Selective serotonin reuptake inhibitors and the risk of cataracts: a nested case-control study

Objective: Older-generation antidepressants have been associated with increasing the risk of cataracts. Although animal studies have alluded to a potential link between selective serotonin reuptake inhibitors (SSRIs) and the development of cataracts, no large population based-study has addressed this potential association. This study sought to quantify the risk of cataracts with SSRIs by conducting a pharmacoepidemiologic study using the linked administrative databases in the province of Quebec, Canada.

Design: Nested case-control study.

Participants: A cohort of subjects who had received a coronary revascularization procedure from 1995 through 2004 in the province of Quebec, Canada.

Methods: Using an administrative data set, a case-control study was conducted within a cohort of Quebec residents who had received a coronary revascularization procedure from 1995 through 2004. Cases were defined as those with the first diagnosis of a cataract diagnosed by an ophthalmologist. For each case, 10 controls were selected and matched to the cases by index date, age, and cohort entry. Crude and adjusted rate ratios (RRs) and corresponding confidence intervals (CIs) were computed for current use of SSRIs. Rate ratios were adjusted for gender, corticosteroid use, statins, high blood pressure, antihypertensives, and antidiabetics.

Main outcome measures: First International Classification for Disease (Ninth Revision) code for a cataract diagnosed by an ophthalmologist.

Results: Eighteen thousand seven hundred eighty-four cases and 187 840 controls met our study inclusion criteria. The adjusted RR for cataracts among current users of SSRIs was 1.15 (95% CI, 1.08-1.23). The risk of cataracts was highest with fluvoxamine (RR, 1.39; 95% CI, 1.07-1.80), followed by venlafaxine (RR, 1.33; 95% CI, 1.14-1.55) and paroxetine for cataract surgery (RR, 1.23; 95% CI, 1.05-1.45). The average time to diagnosis of cataracts while on SSRI therapy was 656 days.

Conclusions: A possible association was found between current exposure to SSRIs, especially fluvoxamine and venlafaxine, and a future diagnosis of cataracts. The possibility that this observation may be the result of the effect of smoking, which could not be controlled for in the study, cannot be excluded. Future studies are needed to confirm this association in other populations.