The Effect of Male Sex on Survival in Systemic Sclerosis

Abstract

Objective.Systemic sclerosis (SSc) has a female predominance, however, little is understood about the effect of sex on SSc manifestations and survival. The objectives of our study were to evaluate differences in disease manifestations, and survival rates between males and females with SSc.Methods.A retrospective cohort study of the Toronto Scleroderma Program was conducted to evaluate sex-based differences in disease manifestations and survival. A relative survival analysis compared SSc survival to the general population.Results.There were 959 patients (791 females, 168 males) identified, with a female:male ratio of 4.7:1. Males more frequently had diffuse SSc [45% vs 30%, relative risk (RR) 1.44, 95% CI 1.18–1.75] and interstitial lung disease (ILD; 41% vs 33%, RR 1.24, 95% CI 1.01–1.52). There were 324 deaths (65 males, 259 females). Males had increased unadjusted mortality compared to females (HR 1.57, 95% CI 1.19–2.06). In an adjusted model including immunosuppressive use, male sex (HR 1.40, 95% CI 1.06–1.85), ILD (HR 1.58, 95% CI 1.26–1.98), and older age at diagnosis (HR 1.05, 95% CI 1.04–1.06) were independently associated with increased mortality, whereas the limited subtype (HR 0.70, 95% CI 0.49–0.77) and anticentromere antibodies (HR 0.70, 95% CI 0.49–0.98) were independently associated with decreased mortality. Male sex was associated with increased risk of mortality (HR 1.16, p = 0.003) in patients with SSc above that observed for males in the general population.Conclusion.The differential effect of disease between sexes is small, yet males have decreased survival compared to females with SSc.