Risk of Cataract and Its Association With Phototherapy Among Patients With Psoriasis

Psoriasis is a chronic inflammatory disease associated with multiple comorbidities, but its association with cataract remains unclear. We aimed to examine the risks of cataract and cataract surgery in psoriasis patients and the associations of ultraviolet phototherapy with these outcomes. Using the Taiwan National Health Insurance Research Database (2012–2023), we conducted a retrospective cohort study of patients with newly diagnosed psoriasis who were matched to non‐psoriasis controls by age, sex, and index year. Cox proportional hazards models were used to estimate hazard ratios (HRs) for cataract and cataract surgery. A nested case–control analysis was then performed among psoriasis patients who developed cataract or underwent cataract surgery, with matching to psoriasis patients without these outcomes. Conditional logistic regression was used to evaluate the associations of psoriasis‐related treatments, including phototherapy and systemic treatments, with cataract and cataract surgery. A total of 61 622 psoriasis patients and 61 622 matched controls were included. Psoriasis was associated with increased risks of cataract (adjusted HR, 1.32; 95% confidence interval [CI], 1.24–1.40) and cataract surgery (adjusted HR, 1.41; 95% CI, 1.30–1.53). These associations were generally consistent across subgroups stratified by age, sex, and psoriatic arthritis status. In the nested case–control analysis, both psoralen plus ultraviolet A (PUVA) (adjusted OR, 1.88) and ultraviolet B (UVB) phototherapy (adjusted OR, 1.22) were associated with increased odds of cataract, without a clear dose–response relationship. In contrast, systemic treatments, including biologics/Janus kinase inhibitors (adjusted OR, 0.49) and conventional disease‐modifying antirheumatic drugs (adjusted OR, 0.74) were associated with reduced odds of cataract. Similar findings were observed for cataract surgery. Psoriasis was associated with increased risks of cataract and cataract surgery. PUVA and UVB phototherapy were associated with higher odds of cataract and cataract surgery, whereas systemic treatments were associated with lower odds.