There has been an increase in global age-standardized prevalence and incidence rates of rheumatoid arthritis (RA), according to results of a systematic analysis published in the Annals of the Rheumatic Diseases. The analysis also indicated that rising rates of prevalence and incidence could contribute to the increased global burden of RA.

Using data from the Global Burden of Diseases, Injuries, and Risk Factors (GBD) 2017 study, researchers examined the trends in global, regional, and national prevalence, incidence, and associated disability-adjusted life years (DALYs) in patients with RA. No such global study has been published since 2010.

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The GBD 2017 study included 195 countries, 7 super regions, and 21 regions across the globe, from 1990 to 2017; data on 354 diseases and injuries, 282 causes of death, and 84 risk factors were systematically analyzed.

Results of the analysis indicated that there were 19,965,115 globally prevalent cases of RA in 2017 (95% uncertainty interval [UI], 17,990,489-21,995,673 cases), with an age-standardized prevalence rate of 246.6 cases/100,000 population (95% UI, 222.4-270.8 cases), which increased by 7.4% between 1990 and 2017.


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The trend for global age-standardized DALY rate decreased from 1990 to 2012, but increased and reached higher levels in the subsequent 5 years (2012-2017). At the global level, RA accounted for 3.4 million DALYs (95% UI, 2.6-4.4 million DALYs) with an age-standardized rate of 43.3 DALYs/100,000 population (95% UI, 33.0-54.5 DALYs). The age-standardized DALY rate decreased by 3.6% (95% UI, -9.7% to 0.3%) from 1990 to 2017.

At the regional level, age-standardized RA prevalence was highest in high-income North America, Western Europe, and the Caribbean (377.6, 346.8, and 338.9, respectively), whereas Southeast Asia, Oceania, and Western Sub-Saharan Africa had the lowest age-standardized rates (100.9, 135.3, and 135.7, respectively).

Age-standardized incidence rates were also highest in high-income North America (22.5), South Asia (20.7), and Western Europe (20.4); Southeast Asia (6.2), Oceania (7.9), and Western Sub-Saharan Africa (8.5) had the lowest rates.

Data from the analysis indicated that the percentage change in age-standardized prevalence rates between 1990 and 2017 was not similar across all GBD 2017 regions: East Asia, high-income North America, and Western Sub-Saharan Africa showed the most increasing significant trends (25%, 19%, and 14%, respectively) compared with Southern Sub-Saharan Africa, high-income Asia-Pacific, and Eastern Sub-Saharan Africa (-12%, -7%, and -5%), that showed decreasing significant trends.

Although the number of prevalent cases doubled from 1990 to 2017 (10,226,042 to 19,965,115), the contribution of the GBD 2017 regions was different.

At the national level, the age-standardized prevalence rate of RA ranged from 91 to 471 cases/100,000 population, with the highest age-standardized prevalence rates in the United Kingdom, Trinidad and Tobago, and Barbados (471.8, 404.4, and 402.6, respectively). Indonesia, Timor-Leste, and Sri Lanka had the lowest rates (91.1, 91.4, and 97.2, respectively). Age-standardized incidence rates ranged from 5.6 to 27.5 cases/100,000 population, with the highest incidence rates in the United Kingdom, Ireland, and Sweden.

Overall, the global age-standardized prevalence rate was higher in women, increasing with age and peaking between 70 to 74 years in men and 75 to 79 years in women in 2017.

Researchers noted a nonlinear association at the regional level between age-standardized DALY rate and sociodemographic index. Overall, they identified the lowest age-standardized DALY rate at a sociodemographic index level of 0.43, which they observed “increased and decreased intermittently with [sociodemographic index] improvement.”

Only high-income North America demonstrated an increase between 1990 and 2017. National-level analyses also identified a nonlinear association; study findings indicated that this association between age-standardized DALY rate, sociodemographic index, and high RA burden was not limited to the most- or less-developed countries.

“Increasing population awareness regarding RA, its risk factors, and the importance of early diagnosis and treatment with disease modifying agents is warranted to reduce the future burden of this condition,” the researchers concluded. “Improving health data for better monitoring of disease burden and health outcomes are strongly suggested.”

Reference

Safiri S, Kolahi AA, Hoy D, et al. Global, regional and national burden of rheumatoid arthritis 1990-2017: a systematic analysis of the Global Burden of Disease study 2017. Ann Rheum Dis. 2019;78:1463-1471.