Automated airway quantification associates with mortality in idiopathic pulmonary fibrosis

ObjectivesThe study was to examine whether the airway metrics associate with mortality in IPF patients.MethodsWe performed an observational cohort study (n=90) of IPF patients identified from Ege University Hospital. An airway analysis tool AirQuant calculated median airway segmental intertapering and segmental tortuosity across 2ndto 6thgenerations of IPF airways. Intertapering measures the difference in median diameter between adjacent airway segments. Tortuosity evaluates the ratio of measured segmental length against direct end- to-end segmental length. Univariable linear regression analyses examined relationships between AirQuant variables, clinical variables and lung function tests. Univariable and Multivariable Cox proportional hazards models estimated mortality risk with the latter adjusted for patient age, gender, smoking status, antifibrotic use, CT usual interstitial pneumonia (UIP) pattern and either forced vital capacity (FVC) or diffusion capacity of carbon monoxide (DLco) if obtained within 3 months of the CT.ResultsNo significant collinearity existed between AirQuant variables and clinical or functional variables. On univariable Cox regression analyses, male gender, smoking history, no antifibrotic use, reduced DLco, reduced segmental intertapering and increased segmental tortuosity associated with increased risk of death. On multivariable Cox regression analyses (adjusted using FVC), segmental intertapering (Hazard Ratio (HR)=0.75, 95% CI=0.66-0.85, pConclusionsAirQuant generated measures of segmental intertapering and tortuosity independently associate with mortality in IPF patients. Abnormalities in proximal airway generations, which are not typically considered to be abnormal in IPF, have prognostic value.Key PointsAirQuant generates measures of segmental intertapering and tortuosity.Automated airway quantification associates with mortality in IPF independent of established measures of disease severity.Automated airway analysis could be used to refine patient selection for therapeutic trials in IPF.