Risk of Non-infectious Uveitis with Metformin Therapy in a Large Healthcare Claims Database

Purpose To determine if metformin is associated with noninfectious uveitis (NIU). Methods Patients in an insurance claims database who initiated metformin (n = 359,139) or other oral anti-diabetic medications (n = 162,847) were followed for NIU development. Both cohort and case-control analyses were performed to assess differing exposure lengths using Cox and conditional logistic regression, respectively. Results The hazard ratio (HR) for incident NIU was not significantly different between the metformin and non-metformin cohorts [HR = 1.19, 95% Confidence Interval (CI): 0.92-1.54, P = .19]. The case control analysis similarly showed no association between any metformin use 2 years before the outcome date and NIU [odds ratio (OR) = 0.64, 95% CI: 0.39-1.04, P = .07]. However, there was a protective 20 association between cumulative metformin duration [(445-729 days) adjusted OR (aOR) = 0.49, 95% CI: 0.27-0.90, P = .02] and dosage (>390,000 mg aOR = 0.44, 95% CI: 0.25-0.78, P = .001) compared with no metformin use. Conclusions Our results suggest metformin use for longer durations may be protective of NIU onset.