Lee JS, et al. • Predictors of Treatment Response in Patients with COPD Table 2. Pulmonary function response to short-acting bronchodilator and 3 months of treatment with salmeterol/fluticasone according to baseline GOLD severity stage Data are expressed as means with standard deviations. FEV1, forced expiratory volume in 1 sec; FVC, forced vital capacity; TLC, total lung capacity; IC, inspiratory capacity; FRC, functional residual capacity; RV, residual volume. Table 3. Correlation between baseline clinical variables and pulmonary function response to 3 months of treatment with salmeterol/fluticasone FEV1 change after 3-month treatment (% predicted) FVC change after 3-month treatment (% predicted) IC/TLC change after 3-month treatment (%) GOLD II (n = 74) 0.178 (0.129) 0.239 (0.280) 0.142 (0.227) 0.145 (0.353) -0.217 (0.625) 0.162 (0.413) 3.121 (5.470) -0.245 (0.407) 0.162 (0.413) P value 0.755 0.820 0.101 0.002 0.114 < 0.001 < 0.001 0.032 < 0.001 0.372 0.030 0.087 0.021 0.432 0.015 0.675 R -0.068 0.054 0.011 -0.340 -0.265 0.257 -0.358 -0.173 0.464 0.216 -0.244 0.286 0.325 -0.025 -0.094 0.053 GOLD III, IV (n = 53) 0.158 (0.139) 0.333 (0.292) 0.184 (0.217) 0.282 (0.406) -0.399 (1.123) 0.113 (0.361) 2.219 (6.840) -0.406 (1.150) 0.113 (0.361) P value 0.447 0.545 0.902 < 0.001 0.003 0.004 < 0.001 0.052 < 0.001 0.015 0.006 0.001 < 0.001 0.785 0.307 0.565 R -0.068 -0.133 0.026 -0.031 0.044 0.254 -0.027 0.022 0.109 0.206 -0.328 0.288 0.232 -0.027 -0.022 0.061 P value 0.464 0.496 0.875 0.160 0.035 0.600 0.227 < 0.001 0.600 P value 0.760 0.137 0.776 0.729 0.628 0.004 0.767 0.811 0.226 0.021 < 0.001 0.001 0.009 0.772 0.811 0.513 Post-bronchodilator FEV1change (L) Post-bronchodilator FVC change (L) FEV1 change after 3 months of treatment (L) FVC change after 3 months of treatment (L) TLC change after 3 months of treatment (L) IC change after 3 months of treatment (L) IC/TLC change after 3 months of treatment (%) FRC change after 3 months of treatment (L) RV change after 3 months of treatment (L) Age (yr) Smoking pack-years Body mass index (kg/m2) Pre-bronchodilator FEV1 (% predicted) Post-bronchodilator FEV1 (% predicted) Post-bronchodilator FEV1 change (% predicted) Pre-bronchodilator FVC (% predicted) Post-bronchodilator FVC (% predicted) Post-bronchodilator FVC change (% predicted) TLC (% predicted) IC/TLC (%) FRC (% predicted) RV (% predicted) DLco (% of predicted) Low attenuation area (%) Wall area (%) R -0.028 0.020 0.146 -0.267 -0.141 0.432 -0.326 -0.191 0.338 0.080 -0.192 0.153 0.205 0.072 -0.222 0.039 R, correlation coefficient; FEV1, forced expiratory volume in 1 sec; FVC, forced vital capacity; TLC, total lung capacity; VC, vital capacity; IC, inspiratory capacity; FRC, functional residual capacity; RV, residual volume; DLco, diffusing capacity for carbon monoxide; Low attenuation area, volume fraction of the lung below -950 HU at full inspiration computed tomography; Wall area, wall area/(wall area + lumen area) × 100 on computed tomography. Univariate analysis of baseline clinical variables and pulmonary function response to 3 months of treatment with salmeterol/fluticasone The FEV1, FVC and IC/TLC changes after 3 months of treatment were normally distributed without evidence of a separate re- sponder group. The mean FEV1, FVC and IC/TLC changes after 3 months of the treatment were 0.160 (0.223) L, 5.1 (7.3)% pre- dicted and 0.202 (0.380) L, 4.8 (9.0)% predicted, and 2.7 (6.1)%, respectively. There were no significant differences in the mean postbronchodilator FEV1 and FVC changes according to base- line GOLD severity stage. Patients with GOLD stage III or IV showed significantly larger TLC and functional residual capaci- ty (FRC) reduction after the 3 months of treatment with salme- terol/fluticasone than patients with GOLD stage II. However, there were no significant differences in the mean FEV1, FVC and IC/TLC changes after 3 months of the treatment (Table 2). Among categorical variables, COPD patients with wheezing history had significantly greater FEV1 and FVC changes after 3 382 http://jkms.org months of treatment than those without wheezing history (7.8% vs 2.7% predicted for FEV1, P < 0.001; 7.3% vs 2.3% predicted for FVC, P = 0.002). Simple correlation analysis indicated that pre- bronchodilator FEV1 and FVC had a weak negative correlation with the FEV1 and FVC changes after 3 months of the treatment but that post-bronchodilator FEV1 and FVC had no significant correlation with FEV1 and FVC changes after 3 months of the treatment. The post-bronchodilator FEV1 and FVC changes had a positive correlation with the FEV1 and FVC changes after 3 months of the treatment. LAA had a weak negative correlation with the FEV1 change after 3 months of the treatment, but mean WA was not correlated with the FEV1, FVC and IC/TLC changes after 3 months of the treatment (Table 3). Prediction models for pulmonary function response to 3 months of treatment with salmeterol/fluticasone Multiple, stepwise, linear regression analysis showed that four variables, wheezing history, pre-bronchodilator FEV1, post-bron- DOI: 10.3346/jkms.2011.26.3.379