Developing classification criteria for polymyalgia rheumatica: Comparison of views from an expert panel and wider survey

Objective. This report summarizes the findings from a consensus process to identify potential classification criteria for polymyalgia rheumatica (PMR). Methods. A 3-stage hybrid consensus approach was used to develop potential PMR classification criteria. The first stage consisted of a facilitated meeting of 27 international experts who anonymously rated the importance of 68 potential criteria. The second stage involved a meeting of the experts, who were provided with the results of the first round of ratings and were then asked to re-rate the criteria. In the third stage, the wider acceptance of the 43 criteria that received > 50% support at round 2 was evaluated using an extended mailed survey of 111 rheumatologists and 53 nonrheumatologists in the United States, Canada, and Northern and Western Europe. Results. A total of 68 and 50 criteria were identified and rated in round 1 and round 2, respectively. In round 2, 43 of the 50 items achieved at least 50% support, including 10 core criteria achieving 100% support. In round 3, over 70% of survey respondents agreed on the importance of 7 core criteria. These were age ≥ 50 years, duration ≥ 2 weeks, bilateral shoulder and/or pelvic girdle aching, duration of morning stiffness > 45 min, elevated erythrocyte sedimentation rate, elevated C-reactive protein, and rapid steroid response (> 75% global response within 1 wk to prednisolone/prednisone 15-20 mg daily). Among physical signs, more than 70% of survey respondents agreed on the importance of assessing pain and limitation of shoulder (84%) and/or hip (76%) on motion, but agreement was low for peripheral signs like carpal tunnel, tenosynovitis, and peripheral arthritis. Conclusion. There are differences in opinion as to what PMR is and how it should be treated. These findings make it important to develop classification criteria for PMR. The next step is to perform an international prospective study to evaluate the utility of candidate classification criteria for PMR in patients presenting with the polymyalgic syndrome.