The Assessment of Burden of COPD (ABC) Scale: A Reliable and Valid Questionnaire

Figures & data

Figure 1. Visualization of the integrated health status, including the five domains of the ABC scale, and including a grey balloon.

Table 1. Baseline characteristics of the study population (n = 162).

Male sex, n (%)	83 (51.2)
Age, years, mean (SD)	64.2 (8.6)
Recruiting health care provider
General practitioners, n (%)	88 (54.3)
Pulmonologist, n (%)	74 (45.7)
Diagnosed COPD since, n (%)
<1 year	11 (6.8)
1-3 year(s)	39 (24.1)
>3 years	99 (61.1)
Unknown	13 (8.0)
FEV1/FVC ratio, mean (SD)	48.7 (12.8)
FEV1, % predicted, mean (SD)	57.2 (17.8)
GOLD stage, n (%)
1 (FEV1 >80% predicted)	14 (8.6)
2 (FEV1 50-80% predicted)	89 (54.9)
3 (FEV1 30-50% predicted)	50 (30.9)
4 (FEV1 <30% predicted)	9 (5.6)
Number of exacerbations/year, n (%)
0	74 (45.7)
1	45 (27.8)
2	21 (13.0)
>2	22 (13.6)
ABC scale T0, mean (SD)
Total score	1.71 (0.89)
Symptoms	2.18 (1.07)
Functional state	1.68 (1.06)
Mental state	0.91 (1.02)
Emotions	1.39 (1.13)
Fatigue	2.36 (1.38)
ABC scale T- 2wks, mean (SD)^*
Total score	1.68 (0.83)
Symptoms	2.11 (0.95)
Functional state	1.61 (1.06)
Mental state	0.83 (1.00)
Emotions	1.47 (1.18)
Fatigue	2.39 (1.35)
SGRQ total score, mean (SD)	39.66 (17.64)
SGRQ activity domain score	44.46 (23.55)
HADS total score, mean (SD)	9.45 (7.00)
HADS depression subscale	4.34 (3.61)
HADS anxiety subscale	5.11 (3.96)

^aAbbreviations: SD: standard deviation, COPD: Chronic Obstructive Pulmonary Disease, FEV₁; Forced Expiratory Volume in 1 second, FVC: Forced Vital Capacity, GOLD: Global Initiative for Chronic Obstructive Lung Disease, ABC scale: Assessment of Burden of COPD-scale, SGRQ: Saint-George Respiratory Questionnaire, HADS: Hospital Anxiety and Depression Scale.

^bT0: baseline measurement of ABC scale together with all other questionnaires (demographics, SGRQ, HADS); T-2wks: measurement of ABC scale only, 2 weeks prior to T0.

^c*: n = 137.

Table 2. ABC scale subscale scores of known groups.

	Known groups, median (interquartile range)
	Exacerbations/year			Gold stage			Activity			Depression
ABC	≥2	<2		3+4	1+2		Inactive†	Active†		(Borderline) Depressed‡	Non-depressed ‡
Subscales	(n = 43)	(n = 119)	p	(n = 59)	(n = 103)	p	(n = 81)	(n = 81)	p	(n = 31)	(n = 131)	p
Symptoms	2.8 (1.8–3.5)	2.0 (1.3–2.5)	0.001^**	2.5 (1.8–3.5)	2.0 (1.3–2.5)	<0.001^**	2.3 (1.6–3.3)	1.8 (1.3–2.5)	0.002^**	2.3 (2.0–3.3)	2.0 (1.5–2.8)	0.027^*
Functional state	2.5 (1.5-3.0)	1.5 (0.8-2.0)	<0.001^**	2.5 (1.5-2.8)	1.3 (0.5-2.0)	<0.001^**	2.5 (1.5-2.9)	1.0 (0.5-1.8)	<0.001^**	2.5 (1.5-2.8)	1.5 (0.8-2.3)	0.001^**
Mental state	1.0 (0.5-2.0)	0.5 (0.0-1.5)	0.008^**	1.0 (0.0-2.0)	0.5 (0.0-1.0)	<0.001^**	1.0 (0.3-2.0)	0.5 (0.0-1.0)	<0.001^**	1.5 (1.0-2.0)	0.5 (0.0-1.0)	<0.001^**
Emotions	1.7 (1.0-2.7)	1.3 (0.3-2.0)	0.033^*	1.3 (0.7-2.3)	1.3 (0.3-2.0)	0.236 ^NS	1.3 (1.0-2.3)	1.0 (0.3-1.8)	0.007^**	2.3 (1.7-3.0)	1.0 (0.3-1.7)	<0.001^**
Fatigue	3.0 (2.0-4.0)	2.0 (1.0-3.0)	0.005^**	2.0 (1.0-3.0)	2.0 (2.0-3.0)	0.724 ^NS	3.0 (2.0-4.0)	2.0 (1.0-3.0)	<0.001^**	3.0 (3.0-5.0)	2.0 (1.0-3.0)	<0.001^**

^aAbbreviations: ABC scale: Assessment of Burden of COPD scale, GOLD: Global Initiative for Chronic Obstructive Lung Disease, p: p-value.

^bSignificance calculated by the Mann–Whitney-U test, depicted as: ^**P < 0.01 ^*P < 0.05 NS: non-significant.

^cABC scale: range 0 – 6: 0 indicating no burden of COPD and 6 indicating the worst burden of COPD.

^d†: Patients were divided according to their score on the subscale Activity on the Saint George Respiratory Questionnaire (SGRQ), the median score (47.6470) was used as cut-off point.

^e‡: As defined by their scores on the Hospital Anxiety and Depression Scale (HADS) depression subscale. A cut-off score of ≥8 was used to discriminate between patients with depression or borderline depression and patients with no depression.

Table

On average, during the past week, how often did you feel:
		Hardly	A few	Several	Many	A great	Almost all
	Never	ever	times	times	times	many times	the time
1 Short of breath at rest?	□	□	□	□	□	□	□
2 Short of breath doing physical activities?	□	□	□	□	□	□	□
3 Concerned about getting a cold or your breathing getting worse?	□	□	□	□	□	□	□
4 Depressed (down) because of your breathing problems?	□	□	□	□	□	□	□
In general, during the past week, how much of the time:
		Hardly	A few	Several	Many	A great	Almost all
	Never	ever	times	times	times	many times	the time
5 Did you cough?	□	□	□	□	□	□	□
6 Did you produce phlegm?	□	□	□	□	□	□	□
On average, during the past week, how limited were you in these activities because of your breathing problems:
	Not limited	Very slightly	Slightly	Moderately	Very	Extremely	Totally limited/
	at all	limited	limited	limited	limited	limited	or unable to do
7 Strenuous physical activities (such as climbing stairs, hurrying, doing sports)?	□	□	□	□	□	□	□
8 Moderate physical activities (such as walking, house work, carrying things)?	□	□	□	□	□	□	□
9 Daily activities at home (such as dressing, washing yourself)?	□	□	□	□	□	□	□
10 Social activities (such as talking, being with children, visiting friends/relatives)?	□	□	□	□	□	□	□
How often in the past week did you suffer from:
		Hardly	A few	Several	Many	A great	Almost all
	Never	ever	times	times	times	many times	the time
11 Worry?	□	□	□	□	□	□	□
12 Listlessness?	□	□	□	□	□	□	□
13 A tense feeling?	□	□	□	□	□	□	□
14 Fatigue?	□	□	□	□	□	□	□

Table

	Assessment of Burden of COPD (ABC) scale
	Symptoms	p	Functional state	p	Mental state	p	Emotions	p	Fatigue	p	Total	p
Convergent validity (n = 133)
SGRQ
Symptoms	0.665	<0.001	0.629	<0.001	0.621	<0.001	0.417	<0.001	0.492	<0.001	0.713	<0.001
Activity	0.416	<0.001	0.750	<0.001	0.372	<0.001	0.144	0.008	0.470	<0.001	0.547	<0.001
Impact	0.535	<0.001	0.726	<0.001	0.509	<0.001	0.324	<0.001	0.537	<0.001	0.669	<0.001
Total	0.605	<0.001	0.794	<0.001	0.560	<0.001	0.324	<0.001	0.560	<0.001	0.721	<0.001
Discriminant validity (n = 162)
FEV1 % predicted	−0.265	<0.001	−0.454	<0.001	−0.281	<0.001	−0.027	0.73	−0.123	0.12	−0.282	<0.001

^aAbbreviations: SGRQ: Saint-George Respiratory Questionnaire, FEV₁ % predicted: Forced Expiratory Volume in 1 second, as a percentage of predicted for age group, ABC scale: Assessment of Burden of COPD scale. ^b Due to non-normal distribution of data regarding the subscales of the ABC scale, Spearman's rank correlation coefficient was calculated.

^cABC scale: range 0 – 6: 0 indicating no burden of COPD and 6 indicating the worst burden of COPD. SGRQ: Saint George Respiratory Questionnaire, range (0-100) (higher score indicates worse Health related Quality of Life).