Study on sensitivity and specificity of diagnostic criteria for early rheumatoid arthritis

Abstract Sensitivity and specificity were compared among the American College of Rheumatology (ACR) 1987 classification criteria, the Yamasaki diagnostic criteria, and the Japan Rheumatism Association (JRA) diagnostic criteria for early rheumatoid arthritis (RA). The study included 90 patients who consulted our department for the first time within 1 year after onset and were suspected of having RA (final diagnosis: RA 45 cases, non-RA 45 cases). We investigated whether physical and laboratory findings at the first examination met these three sets of criteria to determine the sensitivity and specificity of each set of diagnostic criteria. Moreover, the sensitivity and specificity of each item in the diagnostic criteria set were similarly determined. The sensitivity of the ACR 1987 classification criteria, the Yamasaki diagnostic criteria, and the JRA diagnostic criteria for early RA were 71.1%, 88.9%, and 95.6%, respectively, and their specificities were 100%, 93.3%, and 77.8%, respectively. In a study on each diagnostic item, observation for 1 week was considered to be sufficient for morning stiffness, swelling in three joint areas, and symmetrical swelling, while observation for a more prolonged period seemed to be necessary for swelling of the finger and hand joints. The Yamasaki diagnostic criteria are appropriate for the diagnosis of early RA, while the JRA diagnostic criteria are suitable for screening.