Clinical Features of Smokers With Radiological Emphysema But Without Airway Limitation.

Background: The clinical characteristics of patients with emphysema but without airway limitations remain unknown. The goal of this study was to compare the clinical features of current and former smokers without airflow limitation who have radiologic emphysema on chest CT scans vs a control group of current and ex-smokers without emphysema.

Methods: Subjects enrolled had anthropometric characteristics recorded, provided a medical history, and underwent low-dose chest CT scanning. The following parameters were also evaluated: pulmonary function tests including diffusion capacity for carbon monoxide (Dlco), the modified Medical Research Council dyspnea score, COPD assessment test (CAT), and 6-min walk test (6MWT). A comparison was conducted between those with and without CT-confirmed emphysema.

Results: Of the 203 subjects, 154 had emphysema, and 49 did not. Adjusted group comparisons revealed that a higher proportion of patients with emphysema according to low-dose chest CT scanning had an abnormal Dlco value (< 80%) (46% vs 19%; P = .02), a decrease in percentage of oxygen saturation > 4% during the 6MWT (8.5% vs 0; P = .04), and an altered quality of life (CAT score ≥ 10) (32% vs 14%; P = .01). A detailed analysis of the CAT questionnaire items revealed that more patients with emphysema had a score ≥ 1 in the "chest tightness" (P = .05) and "limitation when doing activities at home" (P < .01) items compared with those with no emphysema. They also experienced significantly more exacerbations in the previous year (0.19 vs 0.04; P = .02).

Conclusions: A significant proportion of smokers with emphysema according to low-dose chest CT scanning but without airway limitation had alterations in their quality of life, number of exacerbations, Dlco values, and oxygen saturation during the 6MWT test.