Higher risk of dementia in primary Sjogren's syndrome.

OBJECTIVE: We studied the risk of dementia in patients with primary Sjogren's syndrome (pSS) using a nationwide, population-based cohort in Taiwan. METHODS: Our study analyzed the medical data of the Taiwanese population from 2000 to 2014. We identified 17,072 patients with pSS and 68,270 controls. Dementia risk was analyzed using a Cox proportional hazards regression model stratified by sex, age, and comorbidities. RESULTS: A higher incidence of dementia development in the pSS group during the observation period (P = 0.0001). In multivariate analysis adjusted by age groups, gender, and the comorbidities, the adjusted hazard ratio (aHR) of developing dementia was 1.246 (95% CI 1.123-1.384) times greater in the pSS group than in the non-pSS group. When stratified by sex, age, and comorbidities, the patients with pSS less than 60 years (aHR 1.67, 95% CI 1.16-2.41), and without any comorbidity (aHR 2.27, 95% CI 1.76-2.93) were particularly associated with a higher risk of dementia. Furthermore, the patients with pSS combined with any other comorbidity had an additionally higher risk of dementia (aHR: 3.978, 95% CI 3.309-4.782), also suggesting that pSS was an independent risk factor for the development of dementia. INTERPRETATION: Primary Sjogren's syndrome is associated with increased dementia risk and further study is needed to understand why and what the specific dementia phenotypes are.