Impact of depression and/or anxiety on accelerated lung function decline in patients with chronic obstructive pulmonary disease

Table 1 Comparison of baseline characteristics between the two groups, mean ± SD/n (%)/median (interquartile range)

Variable	Control group (n = 58)	Comorbidity group (n = 64)	Statistic	P value
Age (years)	68.4 ± 7.2	69.8 ± 6.9	t = 1.123	0.264
Male	42 (72.4)	45 (70.3)	χ2 = 0.072	0.788
BMI (kg/m2)	23.1 ± 3.4	22.5 ± 3.8	t = 0.921	0.359
Smoking (pack-years)	40.5 (30.0-55.0)	45.0 (32.8-58.3)	Z = 1.402	0.161
Current smokers	18 (31.0)	22 (34.4)	χ2 = 0.160	0.689
Duration of COPD (years)	7.5 ± 3.8	8.4 ± 4.1	t = 1.273	0.206
Baseline FEV1 (L)	1.52 ± 0.41	1.38 ± 0.39	t = 2.012	0.046
Baseline FEV1% predicted	62.5 ± 13.2	56.8 ± 14.5	t = 2.287	0.024
Baseline FVC (L)	2.88 ± 0.65	2.79 ± 0.71	t = 0.734	0.465
Baseline FEV1/FVC (%)	52.8 ± 7.1	49.5 ± 8.3	t = 2.363	0.020
Acute exacerbation frequency (times/year)	1.0 (0.0-2.0)	2.0 (1.0-3.0)	Z = 3.125	0.002
Hypertension	25 (43.1)	32 (50.0)	χ2 = 0.592	0.442
Diabetes mellitus	11 (19.0)	15 (23.4)	χ2 = 0.367	0.545
Coronary heart disease	9 (15.5)	13 (20.3)	χ2 = 0.489	0.484
Use of inhaled corticosteroids	28 (48.3)	43 (67.2)	χ2 = 4.654	0.031
Use of long-acting β2-agonists	50 (86.2)	58 (90.6)	χ2 = 0.587	0.444
Use of long-acting muscarinic antagonists	52 (89.7)	59 (92.2)	χ2 = 0.256	0.613
HAMD-17 score	8.5 ± 3.2	20.1 ± 4.5	t = 16.543	< 0.001
HAMA score	7.8 ± 2.9	18.9 ± 3.8	t = 18.772	< 0.001

BMI: Body mass index; COPD: Chronic obstructive pulmonary disease; FEV1: Forced expiratory volume in one second; FVC: Forced vital capacity; HAMD-17: 17-item Hamilton Depression Rating Scale; HAMA: Hamilton Anxiety Rating Scale.