Multifaceted associations between walking performance, physical fitness, extremity function, health status, and depression in individuals with COPD

Figures & data

Table 1. Descriptive characteristics of the COPD patients (N = 70).

Parameters	Mean	SD	Range
			Min	Max
Age (years)	63	11	37	88
Weight (kg)	78.88	15.25	47.3	120
Height (cm)	164.87	7.90	150	181
Smoking status, n (%)
Non-smoker	14 (20)
Smoker	17 (24.29)
Ex-smoker	39 (55.71)
FEV1 (L)	1.573	0.5484	.52	2.82
FVC (L)	2.849	0.7314	1.64	4.8
FEV1/FVC ratio	54.73	11.32	26.8	70
FEV1 predicated (%)	55.98	14.97	26.3	102.8
Gender, n (%)
Male	45 (80)
Female	14 (20)
GOLD stage, n (%)
I	4 (5.71)
II	36 (51.43)
III	27 (38.57)
IV	3 (4.29)
PHQ-9	6.77	4.81	0	21
Minimal depression	27 (38.57)
Mild depression	24 (34.29)
Moderate depression	14 (20)
Moderately severe depression	4 (5.72)
Severe depression	1 (1.43)
SGRQ	49.14	24.50	4.57	93.02
Upper Extremity Functional Index	25	17.76	0	70
Lower Extremity Functional Index	40.54	16.50	0	72
Predicted VO2 max*	21.56	15.93	2.75	58.2

Abbreviations: GOLD: Global initiative for chronic obstructive lung disease FEV1: forced expiratory volume in 1 s (), FVC: forced vital capacity (); PHQ-9: patient health questionnaire-9 (); SGRQ:St. George’s respiratory questionnaire(.*Using Duke Activity Status Index (DASI).

Table 2. Comparison of the upper and lower extremity-related functional performance and health status among COPD patients (N = 70).

	Walking	Performance
Characteristics	Low n = 30	High n = 40	p-value^a
6 MWT distance (m)	233.46 ± 81.54	426.97 ± 52.24	<0.001
Predicted VO2peak (mL/kg/min)^b	14.99 ± 12.03	26.50 ± 16.82	0.002
Upper Extremity Functional Index	30.9 ± 19.78	20.57 ± 14.84	0.01
Lower Extremity Functional Index	47.46 ± 14.37	35.35 ± 16.24	0.001
St George’s Respiratory Questionnaire	56.16 ± 21.73	49.13 ± 25.39	0.03
Patient Health Questionnaire
Minimal depression	5 (19)	22 (55)
Mild depression	12 (46)	12 (30)	0.01
Moderate depression	6 (23)	5 (12)
Moderately severe depression	3 (12)	0 (0)
Severe depression	0	1 (3)

Values are mean ± SD or n (%).

^a Independent t-test.

^b Using Duke Activity Status Index (DASI).

Table 3. Multiple linear regression analysis with 6MWT distance as the dependent variable.

Model	Predictors^a	Coefficients						R^2
		β	SE	T	p-value	95% CI
						Lower	Upper
Model*	(Constant)	316.56	91.74	3.45	0.001	133.11	500.01	0.495
	FEV1	56.48	26.56	2.13	0.03	3.34	109.53
	EEV1_ratio	1.55	1.16	1.33	0.18	−0.77	3.89
	VO2peak	3.32	0.75	4.42	<0.001	1.81	4.82
	SGRQ	−1.46	0.50	−2.93	0.005	−2.46	−0.46
	LEFI	−2.30	0.77	−2.97	0.004	−3.85	−0.75
	UEFI	−2.58	0.73	−3.53	0.001	−4.04	−1.12
	PHQ-9	−6.99	2.42	−2.89	0.005	−11.82	−2.15
	F	F(8, 61) = 7.48
	P-value	0.0006

Abbreviations: FEV1: forced expiratory volume in 1 s (; SGRQ: St George’s Respiratory Questionnaire ; UEFI: upper extremity functional index (); LEFI: lower extremity functional index (); PHQ-9: patient health questionnaire-9 .

* Regression model adjusted for age, COPD severity, and gender.

Data availability statement

Data for the current study will be available upon reasonable request from the principal investigator or corresponding author.