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How Are Global Trends in Rheumatoid Arthritis Evolving?
Rheumatoid arthritis (RA) disease burden increased globally from 1980 to 2021, with significant disparities. Local administrative units in the UK and Mexico had the highest rates of incidence and disability-adjusted life years (DALYs), respectively, in 2021.
METHODOLOGY:
Researchers analyzed RA data from the largest spatiotemporal dataset — the Global Burden of Disease 2021 report — covering 953 global to local locations from 1980 to 2021.
They sourced data on incidence, prevalence, mortality, DALYs, years of life lost, and years lived with disability and applied spatiotemporal smoothing methods to address data gaps.
The modified iTransformer model, a deep learning algorithm, used data from a 13-year historical period (1990-2002) to fit and forecast outcomes over the following 19 years (2003-2021). Long-term burdens were forecasted until 2040 using the current trend as a reference.
TAKEAWAY:
The global burden of RA increased, with a 13.2% increase in age-standardized incidence from 1990 to 2021. Western Europe and North America had higher incidence, and local administrative units in the UK and Mexico showed the highest age-standardized incidence and DALY rates, respectively.
RA incidence was highest globally among individuals older than 55 years, but after 2015, trends shifted toward younger age groups, particularly in areas with a high sociodemographic index. Despite its high sociodemographic index, Japan showed declining DALY rates, whereas DALY rates increased in the UK.
The age-standardized death rate for RA decreased by 32.7% from 1980 to 2021, whereas DALY rates increased twofold, with individuals older than 55 years having the highest rates.
Between 1990 and 2021, most countries and regions drifted further away from the ideal disease burden line for both incidence and DALY rates. Population growth, aging, and changes in epidemiology have all led to a rise in the incidence and prevalence of RA worldwide, with aging and population growth influencing variably at the national level.
Forecasts indicate that by 2040, regions with a high medium-to-low sociodemographic index may see increasing age-standardized DALY rates, whereas areas with a high sociodemographic index may experience a decrease.
IN PRACTICE:
'[The study] provides robust evidence for global to local policymakers and stakeholders to formulate interventions and allocate resources effectively, mitigating RA impacts for their populations,' the study authors wrote.
SOURCE:
This study was led by Wenyi Jin of Renmin Hospital of Wuhan University, Wuhan; Qian Wang of Peking Union Medical College Hospital, Beijing; and Cheng Jin of Shenzhen Children's Hospital, Shenzhen, all in China. It was published online on June 16, 2025, in Annals of the Rheumatic Diseases .
LIMITATIONS:
Data quality limitations, along with possible underdiagnosis and underreporting in resource-limited areas, may have led to an underestimated burden of RA. Data were available only from 1990 onward for certain countries and excluded individuals younger than 20 years because of insufficient data on risk factors. The analysis did not consider heterogeneity in healthcare infrastructure, which could introduce confounding effects.
DISCLOSURES:
This study was supported by the World Health Organization and the Bill & Melinda Gates Foundation. The authors declared having no conflicts of interest.
