Is the use of cholesterol-lowering drugs for the prevention of cardiovascular complications in type 2 diabetics evidence-based? A systematic review.

Cholesterol-lowering drugs are often prescribed to patients with type 2 diabetes mellitus despite uncertainty about the benefits of this treatment in the prevention of cardiovascular complications. We here systematically review (PRISMA guidelines) the results of high-quality double blind trials testing whether cholesterol-lowering drugs (statins and fibrates) reduce mortality and cardiovascular complications specifically in type 2 diabetics. Trials with premature termination without pertinent medical justification or using nonrandomized subgroups of diabetics were excluded from the review. Only four trials met our predefined inclusion criteria. Among the 3 statin trials, CARDS was discontinued 2 years before the anticipated end and in the absence of significant effect on both overall and cardiovascular mortality, suggesting that the trial should not have been prematurely stopped. The two other statin trials showed no significant effect on the primary endpoint (relative risk 0.92, 95% CI 0.77 to 1.10 in 4D and 0.90, 95% CI 0.73 to 1.12 in ASPEN) and on both cardiovascular and overall mortality. Finally, the fibrate trial (FIELD) showed no significant benefit on the primary endpoint (relative risk 0.89, 95% CI 0.75 to 1.05) and mortality (relative risk 1.11, 95% CI 0.95 to 1.29). Because of a huge medical heterogeneity between patients in the selected trials, it was consensually decided to stop the analysis at this stage. This review does not support the use of cholesterol-lowering drugs (such as statin and fibrate) to reduce mortality and cardiovascular complications in type 2 diabetics. Official guidelines should be re-examined and reformulated by experts independent from the pharmaceutical industry.