RESULTS: Seventy-four patients were included in the study. Fifty-nine patients (80 %) were males and 15 (20 %) were females. The mean age of the study population was 62 years old with mean height of 160.01 + 8.4 cm and weight of 61.43 + 15.8 kg. Majority of the patients (93 %) were smoker, with mean average pack-year-smoker of 30.93 + 22.1 pack-year. Five patients (7%) who have no smoking history were majority males (4 males and 1 female). The mean FEV1 was 52 % predicted in the post-bronchodilator study. Most of the patients were at GOLD 2 with 33 patients (45%), followed by GOLD 3 with 30 patients ( 40%), then GOLD 4 with 6 patients (8%) and GOLD 1 with 5 patients (7%). Lung volume parameters such as TLC and RV across all stages showed the presence of hyperinflation based on cut-off values using the lower limit of normality but was not statistically significant. On the other hand, RV/TLC ratio was associated with hyperiflation to all GOLD stages, GOLD 1 (40.8 + 9.8), GOLD 2 (50.73 + 11.2), GOLD 3 (54.87 + 9.07) and GOLD 4 (62.33 + 3.56) with a p- value of 0.0027 which was statistically significant. An increasing trend of RV/TLC as COPD category increases was noted. However, looking at the changes between one category to the next, the change in RV/TLC was significantly increased between GOLD 1 and 3 (p value of 0.043) and GOLD 1 and 4 (p value of 0.008) only.