The composite physiological index strongly predicts mortality in interstitial lung disease (ILD) associated pulmonary hypertension (PH-ILD)

Introduction: Pulmonary hypertension is a malignant prognostic factor in ILD. Prognostic tools are required to help prioritise lung transplant allocation and have not been validated in PH-ILD. We hypothesised that the composite physiological index (CPI) would reliably predict prognosis in PH-ILD, as it reflects both the morphological extent of pulmonary fibrosis and pulmonary vascular disease. Methods: Demographics, ILD subtype, pulmonary function tests, and echocardiograms were collected in consecutive patients undergoing right heart catheterisation (RHC) for suspected PH-ILD. Predictors of prognosis were evaluated in their ability to predict mortality with Cox proportional hazard modelling. Results: 228 ILD patients underwent evaluation between 2005-2015, age 61±11 years, 52% were male, and 79% had PH at RHC. Mean pulmonary pressure (mPAP) in the 168 patients with PH was 37±9.3mmHg, mean pulmonary vascular resistance (PVR) 7.0±3.8 Wood units, mean CPI was 61±13. In the patients with PH-ILD, CPI predicted mortality (Hazard ratio (HR): 1.042, Confidence interval (CI): 1.03-1.06, p Conclusion: The CPI strongly predicts mortality in ILD-PH.