Parameter Controls (n: 48) Patients (n: 81) P value  
Carbon Monoxide Diffusing Capacity% of Predicted 86.88 ± 3.6 83.44 ± 6.8 0.02
Total Lung Capacity% of predicted 86.7 ± 3.6 86.88 ± 5.1 0.8
FEV1/FVC% of predicted 81.2 ± 5.3 56.0 ± 6.6 0.013
FEV1% of predicted 85.4 ± 3.7 52.9 ±15.4 0.001
FVC% of predicted 85.4 ± 3.7 86.6 ± 3.9 0.016
Data are presented as Mean ±SD
FEV1: Forced Expiratory Volume (1st second)
FVC: Forced Vital Capacity
*P value < 0.05 significant different between controls and patients groups
**P value< 0.01 highly significant
Table 1: Respiratory function tests for COPD patients and controls.