Global Burden, Demographic and Geographic Disparities of Osteoarthritis by Joint Site Among Adults Aged 55 Years and Older, 1990–2021

Introduction: To assess global osteoarthritis (OA) burden trends (1990– 2021) in adults ≥ 55 years by joint type, sex, age, and SDI. Material and Methods: Using Global Burden of Disease (GBD) 2021 data from 204 countries, we analyzed Estimated Annual Percentage Change (EAPC) in age-Standardized Incidence (ASIR) and DALY rates via Joinpoint regression, stratified for knee, hip, hand, and other OA. Results: Global OA burden increased steadily. Overall EAPC was 0.21 (ASIR) and 0.33 (DALY). Knee OA had the highest burden (ASIR: 1045.52; DALY: 592.26/100,000), while hand OA grew fastest (ASIR EAPC: 0.43; DALY EAPC: 0.49). Women bore higher burden (ASIR: 1813.94 vs. men: 1354.57/100,000; DALY: 1262.98 vs. 891.58/100,000) with faster increases (EAPC 0.24 vs. 0.19). Incidence peaked at 55– 59 years among participants aged ≥ 55 years included in this study (1800.1 per 100,000); DALY peaked at ≥ 90 years (1589.7/100,000). High-SDI regions had highest burden (ASIR: 1873.28; DALY: 1277.17/100,000), but middle-SDI regions showed fastest growth (ASIR EAPC: 0.40; DALY EAPC: 0.56), notably in Southeast Asia (ASIR EAPC: 0.46; DALY EAPC: 0.63), East Asia (0.43; 0.64), and South Asia (0.36; 0.57). Conclusion: OA burden rises globally, with knee OA dominant but hand OA accelerating. Women and older adults face disproportionate impacts. Rapid growth in middle-SDI Asian regions underscores an urgent need for tailored interventions in modernizing aging populations. These findings highlight that joint-site, gender, age and socioeconomic stratifications should be fully integrated into global OA prevention frameworks. Developed regions should focus on long-term disability management for the oldest elderly, while emerging Asian economies require early screening and lifestyle modification strategies targeting middle-aged women and manual workers, which can effectively curb the future surge of OA-related disability. Keywords: osteoarthritis, epidemiology, global burden, age-standardized incidence rate, disability-adjusted life years (DALYs)