Comparative risk of blindness and vision-threatening ocular comorbidities in patients with Behcet's disease versus the general population.

OBJECTIVE: To compare the risk of blindness and vision-threatening ocular comorbidities in patients with Behcet's disease (BD) vs the general population. METHODS: Using 2002-2017 Korea National Health Insurance Service database, we did a population-based cohort study comparing newly diagnosed BD patients and age- and sex-matched non-BD controls at a 1:5 ratio. The primary outcome was blindness, defined as a best-corrected visual acuity of </=20/500 in the better-seeing eye. Secondary outcomes were vision-threatening ocular comorbidities (cataract, glaucoma and retinal disorders) that require surgical interventions and incident uveitis. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% CIs. We performed subgroup analyses by sex and BD diagnosis age. RESULTS: We included 31 228 BD patients and 156 140 controls. During a follow-up of 9.39 years, the incidence rate of blindness per 1000 person-years was 0.24 in BD and 0.02 in controls with an HR of 10.73 (95% CI 7.10, 16.22). The HR for secondary outcomes was 2.06 (95% CI 1.98, 2.15) for cataract surgery, 5.43 (4.57, 6.45) for glaucoma surgery and 2.71 (2.39, 3.07) for retinal surgery. The HR of incident uveitis was 6.19 (95% CI 5.83, 6.58). Males suffered a disproportionately higher risk of blindness than females due to greater severity rather than a lower incidence of uveitis. The risk of uveitis and blindness decreased as BD diagnosis age increased. CONCLUSIONS: In this large population-based cohort study, BD patients compared with the general population have a 10.73-fold risk of blindness in 10 years and also a substantially higher risk of diverse ocular comorbidities that pose potential threats to vision.