Mortality and causes of death in patients with Sjögren disease in Western Australia: a population-based study

Abstract Objectives Sjögren disease (SjD) is a systemic autoimmune disorder with emerging evidence showing increased mortality rates compared to the general population. We compared mortality risk and causes of death in Western Australian (WA) SjD patients with age/sex-matched controls and general population mortality rates. Methods The WA Rheumatic Disease Epidemiological Registry (WARDER) was accessed in this data linkage study to identify patients with primary SjD, SjD associated with rheumatoid arthritis (SjD + RA) and SjD associated with other connective tissue disease (SjD + CTD) using ICD codes and age/sex matched controls (1:5) between 1980–2013. Mortality of SjD cohorts was compared with both age/sex-matched controls from WA and population mortality rates. Multiple cause of death and competing risk analysis was performed for SjD cohorts compared to controls. Results 3,716 controls (1,345 deaths) were compared with 457 primary SjD (204 deaths), 218 SjD + RA (149 deaths) and 77 SjD + CTD (38 deaths). Risk of mortality was increased in primary SjD (HR 1.8 (95% CI 1.5, 2.0)) and in associated SjD (SjD + RA: HR 2.1 (95% CI (1.8, 2.5)); SjD + CTD: HR 3.1 (95% CI 2.2, 4.3)) compared to controls. Survival in primary SjD was 77% (95% CI 0.63, 0.94) at the end of follow-up (25 years). Mortality risk in primary and associated SjD was increased due to infection, ischaemic heart disease, lymphoid malignancy and interstitial lung disease. Conclusions All-cause and specific-cause mortality was increased in primary and associated SjD compared to age/sex-matched controls in an Australian population.