Performance of the new 2012 EULAR/ACR classification criteria for polymyalgia rheumatica: comparison with the previous criteria in a single-centre study.

OBJECTIVE: To compare the performance of published classification/diagnostic criteria for polymyalgia rheumatica (PMR), including the new 2012 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) criteria, in a single-centre study.

METHODS: We studied all consecutive patients with new-onset PMR seen in our centre over 6 years, whose diagnosis was confirmed during a prospective 12-month follow-up period. Subjects were classified by each of the seven different criteria. Sensitivity and specificity were compared. Control population consisted of all consecutive patients aged ≥50 years seen in a 4-year period in our early arthritis clinic who had a 12-month confirmation of a diagnosis of rheumatoid arthritis (RA) or other inflammatory articular diseases.

RESULTS: Data were collected from 136 cases and 149 controls, including 94 patients with RA. The most sensitive criteria were the new 2012 EULAR/ACR classification criteria (92.6%). Adding ultrasound (US) specificity increased from 81.5% to 91.3% in total cases and from 79.7% to 89.9% in RA. Bird criteria had a sensitivity of 89.2% but the lowest specificity (40.2% in total cases and 72.5% in RA). Jones and Nobunaga criteria were the most specific criteria (96.7% and 97.8% in total cases and 98.6% and 99.5% in RA) but the less sensitive (63.1% and 58.2%) ones. Overall, discriminatory ability, as reflected by the area under the receiver operating characteristic curve, was better for the 2012 US EULAR/ACR criteria (0.920 in total cases and 0.910 in RA).

CONCLUSIONS: The new EULAR/ACR criteria in new-onset PMR patients perform best in discriminating PMR from RA and other inflammatory articular diseases. Ultrasound further increases the specificity of the criteria.