title: Clinical features of late-onset ankylosing spondylitis: comparison with early-onset disease.
abstract: OBJECTIVE
  Ankylosing spondylitis (AS) is generally observed in young patients but can occur later in life or in persons ≥ 50 years of age. Our objective was to characterize the clinical features of late-onset AS in a large multicenter national cohort.
  
  
  METHODS
  We studied late-onset AS in the National Registry of Spondyloarthritis of the Spanish Society of Rheumatology (REGISPONSER database) cohort (n = 1257), of whom 3.5% had onset at age ≥ 50 years versus a control group with onset at < 50 years.
  
  
  RESULTS
  There were no differences between late-onset and early-onset AS according to sex and family history of spondyloarthropathies. Patients in the late-onset group more often showed involvement of the cervical spine (22.7% vs 9.7%; p = 0.03) and arthritis of the upper (13.6% vs 3.0%; p = 0.002) and lower limbs (27.3% vs 15.2%; p = 0.03) as first manifestations than did patients in the early-onset group. A higher percentage of mixed forms (axial and peripheral joint disease) during the course of the disease was also recorded in the late-onset group (50% vs 24%; p = 0.0001).
  
  
  CONCLUSIONS
  Our study suggests that age at onset of AS affects the patients' presenting clinical form. Arthritis of the upper limbs requires a differential diagnosis with other conditions frequent in patients over 50 years of age, such as rheumatoid arthritis or crystal-induced arthropathy.
authors.affiliation: Services of Rheumatology of Hospital Clínico Universitario de Salamanca/IBSAL/RETICEF, Salamanca, Spain. montillamorales.carlos@gmail.com
authors.forename: Carlos
authors.initials: C
authors.lastname: Montilla
authors.forename: Javier
authors.initials: J
authors.lastname: Del Pino-Montes
authors.forename: Eduardo
authors.initials: E
authors.lastname: Collantes-Estevez
authors.forename: Pilar
authors.initials: P
authors.lastname: Font
authors.forename: Pedro
authors.initials: P
authors.lastname: Zarco
authors.forename: Juan
authors.initials: J
authors.lastname: Mulero
authors.forename: Jordi
authors.initials: J
authors.lastname: Gratacós
authors.forename: Carlos
authors.initials: C
authors.lastname: Rodríguez
authors.forename: Xavier
authors.initials: X
authors.lastname: Juanola
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Fernández-Sueiro
authors.forename: Raquel
authors.initials: R
authors.lastname: Almodovar
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D000375:Aging / Q000473:pathology / Q000502:physiology*; D015331:Cohort Studies; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007596:Joints / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012042:Registries / Q000706:statistics & numerical data; D013167:Spondylitis, Ankylosing / Q000473:pathology / Q000503:physiopathology*; D014605:Uveitis / Q000473:pathology / Q000503:physiopathology*