Hospitalisation rates among patients with primary Sjögren’s syndrome: a population-based study, 1995–2016

OBJECTIVE: To determine rates and primary discharge diagnoses of hospitalisation in a cohort of patients with incident primary Sjögren’s syndrome (pSS) compared with the general population. METHODS: This was a retrospective population-based cohort study focused on Olmsted County, Minnesota. The pSS cohort consisted of patients with incident pSS in the 1976–2015 period and was compared with a cohort of individuals without pSS matched 3:1 for age, sex and calendar year, randomly selected from the same population. Hospitalisations in 1995–2016 were examined. Discharge diagnoses were categorised using the Clinical Classifications Software for International Classification of Diseases, 9th revision, Clinical Modification. RESULTS: A total of 385 hospitalisations occurred in the 160 patients with pSS during 1592 person-years of follow-up. Among 466 comparators, there were 899 hospitalisations during 4660 person-years of follow-up, resulting in a significantly higher rate of hospitalisations in patients with pSS (rate ratio (RR): 1.25, 95% CI: 1.11 to 1.41). Rates of hospitalisation were increased among patients with pSS for endocrine, nutritional and metabolic diseases and immunity disorders (RR 1.82, 95% CI 1.08 to 2.98), diseases of the musculoskeletal system and connective tissue (RR 1.49, 95% CI 1.05 to 2.05) and for injuries and poisoning (RR 1.46, 95% CI 1.01 to 2.06). While not significantly increased overall, hospitalisations for diseases of the circulatory system were significantly increased in patients with pSS aged ≥75 years (RR 1.54, 95% CI 1.11 to 2.11). CONCLUSIONS: Patients with pSS experienced higher rates of hospitalisation than the general population. Hospitalisations for endocrine/metabolic disorders, diseases of the circulatory system, diseases of the musculoskeletal system and connective tissue disorders, and injuries were more common among patients with pSS than comparators.