Nationwide-incidence and trends of fibromyalgia in South Korea: a population-based study.

Reports of the incidence of fibromyalgia (FM) in Asia are uncommon. Therefore, this study used nationwide representative data to investigate the age- and sex-specific incidence and annual trends of FM in South Korea. This nationwide population-based study used data from the Korean National Health Claims Database. From 2012 to 2021, patients with FM diagnosed according to the ACR 2010 criteria from the entire Korean population aged 20-70 years were included in the enrolment database. Age- and sex-specific cumulative and annual incidences were analyzed and incident cases from 2014 to 2021 were included, considering the 2-year washout period. Among the total cohort of 42 million in the entire Korean population, 270,160 had FM during the study period. The incidence in the general population aged 20-70 years was 751.25 (95% confidence interval [CI] 751.10-751.40) per 100,000 persons (men: 95% CI 608.45-608.98; women: 95% CI 898.02-898.69). The incidence of FM increased with advancing age, peaking at 50-54 years both in men and women. The annual incidence was 88.07 (95% CI 88.02-88.13) in 2014; it increased from 2014 to 2019 and peaked in 2019 (109.20; 95% CI 101.65-101.76). The incidence of FM in South Korea was about twice the global average, with a gradual increase over the study period. These detailed estimates can help with proper planning within the healthcare system.