Prevalence and Incidence of Uveitis: A Systematic Review and Meta-analysis

<b>Background</b>: Although the impact of uveitis on people’s lives is clear, the frequency of this condition is unclear.<b>Objective</b>: To estimate the prevalence and incidence of uveitis.<b>Methods</b>: A systematic review with meta-analysis was conducted. Medline, Embase, and Cochrane Library were searched from inception to January 2019. The quality of the included studies was critically appraised with a grading system based on the Oxford Levels of Evidence. A detailed description of the populations studied and of factors affecting estimates was undertaken. Pooled analyses were conducted using a random-effects approach and expressed as incidence rates per 100,000 with 95% confidence intervals. Subgroup analyses by geographical region were conducted along with meta-regression to analyze possible factors for heterogeneity.<b>Results</b>: A total of 49 studies were included and critically appraised. Twenty-two were population-based, and 27 hospital-based. Heterogeneity was substantial in terms of populations studied, methods for ascertaining uveitis, including definitions, and reporting of results. This was especially important in prevalence studies, with data ranging from 9 to 730 cases per 100,000. For incidence studies, the meta-analysis yielded a pooled incidence of 50.45 per 100.000. The meta-regression showed the geographic region as an important explanatory factor of the heterogeneity between studies.<b>Conclusion</b>: Population-based estimates of the epidemiology of uveitis vary widely, owing to methodologies employed, definitions of uveitis and geographical regions; the representativeness and generalizability of many epidemiological studies of uveitis are limited.