title: Prevalence of axial spondylarthritis in the United States: estimates from a cross-sectional survey.
abstract: OBJECTIVE
  The US national prevalence of spondylarthritis (SpA) was estimated for 2 published sets of classification criteria: the Amor criteria and the European Spondylarthropathy Study Group (ESSG) criteria. These 2 SpA criteria sets have been the most widely utilized in previous population-based studies of SpA.
  
  
  METHODS
  The US SpA prevalence estimates were based on a representative sample of 5,013 US adults ages 20-69 years who were examined in the US National Health and Nutrition Examination Survey (NHANES) 2009-2010.
  
  
  RESULTS
  The overall age-adjusted prevalence of definite and probable SpA by the Amor criteria was 0.9% (95% confidence interval [95% CI] 0.7-1.1%), corresponding to an estimated 1.7 million persons (95% CI 1.4-2.1 million persons). The age-adjusted prevalence of SpA by the ESSG criteria was 1.4% (95% CI 1.0-1.9%), corresponding to an estimated 2.7 million persons (95% CI 1.9-3.7 million persons). There were no statistically significant sex differences in SpA prevalence. The SpA prevalence among non-Hispanic white persons was 1.0% (95% CI 0.7-1.5%) by the Amor criteria and 1.5% (95% CI 1.0-2.3%) by the ESSG criteria. SpA prevalence could not be reliably estimated in other race/ethnicity subgroups due to sample size imitations.
  
  
  CONCLUSIONS
  The SpA prevalence estimates are in the range of SpA prevalence estimates reported elsewhere in population-based surveys and it is likely that SpA may affect up to 1% of US adults, a prevalence similar to that reported for rheumatoid arthritis. The current US SpA prevalence estimates may be lower than the true value because the NHANES 2009-2010 data collection did not capture a complete set of the elements specified in the 2 SpA criteria sets.
authors.affiliation: The University of Texas Health Science Center at Houston, TX, USA.
authors.forename: John D
authors.initials: JD
authors.lastname: Reveille
authors.forename: James P
authors.initials: JP
authors.lastname: Witter
authors.forename: Michael H
authors.initials: MH
authors.lastname: Weisman
mesh_terms: D000328:Adult; D000368:Aged; D001368:Axis, Cervical Vertebra; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D015995:Prevalence; D012189:Retrospective Studies; D025241:Spondylarthritis / Q000453:epidemiology* / Q000208:ethnology; D014481:United States / Q000453:epidemiology; D044465:White People / Q000208:ethnology