Main causes and risk factors for hospitalisation in patients with primary Sjögren's syndrome.

To identify the causes and risk factors for hospitalisation in primary Sjögren's syndrome (pSS).We included 170 pSS patients who regularly attended our Institution (2000-2013) and retrospectively collected demographic, clinical (glandular and extraglandular features) and serological (anti-Ro/SSA, anti-La/SSB, RF, low C3 or C4 and immunoglobulin levels) data. If they were hospitalised, a rheumatologist determined the primary cause. We registered the length of hospitalisation, need for Intensive Care Unit (ICU) admission, number of hospitalisations and death. The Disease Damage Index (SSDDI) (excluding the oral and ocular items) and the Charlson comorbidity Index were assessed. We used a logistic regression analysis and multiple imputation method for missing data.Fifty-five (32%) patients were hospitalised, representing 111 hospitalisations (28 patients had ≥1 hospital admission). The hospitalisation incidence density rate was 6.49/100 patient / years. The median length of hospital stay was 9 days (IQR 6-15), there were 7 ICU admissions and 6 deaths. The main causes of admissions were disease activity (33.3%) and infection (32.4%). At the multivariate analysis, the variables associated with hospitalisation were hepatic involvement (OR=5.4; 95% CI 1.61-18.15; p=0.006), vasculitis (OR=3.8; 95% CI 1.11-13.09; p=0.03), the SSDDI (OR=1.3; 95% CI 1.01-1.66; p=0.03) and the use of antimalarials (OR=0.08; 95% CI 0.02-0.22; p<0.001).The major causes for hospitalisation were disease activity and infection. Patients with hepatic involvement, vasculitis and more damage accrual had the highest risk for being hospitalised, while the use of antimalarials was protective.