Association of statin use with cataracts: a propensity score-matched analysis

Abstract

Importance: Cataracts are a main cause of low vision; with the growing elderly population, the incidence of cataracts is likely to increase. Investigators have previously hypothesized that statin antioxidant effects may slow the natural aging process of the lens.

Objective: To compare the risks for development of cataracts between statin users and nonusers.

Design: A propensity score-matched cohort analysis using retrospective data from October 1, 2003, to March 1, 2010. A propensity score-matched cohort of statin users and nonusers was created using 44 variables.

Setting: Database of a military health care system.

Participants: Based on medication fills during fiscal year 2005, patients were divided into 2 groups: (1) statin users (received at least a 90-day supply of statin) and (2) nonusers (never received a statin throughout the study). Among 46,249 patients meeting study criteria, we identified 13,626 statin users and 32,623 nonusers.

Exposure: Use of statin therapy for more than 90 days.

Main outcomes and measures: Primary analysis examined the risks for cataract in the propensity score-matched cohort. Secondary analyses examined the risks for cataract in patients with no comorbidities according to the Charlson Comorbidity Index (patients with no Charlson comorbidity). A sensitivity analysis was conducted to repeat the secondary analysis in patients taking statins for durations of 2, 4, and 6 years.

Results: For our primary analysis, we matched 6972 pairs of statin users and nonusers. The risk for cataract was higher among statin users in comparison with nonusers in the propensity score-matched cohort (odds ratio, 1.09; 95% CI, 1.02-1.17). In secondary analyses, after adjusting for identified confounders, the incidence of cataract was higher in statin users in comparison with nonusers (odds ratio, 1.27; 95% CI, 1.15-1.40). Sensitivity analysis confirmed this relationship.

Conclusions and relevance: The risk for cataract is increased among statin users as compared with nonusers. The risk-benefit ratio of statin use, specifically for primary prevention, should be carefully weighed, and further studies are warranted.