Aspirin for the Primary Prevention of Cardiovascular Events: A Systematic Review and Meta-Analysis Comparing Patients With and Without Diabetes
- Andrew D Calvin, MD, MPH1,
- Niti R Aggarwal, MD1,
- Mohammad Hassan Murad, MD, MPH2,
- Qian Shi, PhD3,
- Mohamed B Elamin, MBBS2,
- Jeffrey B Geske, MD1,
- M Merce Fernandez Balsells, MD4,
- Felipe N Albuquerque, MD2,
- Julianna F Lampropulos, MD2,
- Patricia J Erwin, MLS5,
- Steven A Smith, MD6 and
- Victor M Montori, MD, MSc (montori.victor{at}mayo.edu)7
- From the 1Mayo School of Graduate Medical Education
- 2Knowledge and Encounter Research Unit
- 3Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minn
- 4Servei d'Endocrinologia, Hospital Universitari de Girona Dr Josep Trueta, Girona, Spain
- 5Medical Library
- 6Division of Endocrinology and Metabolism
- 7Knowledge and Encounter Research Unit and Division of Endocrinology and Metabolism, Mayo Clinic, Rochester, Minn
Abstract
Objective - The negative results of two randomized controlled trials (RCT) have challenged current guideline recommendations for using aspirin for primary prevention of cardiovascular events among patients with diabetes. We therefore sought to determine if the effect of aspirin for primary prevention of cardiovascular events and mortality differs between patients with and without diabetes.
Research Design and Methods - We conducted a systematic search of MEDLINE, EMBASE, Cochrane Library, Web of Science, and Scopus since their inception until November 2008 for RCTs of aspirin for primary prevention of cardiovascular events. Blinded pairs of reviewers evaluated studies and extracted data. Random effects meta-analysis and Bayesian logistic regression were used to estimate the ratios of relative risks of outcomes of interest among patients with and without diabetes. A 95% confidence interval (CI) that crosses 1.00 indicates that the effect of aspirin does not differ between patients with and without diabetes.
Results - Nine RCTs with moderate to high methodological quality contributed data to the analyses. The ratios of relative risks comparing the benefit of aspirin among patients with diabetes compared to patients without diabetes for mortality, myocardial infarction and ischemic stroke were 1.12 (95% CI, 0.92, 1.35), 1.19 (95% CI, 0.82, 1.17) and 0.70 (95% CI, 0.25, 1.97), respectively.
Conclusions - While estimates of benefit among patients with diabetes remain imprecise, our analysis suggests that the relative benefit of aspirin is similar in patients with and without diabetes.
Footnotes
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- Received July 16, 2009.
- Accepted September 2, 2009.
