Disease Severity Dependence of the Longitudinal Association Between CT Lung Density and Lung Function in Smokers

Citation:

Diaz AA, Strand M, Coxson HO, Ross JC, Estepar RSJ, Lynch D, van Rikxoort EM, Rosas IO, Hunninghake GM, Putman RK, et al. Disease Severity Dependence of the Longitudinal Association Between CT Lung Density and Lung Function in Smokers. Chest. 2018;153 (3) :638-645.

Date Published:

2018 Mar

Abstract:

BACKGROUND: In smokers, the lung parenchyma is characterized by inflammation and emphysema, processes that can result in local gain and loss of lung tissue. CT measures of lung density might reflect lung tissue changes; however, longitudinal data regarding the effects of CT lung tissue on FEVin smokers with and without COPD are scarce. METHODS: The 15th percentile of CT lung density was obtained from the scans of 3,390 smokers who completed baseline and 5-year follow-up of the Genetic Epidemiology of COPD (COPDGene) study visits. The longitudinal relationship between total lung capacity-adjusted lung density (TLC-PD15) and FEVwas assessed by using multivariable mixed models. Separate models were performed in smokers at risk, smokers with preserved ratio and impaired spirometry (PRISm), and smokers with COPD according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) staging system. RESULTS: The direction of the relationship between lung density and lung function was GOLD stage dependent. In smokers with PRISm, a 1-g/L decrease in TLC-PD15 was associated with an increase of 2.8 mL FEV(P = .02). In contrast, among smokers with GOLD III to IV COPD, a 1-g/L decrease in TLC-PD15 was associated with a decrease of 4.1 mL FEV(P = .002). CONCLUSIONS: A decline in TLC-PD15 was associated with an increase or decrease in FEVdepending on disease severity. The associations are GOLD stage specific, and their presence might influence the interpretation of future studies that use CT lung density as an intermediate study end point for a decline in lung function. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT00608764; URL: www.clinicaltrials.gov.
Last updated on 04/04/2018