Risk factors for depression in patients with chronic obstructive pulmonary disease

Table 1 Baseline characteristics of patients, n = 293 (%)

Patient characteristics	Number of patients
Age at diagnosis (mean ± SD, yr)	65.62 ± 7.31
Gender
Female	53 (18.09)
Male	240 (81.91)
Smoking history
Never smoker	80 (27.30)
Past smoker	114 (38.91)
Current smoker	99 (33.79)
Household income
Low income	149 (50.85)
Medium income	105 (35.84)
High income	39 (13.31)
Patients with depression	65 (22.18)
HADS-D score	5.09 ± 2.73

HADS-D: Hospital anxiety and depression scale-depression.

Table 2 Correlation between diverse clinical factors and depression

Factors	Depression	No depression	P value
Age at diagnosis (mean ± SD, yr)	65.12 ± 7.62	65.76 ± 7.23	NS
Gender	65	228	NS
Female	9	44
Male	56	184
Marital status	65	228	NS
Married or partner	52	194
Single, divorced, separated or widowed	13	34
Household income	65	228	NS
High income	12	27
Medium income	20	82
Low income	33	119
Smoking history	65	228	NS
Never smoker	15	49
Past smoker	24	96
Current smoker	26	83
Duration of respiratory symptoms (mo)	111.28 ± 41.92	79.51 ± 112.47	0.026
Exacerbation rate (prior yr)	2.09 ± 1.28	1.58 ± 0.94	0.004
BMI (kg/m2)	18.51 ± 3.34	20.75 ± 4.09	0.000
FEV1 (L)	0.82 ± 0.30	1.11 ± 0.44	0.000
mMRC dyspnea scale	1.86 ± 0.75	1.67 ± 0.69	NS
CAT score	13.08 ± 3.71	10.30 ± 4.20	0.002
HADS score	9.18 ± 1.27	3.93 ± 1.72	0.000

BMI: Body mass index; FEV1: Forced expiratory volume in 1 s; mMRC: Modified medical research council; CAT: Chronic obstructive pulmonary disease assessment test; HADS: Hospital Anxiety and Depression Rating Scale; NS: Not significant.

Table 3 Multivariate logistic regression analysis of risk factors

Factors	β	OR	95%CI	P value
Duration of respiratory symptoms	0.002	1.002	0.999-1.004	NS
Exacerbation rate (prior yr)	0.13	1.139	0.854-1.518	NS
BMI (kg/m2)	-0.113	0.893	0.830-0.962	0.003
FEV1 (L)	-1.124	0.325	0.132-0.803	0.002
CAT score	0.105	1.111	1.021-1.209	0.004

β: Coefficient regression; OR: Odds ratio; CI: Confidence interval; BMI: Body mass index; FEV1: Forced expiratory volume in 1 s; CAT: Chronic obstructive pulmonary disease assessment test; NS: Not significant.

Table 4 Cutoff value, sensitivity, and specificity of body mass index, forced expiratory volume in 1 s, and chronic obstructive pulmonary disease assessment test score for diagnosing depression

Factors	Cutoff value	Sensitivity (%)	Specificity (%)	AUC	95%CI	P value
BMI (kg/m2)	21.375	49.6	83.1	0.705	0.633-0.776	0.001
FEV1 (L)	0.855	71.5	63.1	0.702	0.634-0.770	0.003
CAT score	12.5	63.1	70.6	0.694	0.624-0.765	0.001
BMI+FEV1		76.9	66.7	0.745	0.684-0.807	0.000
BMI+CAT		72.3	67.1	0.735	0.669-0.802	0.000
FEV1+CAT		76.9	60.5	0.730	0.667-0.794	0.000
BMI+FEV1+CAT		72.3	75.0	0.766	0.705-0.827	0.000

BMI: Body mass index; FEV1: Forced expiratory volume in 1 s; CAT: Chronic obstructive pulmonary disease assessment test; AUC: Area under curve; CI: Confidence interval.