Table 1

Baseline characteristics of the study population according to disease status
Variables Groups pValue
COPD (n = 1100) Controls (n = 1100)
Number (Percentage, %)
Female sex 273 (24.8) 273 (24.8) ≥0.05
Educated level to high school or beyond 21 (1.9) 21 (1.9) ≥0.05
Smoking history
Past smoker 264 (24.0) 12 (1.1) <0.05
Current smoker 226 (20.5) 235 (21.4)
Never smoker 610 (55.5) 853 (77.5)
HADS-A ≥ 8 201 (18.3) 58 (5.3) <0.05
HADS-D ≥ 8 393 (35.7) 79 (7.2) <0.05
Mean (SD) or median (quartile)
Age 63.2 (40–75) 62.1 (39–76) ≥0.05
Average number of family members 2.86 (1–4) 2.86 (1–4) ≥0.05
Annual net income per family (yuan) 17002 (440) 17477 (469) <0.05
BMI (kg/m2) 23.3 (2.8) 23.4 (3.0) ≥0.05
FEV1(L) 1.27 (0.36) 2.55 (0.68) <0.05
FEV1, % of predicted value 45.2 (10.8) 88.6 (9.2) <0.05
FEV1/FVC 47.9 (11.5) 83.6 (9.3) <0.05
6MWD (m) 445.0 (91.0) 580.1 (99.8) <0.05
HADS-A score 4.8 (2.3) 3.1 (1.6) <0.05
HADS-D score 5.4 (2.6) 3.5 (2.4) <0.05

HADS: Hospital Anxiety and Depression Scale: HADS-A: HADS—anxiety; HADS-D: HADS—depression; FEV1, forced expiratory volume in one second; FVC, forced vital capacity; BMI:body mass index; 6MWD: six-minute walking distance; MRC: Medical Research Council; SGRQ: Saint George’s Respiratory Questionnaire: BODE: body mass index, degree of airway obstruction, dyspnea and exercise capacity; Possible anxiety (8 ≤ HADS-A ≤ l0) and probable anxiety (HADS-A ≥ 11) were combined and referred to as anxiety (HADS-A ≥ 8). Possible depression (8 ≤ HADS-D ≤ l0) and probable depression (HADS-D ≥ 11) were combined and referred to and as depression (HADS-D ≥ 8).

Lou et al.

Lou et al. BMC Pulmonary Medicine 2012 12:53   doi:10.1186/1471-2466-12-53

Open Data