Physical Activity in Patients with Chronic Obstructive Pulmonary Disease on Long-Term Oxygen Therapy: A Cross-Sectional Study

Figures & data

Table 1 Demographic, Anthropometric, Physiological and Clinical Characteristics of Patients. Mean (SD) or n (%)

	All Patients (n=200)	COPD (n=96)	HYPOX (n=63)	LTOT (n=41)	P
Male, %	77.0	78.1	74.6	78.0	0.861
Age, years	68.7 (9.1)	69.9 (8.6)	67.9 (11.0)	67.0 (6.4)	0.153
BMI, kg/m^2	26.3 (5.4)	26.6 (5.0)	26.3 (6.0)	25.6 (5.4)	0.655
6MWD, m	432.0 (111.5)	457.8 (97.9)	442.3 (113.5)	354.0 (106.2)	<0.001 (&=<0.001, #=<0.001)
Mean SpO2 6MWD, %	90.54 (3.82)	93.50 (2.07)	88.47 (2.60)	86.76 (3.15)	<0.001 (*=<0.001, &=<0.001, #=0.003)
FEV1, % pred.	61.5 (23.6)	72.3 (21.1)	57.5 (21.5)	42.9 (18.3)	<0.001 (*=<0.001, &=<0.001, #=0.002)
FVC, % pred.	87.1 (21.7)	95.0 (20.6)	83.1 (20.4)	75.5 (19.4)	<0.001 (*=0.003, &=<0.001)
FEV1/FVC,%	53.3 (16.8)	57.6 (12.4)	52.7 (20.7)	44.0 (15.3)	<0.001 (&=<0.001, #=0.033)
RV, % pred.	143.7 (49.1)	133.3 (36.0)	149.3 (49.1)	159.9 (68.0)	0.027 (&=0.034)
CI, score	1.6 (0.3)	1.6 (0.3)	1.6 (0.3)	1.8 (0.3)	<0.001 (&=0.002, #=0.001)
SI, score	2.8 (1.6)	2.8 (1.5)	2.5 (1.7)	3.4 (1.4)	0.023 (#=0.020)
PaO2/FiO2	340 (54)	366 (44)	337 (47)	284 (42)	<0.001 (*=<0.001, &=<0.001, #=<0.001)
PaCO2, mmHg	37.94 (4.78)	36.9 (4.1)	37.6 (4.2)	40.7 (5.8)	<0.001 (&=<0.001, #=0.003)
MVC quadriceps, kg	30.4 (10.6)	29.8 (10.2)	31.8 (11.6)	29.4 (10.3)	0.422
MVC biceps, kg	22.0 (7.4)	22.8 (7.7)	22.4 (7.3)	19.8 (6.2)	0.079
MIP, cmH2O	75.0 (23.3)	72.4 (25.0)	76.2 (19.8)	79.0 (24.0)	0.286
MEP, cmH2O	101.3 (34.6)	102.1 (35.7)	101.9 (32.9)	98.4 (33.6)	0.839
EQ-5D, score	0.68 (0.34)	0.72 (0.31)	0.71 (0.30)	0.54 (0.47)	0.035 (&=0.037)
EQ-5D-VAS	64.0 (19.7)	66.3 (19.5)	62.2 (21.7)	61.0 (15.0)	0.333

Notes: P=ANOVA test. In brackets P of post hoc analysis with Bonferroni correction: #= LTOT vs HYPOX; & = LTOT vs COPD; * = COPD vs HYPOX.

Abbreviations: 6MWD, 6-min walk distance; BMI, body mass index; CI, Comorbidity Index; COPD, chronic obstructive pulmonary disease; EQ-5D, EuroQol five dimension questionnaire; EQ-5D-VAS, EuroQol five dimension – VAS; FEV_1, forced expiratory flow in one second; FVC, forced vital capacity; MEP, maximal expiratory pressure; MIP, maximal inspiratory pressure; MVC, maximal voluntary contraction; PaCO₂, arterial carbon dioxide tension; PaO₂, arterial oxygen tension; SI, Severity Index.

Table 2 Physical Activity Profiles of the Whole Study Population and Patients Subdivided into 3 Groups

	Overall (n=200)	COPD (n=96)	HYPOX (n=63)	LTOT (n=41)	P
Total Energy Expenditure, Cal/day	2219 (537)	2264 (592)	2261 (503)	2049 (418)	0.074
Energy expenditure, mean METs	1.3 (0.5)	1.3 (0.3)	1.3 (0.2)	1.2 (0.2)	0.034 (&=0.035)
Time spent lying down, min/day	509.9 (127.8)	528.9 (112.6)	489.5 (150.0)	496.0 (121.1)	0.122
Time spent sleeping, min/day	412.0 (122.8)	422.2 (114.1)	404.4 (139.7)	398.7 (117.5)	0.523
Energy expenditure < 1.5 METs, min/day	1107.1 (203.9)	1069.3 (242.8)	1104.9 (149.1)	1199.1 (142.7)	0.003 (&=0.002)
Time spent > 3.0 METs, min/day	82.6 (155.0)	112.0 (209.8)	66.4 (72.1)	38.6 (50.6)	0.025 (&=0.035)
Daily steps, steps/day	5033 (3304)	5740 (3486)	5394 (3150)	2822 (1908)	<0.001 (&=<0.001, #=0.001)
Sedentary time, min/day	689.2 (220.4)	642.7 (254.8)	692.3 (160.8)	794.3 (168.3)	0.001 (&=0.001)

Notes: P=ANOVA test. In brackets P of post hoc analysis with Bonferroni correction: & = LTOT vs.COPD, # = LTOT vs HYPOX.

Figure 1 Daily steps. ANOVA test p<0.001. Difference between groups: *LTOT vs HYPOX: p<0.001; °LTOT vs COPD: p<0.001.

Figure 2 Comparison of total energy expenditure (Cal/day) between trolley and portable cylinder users in the LTOT group. Difference between groups: *p=0.022. Portable Cyl= portable cylinder. Cal/day=Calories/day.

Table 3 Correlations Between Daily Steps and Parameters of Physical Activity

	R	P
Total Energy Expenditure, Cal/day	0.5889	<0.001
Energy expenditure, mean METs	0.4212	<0.001
Time spent lying down, min/day	−0.2298	0.001
Time spent sleeping, min/day	−0.1811	0.013
Energy expenditure <1.5 METs, min/day	−0.4117	<0.001
Time spent > 3.0 METs, min/day	0.4136	<0.001
Sedentary time, min/day	−0.2880	<0.001

Table 4 Significant Correlations Between Patient Characteristics and Daily Steps

	All Patients		COPD		HYPOX		LTOT
	R	P	R	P	R	P	R	P
Age, years	−0.2853	<0.001	−0.4581	<0.001	−0.3151	0.012
BMI, kg/m^2
6MWD, m	0.5798	<0.001	0.5106	<0.001	0.5736	<0.001	0.5418	<0.001
Mean SpO2 during 6MWD, %	0.1692	0.023
FEV1, % pred.	0.3054	<0.001					0.4725	0.002
FVC, % pred.	0.2893	<0.001			0.3173	0.017
FEV1/FVC,%	0.1692	0.023
RV, % pred.	−0.1878	0.023			−0.3149	0.040
CI, score	0.1651	0.027					−0.3955	0.015
SI, score							−0.3653	0.026
PaO2/FiO2	0.5222	<0.001	0.3700	0.001	0.5453	<0.001	0.4298	0.005
PaCO2, mmHg
MVC quadriceps, Kg	0.3043	<0.001	0.2502	0.014	0.4453	<0.001
MVC biceps, kg	0.2991	<0.001			0.4921	<0.001
MIP, cmH2O	0.1693	0.017	0.2223	0.029	0.3039	0.015
MEP, cmH2O	0.2489	0.001			0.4050	0.001
EQ-5D, score							0.4721	0.007
EQ-5D-VAS	0.2896	0.001

Notes: Color legend: pale yellow = weak correlation (r=|0-0.299|), pale pink = moderate correlation (r=|0.3–0.499|), red = strong correlation (r >|0.5|), grey= no significant correlation.³⁰

Abbreviations: BMI, Body-Mass Index; CI, Comorbidity Index; EQ-5D, EuroQol five dimension questionnaire; EQ-5D-VAS, EuroQol five dimension – VAS; FEV₁, Forced Expiratory Flow in one second; FVC, Forced Vital Capacity; MIP, Maximal Inspiratory Pressure; MEP, Maximal Expiratory Pressure; MVC, Maximal Voluntary Contraction; PaCO², arterial carbon dioxide tension; PaO₂, arterial oxygen tension; RV, Residual volume; SI, Severity Index; 6MWD, Six minute walk distance.

Pickard AS, Wilke C, Jung E, Patel S, Stavem K, Lee TA. Use of a preference-based measure of health (EQ-5D) in COPD and asthma. Respir Med. 2008;102(4):519–536. doi:10.1016/j.rmed.2007.11.01618180151

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