Self-reported Diagnosis of Rheumatoid Arthritis or Ankylosing Spondylitis Has Low Accuracy: Data from the Nord-Trøndelag Health Study

J Rheumatol. 2017 Aug;44(8):1134-1141. doi: 10.3899/jrheum.161396. Epub 2017 Apr 15.

Abstract

Objective: Self-reported diagnoses of inflammatory arthritis are not accurate. The primary study aim was to ascertain self-reported diagnoses of rheumatoid arthritis (RA) and ankylosing spondylitis (AS) in the Norwegian population-based Nord-Trøndelag Health Study (HUNT) using hospital case files. The secondary aim was to provide updated estimates of the prevalence and incidence of RA and AS.

Methods: All inhabitants ≥ 20 years old from the county of Nord-Trøndelag were invited. Data from 70,805 unique participants from HUNT2 (1995-1997) and HUNT3 (2006-2008) were included. For participants who self-reported RA or AS, case files from all 3 hospitals in the catchment area were evaluated using standardized diagnostic criteria.

Results: Of 2703 self-reported cases of RA, 19.1% were verified in hospital files. Of 1064 self-reported cases of AS, 15.8% were verified. Of 259 cases self-reporting both RA and AS, 8.1% had RA and 5.4% had AS. Overall, a self-report of 1 or both diagnoses could not be verified in 82.1%, including 22.8% with insufficient information or no case file. The prevalence of RA was 768 (95% CI 705-835) per 100,000. The incidence of RA from HUNT2 to HUNT3 was 0.48 (0.41-0.56) per 1000 per year. The prevalence of AS was 264 (228-305) per 100,000. The incidence of AS from HUNT2 to HUNT3 was 0.19 (0.15-0.24) per 1000 per year.

Conclusion: Self-reported diagnoses of RA and AS are often false-positive. The prevalence and incidence of RA were comparable to reports from similar populations. The incidence of AS was higher than previously reported in a mixed population from Norway.

Keywords: ANKYLOSING SPONDYLITIS; EPIDEMIOLOGY; RHEUMATOID ARTHRITIS.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Arthritis, Rheumatoid / diagnosis*
  • Arthritis, Rheumatoid / epidemiology
  • Diagnostic Self Evaluation
  • Female
  • Health Surveys
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Norway / epidemiology
  • Prevalence
  • Self Report*
  • Spondylitis, Ankylosing / diagnosis*
  • Spondylitis, Ankylosing / epidemiology