Clinical Features of Smokers with Radiological Emphysema but without Airway Limitation

RATIONALE:
The clinical characteristics of patients with emphysema but without airway limitation remain unknown.

OBJECTIVE:
To compare the clinical features of current and former smokers without airflow limitation who have radiological emphysema on chest CT with a control group of current and ex-smokers without emphysema.

METHODS:
Subjects enrolled had anthropometrics, medical history and a low dose chest computed tomography (LDCT). The following parameters were also evaluated: pulmonary function tests (PFT) including diffusion capacity for carbon monoxide (DLCO), modified MRC dyspnea score, COPD assessment test (CAT) and 6-min walk distance (6MWD). A comparison was conducted between those with and those without CT emphysema.

RESULTS:
Of the 203 subjects, 154 had emphysema (78%) while 49 did not. Adjusted group comparisons revealed that a higher proportion of patients with emphysema on LDCT had an abnormal DLCO (<80%) (46% vs 19%, p=0.02), a fall of SpO2% >4% during the 6MWD (8,5% vs 0%, p= 0,04) and an altered quality of life (CAT score ≥ 10) (32% vs 14%, p=0.01).

A detailed analysis of the CAT questionnaire items revealed that more patients with emphysema had a score≥1 in the "chest tightness" (p=0.05), and "limitation when doing activities at home" items (p<0.01) compared with no emphysema. They also had significantly more exacerbations in the previous year (0.19 vs 0.04, p=0.02).

CONCLUSIONS:
A significant proportion of smokers with emphysema on LDCT but without airway limitation have alterations in their quality of life, number of exacerbations, diffusion capacity and oxygen saturation during the 6MWD test.

CITA DEL ARTÍCULO Chest. 2016 Nov 3. pii: S0012-3692(16)62332-2. doi: 10.1016/j.chest.2016.10.044