Risk of cataract in patients with multiple sclerosis: A population-based cohort study

Background: Patients with multiple sclerosis (MS) are at increased risk for ocular complications and are more often exposed to oral glucocorticoids (GCs) compared to the general population. The risk of cataract has not yet been determined in patients with MS. Objectives: To evaluate the risk of cataract in patients with MS compared to population-based controls. Methods: We conducted a prospective population-based cohort study utilizing the UK General Practice Research Database (GPRD) that was linked to the national hospital statistics of England (2001-2009). All incident MS patients (5,571 cases) were identified and matched by age, gender, and practice to 6 patients without MS (controls). Cox proportional hazard models were used to estimate the hazard ratio (HR) of cataract in MS. Time-dependent adjustments were made for age, gender, body mass index, smoking, history of diseases and drug use. Results: 1017 of all patients developed a cataract during follow- up. Compared to controls, MS patients had no increased risk of cataract: adjusted (adj.) HR 1.18 (95% CI 0.97-1.42). This risk increased to significance in patients exposed to GCs six month prior to cataract diagnosis: (adj.) HR 2.69 (95% CI 1.65-4.38). Risk of cataract was significantly larger in patients younger than 50 years: (adj.) HR 2.31 (95% CI 1.54-3.48). In particular men younger than 50 had a markedly higher risk of cataract than women: (adj.) HR men 4.21 (95% CI 2.39-7.42), (adj.) HR women 1.63 (95% CI 0.94-2.82). Conclusions: The risk of cataract was more pronounced in MS patients younger than 50 years, particularly in younger men. In addition, the risk of cataract was increased in MS patients on oral GC therapy.