Sarcoidosis in hospitalised patients in Western Australia: A long-term study on prevalence, comorbidity and mortality.

OBJECTIVE: To determine disease prevalence, comorbidity and mortality for hospitalised patients with sarcoidosis in Western Australia (WA). METHODS: A retrospective statewide cohort study of patients over 15 years of age hospitalised with sarcoidosis between 1980 and 2014. Sarcoidosis was identified based on validated ICD -9CM/ICD10-AM based algorithms with index admission treated as baseline. Period and point prevalence per 100.000 adult population and mortality rate (MR) per 100 person years were estimated with 95% confidence intervals (CI). Kaplan Meyer survival curves and other outcomes were compared with a comparator group of Rheumatoid Arthritis patients with interstitial lung disease (RA-ILD). Median values are given with interquartile range (IQR). RESULTS: We included 276 patients with sarcoidosis (index age 58 yrs IQR 46-69, 51.4 % females, invasive assessment in 68%) for a period prevalence of 21.1 (CI 18.7-23.7) and a 2015-point prevalence of 12.1 (CI 10.6-13.8). No specific risk factors were identified and extrapulmonary manifestations were recorded in 15%. During follow-up (3428-person years; median 11 years, IQR 5-19), patients with sarcoidosis were more likely to develop hypercalcemia (10.9 vs 4. 1%, p<0.01), new onset autoimmune rheumatic disease (9.3 vs 2.3%, p<0.01) and incident cancer (21.5 vs15%, p=0.07) and less likely to develop heart failure (18.5 vs 40%, p<0.01) than RA-ILD patients. In contrast to RA-ILD patients, age adjusted standardised MR was not increased for patients with sarcoidosis and respiratory causes of death significantly less frequent (p<0.01) Conclusion: The hospital-based prevalence of sarcoidosis in WA is higher than previously reported from Australia. Due to lower burden of comorbidity, the overall and respiratory prognosis for sarcoidosis is much better than for RA associated lung disease.