AB1274 ADULT-ONSET STILL’S DISEASE IN WESTERN AUSTRALIA: EPIDEMIOLOGY, COMORBIDITY AND LONG-TERM OUTCOME

BackgroundAdult-onset Stills disease (AOSD) is a rare, potentially life-threatening autoinflammatory condition for which the reported prevalence shows regional variation and where comparative long-term outcome data are scarce (1).ObjectivesTo investigate annual incidence and point prevalence of AOSD in Western Australia (WA) and compare long-term health-related outcomes between AOSD patients and hospital-based controls.MethodsPopulation-based cohort study using longitudinally linked administrative health data from all hospitals in WA between 1999 and 2013. ASD patients (ICD-10-AM code M06.1) were matched to controls for age and gender. Rate and odds ratios (RR/OR) with 95% confidence intervals (CI) were used to compare ASD patients and controls for serious infections (SI), osteoporosis, joint replacement and the modified Charlson Comorbidity (mCCI).ResultsIn total 52 patients had incident AOSD for an average period incidence of 0.22/100,000 and a point prevalence of 2.4 /100.000 (per 30/12/2013). Compared to controls, ASD patients (median age 41.5 years, 59.6% females) had higher odds of prior liver disease (OR 2.67, 95%CI: 1.31-5.45), fever (OR 54.1, 95%CI: 6.6-43), rash (OR 15.7, 95%CI: 4.08-60.8) and SI (OR 4.36, 95%CI: 2.11-22.8). During 49 months of follow up, crude mortality (11.5% vs 7.5%; p=0.34), survival at one and five years (p=0.78) and m-CCI score at last observation (median 2 vs 2) were similar for ASD patients and controls. However, the odds for subsequent joint replacement (in 7 patients; 13.5%) (OR 45.5, 95%CI: 4.57-93), osteoporosis (OR 31.3, 95%CI: 3.43-97) and SI (RR 5.68, 95%CI: 6.61-8.74) were significantly higher in ASD patients.ConclusionThe epidemiology and demographics of AOSD in Western Australia fall within the internationally reported range. Compared to controls, AOSD patients presented higher rates of liver disease, rash and SI before disease onset. Mortality following AOSD was not increased for five years despite high rates of chronic arthritis requiring joint replacement, SI, and osteoporosis.References[1]Tomaras, S.; Goetzke, C.C.; Kallinich, T.; Feist, E. Adult-Onset Still’s Disease: Clinical Aspects and Therapeutic Approach. J. Clin. Med.2021, 10, 733.AcknowledgementsSupported by a grant from the Arthritis Foundation of Western AustraliaDisclosure of InterestsNone declared