Objective: The European Spondylarthropathy Study Group (ESSG) criteria for the classification of spondyloarthropathies (SpA) were developed with the aim of unifying and facilitating international medical communication. We assessed the potential of ESSG criteria as a diagnostic aid for rheumatology practices in terms of sex and prevalence rate.

Methods: Data from 2 similarly designed and developed studies conducted in France and Spain were examined. Data were obtained from 3,494 patients seen at rheumatology outpatient services (28 in each country). The sensitivity and specificity of each ESSG criterion (except the radiological one) were assessed in terms of sex and country. Patients were divided into 4 groups according to number of criteria present at the time of the study: Group I had neither inflammatory spinal pain (ISP) nor synovitis; Group 2 had ISP and/or synovitis; Group 3 ISP and/or synovitis plus one additional criterion; Group 4 ISP and/or synovitis plus more than one additional criterion. The predictive value was determined by using different prevalence rates.

Results: A prevalence of 27.6% for male and 8.0% for female patients was found at Spanish services; prevalence in French services was 9.1% males and 3.2% females. No significant differences in sensitivity and specificity for each sex between French and Spanish individuals were detected; the overall sensitivity and specificity were similar for men and women. By contrast, there were differences between patients from the 2 countries regarding individual ESSG criteria; thus, inflammatory spinal pain and synovitis were less specific in the female and male Spanish patients, respectively, relative to the French patients.

Conclusion: ESSG criteria can be used meaningfully to aid diagnosis when the prevalence of SpA exceeds 10% and the patient meets more than one of the additional criteria, or when prevalence exceeds 30% and the patient meets only one additional criterion.