Pulmonary hypertension (PH) complicating systemic sclerosis (SSc)-related interstitial lung disease (ILD) is usually associated with a poor prognosis. However, data are either lacking or scarce on prognostic factors in this condition. The objectives of this study were to compare the survival of patients with ILD-associated PH (PH-ILD) or pulmonary arterial hypertension (PAH) and to determine whether the severity of PH has prognostic value in SSc-associated PH-ILD.
Consecutive patients with SSc and PH-ILD (n = 47) or PAH (n = 50) confirmed by right-sided heart catheterization were included in a cross-sectional analysis. PH was classified as mild (mean pulmonary arterial pressure [mPAP] ≤ 35 mm Hg) or moderate to severe (mPAP > 35 mm Hg).
As compared with patients with PAH, subjects with PH-ILD were younger, were more frequently men with a history of smoking, had more frequently diffuse SSc, less frequently anticentromere antibodies, and a lower FVC/diffusing capacity of lung for carbon monoxide (DLCO) ratio. They had a worse prognosis than patients with PAH (3-year survival of 47% vs 71%, respectively; P = .07). Patients with mild PH-ILD had similar poor outcomes when compared with those with moderate to severe PH-ILD. Pericardial effusion (hazard ratio [HR], 2.44; P = .04) and lower DLCO (HR, 0.96; P = .01) were the only independent factors predictive of a poor survival in the PH-ILD group.
Patients with SSc with PH-ILD had a different phenotype and a worse prognosis than those with SSc and PAH. Lower DLCO and presence of pericardial effusion were predictive of a poor outcome in PH-ILD, whereas mPAP seemed to have no prognostic significance.