounted for over 1 in 20 hospital admissions and almost 7.5% of all deaths occurring in Australia were injury-related deaths (Australian Institute of Health and Welfare 2008). Explicitly, there were 9,768 fatalities within that financial year or about 27 fatalities every day, where persons aged 1 to 44 years accounted for half of these deaths and consequently, injury prevention and control was proclaimed one of Australia's National Health Priority Areas (Australian Institute of Health and Welfare 2008).

National hospital morbidity data have gained importance in shaping injury prevention policies and practice worldwide. Injury hospitalisation data together with external cause of injury coding have been documented as a valuable and cost-effective source of information for population-based non-fatal injury surveillance (Langlois et al. 1995). Therefore, for the data to be useful, it is imperative that there is complete and accurate documentation in the medical record so that hospital morbidity datasets contain high quality information available for injury prevention experts and policy makers.

The International Statistical Classification of Diseases and Related Health Problems, Tenth revision, Australian Modification (ICD-10-AM) is used nationally to capture morbidity data. The National Centre for Classification in Health (NCCH) is responsible for the development, introduction and maintenance of ICD-10-AM, which is revised biennially to ensure currency and appropriateness for use within clinical practice in Australia (National Centre for Classification in Health 2004). New editions of ICD-10-AM amend and clarify the previous edition and address new and emerging trends based on advice from expert bodies about themes within the classification that would increase the value of hospital data to relevant stakeholders (National Centre for Classification in Health 2004).

There have been significant changes in the ICD-10-AM framework, particularly Chapter XX External Causes of Morbidity and Mortality, largely in the form of additional comprehensive codes to capture additional external causes of injury information. Sports and work-related injuries are now beginning to be described to a higher level of detail consistent with the significance of these activities as a setting for injuries (Harrison 2001). Activity codes are of particular interest as they indicate the different types of activities, such as sports-, leisure- or work-related activities that were undertaken at time of injury (National Centre for Classification in Health 2004). Previously located at Y93 with 16 available codes, activity codes now occupy an Activity block (U50-U73) within Chapter XX External Causes of Morbidity and Mortality from third edition onwards, with 236 mutually exclusive codes present (Harrison 2001; National Centre for Classification in Health 2000, 2002). A forward map of the second edition activity codes to third edition activity codes has been provided to detail the changes in activity codes (Table 1).

In order to provide information that is useful in aiding injury initiatives, data must be collected in a consistent fashion. When used in conjunction with the Australian Coding Standards (ACS) guidelines, the ICD-10-AM codes enable morbidity data to be collected in a standardised manner (National Centre for Classification in Health 2004). This ensures consistency and quality of data nationwide so that comparisons of these standardised codes can be made across hospitals, states and countries (McKenzie et al. 2006). Despite the presence of these guidelines, the reliability and integrity of medical record documentation and coded hospitalisation data are potentially questionable since data often lack specificity or are missing. Data quality issues have been the focus of much research (Mitchell & Hayen 2006), with previous studies indicating that the accuracy of injury coding ranges from 82% to 87% (Langley et al. 2006; LeMier, Cummings & West 2001; MacIntyre, Ackland & Chandraraj 1997).

To assess injury data, three particularly important data attributes relating to coding reliability must be addressed: accuracy, specificity and completeness. Accuracy assesses the validity and correctness of the data. Specificity refers to the data value being defined to the correct level of precision or granularity permitted by documentation in the medical record (AHIMA Data Quality Task Force 1998). Completeness ensures that the entire scope of data items are collected to code all necessary factors; especially, in the case of injury admissions, information regarding injury mechanism, place of occurrence (POO) and activity at time of injury (AHIMA Data Quality Task Force 1998; National Centre for Classification in Health 2004). Previous studies have explored the quality of injury coding, especially the accuracy of injury mechanism codes assigned (Hunt et al. 2007; LeMier, Cummings & West 2001), completeness of external cause code coding (Lawrence et al. 2007; Coben et al. 2006) and the specificity of external cause coding (Langley, Davie & Simpson 2007; McKenzie et al. 2006; Finch & Boufous 2008) within ICD-10-AM or its predecessor the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM).

Nationally, the ACS is used in conjunction with the ICD-10-AM and Australian Classification of Health Interventions (ACHI) to provide standards for clinical coding. It mandates that all records assigned an injury code must include one or more of the ICD-10-AM external cause codes sequenced directly after the diagnosis code(s) to which they relate (National Centre for Classification in Health 2004). The National Hospital Morbidity Database (NHMD) collects multiple codes for all hospital separations and for this study we examined injury codes in the Principal Diagnosis (PDx) field only. It is assumed that the injury PDx correlates with the first code in the injury mechanism field, place of occurrence field and activity field. For the purpose of this study, coding completeness is defined as the presence of the whole set of external cause codes (i.e. injury mechanism, place of occurrence and activity at the time of injury [as required for all injury mechanisms where V01-Y34 is assigned]) (National Centre for Classification in Health 2004). All of this information is necessary to describe the injury circumstances.

The ACS also provides guidance to the use of residual codes, stating that the convention used to indicate 'Other specified' or 'Not elsewhere classified' (NEC) in most categories is represented by the final digit '8', where there is exact information documented in the medical record for which there is no unique code available (McKenzie et al. 2006; National Centre for Classification in Health 2004). A final digit of '9' represents 'Unspecified' or 'Not Otherwise Specified' (NOS) and is chiefly used when it is reasonably obvious that no information is available that would authorise a more specific assignment elsewhere (National Centre for Classification in Health 2004; McKenzie et al. 2006). Occasionally, 'Other specified' and 'Unspecified' are combined into the one code to form 'Other and Unspecified' and because of this it is difficult to verify whether the use of the residual category is due to a lack of available codes or lack of clinical documentation (National Centre for Classification in Health 2004; McKenzie et al. 2006). Subsequently in this study, specificity will be described in terms of the use of specific and non-specific codes, encompassing, 'Other specified', 'Unspecified' and 'Other and unspecified'.

The authors are not aware of any other studies that have previously examined the usage of activity codes for injuries and the impact of activity coding on injury data in countries utilising the ICD-10-AM. Due to the strong user demand for the expansion of the activity codes and the fact that external cause codes provide the only available information regarding injury circumstances, it would be useful to determine the level of usage of the additional activity codes.

Aims

The current study sought to examine the effects of the additional activity codes on data quality within the NHMD. The specific aims of the study were to:

* ascertain whether additional activity codes have a profound impact on the usage of activity codes

* examine the effects of activity coding completeness on injury data investigate the usage of activity codes being assigned to specific and non-specific categories.

Methods

Data on hospital separations for years 2001/02 to 2005/06 provided by the Australian Institute of Health and Welfare (AIHW) obtained from the NHMD were examined. The 2001/02 dataset consists of approximately 6.4 million separations and separations have since increased gradually per annum to 7.3 million separations in 2005/06.

Cases extracted were all injury episodes of inpatient care provided by acute hospital facilities in Australia with an ICD-10-AM Principle Diagnosis (PDx) specifying a 'true injury' using Chapter XIX Injury, poisoning and certain other consequences of external causes within the code range S00-T75 and T79. 'Complications of surgical and medical care' result from the action(s) of persons employed within the healthcare system and are assigned codes from categories T80 to T88 and are therefore excluded from the study (Berry & Harrison 2007). The ACS defines PDx as the 'diagnosis established after study to be chiefly responsible for occasioning an episode of admitted patient care ...' (National Centre for Classification in Health 2004). For this reason, cases without an injury as a PDx were excluded from analysis because injury was not recorded as being the main reason for the hospitalisation. The complete set of external cause codes were also extracted from the first external cause, POO and activity fields, that is fields E01, PL01 and A01 as these codes are required by ACS guidelines to be assigned when an injury diagnosis is present.

A data extraction program was written using SPSS. All selected injury records were exported from the SPSS source file and imported into Microsoft Access database table and/or Microsoft Excel where descriptive analyses were performed. There were 363,376 records that satisfied the criteria for 2001/02 dataset, 366,890 records for 2002/03 dataset, 372,533 records for 2003/04 dataset, 384,104 records for 2004/05 dataset and 400,019 records for 2005/06 dataset and these records were extracted for analysis.

Part 1. Activity code usage

A. Impact of external cause coding usage To determine whether the additional activity codes have an impact on external cause coding:

1. Third and fourth edition activity codes present in 2002/03 to 2005/06 datasets were examined separately.

2. Codes present in the second edition and logically mapped to the third and subsequent fourth edition (Table 1) were extracted from 2001/02 to 2005/06 datasets and analysed across the five-year period so that comparisons of usage can be made. 'Other codes' denote codes that are available in the third edition onwards but not in the second edition.

B. ICD-10-AM activity code usage, 2001/02-2005/06

To investigate the usage of ICD-10-AM activity codes, data collected on the third edition is made compatible with the second edition by collapsing new categories into broader categories available in the second edition (Berry & Harrison 2007; National Centre for Classification in Health 2004)

Part 2. Data quality

A. Completeness of external cause coding, 2001/02-2005/06

External cause coding completeness were examined for the five-year period and the presence of the first external cause code, POO and activity code were evaluated.

B. Specificity of activity codes, 2005/06

To assess specificity of activity codes, the use of specific and non-specific codes (namely, 'Other specified', 'Unspecified' and 'Other and unspecified') were explored for the year 2005/06 only.

The U71 code indicates that the activity was sports/leisure related but the specific activity was unknown and U72 indicates the activity was leisure related and not identified as a sport (National Centre for Classification in Health 2004).

C. Usage of non-specific of activity codes, 2005/06

In this stage the usage of non-specific activity codes for 2005/06 dataset was examined.

Results

Part 1. Activity code usage

A. Impact of external cause coding usage

1. Impact of additional activity codes, 2002/03 to 2005/06 There are 16 activity codes available for selection in ICD10-AM Second Edition and 236 activity codes available for selection in ICD-10-AM Third and Fourth Editions. Within the 2002/03 dataset, 94 separations were coded using ICD-10-AM Second Edition. These codes were logically mapped to the ICD-10-AM Third Edition activity codes so that they could be examined. Across the four-year period, there are 39 codes that are rarely used (frequency of 5 or less) (data not shown). Of the 39 codes that are rarely used, 16 codes are residual categories, that is Other specified and Unspecified categories.

The most frequent category to be repetitively assigned a code less than 5 times annually over the four-year period was Power sports (U62) where 5 of the 7 available codes were infrequently used followed by Combative sports (U61) where 9 of the 20 codes available within the category were infrequently used. Interestingly, 8 out of 10 codes available within Multidiscipline sports (U67) were also seldom used with 3 codes having a frequency of zero over the four-year period.

Of the 236 codes available, 7 codes have never been used since the introduction of the of Activity block in ICD-10-AM Third Edition, explicitly Synchronised swimming (U52.0), Curling (U55.7), Unspecified aesthetic sport (U58.9), Winter biathlon (U67.0), Heptathlon (U67.2), Modern pentathlon (U67.3) and Hot air ballooning (U68.6). Altogether, the 46 codes represent nearly one-fifth of codes available for coding but are seldom assigned where 26 of these codes were specified and 17 were residual codes.

2. Usage of ICD-10-AM Second Edition activity codes, 2001/02 to 2005/06

By comparing the ICD-10-AM Second Edition activity codes to Third and Fourth editions, we found that the usage of the second edition activity codes in 2001/02 was much higher in a majority of cases compared to the same activities extracted in 2002/03 to 2005/06. The additional activity codes ('Other codes') represent a tenth of all codes assigned (Table 2).

B. ICD-10-AM activity code usage, 2001/02-2005/06

Table 3 summarises results for annual patterns in activity code usage across the five-year study period. While engaged in sports (U50-U71), While resting, sleeping, eating or engaging in other vital activities (U73.2), and Unspecified activity (U73.9) showed an overall upward trend, Other specified activity (U73.8) and missing activity codes declined. Specified activity codes (U50-U73.2) were assigned in less than 30% of all injury admissions across the five-year period and residual (U73.8 and U73.9) and missing activity codes accounted for the majority of activity codes assigned. The abundance of non-specific codes provides little or no information surrounding the injury circumstances.

Prior to the introduction of ICD-10-AM Third Edition, 2001/02 data depicted results fairly consistent with those of later years except that While engaged in leisure (U72) showed higher than average percentages. Figure 1 illustrates that across the study period, missing activity codes remained relatively low apart from 2002/03.

Part 2. Data quality

A. Completeness of External Cause coding

The five datasets under study demonstrated very high levels of completeness, with all years recording a completeness level greater than 97% (data not shown). Injury mechanism possessed the lowest frequency of missing codes followed by POO (data not shown) and missing activity codes comprise the majority of missing external cause codes highlighted in Table 3.

Further analysis of the missing activity codes reveals the PDx, injury mechanism and POO categories contribute consistently across the five-year period although the pattern varies. For 2004/05 and 2005/06, the high number of cases of Injury to the head (S00S09) and Poisoning by drugs, medicaments and biological substances (T36-T50) as the PDx are responsible for the lack of activity codes (Figure 2). Injury mechanisms Accidents (V01-X59) and missing injury mechanism justified a majority of missing activity codes assigned (Figure 3). Missing POO codes and POO of Home (Y92.0) were pinpointed as the bulk of missing activity codes, followed by other POO codes for Unspecified place of occurrence (Y92.9) and Street and highway (Y92.4) (Figure 4).

[FIGURE 2 OMITTED]

[FIGURE 3 OMITTED]

[FIGURE 4 OMITTED]

B. Specificity of data across activity categories, 2005/06

The Activity block is organised into two broad categories, namely While engaged in sports or leisure (U50-U72) and While engaged in other activity (U73). Within these broad categories are 24 specific categories from which there are comprehensive codes to describe the activity at time of injury and non-specific residual codes to capture information that cannot be assigned a more detailed code within the classification.

Ten of the 24 categories showed high levels of specificity, with more than 90% of cases assigned specific activity code, therefore these activities are not reported in Table 4. The remaining 14 Activity code categories demonstrated a strong reliance of non-specific codes (Table 4).

C. Usage of non-specific activity codes, 2005/06

Due to the high frequencies of unspecified codes within sports categories, further examination of activity categories was conducted. Team ball sports (U50) and Wheeled nonmotored sports (U66) were chosen for their high levels of non-specific code coding of 34.4% and 44.6% respectively. These categories were examined in greater detail to ascertain the usage of residual categories. Both categories utilised available specified codes but it was found that the usage of residual categories within particular sports, for example, Football unspecified (U50.09), Rugby unspecified (U50.03) and Cycling unspecified (U66.09) were allocated frequently in contrast to the category's residual codes (Figure 5 and 6). Other specified and unspecified Team ball sports (U50.8 and U50.9) and Other specified and unspecified Wheeled non-motor sports (U66.8 and U66.9) only represents 0.18% and 0.38% of all codes assigned to each category respectively. Football unspecified (U50.09) and Rugby unspecified (U50.03) represents 16.9% and 9.98% of all Team ball sport (U50) injuries. Cycling unspecified (U66.09) accounts for 65.55% of all cycling injuries and 38.15% of all Wheeled non-motored sport (U66) injuries.

In addition, further analysis of Unspecified activity (U73.9) was conducted to determine the injury mechanisms responsible for the high frequency of this activity code (N = 225,048) (Table 5). Accidents (V01-X59) accounted for more than 85% of all injury mechanisms assigned an Unspecified activity (U73.9) code. Falls (W00-W19), Transport accidents (V01V99), Exposure to inanimate mechanical forces (W20-W49) and Accidental exposure to other and unspecified factors (X58X59) constituted the majority of injury mechanisms assigned an Unspecified activity (U73.9) code.

Discussion

ICD-10-AM provides a valuable means of standardising cause of injury data on a national and international level. Hospital morbidity datasets are used extensively in Australia (Berry & Harrison 2007), New Zealand (Langley et al. 2006), the United Kingdom (Campbell et al. 2007) and the United States (Lawrence et al. 2007), and contain information valuable to injury control professionals. The availability of quality external cause of injury information, and comprehensive analysis and reporting of this information enables identification of significant injury risks for injury prevention activities. It establishes the magnitude of injury hospitalisations and facilitates the comparison of external cause code information across hospitals, states and countries (Hayen & Mitchell 2006; McKenzie et al. 2006).

Since its inception in 1998, NCCH has released a new edition of ICD-10-AM every two years. Numerous revisions to the coding framework have been made following the release of the ICD-10-AM First Edition that improves upon each edition. Emerging trends are addressed to capture valuable data pertaining to the circumstances surrounding injury hospitalisations in a more specific manner through the addition of new codes (National Centre for Classification in Health 2004). The third edition expands upon the 16 activity codes available in the second edition to a comprehensive 236 code Activity block that provides greater specificity, keeping abreast of the significance of these activities as a setting for injuries (National Centre for Classification in Health 2004).

This study demonstrates that the expanded Activity block provides a sufficient amount of codes to illustrate the activity at time of injury. Over 80% of the codes available have been utilised with only 39 codes that are infrequently used and 7 codes never used since the introduction of the Activity block in ICD-10-AM Third Edition. Combative sports (U61), Power sports (U62) and Multidiscipline sports (U67) were found to be the least used categories within the Activity block and should be examined to ensure codes within the Activity block are current for clinical practice. The ICD-10AM Second Edition activity codes proved to be a valuable means of assessing the usage of the additional activity codes.

Activity codes available in the second edition were used substantially from 2002/03 to 2005/06 datasets in contrast to the additional activity codes present in third and fourth editions only, comprised of approximately 10% of all activity codes assigned per year.

Furthermore, the research indicates that there is a high level of completeness for external cause coding across the five-year period, similar to that reported in other studies (Coben et al. 2006; MacIntyre,

Ackland & Chandraraj 1997). It is concerning that missing activity codes are responsible for the bulk of missing codes. The introduction of the Activity block in 2002/03 saw injury data containing numerous missing activity codes (N = 3,957) but has declined in later years as coders are more familiar with these codes (Figure 1). Results reveal for years 2004/05 to 2005/06 that Injury to the Head (S00-S09) and Poisoning by drugs, medicaments and other substances (T36-T50) are the PDx responsible for the lack of activity codes. Corresponding injury mechanism Accidents (V01-X59) and missing injury mechanism justify the majority of missing activity codes. Missing POO and Home (Y92.0) were the POO where the majority of these cases happened.

The high levels of missing activity codes prove to be a major obstacle to developing injury prevention policies when the exact circumstances surrounding injury events are not present. It is necessary that the specific type of activity be documented so that effective prevention strategies can be targeted for specific sports. Langley, Davie and Simpson (2007) suggest that the relatively high use of Unspecified activity could be due to the fact that some hospitals deem this aspect not as important as injury mechanism. Our results support this notion, indicating injury mechanism codes had the lowest amount of missing codes compared to POO and activity at time of injury.

The broad Activity categories illustrate reasonable usage of activity codes (Table 3). Unfortunately, the results demonstrate that activity codes assigned lacked precision. The relatively high use of non-specific sports activity codes within the specified categories such as Football unspecified (U50.09), Rugby unspecified (U50.03) and Cycling unspecified (U66.09) demonstrates activity codes are not being assigned to the highest level of specificity available in the classification. Similar results were found in studies focusing on injury mechanism (Lawrence et al. 2007; McKenzie et al. 2006).

Moreover, our analysis also found that over the five-year period, specified activity codes were overshadowed by the abundance of non-specific activity coding. Although there was a decline in Other specified and missing activity codes, this was made up by the ever increasing number of Unspecified activity (U73.9) codes despite the availability of over 230 activity codes. The results indicate that 47%-56% of activity codes were assigned an Unspecified activity code over the five-year period, a result much higher than that reported by Finch and Boufous (2008) who reported an Unspecified activity code of less than 30% for the state of New South Wales. Our study shows Falls (W00-W19), Transport accidents (V01-V99), Exposure to inanimate mechanical forces (W20-W49) and Accidental exposure to other and unspecified factors (X58-X59) were the injury mechanisms that accounted for the majority of Unspecified activity (U73.9) codes.

The findings here support previous studies in the United States where Lawrence et al. (2007) established that the high levels of external cause coding completeness was achieved by excessive use of non-specific codes. The high level of non-specific coding reflects a need to acquire additional information regarding the circumstances surrounding the injury admission. Also, coders surveyed in the study by McKenzie and colleagues (2008) insinuate missing documentation and missing external cause information impact significantly on the external cause codes allocated.

Causes for the high level of non-specific ICD10-AM activity codes must be addressed so that solutions can be developed and implemented to decrease these data inadequacies. The large quantity of non-specific activity codes offers a significant amount of non-meaningful information regarding the specific cause of injuries. This provides limited benefit for injury prevention professionals in determining the cause of the injury, where the results imply that the level of specificity of injury coding can be improved. The high percentage of 'Other specified' codes, especially within Other specified sport and exercise activity (U70.8, 87.1%) indicates an area of potential classification development. The high proportion of 'Unspecified' code represents insufficient documentation to permit more specific code assignment (McKenzie et al. 2006) as this study highlights the insufficient clinical documentation within the medical records by clinicians. Unfortunately, clinicians may be unaware of the level of documentation necessary to detail the complete circumstances surrounding the injury event in the medical records because their priorities lie in the immediate clinical care of the patient especially if the patient was admitted for an injury.

Conclusion

Injuries are preventable occurrences and in order for injury prevention and control organisations to identify and implement mechanisms to effectively reduce injury events, access to quality information is necessary. This determines the degree of injury hospitalisations and enables the identification of priority areas for injury prevention initiatives (Hayen & Mitchell 2006).

In 2002, the NCCH released an update on the revision of activity codes. The expanded classification provides a variety of mutually exclusive categories for a large number of specific types of sport and related activities applicable to the Australian environment. The results illustrate that the new Activity categories have been used extensively and that the resultant data were adequate to warrant detailed analysis of activity code usage and the quality of external cause code coding, in particular, specificity and completeness.

The comprehensive nature of ICD-10-AM allows non-specific information to be captured in residual categories when documentation in the medical record is insufficient to permit a more detailed code assignment (Bramley 2005). It is essential for injury prevention activities that there is minimal use of these non-specific codes to develop tailored prevention policies and strategies as the results imply that improvements in the quality of injury coding are required.

Clinicians and coders need to acknowledge the importance of quality clinical documentation for research purposes so that circumstances surrounding injury events can be coded to the highest level of detail possible to improve injury prevention and control initiatives and monitor injury incidence among Australians nationally. The results highlighted in this study indicate that the completeness of external cause coding is high but found that missing activity codes and non-specific coding hinders the usefulness of the data to make specific recommendations for injury initiatives.

Recommendations and further research

Some recommendations and further research activities that would aid in improving injury prevention activities include but are not limited to the following:

* Medical records/admissions should be validated by an external coder to determine whether more appropriate codes can be assigned or new codes created to accommodate activities assigned to Other specified sport and exercise activity and Unspecified activity.

* Improvement of communication among stakeholders regarding external cause codes by addressing the need and uses of high quality injury data for injury prevention purposes would be beneficial.

* Further research and education to examine state-specific external cause coding accuracy, specificity and completeness to explore issues and address the overuse of non-specific codes to enable more specific code assignment are indicated. Efforts to make coding of external cause of injury required data elements in medical record forms, electronic patient records and associated software mandatory for injury separations (McKenzie et al. 2006) should be considered.

Acknowledgements

Data for this project were provided by the AIHW as part of the work program under the AIHW and NCCH collaboration agreement.

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Irene Hoi-Yen Soo BAppSc(HIM)(Hons)

Research Student

Discipline of Health Informatics

Faculty of Health Sciences

The University of Sydney

Lidcombe NSW 1825

AUSTRALIA

Corresponding author

Mary K Lam BA(Hons), MHIM, PhD

Lecturer

Discipline of Health Informatics

Faculty of Health Sciences

The University of Sydney

PO Box 170

Lidcombe NSW 1825

AUSTRALIA

Tel: +61 2 9351 9570

Fax: +61 2 9351 9672

email: m.lam@usyd.edu.au

Julie Rust BAppSc(HIM)

Project Officer

National Centre for Classification in Health

Faculty of Health Sciences

The University of Sydney

PO Box 170

Lidcombe NSW 1825

AUSTRALIA

Richard Madden PhD

Professor and Director

National Centre for Classification in Health

Faculty of Health Sciences

The University of Sydney

PO Box 170

Lidcombe NSW 1825

AUSTRALIA
Table 1: Forward one-to-one map of ICD-10-AM
Second Edition activity codes to Third Edition

ICD-10-AM                                             ICD-10-AM
SECOND                                                THIRD
EDITION     CODE DESCRIPTION                          EDITION

Y93.00      Football, Rugby                           U50.03
Y93.01      Football, Australian                      U50.00
Y93.02      Football, Soccer                          U50.04
Y93.03      Hockey                                    U51.29
Y93.04      Squash                                    U59.2
Y93.05      Basketball                                U50.1
Y93.06      Netball                                   U50.39
Y93.07      Cricket                                   U51.1
Y93.08      In-line skating and rollerblading         U66.1
Y93.09      Other and unspecified sporting activity   U71
Y93.1       While engaged in leisure                  U72
Y93.2       While working for income                  U73.09
Y93.3       While engaged in other types of work      U73.1
Y93.4       While resting, sleeping, eating or
            engaging in other vital activities        U73.2
Y93.8       Other specified activity                  U73.8
Y93.9       Unspecified activity                      U73.9

Table 2: Usage of activity codes from ICD-10-AM Second Edition
made compatible with later editions, 2001/02-2005/06

                                                    2001/02

CODE     DESCRIPTION                             NO.        %

U50.00   Australian Rules                       4911      1.36
U50.03   Rugby, unspecified                     6403      1.78
U50.04   Soccer                                 3981      1.11
U50.1    Basketball                             1504      0.42
U50.39   Netball, other and unspecified         1275      0.35
U51.1    Cricket                                1102      0.31
U51.29   Hockey, unspecified                     417      0.12
U59.2    Squash                                  232      0.06
U66.1    In-line skating and rollerblading      1672      0.46
U71      Unspecified sport and
         exercise activity                      9976      2.77
U72      Leisure activity,
         not elsewhere classified              20135      5.59
U73.09   While working for income,
         unspecified                           23616      6.56
U73.1    While engaged in other
         types of work                         12848      3.57
U73.2    While resting, sleeping, eating or
         engaging in other vital activities    16707      4.64
U73.8    Other specified activity              82560     22.94
U73.9    Unspecified activity                 172090     47.81
         Other Codes
         Missing                                 519      0.14
         Total                                359948    100.00

                                          2002/03            2003/04

DESCRIPTION                             NO.       %       NO.       %

Australian Rules                       3959     1.09     3895     1.05
Rugby, unspecified                      695     0.19     1424     0.38
Soccer                                 3284     0.90     3285     0.89
Basketball                             1206     0.33     1204     0.33
Netball, other and unspecified          992     0.27     1011     0.27
Cricket                                 987     0.27      883     0.24
Hockey, unspecified                     178     0.05      199     0.05
Squash                                  192     0.05      202     0.05
In-line skating and rollerblading       567     0.16      561     0.15
Unspecified sport and
exercise activity                       879     0.24      896     0.24
Leisure activity,
not elsewhere classified               8856     2.44     7949     2.15
While working for income,
unspecified                            7189     1.98     7546     2.04
While engaged in other
types of work                         13554     3.73    13377     3.61
While resting, sleeping, eating or
engaging in other vital activities    18179     5.01    18593     5.02
Other specified activity              84085    23.16    83617    22.59
Unspecified activity                 175104    48.23   183897    49.67
Other Codes                           39193    10.80    40433    10.92
Missing                                3957     1.09     1235     0.33
Total                                363056   100.00   370207   100.00

                                           2004/05          2005/06

DESCRIPTION                             NO.       %       NO.       %

Australian Rules                       4335     1.14     4156     1.17
Rugby, unspecified                     1619     0.42     1741     0.49
Soccer                                 3386     0.89     3424     0.96
Basketball                             1383     0.36     1436     0.40
Netball, other and unspecified         1022     0.27     1153     0.32
Cricket                                 943     0.25     1033     0.29
Hockey, unspecified                     225     0.06      270     0.08
Squash                                  190     0.05      177     0.05
In-line skating and rollerblading       440     0.12      388     0.11
Unspecified sport and
exercise activity                       953     0.25     1251     0.35
Leisure activity,
not elsewhere classified               6999     1.83     6715     1.89
While working for income,
unspecified                            8019     2.10     8739     2.46
While engaged in other
types of work                         13572     3.55    13719     3.86
While resting, sleeping, eating or
engaging in other vital activities    19260     5.04    19890     5.60
Other specified activity              76635    20.07    66241    18.64
Unspecified activity                 200873    52.61   225048    63.33
Other Codes                           41272    10.81    41767    11.75
Missing                                 704     0.18      671     0.19
Total                                381830   100.00   397819   100.00

Table 3: Patterns of Activity code usage
when injury occurred, 2001/02 to 2005/06

                                                    2001/02

CODE      ACTIVITY                               NO.        %

U50-U71   While engaged in sports              31473     8.74
U72       While engaged in leisure             20135     5.59
U73.0     While working for income             23616     6.56
U73.1     While engaged in other
          types of work                        12848     3.57
U73.2     While resting, sleeping, eating or
          engaging in other vital activities   16707     4.64
U73.8     Other specified activity             82560    22.94
U73.9     Unspecified activity                172090    47.81
          Activity code not reported
          or missing                             519     0.14
          Total                               359948   100.00

                                          2002/03           2003/04

ACTIVITY                               NO.        %      NO.        %

While engaged in sports              36536    10.06    38173    10.31
While engaged in leisure              8856     2.44     7949     2.15
While working for income             22785     6.28    23366     6.31
While engaged in other
types of work                        13554     3.73    13377     3.61
While resting, sleeping, eating or
engaging in other vital activities   18179     5.01    18593     5.02
Other specified activity             84085    23.16    83617    22.59
Unspecified activity                175104    48.23   183897    49.67
Activity code not reported
or missing                            3957     1.09     1235     0.33
Total                               363056   100.00   370207   100.00

                                          2004/05           2005/06

ACTIVITY                               NO.        %      NO.        %

While engaged in sports              39621    10.38    40234    10.11
While engaged in leisure              6999     1.83     6715     1.69
While working for income             24166     6.33    25301     6.36
While engaged in other
types of work                        13572     3.55    13719     3.45
While resting, sleeping, eating or
engaging in other vital activities   19260     5.04    19890     5.00
Other specified activity             76635    20.07    66241    16.65
Unspecified activity                200873    52.61   225048    56.57
Activity code not reported
or missing                             704     0.18      671     0.17
Total                               381830   100.00   397819   100.00

Table 4: Specificity of data across Activity categories, 2005/06

CODE   DESCRIPTIONS                  SPECIFIED        OTHER SPECIFIED

                                     n        %         n        %

U50    Team ball sports            11446    65.63      128     0.73
U51    Team bat or stick sports     1551    83.66       32     1.73
U52    Team water sports               7    87.50        1    12.50
U53    Boating sports                235    66.20       31     8.73
U54    Individual water sports      1878    71.82      200     7.65
U55    Ice and snow sports           771    67.34       43     3.76
U57    Acrobatic sports              230    61.50       47    12.57
U61    Combative sports              378    67.14       30     5.33
U63    Equestrian activities        1661    89.93       48     2.60
U66    Wheeled non-motor sports     2820    55.42      119     2.34
U67    Multidiscipline sports         23    79.31        1     3.45
U69    Other school-related
       recreational activities       434    56.00       91    11.74
U70    Other specifi ed sport
       and exercise activity         126    12.88      852    87.12
U73    Other activity              45394    12.96    71018    20.28

                                              OTHER SPECIFIED
DESCRIPTIONS                  UNSPECIFIED      & UNSPECIFIED     TOTAL

                               n        %        n        %

Team ball sports             4712    27.02     1153     6.61     17439
Team bat or stick sports      271    14.62                        1854
Team water sports                                                    8
Boating sports                 89    25.07                         355
Individual water sports       537    20.54                        2615
Ice and snow sports           331    28.91                        1145
Acrobatic sports               97    25.94                         374
Combative sports              155    27.53                         563
Equestrian activities         138     7.47                        1847
Wheeled non-motor sports     1955    38.42      194     3.81      5088
Multidiscipline sports          5    17.24                          29
Other school-related
recreational activities       250    32.26                         775
Other specifi ed sport
and exercise activity                                              978
Other activity             233787    66.76                      350199

Table 5: Analysis of injury mechanism responsible
for high frequency of Unspecified activity, 2005/06

CODE
RANGE     DESCRIPTION                                 COUNT       %

V01-X59   Accidents                                  196617     87.37
          V01-V99       Transport accidents           36519     18.57
          W00-W19       Falls                         86849     44.17
          W20-W49       Exposure to inanimate
                          mechanical forces           27144     13.81
          W50-W64       Exposure to animate
                          mechanical forces            5839      2.97
          W65-W74       Accidental drowning
                          and submersion                214      0.11
          W75-W84       Other accidental threats
                          to breathing                  270      0.14
          W85-W99       Exposure to electric
                          current, radiation and
                          extreme ambient air
                          temperature and pressure      205      0.10
          X00-X09       Exposure to smoke, fire
                          and flames                   1226      0.62
          X10-X19       Contact with heat and hot
                          substances                   1963      1.00
          X20-X29       Contact with venomous
                          animals and plants           2171      1.10
          X30-X39       Exposure to forces of
                          nature                        395      0.20
          X40-X49       Accidental poisoning by
                          and exposure to noxious
                          substances                   4704      2.39
          X50-X57       Overexertion, travel and
                          privation                    2436      1.24
          X58-59        Accidental exposure to
                          other and unspecified
                          factors                     26682     13.57
X60-X84   Intentional self-harm                        6904      3.07
X85-Y09   Assault                                     18736      8.33
Y10-Y34   Event of undetermined intent                 2741      1.22
          Missing                                        50      0.02
          Total                                      225048    100.00

Figure 1. Frequency of missing Activity codes, 2001/02 to 2005/06

Year      Activity code not
          reported / Missing

2001/02          519
2002/03         3957
2003/04         1235
2004/05          704
2005/06          671

Note: Table made from bar graph.

Figure 5: Specificity of Team ball sports, 2005/06

Specified Team ball sports          66%
Non-specific Team ball sports       34%

Netball, other and unspecified    6.61%
Football, unspecified            16.92%
Other, specified football         0.68%
Rugby, unspecified                9.98%

Note: Table made from pie chart.

Note: Table made from bar graph.

Figure 6: Specificity of Wheeled non-motored sports, 2005/06

Specified Wheeled non-motored sports                       55%
Non-specific Wheeled non-motored sports                    45%

Scooter riding, other unspecified non-motored scooter    3.81%
Cycling, unspecified                                    38.15%
Other specified cycling                                  2.24%

Note: Table made from pie chart.

Note: Table made from bar graph.
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