Survival of patients with idiopathic pulmonary fibrosis and pulmonary hypertension under therapy with nintedanib or pirfenidone

Idiopathic pulmonary fibrosis (IPF) is a specific form of chronic, progressive, fibrosing interstitial pneumonia of unknown cause that leads to respiratory failure and death within few years of diagnosis. Pulmonary hypertension (PH) is a common complication in IPF, where it is strongly associated with increased morbidity and mortality. Patients with IPF and PH have particularly poor prognosis, despite current best medical therapies and the anti-fibrotic therapy with pirfenidone or nintedanib. The aim of our study was to assess the clinical and prognostic impact of PH in patients affected by IPF, already treated with pirfenidone or nintedanib. Seventy-four consecutive outpatients with a diagnosis of IPF, in therapy with pirfenidone or nintedanib, were prospectively enrolled in the study. All patients underwent pulmonary and cardiology assessment by clinical exam, spirometry, DLCO test, chest CT, 6MWT and echocardiography performed by a cardiologist experienced in PH in an ambulatory setting under resting conditions. GAP index has been determinate for all patients. During follow-up, all patients were evaluated every 6 months, or less if necessary. Data about mortality were then collected in a 3-year follow-up. Of the seventy-four patients enrolled, 38 were treated with pirfenidone and 36 with nintedanib. The two groups were comparable for age, gender, FVC, DLCO and PAPS. The patients were also divided in four groups, based on presence of mild/moderate/severe PH by echocardiography at baseline. Significant differences were found for DLCO and the GAP index. Severity of PH was significantly associated with a reduction of DLCO and with an increased GAP index. Survival was directly correlated with 6MWT (R = 0.48), DLCO (R = 0.29, p < 0.01), and reversely with tGAP index (- 0.31, p < 0.01 in all cases), while no significant correlation was found with PAsP. 36-month survival analysis showed an HR of 4.05 (95% CI 1.07-7.34, p = 0.02) for DLCO < 50% and of 1.56 (95% CI 1.02-2.39, p = 0.03) for GAP index. The development and progression of PH in patients affected by IPF reduce the survival and the severity of PH is associated with a reduction of DLCO value and an increase of the GAP index. Echocardiographic stratification based on PAsP values may be useful in stratifying prognosis in IPF patients and deciding specific PAH drugs.