Impact of male sex in clinical and laboratory features of systemic sclerosis

Although systemic sclerosis (SSc) predominantly affects the female sex, male patients tend to present a more severe visceral profile and worse prognosis. This study aims to analyze the clinical and laboratory characteristics of male patients in a large single SSc cohort. This retrospective study analyzed 700 patients followed regularly at a single tertiary outpatient SSc center. Patients were classified according to the 2013 ACR/EULAR SSc criteria, and all data were retrieved from an electronic database. Statistical analyses included comparing demographic and clinical data, Kaplan-Meier survival curves, and multivariate analyses using SigmaStat 14.5. There were 612 women (87.4%) and 88 men (12.6%). Male patients were more frequently African-Brazilians (p = 0.005), and showed a significantly shorter disease duration compared to females (10.1 vs. 13.8 years, p < 0.001), with higher rates of environmental exposures (37.5% vs. 8.2%, p < 0.001), and more severe fibrotic manifestations, including skin thickening score (p = 0.004), diffuse SSc (p = 0.005), and extensive interstitial lung disease (p = 0.013). Men also had higher rates of group 3 pulmonary hypertension (p = 0.018), congestive heart failure (p = 0.001), and required more aggressive treatments such as cyclophosphamide (p < 0.001) and rituximab (p = 0.002). Although there were no significant sex differences in the frequency of vascular manifestations or joint involvement, men had lower rates of positivity for antinuclear antibodies (ANA) (p = 0.047) and anti-centromere antibodies (ACA) (p = 0.001). Male sex was associated with increased mortality (hazard ratio 2.3; 95% CI 1.4 to 3.8; p = 0.002) and survival rates at 1, 3, 5, and 10 years from diagnosis were 99.2%, 96%, 89%, and 75% for men, and 99%, 98%, 97%, and 93% for women (p < 0.001). Our study reinforces the association between male sex and more severe SSc, marked by greater skin involvement, worse pulmonary and cardiac outcomes, a higher prevalence of environmental exposures, and lower ACA positivity. These factors contributed to poorer survival outcomes in men compared to women. These findings underscore the need for a more comprehensive evaluation of clinical manifestations to better assess disease progression in male SSc patients.