Characteristics of subgroups classified by pulmonary function test in chronic obstructive pulmonary disease patients

Abstract

To compare the clinical characteristics and the therapeutic responses in chronic obstructive pulmonary disease (COPD) subgroups, classified by diffusing capacity of the lung for carbon monoxide (D(L)CO) and inspiratary capacity (IC). A total of 105 mild-severe patients (70 males, 35 females, 44 to 85 years of age), with stable COPD were recruited in Cangzhou Central Hospital from June 2012 to June 2014. According to baseline D(L)CO and IC, the patients were divided into normal D(L)CO/IC group (group A, n=10), low D(L)CO/normal IC group (group B, n=18), normal D(L)CO/low IC group (group C, n=22) and low D(L)CO/IC group (group D, n=55). We compared the clinical characteristics, induced sputum cells and the therapeutic responses to 3-month treatment of budesonide/formoterol(320 µg/9 µg, inhale, bid)among the 4 groups. Group D showed the highest CAT scores(27.6 ± 6.4). Group C showed a higher prevalence of patients with wheezing(81.8)% and the highest percentage of sputum eosinophils (7.6 ± 3.2)%. Group C showed the greatest FEV(1) increase(0.214 ± 0.053)L. Group D showed a greater FEV(1) increase than Group B [(0.137 ± 0.063) vs (0.092 ± 0.048)L]. Group C showed a greater FVC[(0.342 ± 0.073), (0.190 ± 0.081), (0.223 ± 0.094)L] increase and CAT[(4.4 ± 2.0), (2.3 ± 1.3), (3.9 ± 1.9)] decrease than Group B and Group D(P<0.05). These findings suggest that COPD subgroups classified by D(L)CO and IC show several clinical characteristics and may be helpful to predict responses to treatment.