Purpose Systemic diseases are frequently associated with uveitis but are often not recognised by clinicians. An estimate of the prevalence in a large-scale uveitis population is essential for understanding the epidemiological profile and may be helpful for clinical practice.

Design A nationwide survey.

Methods Data were obtained from a national database which included the registration of uveitis cases from 23 provinces, 5 autonomous regions and 4 municipalities across mainland China. The primary outcome was identification of a systemic disease associated with uveitis.

Results From April 2008 through August 2018, 15 373 uveitis patients were included in the study. Males accounted for 52.9%, and the mean (SD) age of uveitis onset was 35.4 (15.9) years. After standardisation for age, the prevalence of systemic disease among patients with uveitis was 30.8% (95% CI, 30.1% to 31.6%). Vogt-Koyanagi-Harada disease (VKH; age-standardised prevalence, 12.7%; 95% CI, 12.1% to 13.2%), Behçet’s disease (BD; 8.7%; 95% CI, 8.3% to 9.2%), ankylosing spondylitis (AS; 5.0%; 95% CI, 4.6% to 5.3%) and juvenile idiopathic arthritis (JIA; 1.2%; 95% CI, 1.0% to 1.3%) were the most common entities among 36 different forms of systemic diseases identified. The prevalence was significantly higher in males (37.0%; 95% CI, 36.0% to 38.1%) than in females (23.6%; 95% CI, 22.6% to 24.6%), and also higher in bilateral uveitis patients (41.2%; 95% CI, 40.2% to 42.2%) compared with unilateral cases (14.3%; 95% CI, 13.4% to 15.2%), and was highest in panuveitis (59.5%; 95% CI, 58.2% to 60.8%).

Conclusion Approximately one third of uveitis patients in this nationwide survey have an associated systemic disease, whereby VKH, BD, AS and JIA are the most frequent entities seen in China.