Table 1 Demographic characteristics of COPD patients according to the severity of airflow limitation based on PB-FEV1
Characteristics | All COPD patients, N = 374 | Severity of airflow limitation based on PB-FEV1 (% predicted) | p-value | |||
|---|---|---|---|---|---|---|
< 30% | 30–49% | 50–79% | ≥ 80% | |||
Number of COPD patients (% of total COPD patients) | ||||||
85 (22.7) | 142 (38.0) | 111 (29.7) | 36 (9.6) | |||
Age, years (mean ± SD, 95% CI) | 67.3 ± 11.8; 66.1–68.5 | 65.7 ± 10.5; 63.4–67.9 | 67.7 ± 11.4; 65.8–69.6 | 67.2 ± 12.4; 64.9–69.5 | 70.0 ± 13.7; 65.1–74.4 | 0.345 |
Gender, n (%) Male Female | 317 (84.8) 57 (15.2) | 77 (90.6) 8 (9.4) | 120 (84.5) 22 (15.5) | 90 (81.1) 21 (18.9) | 30 (83.3) 6 (16.7) | 0.326 |
Ethnicity, n (%) Malay Chinese Indian Others | 104 (27.8) 104 (27.8) 31 (8.3) 135 (36.1) | 24 (28.2) 18 (21.2) 6 (7.1) 37 (43.5) | 42 (29.6) 37 (26.1) 14 (9.9) 49 (34.5) | 27 (24.3) 33 (29.7) 11 (9.9) 40 (36.0) | 11 (30.6) 16 (44.4) 0 9 (25.0) | 0.283 |
Smoking status, n (%) Never smoker Former smoker Current smoker | 69 (18.4) 201 (53.7) 104 (27.8) | 13 (15.3) 45 (52.9) 27 (31.8) | 27 (19.0) 78 (54.9) 37 (26.1) | 22 (19.8) 54 (48.6) 35 (31.5) | 7 (19.4) 24 (66.7) 5 (13.9) | 0.422 |
Smoking quantity, pack-years (mean ± SD, 95% CI) | 30.2 ± 27.6; 27.4–33.0 | 27.1 ± 22.3; 22.3–31.9 | 30.5 ± 29.5; 25.6–35.3 | 32.6 ± 29.3; 27.1–38.1 | 28.4 ± 25.6; 19.8–37.1 | 0.559 |
Biomass smoke exposure, n (%) No Yes | 242 (64.7) 132 (35.3) | 44 (51.8) 41 (48.2) | 97 (68.3) 45 (31.7) | 72 (64.9) 39 (35.1) | 29 (80.6) 7 (19.4) | 0.012 |