Joevy Lim, Jo Sims, Rachael Niederer

Purpose: To investigate the aetiology of all-cause mortality in uveitis and scleritis.

Method: A retrospective, cross-sectional chart review study was conducted on 2732 subjects presenting with their first episode of uveitis or scleritis to a single-centre hospital between 2006 and 2020. The main outcome was the mortality status of each subject.

Results: Median age of onset of uveitis or scleritis was 45 years (interquartile range [IQR] 32.2-60.9). 49.6% of subjects were female. Idiopathic disease comprised 30.8% of subjects, followed by HLA-B27 in 20.0% and sarcoidosis in 4.7%. 7.2% (N = 196) were deceased at a median follow- up time of 8.0 years (IQR 4.0-11.6). Idiopathic disease was the most common aetiology in subjects that were deceased within one year of presentation (N = 5) and in premature deaths <65 years (N = 11). Mortality peaked in the first seven years following diagnosis, then sharply declines. When adjusted for age, gender and ethnicity, the following aetiologies demonstrated a higher risk of mortality when compared to HLA-B27 (hazard ratio, p-value): intraocular tumours (64.9, p < 0.001), GPA/ANCA positive vasculitis (10.8, p < 0.001), toxoplasmosis (3.8, p = 0.012), sarcoidosis (3.8, p = 0.031), HZV (2.5, p = 0.035), idiopathic (2.2, p = 0.047) and other aetiologies (2.7, p = 0.012). Conclusions: Idiopathic disease remains the most com- mon aetiology of uveitis. In our study, idiopathic uveitis was the most common aetiology in those deceased within the first year and in premature deaths. This study demonstrates the importance of careful systemic evaluation in patients presenting with the first episode of uveitis or scleritis. Repeating select investigations should be considered in those with idiopathic disease.