Treatment of systemic sclerosis-associated pulmonary hypertension with and without interstitial lung disease and its impact on survival: a large cohort study of the German network for systemic sclerosis

OBJECTIVES: This study aimed to analyze survival in systemic sclerosis-associated pulmonary hypertension (SSc-PH) patients with or without interstitial lung disease (ILD) stratified by PH monotherapy and PH combination therapy, respectively. METHODS: Out of 6003 patients of the German Network for Systemic Sclerosis (DNSS) registry, SSc patients with incident PH diagnosed after registry entry were included. Kaplan-Meier analysis was performed to estimate the overall survival, and log-rank test was used to assess differences between groups stratified by presence of ILD or PH treatment. RESULTS: 384 patients fulfilled inclusion criteria. 271 had concomitant ILD (70.6%). Mean follow up was 8.69 ± 4.94 years. Forced vital capacity (FVC) and diffusing capacity of the lungs for carbon monoxide (DLCO) numerically decreased in both PH patients with and without ILD and were significantly lower in patients with ILD (mean value of minimal FVC during follow up: 70.79 ± 24.36%). There was no significant difference in the distribution of PH therapy categories (mono, dual, or triple therapy) between PH patients with and without ILD involvement (p= 0.865). No survival difference was observed between monotherapy and combination therapy groups (p= 0.197). Subgroup analysis indicated that varying treatment strategies did not significantly impact survival outcomes of PH patients whether or not ILD was present. CONCLUSIONS: SSc patients with ILD and incident PH are often treated with PH combination therapy in Germany. This treatment strategy seems feasible and does not worsen survival in PH patients, provided that ILD is not severe.