Temporal trends in the prevalence of autoimmune diseases from 1990 to 2019.

Aim: To describe current situation and analyze temporal trends of prevalence for four autoimmune diseases including rheumatoid arthritis (RA), inflammatory bowel disease (IBD), multiple sclerosis (MS) and psoriasis, at the global, continental, and national levels.

Methods: The estimates and 95% uncertainty interval (UI) for age-standardized prevalence rate (ASPR) of RA, IBD, MS and psoriasis were obtained from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019. ASPR of RA, IBD, MS and psoriasis in 2019 was illustrated at the global, continental, and national levels. Joinpoint regression analysis was adopted to analyze the 1990-2019 temporal trends by calculating the annual percentage change (APC) and average APC (AAPC), as well as their 95% confidence interval (CI).

Results: In 2019, the global ASPR of RA, IBD, MS and psoriasis was 224.25 (95% UI: 204.94 to 245.99), 59.25 (95% UI: 52.78 to 66.47), 21.25 (95% UI: 18.52 to 23.91) and 503.62 (95% UI: 486.92 to 519.22), respectively, with ASPRs generally higher in Europe and America than in Africa and Asia. From 1990 to 2019, the global ASPR increased significantly for RA (AAPC = 0.27%, 95% CI: 0.24 to 0.30; P < 0.001) and decreased significantly for IBD (AAPC = -0.73%, 95% CI: -0.76 to -0.70; P < 0.001), MS (AAPC = -0.22%, 95% CI: -0.25 to -0.18; P < 0.001) and psoriasis (AAPC = -0.93%, 95% CI: -0.95 to -0.91; P < 0.001), with the most substantial changes occurring at different continents and periods. The trends of ASPR of these four autoimmune diseases varied significantly across 204 countries and territories.

Conclusions: There is a strong heterogeneity in prevalence (2019), as well as their temporal trends (1990-2019) of autoimmune diseases across the world, highlighting the strong distributive inequities of autoimmune diseases worldwide, which may be instructive for better understanding the epidemiology of these diseases, appropriately allocating the medical resources, as well as making relevant health policies.