title: Main causes and risk factors for hospitalisation in patients with primary Sjögren's syndrome.
abstract: OBJECTIVE
  To identify the causes and risk factors for hospitalisation in primary Sjögren's syndrome (pSS).
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
authors: Department of Medicine, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.
authors: Yemil
authors: Y
authors: Atisha-Fregoso
authors: Department of Immunology and Rheumatology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.
authors: Yahaira
authors: Y
authors: Rivera-Vicencio
authors: Department of Immunology and Rheumatology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.
authors: Miguel
authors: M
authors: Baños-Pelaez
authors: Department of Immunology and Rheumatology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.
authors: Gabriela
authors: G
authors: Hernández-Molina
mesh_terms: D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D003141:Communicable Diseases / Q000175:diagnosis / Q000209:etiology* / Q000401:mortality; D018450:Disease Progression; D005260:Female; D006760:Hospitalization; D006801:Humans; D053208:Kaplan-Meier Estimate; D007902:Length of Stay; D016015:Logistic Models; D008297:Male; D008800:Mexico; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D065840:Protective Factors; D012189:Retrospective Studies; D012307:Risk Factors; D012859:Sjogren's Syndrome / Q000150:complications* / Q000175:diagnosis / Q000401:mortality; D013997:Time Factors