Author’s Name(s): Tina Felfeli, Laura Rosella, Sherif El-Defrawy, Efrem D. Mandelcorn, Jessica Widdifield

Author’s Disclosure Block: Tina Felfeli, none; Laura Rosella, none; Sherif El-Defrawy, none; Efrem D. Mandelcorn, none; Jessica Widdifield, none

Abstract Body
Purpose: To identify individuals with uveitis using health administrative data in Ontario and support surveillance to analyze evolving trends in epidemiology and care. Study Design: Retrospective, population-based study using Ontario health administrative data from 2000 to 2021. Methods: The study encompasses a 21-year period, allowing for a longitudinal analysis of uveitis trends. A cohort of 200,386 eligible patients was drawn from Ontario’s primary care electronic medical records, from which 1,020 individuals were selected for detailed chart review. Multiple case definitions were employed to assess the performance of administrative data for identifying uveitis cases. Annual age- and sex-standardized incidence and prevalence rates with 95% confidence intervals (CI) were determined using annual population denominators. Patient demographics, comorbidities, resource utilization, and temporal trends in incidence were analyzed. Furthermore, cases were classified as limited (≤3 months) or persistent (>3 months) uveitis. Results: The median age of identified uveitis patients was 55 years, with a higher prevalence of females (59.9%) and anterior uveitis (64%). The age- and sex-standardized prevalence ranged from 1,998.3 per 100,000 (95% CI: 1,989.1-2,007.5) in 2000 to 2,761.2 per 100,000(95% CI: 2,752.7-2,769.7)in 2021, representing a significant rise in the burden of uveitis over the past two decades. From 2000 to 2021, incidence rates declined, dropping from 184.4 per 100,000 (95% CI: 181.5-187.2) in 2000 to 109.2 per 100,000 (95% CI: 107.4-110.9) in 2021. Amongst the total of 289,031 limited and 41,482 persistent uveitis cases identified, 89-91% resided in urban areas. The incidence of uveitis in the 1-12 years old age group showed an upward trajectory in the limited cases, with 25.4 per 100,000(95% CI: 23.2-27.8)in 2021, respectively. Thecomorbidity burden wasmoderate-highin 86% of persistent versus 16% of limited uveitis cases.Notably, persistent uveitis cases had substantially higher resource utilization, with 97% falling in the moderate-high resource utilization bands (RUB, ranging from 0 for no utilization to 5 for very high expected utilization), compared to limited uveitis cases where 39% were in the moderate-high RUB. Conclusions: Administrative data case definitions offer a valid method for identifying uveitis cases for population-based epidemiology studies. Over the study period, incidence rates declined while prevalence rose, indicating an increasing burden of chronic uveitis. Persistent uveitis cases were associated with higher comorbidities and resource utilization. These findings emphasize the importance of ongoing efforts in uveitis diagnosis, and public health awareness to mitigate the impact of this eye condition on the population.