Rheumatoid arthritis continues to increase in low-middle SDI and low SDI quintiles based on GBD 1990–2021

Introduction: Age-standardized incidence rate (ASIR), age-standardized prevalence rate (ASPR), and age-standardized disability-adjusted life years (ASDR) of rheumatoid arthritis (RA) and their trends at the global, regional, and national levels were determined using data from the Global Burden of Disease (GBD) 2021 study. Methods: The burden of RA was investigated in relation to age, sex, and sociodemographic index (SDI), drawing upon data from the GBD 2021 study. The ASIR, ASPR, and ASDR at the global, regional, and national levels were extracted. The estimated annual percentage change (EAPC) in the ASIR, ASPR, and ASDR was calculated across all levels from 1990 to 2021, supplemented by cluster and frontier analyses. Results: In 2021, there were 17.92 million cases of RA globally, with the ASIR increasing from 10.42 to 11.8 cases per 100,000 individuals (EAPC of 0.49 [95% confidence interval: 0.46–0.52]) between 1990 and 2021. This considerable increase was evident across all age and sex groups, SDI quintiles, and GBD regions. The most pronounced increase was in the low-middle SDI quintile in the ASIR for RA between 1990 and 2021. Among 54 GBD regions, the most significant increase was observed in Andean Latin America and Equatorial Guinea. Conclusion: By 2021, the global burden of RA was largely concentrated in the low-middle and low SDI quintiles, especially in Andean Latin America and Northern Africa, with the burden continuing to grow.