Association of heart rate variability index with depressive symptoms and lung function in chronic obstructive pulmonary disease

Table 1 Socio-demographic and clinical characteristics of 120 patients with chronic obstructive pulmonary disease, mean ± SD

	Patient (n = 120)	Percentage (%)
BDI score		8.2 ± 6.5
Depression	43.00	35.80
Males	110	91.67
Age (years), median (P25-P75)	67.7 (61.2-73.8)
Married	96	80.00
Less than primary education	49	40.83
Low socioeconomic status (IV-V)	97	80.83
Current workers	19	15.83
Smoking status
Current smoker	39	32.50
Former smoker	80	66.67
Never smoked	1	0.83
MMRC dyspnea scale, median (P25-P75)	2 (2-3)
Hemoglobin, g/dL	14.5 ± 1.4
Albumin, g/dL	4.2 ± 0.5
Diffusing capacity for carbon monoxide	65.1 ± 18.3
PaO2 (mmHg)	73.5 ± 10.4
PaCO2 (mmHg)	52.6 ± 17.3

BDI: Beck depression inventory; MMRC: Modified medical research council; PaO₂: Partial pressure of oxygen in arterial blood; PaCO₂: Partial pressure of carbon dioxide in arterial blood.