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.

Table 2 Multiple linear regression analysis of factors influencing the annual decline rate of forced expiratory volume in one second

Independent Variable	Unstandardized coefficient (B)	SE	Standardized coefficient (β)	Variance inflation factor	t	P value
Constant	18.735	10.246			1.828	0.070
Comorbid depression/anxiety (yes vs no)	10.892	2.138	0.312	1.168	5.094	< 0.001
Current smoking status (yes vs no)	9.521	2.931	0.284	1.325	3.248	0.002
Baseline FEV1% predicted	-0.295	0.108	-0.230	1.289	-2.731	0.007
Frequency of acute exacerbations (times/year)	2.874	1.235	0.251	1.467	2.327	0.022
Use of ICS (yes vs no)	3.128	1.876	0.142	1.412	1.667	0.098
Age (years)	0.148	0.195	0.055	1.102	0.759	0.450
Sex (male vs female)	-1.198	2.857	-0.031	1.115	-0.419	0.676
BMI (kg/m2)	-0.284	0.402	-0.052	1.087	-0.706	0.482
Smoking (pack-years)	0.041	0.057	0.061	1.435	0.719	0.474
Duration of COPD (years)	0.328	0.387	0.064	1.218	0.848	0.398
Hypertension (yes vs no)	1.025	1.894	0.041	1.194	0.541	0.590
Diabetes mellitus (yes vs no)	1.873	2.145	0.065	1.176	0.873	0.385
Coronary heart disease (yes vs no)	2.016	2.378	0.063	1.152	0.848	0.398

Dependent variable: Annual rate of decline in forced expiratory volume in one second (mL/year). FEV1: Forced expiratory volume in one second; ICS: Inhaled corticosteroids; BMI: Body mass index; COPD: Chronic obstructive pulmonary disease.