title: Primary Sjögren's syndrome as a systemic disease: a study of participants enrolled in an international Sjögren's syndrome registry.
abstract: OBJECTIVE
  To study the prevalence of extraglandular manifestations in primary Sjögren's syndrome (SS) among participants enrolled in the Sjögren's International Collaborative Clinical Alliance (SICCA) Registry.
  
  
  METHODS
  A total of 1,927 participants in the SICCA registry were studied, including 886 participants who met the 2002 American-European Consensus Group (AECG) criteria for primary SS, 830 "intermediate" cases who had some objective findings of primary SS but did not meet AECG criteria, and 211 control individuals. We studied the prevalence of immunologic and hematologic laboratory abnormalities, specific rheumatologic examination findings, and physician-confirmed thyroid, liver, and kidney disease, as well as lymphoma among SICCA participants.
  
  
  RESULTS
  Laboratory abnormalities, including hematologic abnormalities, hypergammaglobulinemia, and hypocomplementemia, frequently occurred among primary SS cases and were more common among the intermediate cases than among control participants. Cutaneous vasculitis and lymphadenopathy were also more common among primary SS cases. In contrast, the frequency of physician-confirmed diagnoses of thyroid, liver, and kidney disease and lymphoma was low and only primary biliary cirrhosis was associated with primary SS case status. Rheumatologic and neurologic symptoms were common among all SICCA participants, regardless of case status.
  
  
  CONCLUSIONS
  Data from the international SICCA registry support the systemic nature of primary SS, manifested primarily in terms of specific immunologic and hematologic abnormalities. The occurrence of other systemic disorders among this cohort is relatively uncommon. Previously reported associations may be more specific to select patient subgroups, such as those referred for evaluation of certain neurologic, rheumatologic, or other systemic manifestations.
authors.affiliation: Division of Rheumatology, University of California-San Francisco, 374 Parnassus Avenue, San Francisco, CA 94143, USA.
authors.forename: Arundathi S
authors.initials: AS
authors.lastname: Malladi
authors.forename: Kenneth E
authors.initials: KE
authors.lastname: Sack
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Shiboski
authors.forename: Caroline H
authors.initials: CH
authors.lastname: Shiboski
authors.forename: Alan N
authors.initials: AN
authors.lastname: Baer
authors.forename: Ratukondla
authors.initials: R
authors.lastname: Banushree
authors.forename: Yi
authors.initials: Y
authors.lastname: Dong
authors.forename: Pekka
authors.initials: P
authors.lastname: Helin
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Kirkham
authors.forename: Mengtao
authors.initials: M
authors.lastname: Li
authors.forename: Susumu
authors.initials: S
authors.lastname: Sugai
authors.forename: Hisanori
authors.initials: H
authors.lastname: Umehara
authors.forename: Frederick B
authors.initials: FB
authors.lastname: Vivino
authors.forename: Cristina F
authors.initials: CF
authors.lastname: Vollenweider
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.forename: John S
authors.initials: JS
authors.lastname: Greenspan
authors.forename: Troy E
authors.initials: TE
authors.lastname: Daniels
authors.forename: Lindsey A
authors.initials: LA
authors.lastname: Criswell
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000569:Americas / Q000453:epidemiology; D001208:Asia / Q000453:epidemiology; D015897:Comorbidity; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D006942:Hypergammaglobulinemia / Q000453:epidemiology*; D007390:International Agencies; D008206:Lymphatic Diseases / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012042:Registries; D012859:Sjogren's Syndrome / Q000453:epidemiology*; D014657:Vasculitis / Q000453:epidemiology*