The long-term effect of statins on the risk of new-onset diabetes mellitus in elderly Taiwanese patients with hypertension and dyslipidaemia: a retrospective longitudinal cohort study.

Background: HMG-CoA reductase inhibitors (statins) have been linked to new-onset diabetes (NOD). Individual statins may differ in the extent to which they increase the risk for NOD; however, the effect of statins on the development of NOD in elderly hypertensive and dyslipidaemic patients has not been well studied.

Objective: The aim of this study was to investigate the relative risk for NOD among elderly (age ≥65 years) hypertensive and dyslipidaemic Taiwanese patients who received different statins.

Methods: This was a retrospective cohort study performed using data from claim forms provided to the central regional branch of the Bureau of National Health Insurance in Taiwan from July 2004 to December 2009. Prescriptions for statins before the index date were retrieved from a prescription database. We estimated the hazard ratios (HRs) of NOD associated with statin use. Non-diabetic subjects served as the reference group.

Results: A total of 2735 NOD cases were identified among 15,637 elderly hypertensive and dyslipidaemic patients during the study period. The risk of NOD after adjusting for sex, age, concomitant medication and mean dose of prescription was lower among users of atorvastatin (HR 0.77; 95% CI 0.71, 0.83) and rosuvastatin (HR 0.65; 95% CI 0.51, 0.82) than among non-users. Patients who took lovastatin (HR 1.38; 95% CI 1.26, 1.50) or simvastatin (HR 1.30; 95% CI 1.14, 1.48) were at higher risk of developing NOD than non-users. Pravastatin and fluvastatin were not associated with increased risk of NOD.

Conclusions: The results of this study suggest that elderly hypertensive and dyslipidaemic patients who take atorvastatin or rosuvastatin are at lower risk of NOD. Lovastatin and simvastatin were associated with a significant increase in the risk of NOD.