Global burden and inequalities of rheumatoid arthritis in adults aged 15-49 years from 1990 to 2021 and projections to 2050: a cross-sectional analysis from Global Burden of Disease Study 2021.

OBJECTIVE

Given that rheumatoid arthritis (RA) in working-age adults poses rising global health and economic challenges, we assessed the global, regional, and national burden of RA among adults aged 15-49 years from 1990 to 2021 and projected trends to 2050.

METHODS

We analyzed Global Burden of Disease 2021 data from 204 countries. Age-standardized rates of RA incidence, prevalence, and disability-adjusted life-years (DALYs) were calculated. Decomposition analysis quantified contributions of population growth, aging, and epidemiological changes. Frontier analysis identified best-performing countries. Bayesian age-period-cohort models projected trends to 2050.

RESULTS

Global RA prevalence among 15-49-year-olds increased 87.7% from 3.23 million cases (95% UI: 2.59-3.95 million) in 1990 to 6.07 million (4.90-7.36 million) in 2021. Age-standardized prevalence rose 29% (119.20 to 153.73 per 100,000). Women experienced 2.8-fold higher rates than men (228.3 vs 81.0 per 100,000). High Socio-demographic Index (SDI) countries showed triple the prevalence of low SDI countries (209 vs 65 per 100,000). Latin America recorded the highest regional rates (Andean: 420.7 per 100,000). Population growth accounted for 68% of case increases, with epidemiological changes contributing 24%. Smoking-attributable burden declined from 8.8% to 6.5% of DALYs. Projected cases will reach 7.48 million by 2050 (26.8% increase).

CONCLUSION

RA burden among working-age adults has nearly doubled since 1990, with persistent inequities by sex and development level. The projected increase to 7.48 million cases by 2050 demands urgent global action, including integrating RA into chronic disease programs and expanding early diagnosis access. Key Points • RA cases in working-age adults nearly doubled from 3.23 to 6.07 million (1990-2021) • Women experience 2.8-fold higher RA rates and comprise 73% of all cases • High SDI countries show triple the prevalence of low SDI countries • Projected a 26.8% increase to 7.48 million cases by 2050 without intervention.