Statins and new-onset diabetes: a retrospective longitudinal cohort study

Background: Statins have been linked to new-onset diabetes (NOD); however, the effect of statins on the development of NOD in patients with hypertension and dyslipidemia has not been well studied.

Objective: The goal of this study was to investigate the association between statins and NOD.

Methods: This was a retrospective cohort study performed by using data from claim forms provided to the central regional branch of the Bureau of National Health Insurance in Taiwan from July 2006 to December 2009. Prescriptions for statins before the index date were retrieved from a prescription database. We estimated the hazards ratios (HRs) of NOD associated with statin use. Nondiabetic subjects served as the reference group.

Results: A total of 1360 (8.5%) NOD cases were identified among 16,027 patients with hypertension and dyslipidemia during the study period. The risk of NOD after adjusting for sex and age was higher among users of pravastatin (HR, 1.34 [95% CI, 1.15-1.55]) and atorvastatin (HR, 1.29 [95% CI, 1.16-1.44]) than among nonusers. Patients who took fluvastatin (HR, 0.45 [95% CI, 0.34-0.60]), lovastatin (HR, 0.71 [95% CI, 0.61-0.84]), and rosuvastatin (HR, 0.54 [95% CI, 0.39-0.77]) were at lower risk of developing NOD than nonusers. Simvastatin was not associated with risk of NOD. Furthermore, the risk of NOD after adjusting for concomitant medication usage and mean dose of statins was neutral among users of atorvastatin. Pravastatin, fluvastatin, lovastatin, simvastatin, and rosuvastatin produced similar results as adjusting for sex and age.

Conclusions: These outpatients with hypertension and dyslipidemia who took fluvastatin, lovastatin, and rosuvastatin were at lower risk of NOD, whereas patients who took pravastatin were at greater risk. Simvastatin and atorvastatin seemed to have a neutral effect. Our study also demonstrated that atorvastatin has a dose-response effect on NOD risk. Because this was a descriptive study, temporality and subsequent causality of all statins and NOD could not be shown. Further study and independent confirmation of the causality between statin use and NOD in larger clinical trials are warranted.