Clinical Outcomes of Patients with Combined Idiopathic Pulmonary Fibrosis and Emphysema in the IPF-PRO Registry

Hyun J Kim,Shaun Bender,Anne S Hellkamp,David L Hotchkin,Laurie D Snyder,Daniel A Culver,Thomas B Leonard,Megan L Neely,Lake D Morrison

doi:10.1007/s00408-021-00506-x

Abstract

PurposeTo assess the impact of concomitant emphysema on outcomes in patients with idiopathic pulmonary fibrosis (IPF).MethodsThe IPF-PRO Registry is a US registry of patients with IPF. The presence of combined pulmonary fibrosis and emphysema (CPFE) at enrollment was determined by investigators’ review of an HRCT scan. Associations between emphysema and clinical outcomes were analyzed using Cox proportional hazards models.ResultsOf 934 patients, 119 (12.7%) had CPFE. Compared with patients with IPF alone, patients with CPFE were older (median 72 vs 70 years); higher proportions were current/former smokers (88.2% vs 63.7%), used oxygen with activity (49.6% vs 31.9%) or at rest (30.8% vs 18.4%), had congestive heart failure (13.6% vs 4.8%) and had prior respiratory hospitalization (25.0% vs 16.7%); they had higher FVC (median 71.8 vs 69.4% predicted) and lower DLco (median 35.3 vs 43.6% predicted). In patients with CPFE and IPF alone, respectively, at 1 year, rates of death or lung transplant were 17.5% (95% CI: 11.7, 25.8) and 11.2% (9.2, 13.6) and rates of hospitalization were 21.6% (14.6, 29.6) and 20.6% (17.9, 23.5). There were no significant associations between emphysema and any outcome after adjustment for baseline variables. No baseline variable predicted outcomes better in IPF alone than in CPFE.ConclusionApproximately 13% of patients in the IPF-PRO Registry had CPFE. Physiologic characteristics and comorbidities of patients with CPFE differed from those of patients with IPF alone, but the presence of emphysema did not drive outcomes after adjustment for baseline covariates.Trial registrationClinicalTrials.gov, NCT01915511; registered August 5, 2013.

Highlights

Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial lung disease associated with progressive decline in lung function, debilitating symptoms, and high mortality [1]
Emphysema is a common comorbidity in patients with IPF [2], but the clinical course of combined pulmonary fibrosis and emphysema (CPFE) continues to be debated
Of 934 patients in the analysis cohort, 119 (12.7%) had CPFE at enrollment based on the presence of clinically significant emphysema on an high-resolution computed tomography (HRCT) scan, in the opinion of the investigator

Summary

Introduction

Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial lung disease associated with progressive decline in lung function, debilitating symptoms, and high mortality [1]. How emphysema in patients with IPF affects disease progression and survival and how patients with CPFE should be followed remain poorly understood. Compared with patients with IPF alone, patients with CPFE typically have higher forced vital capacity (FVC) but lower diffusing capacity of the lungs for carbon monoxide (DLco) [4]. Different studies have suggested that the measure of lung function that provides the best indicator of prognosis in patients with CPFE may be DLco [11] or forced expiratory volume in 1 s (FEV1) [12]. We used data from the IPF-PRO Registry, a multicenter US registry of patients with IPF, to compare the clinical characteristics and outcomes of patients with CPFE and IPF alone and to determine whether baseline measures, such as pulmonary function tests, correlate differently with outcomes in patients with CPFE versus IPF alone

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Results

Conclusion