Background/Purpose: Systemic sclerosis (SSc) is more common in women than men, but men tend to have a faster disease progression than women. However, conflicting results with regards to sex differences in SSc mortality have been reported. A few studies found standardized mortality ratios for SSc to be similar between men and women, whereas others found SSc standardized mortality ratios to be higher in men than women. We conducted a population-based study comprising of all recorded SSc deaths across the US to determine: a) the median age at SSc death by sex and race, b) odds ratios for the risk of SSc deaths by sex and race in different age groups, c) trends in the proportions of total SSc deaths by sex and race at different age groups over 5 decades, and d) SSc age-standardized mortality rate (ASMR) and case-fatality rate by sex and race.

Methods: We constructed histograms that depict the absolute number of SSc deaths for each age separately by sex and race. We then assessed the cumulative percent death at each age and determined the median age at death for each demographic group. We then calculated the percent of total SSc deaths by sex/race at different age groups every 10 yrs from 1970. We performed Chi-square test with Yates correction and quantified the odds ratio (OR) with 95% CI. Finally, we calculated ASMRs, and case-fatality rates (i.e., mortality rate in SSc population = SSc mortality rate / SSc prevalence) by sex and race.

Results: SSc was recorded as the cause of death in 5,061 women and 1,222 men in the US during 2011-2015. Deceased SSc persons were 4,426 white and 956 black. The median age at SSc death was 63 yrs in men vs. 68 yrs in women, and 57 yrs for black persons vs. 70 yrs for white persons during 2011-2015. Higher proportions of men than women (54.5% vs. 40.2%), and of black than white persons (72.5% vs. 34.0%) died of SSc before 65 yrs of age. The risk of SSc death before 65 yrs of age was significantly higher in men than in women (OR 1.8, 95% CI 1.6-2.0, p< 0.0001) and in black than in white persons (OR 5.1, 95% CI 4.4-6.0, p< 0.0001).  We then assessed trends in the proportion of SSc deaths by sex and race over 5 decades. The proportions of male and female SSc deaths were similar in all age groups in 1970, but significantly higher proportions of male SSc deaths relative to female SSc deaths were noted in the younger age groups at later timepoints (1990 and later in 45-64 and 2015 in ≤44 age groups). Compared to white persons, black persons had higher percentages of total SSc deaths in younger age groups (≤44 and 45-64) throughout the study period. Black persons also had significantly higher ASMRs than white persons. Women had 3-4-fold higher ASMRs than men, e.g., SSc-ASMR was 4.9 (95% CI 4.6-5.2) in women and 1.4 (95% CI 1.2-1.5) in men in 2015. However, this difference was obviated when mortality rates were corrected tor the differences in SSc prevalence between women and men, e.g., case-fatality rates for SSc were 3.0 in women and 2.1 in men in 2015.

Conclusion: Men and black persons died of SSc at younger ages than did women and white persons, respectively. Understanding the mechanisms of these disparities and identifying potentially modifiable risk factors might inform targeted research and public health programs to promote health equity in all SSc subpopulations.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/men-and-black-persons-die-at-younger-ages-from-systemic-sclerosis-a-nationwide-population-based-study/