Forced vital capacity as a survival predictor in systemic sclerosis-associated pulmonary hypertension.

Background: Pulmonary hypertension associated with systemic sclerosis (SSc-PH) carries a significant risk of mortality. Although interstitial lung disease (ILD) often coexists with SSc-PH, its impact on prognosis varies considerably depending on disease extension. The prognostic implications of different degrees of functional impairment secondary to ILD in patients with SSc-PH remain poorly understood. Objectives: This study aimed to stratify patients with SSc-PH according to their functional parameters and to identify potential prognostic factors in different patterns of ILD extension. Design: A retrospective study was conducted on consecutive patients with SSc-PH diagnosed according to the European Society of Cardiology/European Respiratory Society guidelines for PH since 2015, from two Italian Scleroderma Centers. Methods: Patients were classified according to high-resolution computed tomography (HRCT) findings and forced vital capacity (FVC) values as pulmonary arterial hypertension (PAH) without ILD, PH-ILD with FVC ⩾70%, or FVC <70%. Survival analysis, clinical outcomes, and prognostic factors were assessed by Kaplan-Meier curves, multivariate logistic regression, and receiver operating characteristic (ROC) analysis. Results: Fifty-three patients with SSc-PH were enrolled, and their 5-year overall survival rate was 66.7%. The 29 patients with PH-ILD demonstrated significantly lower survival than the 24 patients with PAH (48% vs 87%, p = 0.005). FVC <70% was associated with markedly reduced survival (29% vs 80% for FVC ⩾70%, p = 0.003). ROC analysis confirmed FVC as a significant prognostic marker (area under the curve = 0.713, p = 0.005). Multivariate analysis identified the FVC <70% at PH diagnosis as the only significant predictor of mortality. Moreover, PH-ILD patients with FVC <70% showed the most significant functional deterioration during follow-up, with a 19% decline in FVC and a greater deterioration in World Health Organization functional class. Conclusion: An FVC <70% at baseline represents an important negative prognostic factor in patients with SSc-PH, independently of the extension of ILD on HRCT scan. Functional assessment may complement radiological evaluation and emphasize the importance of routine monitoring of lung function for risk stratification in patients with SSc-PH.