Clinical characteristics and prognostic factors for relapse in patients with polymyalgia rheumatica (PMR)

Polymyalgia rheumatica (PMR) is a common inflammatory disease of the elderly in western countries, but the prevalence is apparently different between races and countries. Until now, an epidemiologic study of PMR is limited in Korea. We retrospectively evaluated the clinical data of 78 patients with PMR who were treated in 5 tertiary hospitals, and analyzed initial laboratory data, symptoms, therapeutic responses, and prognostic factors for relapse 1 year after treatments. Sixty percent of patients had pain in both shoulder and hip girdles with 10.6 weeks of duration, 75.9 ± 32.7 mm/h of erythrocyte sedimentation rate (ESR), and 6.2 ± 6.4 mg/dl of C-reactive protein. The rate of relapse and remission at 1 year was 38.4 and 2.5 %, respectively. The rate of overall relapse was 46.1 %, and the relapse occurred mostly in a year, especially between 6 and 12 months after diagnosis. There were more female in relapse group (88.9 %, p = 0.037), and cumulative steroid dose of 1 year was significantly higher in relapse group (5.5 ± 2.7 vs. 4.4 ± 2.5 g, p = 0.018). Independent risk factors for relapse were initial CRP ≥ 2.5 mg/dl (OR 6.296, p = 0.047) and the use of hydroxychloroquine (OR 6.798, p = 0.035). Initial dosage or tapering speed of steroid did not influence on prognosis. In Korean patients with PMR, baseline clinical characteristics and relapse rate were similar to previous studies, but our patients accompanied no giant cell arteritis and showed lower remission rate as well as delayed therapeutic response and later occurrence of relapse. More aggressive management would be needed according to the clinical status of patients.