Sex disparities in systemic sclerosis-associated pulmonary arterial hypertension: a cohort study

BACKGROUND: The impact of male sex as a determinant of health outcomes in systemic sclerosis-associated pulmonary arterial hypertension (SSc-PAH) is controversial. The primary objective of this study was to evaluate the effect of sex on survival in patients with SSc-PAH. The secondary objectives were to evaluate the effect of sex on age of PAH diagnosis, time from SSc diagnosis to PAH diagnosis, and SSc disease manifestations. METHODS: Sex-based disparities were evaluated in a cohort of SSc-PAH patients with a primary outcome of time from PAH diagnosis to all-cause mortality. Secondary outcomes were differences in age of diagnosis, disease duration, and SSc manifestations. Survival differences were evaluated using Kaplan-Meier and Cox proportional hazard models. RESULTS: We identified 378 SSc-PAH (58 males, 320 females) patients, with a female:male ratio of 5.5:1. Males had a shorter mean ± standard deviation time from SSc diagnosis to PAH diagnosis (1.7 ± 14 versus 5.5 ± 14.2 years); shorter PAH duration (3.5 ± 3.1 versus 4.7 ± 4.2 years), increased frequency of renal crisis (19 % versus 8 %, relative risk (RR) 2.33, 95 %CI 1.22, 4.46), interstitial lung disease (67 % versus 48 %, RR 1.41, 95 %CI 1.14, 1.74), and diffuse subtype (40 % versus 22 %, RR 1.84, 95 %CI 1.26, 2.69). Males appeared to have decreased 1-, 2-, 3-, and 5-year survival (83.2 %, 68.7 %, 53.2 %, 45.6 %) compared to females (85.7 %, 75.7 %, 66.4 %, 57.4 %). However, there was no difference in mortality between sexes (HR 1.43 (95 %CI 0.97, 2.13). CONCLUSIONS: Sex disparities appear to exist in the frequency of PAH, time to PAH diagnosis, PAH disease duration and SSc disease burden. However, male sex does not independently impact SSc-PAH survival.