Aspirin for the primary prevention of cardiovascular events: a systematic review and meta-analysis comparing patients with and without diabetes.
OBJECTIVE
The negative results of two randomized controlled trials (RCTs) 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.


METHODS
We conducted a systematic search of MEDLINE, EMBASE, Cochrane Library, Web of Science, and Scopus since their inceptions 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 (RRs) of outcomes of interest among patients with and without diabetes. A 95% 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 RRs comparing the benefit of aspirin among patients with diabetes compared with patients without diabetes for mortality, myocardial infarction, and ischemic stroke were 1.12 (95% CI 0.92-1.35), 1.19 (0.82-1.17), and 0.70 (0.25-1.97), respectively.


CONCLUSIONS
Whereas 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.
Calvin
Andrew D
AD
Mayo School of Graduate Medical Education, Mayo Clinic, Rochester, Minnesota, USA.
Aggarwal
Niti R
NR
Murad
Mohammad Hassan
MH
Shi
Qian
Q
Elamin
Mohamed B
MB
Geske
Jeffrey B
JB
Fernandez-Balsells
M Merce
MM
Albuquerque
Felipe N
FN
Lampropulos
Julianna F
JF
Erwin
Patricia J
PJ
Smith
Steven A
SA
Montori
Victor M
VM
D001241:Aspirin / Q000627:therapeutic use*; D002318:Cardiovascular Diseases / Q000517:prevention & control*; D003925:Diabetic Angiopathies / Q000517:prevention & control*; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006801:Humans; D006973:Hypertension / Q000517:prevention & control; D008297:Male; D009203:Myocardial Infarction / Q000517:prevention & control; D015588:Observer Variation; D011322:Primary Prevention / Q000379:methods*; D016032:Randomized Controlled Trials as Topic; D020521:Stroke / Q000517:prevention & control
D005343:Fibrinolytic Agents; D001241:Aspirin