Characteristics of Korean Patients with Polymyalgia Rheumatica: a Single Locomotive Pain Clinic Cohort Study

BACKGROUND: Polymyalgia rheumatica (PMR) is a common systemic inflammatory disease of the elderly; however, the clinical characteristics and therapeutic response of PMR in Korea have been rarely studied. METHODS: We reviewed the medical records of 54 Korean patients diagnosed with PMR between January 2009 and February 2017 in a locomotive pain clinic of one tertiary referral hospital. We analyzed epidemiologic and clinical characteristics, therapeutic responses, and prognostic factors for remission-failure at one-year after oral prednisolone treatment. RESULTS: In 54 patients with PMR, 32 (59.3%) were female. The average age at diagnosis was 65.0 ± 10.5 years. Duration of symptoms before diagnosis was 8.1 ± 8.6 months. All patients had shoulder pain (54 patients, 100.0%); 49 patients (90.7%) had hip girdle pain, while 19 patients (35.2%) had peripheral joint pain. Four patients (7.4%) were accompanied by the giant cell arteritis (GCA). There was no seasonal preference for symptom development. Only 19 patients were diagnosed with PMR at initial symptom presentation. At one-year follow-up after oral prednisolone treatment, the remission rate was 35.3% (12/34). Multivariate analysis showed that history of relapse (odds ratio, 6.81; 95% confidence interval, 1.035–44.804) was a significant predictor of remission-failure. CONCLUSION: The rate of remission (35.3%) after oral prednisolone treatment was similar to previous reports in western countries; and GCA is not a rare condition in Korean PMR patients. Misdiagnosis of PMR is common, and heightened consideration for PMR is needed in elderly patients who present inflammatory features of bilateral shoulder pain.