Pulmonary involvement in systemic sclerosis: can sex play a role?

Systemic sclerosis (SSc) is a rare and complex autoimmune disease with significant complications. During the past few years, research interest has focused on the differences between female and male patients. However, there is a lack of data regarding the role of sex in the presence of small airway disease (SAD). Therefore, we aimed to investigate the impact of sex on pulmonary involvement in a cohort of SSc patients, focusing primarily on small airways.

For this retrospective study, consecutive patients with a diagnosis of SSc that visited our department up to January 2024 were recruited. Demographic data, disease manifestations, serological profile and internal organ involvement were compared between the two groups.

In total, 393 patients (female-to-male ratio 6:1) were included. Median time to diagnosis after the onset of Raynaud's was significantly longer for female patients. Electrocardiogram abnormalities were more common in male patients, while telangiectasias, calcinosis and arthralgias were more common in female individuals. Moreover, male SSc patients exhibited a higher prevalence of ILD and shorter time until the diagnosis of ILD. However, female individuals demonstrated a lower maximal-mid expiratory flow rate (MMEF) and higher ratio of residual volume to total lung capacity. Interestingly, sex remained an independent predictor of MMEF, in the multivariate analysis.

Our results showed that, although ILD is more common in male SSc patients, SAD was more prevalent among female individuals. Importantly, female sex remained an independent predictor of SAD. This study further supports the presence of sex-related differences in SSc, with important implications in disease course and management.