Clinical features and outcomes in combined pulmonary fibrosis and emphysema in idiopathic pulmonary fibrosis.
BACKGROUND
Combined pulmonary fibrosis and emphysema (CPFE) is increasingly recognized, but its prevalence and prognosis remain unclear. We sought to determine the prevalence, clinical features, and prognosis of CPFE in idiopathic pulmonary fibrosis (IPF), using a standardized and reproducible definition.


METHODS
Patients with IPF were identified from two ongoing cohorts. Two radiologists scored emphysema and fibrosis severity on high-resolution CT (HRCT) scans. CPFE was defined as ≥10% emphysema on HRCT scan. Clinical characteristics and outcomes of patients with CPFE and IPF and those with non-CPFE IPF were compared with unadjusted analysis and then analysis after adjustment for HRCT fibrosis score. Mortality was compared using competing risks regression to handle lung transplantation. Sensitivity analyses were performed using Cox proportional hazards, including time to death (transplantation censored) and time to death or transplant.


RESULTS
CPFE criteria were met in 29 of 365 patients with IPF (8%), with high agreement between radiologists (κ=0.74). Patients with CPFE had less fibrosis on HRCT scans and higher FVC, but greater oxygen requirements (P≤.01 for all comparisons). Findings were maintained with adjustment for fibrosis severity. Inhaled therapies for COPD were used by 53% of patients with CPFE. There was no significant difference in mortality comparing patients with CPFE and IPF to those with non-CPFE IPF (hazard ratio, 1.14; 95% CI, 0.61-2.13; P=.69).


CONCLUSIONS
CPFE was identified in 8% of patients with IPF and is a distinct, clinical phenotype with potential therapies that remain underutilized. Patients with CPFE and IPF and those with non-CPFE IPF have similar mortality.
Department of Medicine, University of British Columbia, Vancouver, BC, Canada. Electronic address: chris.ryerson@hli.ubc.ca.
Christopher J
CJ
Ryerson
Department of Radiology, Mayo Clinic, Rochester, MN.
Thomas
T
Hartman
Department of Radiology, University of California San Francisco, San Francisco, CA.
Brett M
BM
Elicker
Department of Medicine, University of California San Francisco, San Francisco, CA.
Brett
B
Ley
Department of Medicine, University of California San Francisco, San Francisco, CA.
Joyce S
JS
Lee
Pulmonary Institute and Respiratory Intensive Care Unit, S. Maria della Misericordia Hospital, Perugia, Italy.
Marta
M
Abbritti
Department of Pathology, University of California San Francisco, San Francisco, CA.
Kirk D
KD
Jones
Department of Medicine, University of California San Francisco, San Francisco, CA.
Talmadge E
TE
King
Department of Medicine, Mayo Clinic, Rochester, MN.
Jay
J
Ryu
Department of Medicine, University of California San Francisco, San Francisco, CA.
Harold R
HR
Collard
D000368:Aged; D015331:Cohort Studies; D015897:Comorbidity; D004646:Emphysema / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D015995:Prevalence; D011379:Prognosis; D016016:Proportional Hazards Models; D011658:Pulmonary Fibrosis / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D012720:Severity of Illness Index; D015996:Survival Rate; D014057:Tomography, X-Ray Computed