Self-reported daily walking time in COPD: relationship with relevant clinical and functional characteristics

Figures & data

Table 1 Sociodemographic, clinical, and functional characteristics of the patients included in different studies

Parameter	All# n=5,969	INSEPOC n=2,026	FYCEPOC n=2,735	NEREA n=622	DEPREPOC n=586
Age (years)	67.5 (9.6)	67.4 (9.6)	67.0 (9.6)	68.8 (10.0)	68.8 (9.1)
Sex (male)	5,145 (86.3)	1,831 (90.4)	2,273 (83.1)	546 (87.9)	495 (85.1)
Active smokers	1,394 (23.4)	534 (26.5)	616 (23.7)	126 (20.7)	118 (20.31)
Body mass index (kg/m^2)	27.8 (4.4)	27.9 (4.4)	27.7 (4.3)	27.7 (4.1)	27.5 (4.6)
Comorbidities (Charlson index)	2 (1–3)	2 (1–3)	2 (1–2)	2 (1–3)	2 (1–3)
mMRC (n=3,937)
0	246 (6.3)	–	170 (6.2)	51 (8.3)	25 (4.2)
1	1533 (38.9)	–	1,027 (37.5)	299 (48.4)	207 (35.4)
2	1373 (34.9)	–	987 (36.1)	159 (25.8)	227 (38.8)
3	665 (16.9)	–	459 (16.8)	88 (14.3)	118 (20.2)
4	120 (3.0)	–	92 (3.4)	20 (3.2)	8 (1.4)
Ambulatory COPD exacerbation¶	1 (0–2)	2 (1–3)	1 (0–2)	1 (1–2)	2 (1–3)
COPD admissions¶	0 (0–1)	0 (0–1)	0 (0–1)	0 (0–1)	1 (0–2)
FEV1 (% predicted)	50.7 (17.2)	47.7 (16.2)	51.9 (17.9)	52.8 (15.9)	52.8 (16.7)
FEV1 levels
≧80% predicted	319 (5.3)	71 (3.5)	201 (7.4)	18 (2.9)	29 (4.9)
≧50% and <80% predicted	2,634 (44.1)	784 (38.7)	1,225 (44.8)	325 (52.3)	300 (51.2)
≧30% and <50% predicted	2,315 (38.8)	878 (43.3)	1,002 (36.6)	226 (36.3)	209 (35.7)
<30% predicted	701 (11.7)	293 (14.5)	307 (11.2)	53 (8.5)	48 (8.2)
GOLD groups (n=3,209)
A	156 (4.9)	–	141 (5.3)	–	15 (2.8)
B	542 (16.9)	–	491 (18.3)	–	51 (9.7)
C	168 (5.2)	–	146 (5.5)	–	22 (4.2)
D	2,343 (73.0)	–	1,903 (70.9)	–	440 (83.3)
BODEx index (n=3,765)	2 (1–4)	–	2 (1–4)	2 (1–4)	3 (2–4)
CAT (n=3,262)	20.0 (8.3)	–	19.2 (8.2)	–	21.2 (8.1)

Notes: Data are presented as n (%), mean (SD), or median (percentile 25–p75).

# Some variables have missing values: 27 in age, 9 in sex, 169 in active smoker, 54 in body mass index, 165 in ambulatory COPD exacerbation, and 135 in COPD admissions.

¶ Number of events in the previous 12 months.

Abbreviations: BODEx, body mass index, airway obstruction, dyspnea, exacerbation; CAT, COPD assessment test; DEPREPOC, Depression in patients with COPD; FEV₁, forced expiratory volume in the first second; FYCEPOC, Phenotypes and quality of life of patients with COPD; GOLD, Global Initiative for Chronic Obstructive Lung Disease; INSEPOC, Impact of socio-economic status on quality of life of COPD patients; mMRC, modified Medical Research Council dyspnea score; NEREA, New severity scale for COPD in primary care; SD, standard deviation.

Table 2 Self-reported daily walking time according to different characteristics related to disease severity

Characteristics	Patients (n)	Self-reported daily walking time (min/day)
		Mean (SD)	<30 min/day n (%)	≥30 min/day n (%)
mMRC dyspnea score
0–1	1,779	73 (46)	161 (9.1)	1,618 (90.9)
2	1,373	61 (42)	181 (13.2)	1,192 (86.8)
3	665	48 (40)	187 (28.1)	478 (71.9)
4	120	25 (29)	77 (64.2)	43 (35.8)
FEV1 levels
≧80% predicted	319	64 (47)	48 (15.1)	271 (84.9)
≧50% and <80% predicted	2,634	68 (47)	306 (11.6)	2,328 (88.4)
≧30% and <50% predicted	2,315	64 (46)	381 (16.4)	1,934 (83.6)
<30% predicted	701	60 (47)	158 (22.5)	543 (77.5)
COPD admissions¶
0	3,457	71 (48)	398 (11.4)	3,063 (88.6)
1	1,288	63 (46)	198 (15.4)	1,090 (84.6)
2	598	55 (44)	144 (24.1)	454 (75.9)
>2	491	49 (41)	142 (28.9)	349 (71.1)
CAT
<10	522	76 (48)	41 (7.8)	481 (92.2)
10–20	1,212	66 (43)	148 (12.2)	1,064 (87.8)
20–30	1,224	56 (39)	239 (19.5)	985 (80.5)
>30	304	44 (38)	94 (30.9)	210 (69.1)
GOLD groups
A	156	80 (49)	8 (5.1)	148 (94.9)
B	542	64 (42)	66 (12.2)	476 (87.8)
C	168	79 (50)	13 (7.7)	155 (92.3)
D	2,343	58 (42)	431 (18.4)	1,912 (81.6)
BODEx index
0–1	1,082	70 (44)	87 (8.0)	995 (92.0)
2	821	67 (45)	103 (12.6)	718 (87.4)
3–4	1,180	61 (45)	186 (15.8)	994 (84.2)
>4	682	48 (41)	209 (30.7)	473 (69.3)
Charlson index
1	2,302	69 (48)	283 (12.3)	2,019 (87.7)
2	2,045	67 (46)	283 (13.8)	1,762 (86.2)
3	1,080	60 (44)	185 (17.1)	895 (82.9)
≧4	542	55 (47)	142 (26.2)	400 (73.8)

Note:

¶ Number of events in the previous 12 months.

Abbreviations: BODEx, body mass index, airway obstruction, dyspnea, exacerbation; CAT, COPD assessment test; COPD, chronic obstructive pulmonary disease; FEV₁, forced expiratory volume in the first second; GOLD, Global Initiative for Chronic Obstructive Lung Disease; mMRC, modified Medical Research Council dyspnea scale; SD, standard deviation.

Figure 1 Distribution of self-reported daily walking times in the 5,969 COPD study patients.

Abbreviation: COPD, chronic obstructive pulmonary disease.

Figure 2 Self-reported daily walking times according to (A) mMRC, (B) FEV₁% predicted, (C) COPD admissions in the previous 12 months, (D) CAT, (E) GOLD A–D groups, (F) BODEx index, and (G) Charlson index of comorbidities. Data are presented as mean values with 95% confidence intervals.

Abbreviations: BODEx, body mass index, airway obstruction, dyspnea, exacerbation; CAT, COPD assessment test; COPD, chronic obstructive pulmonary disease; FEV₁, forced expiratory volume in the first second; GOLD, Global Initiative for Chronic Obstructive Lung Disease; mMRC, modified Medical Research Council dyspnea scale.

Figure 3 Percentage of patients with self-reported walking time <30 min/day (), between 30 and 60 min/day (), and >60 min/day () according to (A) mMRC, (B) FEV₁% predicted, (C) COPD admissions in the previous 12 months, (D) CAT, (E) GOLD A–D groups, (F) BODEx index, and (G) Charlson index of comorbidities. Abbreviations: BODEx, body mass index, airway obstruction, dyspnea, exacerbation; CAT, COPD assessment test; COPD, chronic obstructive pulmonary disease; FEV₁, forced expiratory volume in the first second; GOLD, Global Initiative for Chronic Obstructive Lung Disease; mMRC, modified Medical Research Council dyspnea scale.

Table 3 ORs for the determinants of reduced self-reported walking time

Determinant	OR for self-reported walking time <30 min/day (95% CI)	P-value
mMRC dyspnea score
0–1	1.00
2	1.86 (1.57–2.20)	<0.001
3	3.57 (2.92–4.37)	<0.001
4	16.35 (11.07–24.13)	<0.001
FEV1 levels
≧80% predicted	1.00
≧50% and <80% predicted	0.74 (0.53–1.03)	0.080
≧30% and <50% predicted	1.11 (0.80–1.54)	0.522
<30% predicted	1.64 (1.15–2.34)	0.006
COPD admissions¶
0	1.00
1	1.41 (1.17–1.70)	<0.001
2	2.47 (1.99–3.06)	<0.001
>2	3.16 (2.53–3.95)	<0.001
CAT
<10	1.00
10–20	1.63 (1.14–2.34)	0.008
20–30	2.85 (2.01–4.03)	<0.001
>30	5.25 (3.52–7.84)	<0.001
GOLD groups
A	1.00
B	2.57 (1.20–5.47)	0.015
C	1.55 (0.63–3.85)	0.344
D	4.17 (2.03–8.56)	<0.001
BODEx index
0–1	1.00
2	1.52 (1.19–1.93)	0.001
3–4	2.10 (1.70–2.60)	<0.001
>4	5.08 (4.06–6.37)	<0.001
Charlson index
1	1.00
2	1.15 (0.96–1.37)	0.131
3	1.47 (1.21–1.80)	<0.001
≧4	2.53 (2.01–3.18)	<0.001

Note:

¶ Number of events in the previous 12 months.

Abbreviations: 95% CI, 95% confidence interval; BODEx, body mass index, airway obstruction, dyspnea, exacerbation; CAT, COPD assessment test; COPD, chronic obstructive pulmonary disease; FEV₁, forced expiratory volume in the first second; GOLD, Global Initiative for Chronic Obstructive Lung Disease; mMRC, modified Medical Research Council dyspnea scale; OR, odds ratio.