Reassessing the benefits of statins in the prevention of cardiovascular disease in diabetic patients--a systematic review and meta-analysis

Abstract

Objectives: Despite the fact that statins have been prescribed widely, cardiovascular disease (CVD) remains the leading cause of death in diabetic patients. The aim of this study was to reassess the benefits of statins for CVD prevention in patients with diabetes mellitus.

Methods: Two independent investigators searched for prospective, randomized statin trials that investigated the power of reducing CVD in statin-treated patients. The search was performed using Pubmed, Web of Science, and CENTRAL databases. Data was extracted from eligible studies.

Results: A total of 7061 articles were surveyed and 22 articles were identified as eligible articles. The meta-analyses of the 22 trials showed that statin treatment was positively associated with a lowered risk of CVD in the following groups: (i) total population with pooled odds ratios (OR) of 0.791 (95 % CI: 0.74-0.846, p < 0.001), (ii) diabetic population with OR 0.792 (95% CI: 0.721-0.872, p < 0.001), and (iii) non-diabetic population with OR 0.791 (95% CI: 0.730-0.857, p < 0.001). In diabetic patients, statins were also helpful in the primary and secondary prevention of CVD, with pooled ORs of 0.757 (95% CI: 0.676 to 0.847, p < 0.001) and 0.800 (95% CI: 0.712 to 0.898, p < 0.001), respectively. However, when trials that investigated only diabetic patients (i.e., CARDS, 4D, and ASPEN) were included in the analysis, statin treatment was not found to reduce CVD significantly (OR: 0.817, 95% CI: 0.649 to 1.029, p = 0.086). Furthermore, after performing subgroup analysis, no benefit of statin treatment was found in primary prevention (OR: 0.774, 95% CI: 0.506 to 1.186, p = 0.240) or secondary prevention (OR: 0.893, 95% CI: 0.734 to 1.088, p = 0.262) of CVD in diabetic patients.

Conclusions: Although our study may be limited by unmeasured confounders and heterogeneity among the studies included, the results suggest that the effects of statins in the prevention of CVD in diabetic patients are not only beneficial. More informative data are needed to verify the benefits of statins in the protection against CVD in diabetic patients.

Figure 1

Flow diagram of the selection of statin trials.

Figure 2

Forest plot of statin treatment for CVD prevention studies in the overall population.

Figure 3

Forest plot of statin treatment for CVD prevention studies stratified into diabetic and non-diabetic patients.

Figure 4

Forest plot of statin therapy for CVD prevention studies in patients with diabetes mellitus stratified by primary and secondary prevention trails.

Figure 5

Forest plot of statin therapy for CVD prevention in studies designed with double-blind, randomized controlled trials in patients with diabetes mellitus and subgroups by primary and secondary prevention trials.