Epidemiology of Paget's disease of bone in South Korea.

Paget's disease of bone (PDB) is a chronic disorder characterized by abnormal bone remodeling, leading to enlarged and deformed bones, and commonly affecting older adults. The disease frequently involves the pelvis, skull, spine, and long bones. Despite significant geographical variations in PDB prevalence, data from Asian populations remain sparse. This study evaluates the incidence, skeletal distribution, comorbidities, and bisphosphonate use for PDB in South Korea from 2010 to 2020, using a retrospective analysis of the Korean Health Insurance Review and Assessment database. We identified 4252 patients diagnosed with PDB via ICD-10 codes (M880, M888, and M889) over the study period. The primary outcome measured was the incidence of PDB, stratified by sex and age, with secondary outcomes including anatomical site involvement, associated comorbidities, and bisphosphonate use. The mean age of patients was 56.3 ± 14.8 yr, with a mean prevalence of 1.20 per 100 000 and an age-adjusted incidence ranging from 0.38 to 1.26 per 100 000 person-years. The incidence of PDB decreased in men but showed a significant increase in women, especially after 2015. The spine (23.5%) and pelvis & femur (17.0%) were the most commonly affected sites. Gastritis and gastroesophageal reflux disease (91.6%), upper respiratory infections (78.9%), and endocrine disorders (69.5%) were frequent comorbidities. Despite the established efficacy of bisphosphonates in managing PDB, only 9.8% of patients received these treatments, predominantly etidronate (3.2%) and alendronate (2.2%). This study is the first comprehensive epidemiologic assessment of PDB in South Korea, highlighting a low but increasing incidence, particularly among women. The findings underscore the need for greater clinical awareness and more proactive management strategies, especially regarding the use of bisphosphonates to improve patient outcomes.