title: Secondary Sjogren's syndrome in systemic lupus erythematosus defines a distinct disease subset.
abstract: OBJECTIVE
  Sjögren's syndrome (SS) may occur in patients with systemic lupus erythematosus (SLE). We sought to determine whether the presence of SS in a large cohort of patients with SLE defines a subset with distinctive sociodemographic, clinical, and laboratory features.
  
  
  METHODS
  The Johns Hopkins Lupus Cohort was divided into 2 groups, based on the presence or absence of SS, defined by the presence of an objective measure of sicca or an abnormal minor salivary gland biopsy in a patient with sicca symptoms. These groups were compared with regard to sociodemographic, clinical, and laboratory features. Multivariable logistic regression was then performed to adjust the findings for potential sociodemographic, clinical, and laboratory confounders.
  
  
  RESULTS
  The 259 patients with SS (14% of the cohort), when compared with the 1531 patients without SS, were older at the time of SLE diagnosis and were more commonly women and white. Photosensitivity, oral ulcers, Raynaud's phenomenon, anti-Ro antibodies, and anti-La antibodies had a significant positive association while renal disease, anti-ribonucleoprotein (RNP) antibodies, and anti-dsDNA antibodies had a negative association with the presence of SS after adjustment for age (at last cohort visit), gender, ethnicity, and anti-Ro antibodies. The older age at diagnosis of SLE among the patients with SS did not remain a significant finding after adjustment for the age of the patient at last cohort visit.
  
  
  CONCLUSIONS
  The subset of patients with SLE and SS has a distinct clinical and laboratory phenotype, with a higher frequency of older white women with photosensitivity, oral ulcers, Raynaud's phenomenon, anti-Ro antibodies, and anti-La antibodies and a lower frequency of renal disease, anti-dsDNA antibodies, and anti-RNP antibodies.
authors.affiliation: Division of Rheumatology, Good Samaritan Hospital, Russell Morgan Building, Suite 508, 5601 Loch Raven Blvd., Baltimore, MD 21239, USA. alanbaer@jhmi.edu
authors.forename: Alan N
authors.initials: AN
authors.lastname: Baer
authors.forename: Janet W
authors.initials: JW
authors.lastname: Maynard
authors.forename: Fasil
authors.initials: F
authors.lastname: Shaikh
authors.forename: Laurence S
authors.initials: LS
authors.lastname: Magder
authors.forename: Michelle
authors.initials: M
authors.lastname: Petri
mesh_terms: D000328:Adult; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D006801:Humans; D016015:Logistic Models; D008180:Lupus Erythematosus, Systemic / Q000453:epidemiology* / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008396:Maryland / Q000453:epidemiology; D015999:Multivariate Analysis; D012859:Sjogren's Syndrome / Q000453:epidemiology* / Q000473:pathology / Q000503:physiopathology