Background Polymyalgia rheumatica (PMR) is a chronic inflammatory disease affecting people older than 50 years. Diagnosis is made based on clinical features and the current standard of treatment is low-dose glucocorticoids. PMR is known to be more frequent in Caucasian ethnicity and females. But up to date, there has been a scant epidemiologic study of PMR in Asian countries including Korea.
Objectives We aimed to estimate incidence and prevalence rates of PMR and current treatment state in Korea.
Methods We performed nationwide retrospective review of PMR using the Korean National Health Insurance (NHI) and Health Insurance Review and Assessment (HIRA) database from 2007 to 2012. NHI is the sole public medical insurance system in Korea, which covers 100% of the Korean population and HIRA is a government incorporated organization to build an accurate claims review and quality assessment system for the NHI. We defined PMR cases by both diagnostic codes and medication codes simultaneously, in other words, by proper ICD code (M 35.3) and concurrent appropriate prescription codes (glucocorticoids).
Results We identified total 1,463 newly diagnosed cases of PMR for the 5 years. The annual incidence rate of PMR per 100,000 Korean individuals was estimated as 2.06 (1.45 in male, 2.59 in female), and the prevalence rate was 8.21 per 100,000 individuals in 2012 (5.60 in male, 10.42 in female). Among the 1,463 cases, 992 (67.8%) were female and 471 (32.2%) were male and the median age at the time of diagnosis was 67 years old. The incidence rate according to age appeared to increase with advancing age peaking 70 years old, as similar as previous reports of western studies. The most frequently prescribed agent was prednisolone, and the starting daily dosage of glucocorticoids as prednisolone equivalent was between 5 to 15 mg daily in 74.5% of the patients.
Conclusions This is the first study that evaluated epidemiologic data of PMR in Korea, and included population was the largest among those of studies published in East Asia so far. The incidence and prevalence rates of PMR are estimated considerably lower than that of Western populations. And this result supports that both genetic and environmental factor would play important roles in pathogenesis of PMR.
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Disclosure of Interest None declared