In this single-center longitudinal VEDOSS cohort, early pulmonary function—particularly DLCO—emerged as a meaningful signal of disease trajectory. Patients who progressed to systemic sclerosis had significantly lower baseline DLCO, and a threshold <70% identified a subgroup with faster progression, even in the absence of radiographic ILD. Notably, subtle declines in DLCO and FVC also occurred in “stable” VEDOSS, suggesting ongoing subclinical pulmonary involvement—likely vascular—before overt disease, reinforcing the value of serial PFT monitoring in early SSc risk stratification.