Research has suggested that statin therapy, used to lower cholesterol levels and, consequently, the risk of cardiovascular events, increases patients' risk of developing diabetes. According to a recent meta-analysis, evidence is growing that the risk is also dose dependent. Five randomized controlled trials of statins in which intensive-dose therapy (80 mg of either simvastatin or atorvastatin) was compared with moderate-dose therapy, using cardiovascular outcomes as the end point, in 32,752 nondiabetic patients with a history of coronary heart disease served as the basis for this analysis. Data on incident (new-onset) diabetes were obtained from the trials' investigators.

Over a mean follow-up of 4.9 years, 1,449 trial participants who were assigned to intensive-dose therapy and 1,300 who were assigned to moderate-dose therapy developed diabetes. The larger number of cases of incident diabetes in the intensive-dose group corresponded to a 12% increased relative risk, or an excess of two cases of diabetes per 1,000 patient-years. The odds of developing diabetes were similar in patients taking either intensive-dose statin regimen.

Patients assigned to intensive-dose statins suffered 416 fewer cardiovascular events, corresponding to a relative reduction of 16% over moderate-dose therapy, or 6.5 fewer first major cardiovascular events per 1,000 patient-years. However, only atorvastatin 80 mg was associated with a significant cardiovascular benefit, in comparison with moderate-dose statin therapy; the 5% relative reduction in cardiovascular risk observed with simvastatin 80 mg failed to achieve statistical significance.

The authors point out that despite the apparently dose-dependent increase in diabetes risk with statin therapy, the net cardiovascular benefit seen in these trials still favors intensive-dose statin therapy in high-risk patients.-WK

Reference