Incidence and prevalence of episcleritis and scleritis in Northern California

PURPOSE:: To evaluate the incidence and prevalence of episcleritis and scleritis in a large well-defined population in Northern California. METHODS:: Secondary analysis was performed on data from the Northern California Epidemiology of Uveitis Study. The patient database of a large regional health maintenance organization was searched for all patients who potentially experienced ocular inflammatory disease during the 12-month study period. Medical records were reviewed for all potential patients to confirm ocular inflammatory disease and specific diagnosis, establish the time of onset, and collect additional data. Age- and sex-stratified quarterly study population data were used to calculate incidence rates and prevalence ratios. RESULTS:: After reviewing 2011 possible cases, 297 new-onset cases of episcleritis, 39 prior-onset cases of episcleritis, 25 new-onset cases of scleritis, and 8 prior-onset cases of scleritis were confirmed. For episcleritis, the overall incidence was 41.0 per 100,000 person-years and an annual prevalence ratio of 52.6 per 100,000. The overall incidence of scleritis was 3.4 per 100,000 person-years and an annual prevalence ratio of 5.2 per 100,000 persons. For both episcleritis and scleritis, there was a statistically significant increase in eye disease in older patients (P = 0.05 and <0.001, respectively) and for women in comparison with men (P = 0.001 and <0.001, respectively). Patients with scleritis were older than those with episcleritis (P = 0.017). CONCLUSIONS:: This study found that patients with scleritis were older than those with episcleritis and that women had higher rates of both episcleritis and scleritis compared with what men had.