Temporal Trends and Cross-Country Inequalities in the Burden of Osteoarthritis, 1990-2021: Findings From the Global Burden of Disease Study 2021.

AIM: This study aimed to assess the long-term trends in cross-country inequalities related to the burden of osteoarthritis from 1990 to 2021.

METHODS

Data on osteoarthritis incidence, prevalence, years lived with disability, and sociodemographic index (SDI) were extracted from the Global Burden of Diseases Study 2021. Slope index of inequality and concentration index were calculated to quantify the absolute and relative cross-country inequalities in osteoarthritis burden. Joinpoint regression was used to measure the average annual percentage change. Decomposition analysis was applied to quantify the contributions of population growth, population aging, and epidemiological changes to changes in osteoarthritis burden.

RESULTS

Globally, more than 600 million people had osteoarthritis in 2021, with an increase of 137.03% since 1990. Significant absolute and relative SDI-related inequalities in osteoarthritis burden were observed across 204 countries/territories, with the burden disproportionately concentrated among countries/territories with higher SDI rankings. The slope index of inequality for all-age osteoarthritis prevalence rose from 5759.73 to 11151.93, while the concentration index increased from 0.26 to 0.28 from 1990 to 2021. Sensitivity analyses using age-standardized rates showed that the direction of inequality remained unchanged, whereas the increasing trend was attenuated for total osteoarthritis and persisted for knee osteoarthritis and other types of osteoarthritis. Population growth was the largest contributor to the increase in osteoarthritis burden, and population aging became the second-largest contributor globally after 2011.

CONCLUSIONS

Osteoarthritis is a growing health problem with widening cross-country inequalities, suggesting an urgent need to adopt specific measures according to different levels of sociodemographic development.