This prospective study aimed to evaluate the diagnostic performance of the 2012 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria for polymyalgia rheumatica (PMR) compared to that of previous classification/diagnostic criteria in the Korean population.
We consecutively included 77 patients aged ≥50 years presenting with bilateral shoulder pain and elevated acute-phase reactants. All patients were evaluated for fulfillment of each of the 5 different criteria for PMR (Chuang et al, Bird, Jones and Hazleman, Healey, and the EULAR/ACR criteria). At baseline, bilateral ultrasound (US) examinations of the shoulders and hips were performed. Final diagnosis was made by an experienced rheumatologist at the 12-month follow-up. The area under the curve (AUC), sensitivity, and specificity of criteria sets were assessed.
At the end of follow-up, 38 and 39 patients were diagnosed with PMR and non-PMR including rheumatoid arthritis (RA, n = 20), respectively. The EULAR/ACR classification criteria with US showed the best discriminating capacity (AUC 0.843). Adding US to EULAR/ACR criteria increased specificity from 74.4% to 89.7%, but decreased sensitivity from 89.5% to 78.9%. The two US items of the EULAR/ACR criteria were significantly more frequent in patients with PMR than in controls. However, the second criterion consisting of both shoulders inflamed were similar between PMR (60.5%) and RA (60.0%) groups.
The 2012 EULAR/ACR classification criteria for PMR performed best in classifying PMR from other inflammatory and non-inflammatory disorders with shoulder pain in Asian populations.