Female hormonal therapy may promote noninfectious uveitis

Women exposed to hormonal therapy are at risk of developing noninfectious uveitis, although the risk increase is modest, according to a study.

The analysis included 217,653 women with female hormonal therapy (FHT) exposure and 928,408 matched women unexposed to the drugs. The mean age of the entire cohort was 50.5 years. The FHT and unexposed cohorts were followed for a median of 68 days after the index date, while the unexposed cohort was monitored for a median of 508 days.

In an analysis defining the primary outcome as a new diagnosis code for noninfectious uveitis followed by a second instance of a noninfectious uveitis code within 120 days, there were 158 events occurring over 161,762 years (rate, 0.0010) in the FHT cohort and 1,852 events over 1,887,935 years (rate, 0.0010) in the unexposed cohort. There was no significant between-group difference (hazard ratio [HR], 0.99, 95 percent confidence interval [CI], 0.83–1.17; p=0.87).

However, using the alternative outcome definition, which was a corticosteroid prescription or code for an ocular corticosteroid injection within 120 days of the uveitis diagnosis code, FHT exposure conferred a risk increase (HR, 1.21, 95 percent CI, 1.04–1.41; p=0.01).

When examined by anatomic subtype, anterior uveitis risk was substantially high in the exposed cohort (HR, 1.23, 95 percent CI, 1.05–1.45; p=0.01) for the alternative outcome definition but not for the primary outcome.

In an analysis stratified by age, women aged ≥45 years at the time of FHT prescription were more likely to develop uveitis (HR, 1.23, 95 percent CI, 1.03–1.47; p=0.03) according to the alternative outcome definition. Women aged ≤44 years at the time of prescription also showed a similar risk increase (HR, 1.22), although this association did not meet statistical significance (p=0.20).

The findings indicate that although exposure to FHT increases the risk of incident noninfectious uveitis when uveitis is defined on the basis of diagnostic codes and documentation of corticosteroid treatment, the absolute risk is low. This means that FHT is generally safe for most patients. Nevertheless, further investigation is needed.