Shifting mortality profiles in rheumatoid arthritis in the United States, 1999–2024: a multiple-cause-of-death study

Background Analyses restricted to rheumatoid arthritis (RA) as the underlying cause of death may incompletely characterize mortality involving RA. We examined population-based mortality trends and underlying-cause distributions among U.S. deaths mentioning RA. Methods We conducted a repeated cross-sectional study using CDC WONDER Multiple Cause of Death data for 1999–2024. Deaths were classified as any mention of RA (RA-AM), RA as the underlying cause (RA-UCD), or RA recorded with another condition as the underlying cause (RA-nonUCD). Age-adjusted mortality rates (AAMRs) were standardized to the 2000 U.S. population and expressed per million population. Trends were assessed using joinpoint regression. Results Among 244,813 deaths mentioning RA, 184,537 were RA-nonUCD. The RA-nonUCD proportion increased from 72.60% in 1999 to 82.03% in 2024. AAMRs declined from 36.67 to 23.16 for RA-AM, 10.07 to 4.13 for RA-UCD, and 26.62 to 19.01 for RA-nonUCD, with average annual percentage changes of −1.79%, −3.62%, and −1.39%, respectively. Among RA-nonUCD deaths, circulatory diseases remained the leading underlying cause, although their share declined from 46.75% to 30.05%. Within this category, the ischemic heart disease share decreased from 54.68% to 38.33%. The shares attributed to endocrine, nutritional and metabolic diseases, mental and behavioral disorders, and diseases of the nervous system increased from 4.47% to 7.77%, 1.38% to 4.72%, and 2.93% to 7.89%, respectively. Cancer and respiratory diseases ranked second and third by cumulative death counts. Conclusions Population-based age-adjusted mortality rates involving RA declined during 1999–2024, with the largest relative decline observed when RA was the underlying cause. RA-nonUCD accounted for an increasing proportion of deaths mentioning RA. Within this group, circulatory diseases remained the leading underlying cause, while the proportions attributed to endocrine, nutritional and metabolic diseases, mental and behavioral disorders, and diseases of the nervous system increased.