Aspirin for primary prevention of cardiovascular events in people with diabetes: meta-analysis of randomised controlled trials.
OBJECTIVE
To evaluate the benefits and harms of low dose aspirin in people with diabetes and no cardiovascular disease.


METHODS
Meta-analysis of randomised controlled trials.


METHODS
Medline (1966-November 2008), the Cochrane central register of controlled trials (Cochrane Library 2008;issue 4), and reference lists of retrieved articles. Review methods Randomised trials of aspirin compared with placebo or no aspirin in people with diabetes and no pre-existing cardiovascular disease were eligible for inclusion. Data on major cardiovascular events (death from cardiovascular causes, non-fatal myocardial infarction, non-fatal stroke, and all cause mortality) were extracted and pooled with a random effect model. Results are reported as relative risks with 95% confidence intervals.


RESULTS
Of 157 studies in the literature searches, six were eligible (10 117 participants). When aspirin was compared with placebo there was no statistically significant reduction in the risk of major cardiovascular events (five studies, 9584 participants; relative risk 0.90, 95% confidence interval 0.81 to 1.00), cardiovascular mortality (four studies, n=8557, 0.94; 0.72 to 1.23), or all cause mortality (four studies, n=8557; 0.93, 0.82 to 1.05). Significant heterogeneity was found in the analysis for myocardial infarction (I(2)=62.2%; P=0.02) and stroke (I(2)=52.5%; P=0.08). Aspirin significantly reduced the risk of myocardial infarction in men (0.57, 0.34 to 0.94) but not in women (1.08, 0.71 to 1.65; P for interaction=0.056). Evidence relating to harms was inconsistent.


CONCLUSIONS
A clear benefit of aspirin in the primary prevention of major cardiovascular events in people with diabetes remains unproved. Sex may be an important effect modifier. Toxicity is to be explored further.
De Berardis
Giorgia
G
Department of Clinical Pharmacology and Epidemiology, Consorzio Mario Negri Sud, Via Nazionale 8/a, 66030 S. Maria Imbaro, Italy.
Sacco
Michele
M
Strippoli
Giovanni F M
GF
Pellegrini
Fabio
F
Graziano
Giusi
G
Tognoni
Gianni
G
Nicolucci
Antonio
A
D001241:Aspirin / Q000008:administration & dosage* / Q000009:adverse effects; D002317:Cardiovascular Agents / Q000008:administration & dosage* / Q000009:adverse effects; D003925:Diabetic Angiopathies / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008297:Male; D011322:Primary Prevention; D011379:Prognosis; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors
D002317:Cardiovascular Agents; D001241:Aspirin