Global, regional and national burden of rheumatoid arthritis from 1990 to 2021, with projections of incidence to 2050: a systematic and comprehensive analysis of the Global Burden of Disease study 2021

To provide insights into rheumatoid arthritis (RA) epidemiological trends, including prevalence, incidence, disability-adjusted life years (DALYs), corresponding average annual percentage change (AAPC), gender disparities, regional variations, age-specific rates, socio-economic correlations, risk factors, and future projections.

Data were extracted from the Global Burden of Disease Study (GBD) 2021. AAPC was calculated by joinpoint regression and two-sample Mendelian randomization (MR) analysis was performed to verify the causal relationship between the smoking factor and RA. The future incidence trend was predicted by the Bayesian age-period-cohort (BAPC) model.