56-year trends and disparities in systemic sclerosis mortality in the United States, 1968–2023: a retrospective population-based study

Objectives To describe long-term U.S. trends in systemic sclerosis (SSc) mortality and disparities by sex, race, region, and age. Methods This was a retrospective population-based mortality study using CDC WONDER data from 1968 to 2023. We identified deaths with SSc as the underlying cause of death (UCD) and calculated annual age-adjusted mortality rates (AAMRs) per 1,000,000 population standardized to the 2000 U.S. standard population. Joinpoint regression estimated annual percent change (APC) and average annual percent change (AAPC). Sensitivity analyses used multiple cause of death (MCOD) data (1999-2023). Results Among 55,567 SSc-UCD deaths, the annual number increased from 466 in 1968 to 1,005 in 2023. The national AAMR rose from 2.66 (1968) to 4.87 (2001) and declined to 2.37 (2023). Joinpoints occurred in 1987, 2001, and 2013, the steepest decline followed 2013 (APC -4.07%), with an overall AAPC of -0.44%. Female AAMR exceeded male AAMR throughout (female-to-male from 2.0 to 3.6), and mortality declined more in males than females (AAPC -1.08% vs -0.02%). Black/African American individuals had higher AAMR than White individuals but a larger net decline (AAPC -0.80% vs -0.33%). Mortality increasingly concentrated in adults aged ≥65 years, who showed a net increase over 1968-2023 (AAPC 1.07%). Across U.S. Census regions, mortality peaked in the early 2000s and declined thereafter, with broadly similar post-peak trajectories. In MCOD sensitivity analyses, AAMRs declined overall from 7.06 to 3.79 during 1999–2023 (AAPC -2.45%), although the most recent MCOD segment did not show a statistically significant decline. Conclusion Despite the observed long-term decline in SSc-UCD mortality, deaths remained unevenly distributed by sex, race, and age. These findings support risk-stratified follow-up and closer monitoring of older adults, women, Black/African American patients, and other patients at elevated risk.