Open AccessQuantitative computed tomography phenotypes, spirometric parameters, and episodes of exacerbation in heavy smokers: An analysis from South America
Author(s) -
Marcelo Cardoso Barros,
Bruno Hochhegger,
Stephan Altmayer,
Guilherme Watte,
Matheus Za,
Ana Paula Sartori,
Daniella Blanco,
Gabriel Sartori Pacini,
José Miguel Chatkin
Publication year - 2018
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0205273
Subject(s) - medicine , exacerbation , vital capacity , hounsfield scale , copd , pulmonary function testing , spirometry , quantitative computed tomography , computed tomography , cardiology , lung , lung function , radiology , diffusing capacity , asthma , bone density , osteoporosis
Objective To evaluate the quantitative computed tomography (QCT) phenotypes, airflow limitations, and exacerbation-like episodes in heavy smokers in Southern Brazil. Methods We enrolled 172 smokers with a smoking history ≥30 pack-years who underwent pulmonary function tests (PFTs) and CT scan for lung cancer screening. Patients were classified regarding airflow limitation (FEV 1 /FVC <0.7 forced expiratory volume in 1 second/forced vital capacity) and the presence of emphysema on the QCT. The QCT were analyzed in specialized software and patients were classified in two disease-predominant phenotypes: emphysema-predominant (EP) and non-emphysema-predominant (NEP). EP was determined as ≥6% of percent low-attenuation areas (LAA%) with less than -950 Hounsfield units. NEP was defined as having a total LAA% of less than 6%. Results Most of our patients were classified in the EP phenotype. The EP group had significantly worse predicted FEV 1 (60.6 ±22.9 vs. 89.7 ±15.9, p <0.001), higher rates of airflow limitation (85.7% vs. 15%; p <0.001), and had more exacerbation-like episodes (25.8% vs. 8.3%, p <0.001) compared to the NEP group. Smoking history, ethnicity, and BMI did not differ between the groups. The total LAA% was the QCT parameter with the strongest correlation to FEV 1 (r = -0.669) and FEV 1 /FVC (r = -0.787). Conclusions Heavy smokers with the EP phenotype on QCT were more likely to have airflow limitation, worse predicted FEV 1, and a higher rate of exacerbation-like episodes than those with the NEP phenotype. Approximately 23% of patients with no airflow limitation on PFTs were classified in EP phenotype.