Document Detail


Collaborative overview of randomised trials of antiplatelet therapy--I: Prevention of death, myocardial infarction, and stroke by prolonged antiplatelet therapy in various categories of patients. Antiplatelet Trialists' Collaboration.
MedLine Citation:
PMID:  8298418     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: To determine the effects of "prolonged" antiplatelet therapy (that is, given for one month or more) on "vascular events" (non-fatal myocardial infarctions, non-fatal strokes, or vascular deaths) in various categories of patients. DESIGN: Overviews of 145 randomised trials of "prolonged" antiplatelet therapy versus control and 29 randomised comparisons between such antiplatelet regimens. SETTING: Randomised trials that could have been available by March 1990. SUBJECTS: Trials of antiplatelet therapy versus control included about 70,000 "high risk" patients (that is, with some vascular disease or other condition implying an increased risk of occlusive vascular disease) and 30,000 "low risk" subjects from the general population. Direct comparisons of different antiplatelet regimens involved about 10,000 high risk patients. RESULTS: In each of four main high risk categories of patients antiplatelet therapy was definitely protective. The percentages of patients suffering a vascular event among those allocated antiplatelet therapy versus appropriately adjusted control percentages (and mean scheduled treatment durations and net absolute benefits) were: (a) among about 20,000 patients with acute myocardial infarction, 10% antiplatelet therapy v 14% control (one month benefit about 40 vascular events avoided per 1000 patients treated (2P < 0.00001)); (b) among about 20,000 patients with a past history of myocardial infarction, 13% antiplatelet therapy v 17% control (two year benefit about 40/1000 (2P < 0.00001)); (c) among about 10,000 patients with a past history of stroke or transient ischaemic attack, 18% antiplatelet therapy v 22% control (three year benefit about 40/1000 (2P < 0.00001)); (d) among about 20,000 patients with some other relevant medical history (unstable angina, stable angina, vascular surgery, angioplasty, atrial fibrillation, valvular disease, peripheral vascular disease, etc), 9% v 14% in 4000 patients with unstable angina (six month benefit about 50/1000 (2P < 0.00001)) and 6% v 8% in 16,000 other high risk patients (one year benefit about 20/1000 (2P < 0.00001)). Reductions in vascular events were about one quarter in each of these four main categories and were separately statistically significant in middle age and old age, in men and women, in hypertensive and normotensive patients, and in diabetic and nondiabetic patients. Taking all high risk patients together showed reductions of about one third in non-fatal myocardial infarction, about one third in non-fatal stroke, and about one third in vascular death (each 2P < 0.00001). There was no evidence that non-vascular deaths were increased, so in each of the four main high risk categories overall mortality was significantly reduced. The most widely tested antiplatelet regimen was "medium dose" (75-325 mg/day) aspirin. Doses throughout this range seemed similarly effective (although in an acute emergency it might be prudent to use an initial dose of 160-325 mg rather than about 75 mg). There was no appreciable evidence that either a higher aspirin dose or any other antiplatelet regimen was more effective than medium dose aspirin in preventing vascular events. The optimal duration of treatment for patients with a past history of myocardial infarction, stroke, or transient ischaemic attack could not be determined directly because most trials lasted only one, two, or three years (average about two years). Nevertheless, there was significant (2P < 0.0001) further benefit between the end of year 1 and the end of year 3, suggesting that longer treatment might well be more effective. Among low risk recipients of "primary prevention" a significant reduction of one third in non-fatal myocardial infarction was, however, accompanied by a non-significant increase in stroke. Furthermore, the absolute reduction in vascular events was much smaller than for high risk patients despite a much longer treatment period (4.4% antiplatelet therapy v 4.8% control; five year
Authors:
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Publication Detail:
Type:  Journal Article; Meta-Analysis; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  BMJ (Clinical research ed.)     Volume:  308     ISSN:  0959-8138     ISO Abbreviation:  BMJ     Publication Date:  1994 Jan 
Date Detail:
Created Date:  1994-03-09     Completed Date:  1994-03-09     Revised Date:  2010-03-24    
Medline Journal Info:
Nlm Unique ID:  8900488     Medline TA:  BMJ     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  81-106     Citation Subset:  AIM; IM    
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MeSH Terms
Descriptor/Qualifier:
Cause of Death
Cerebrovascular Disorders / mortality,  prevention & control*
Humans
Myocardial Infarction / mortality,  prevention & control*
Platelet Aggregation Inhibitors / therapeutic use*
Randomized Controlled Trials as Topic
Recurrence
Risk Factors
Time Factors
Chemical
Reg. No./Substance:
0/Platelet Aggregation Inhibitors
Comments/Corrections
Comment In:
BMJ. 1994 Jan 8;308(6921):72-4   [PMID:  8298415 ]
ACP J Club. 1994 Jul-Aug;121 Suppl 1:4-6
BMJ. 1998 Dec 5;317(7172):1587-8   [PMID:  9836671 ]
BMJ. 1994 Jan 8;308(6921):71-2   [PMID:  8298414 ]
Erratum In:
BMJ 1994 Jun 11;308(6943):1540

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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