Impact of current cough on health-related quality of life in patients with COPD

Figures & data

Table 1 Clinical characteristics of the population (N=178)

Variables	Missing data, n	Median (Q1–Q3) or n (%)
Age, years	0	62 (56–69)
Male	0	128 (72)
Smoking, pack-year	2	36 (24–53)
Current smokers	2	63 (36)
Body mass index	0	25 (22–29)
Chronic bronchitis	8	123 (69)
Exacerbations in previous year	1
0		61 (34)
1		51 (29)
>2		65 (37)
Congestive heart failure and coronary artery disease	0	41 (23)
mMRC dyspnea scale	4
0		19 (11)
1		69 (40)
2		44 (25)
3		37 (21)
4		5 (3)
FEV1	0	57 (37–72)
Anxiety HADS ≥10	6	49 (28)
Depression HADS ≥10	5	29 (16)
SGRQ total score	0	44 (29–57)
CASA-Q score
Cough symptoms	0	70.8 (50.0–91.7)
Cough impact	1	84.4 (59.4–100.0)
Sputum symptoms	5	66.7 (41.7–88.1)
Sputum impact	6	87.5 (66.7–100.0)

Note: Data are presented as median (Q1–Q3) or number (n) and percentage (%).

Abbreviations: CASA-Q, cough and sputum assessment questionnaire; FEV₁, forced expiratory volume in 1 second; HADS, Hospital Anxiety Depression Scale with higher scores indicating more severe symptoms; mMRC, modified Medical Research Council dyspnea score from 0 to 4 with higher score indicating more severe dyspnea; SGRQ, Saint George’s Respiratory Questionnaire ranging from 0 to 100 with lower score indicating more severe health-related quality of life impairment.

Figure 1 CASA-Q scores for each domain and chronic bronchitis.

Notes: The CASA-Q assessed symptoms and impact in the previous 7 days. Chronic bronchitis was defined as daily cough and sputum production for at least 3 months each year during the past 2 years. All four CASA-Q domains (cough symptoms, cough impact, sputum symptoms, and sputum impact) were lower when chronic bronchitis was present (*P<0.0001), indicating more cough and sputum symptoms or impact.
Abbreviation: CASA-Q, cough and sputum assessment questionnaire.

Table 2 Associations between the total SGRQ score and other characteristics of patients in univariate analyses

Variables	R	P-value
Age	−0.02	0.7876
Sex		0.7049
Smoking, current		0.8014
Body mass index	−0.003	0.9586
Chronic bronchitis	−0.41	0.0002
Exacerbations (previous year)	0.391	<0.0001
Cardiovascular comorbidity		0.3377
mMRC dyspnea scale	0.602	<0.0001
FEV1	−0.372	<0.0001
Anxiety HADS ≥10		0.0001
Depression HADS ≥10		0.0002
CASA-Q score
Cough symptoms	−0.391	<0.0001
Cough impact	−0.586	<0.0001
Sputum symptoms	−0.263	0.0005
Sputum impact	−0.481	<0.0001

Abbreviations: CASA-Q, cough and sputum assessment questionnaire; FEV₁, forced expiratory volume in 1 second; HADS, Hospital Anxiety Depression Scale with higher scores indicating more severe symptoms; mMRC, modified Medical Research Council dyspnea score from 0 to 4 with higher score indicating more severe dyspnea; SGRQ, Saint George’s Respiratory Questionnaire ranging from 0 to 100 with lower score indicating more severe health-related quality of life impairment.

Table 3 Relationships between the SGRQ total score, and CASA-Q domain scores and clinical variables in multivariate analyses

Candidate variables	Model 1	Model 2	Model 3	Model 4	Model 5	Model 6	Model 7
CASA-Q cough impact	<0.0001	<0.0001	<0.0001
CASA-Q cough symptoms	0.0435	NS		0.00012
CASA-Q sputum impact	0.0581	NS			<0.0001
CASA-Q sputum symptoms	NS	NS				0.0020
FEV1, %		0.0058	0.0024	0.00019	0.0072	0.0068	0.0042
mMRC dyspnea scale		<0.0001	<0.0001	<0.0001	<0.0001	<0.0001	<0.0001
Exacerbations		0.0334	0.0266	0.0028	0.0320	0.0046	0.0037
Depression		0.0558	0.0229	0.0037	0.0338	0.0080	0.0017
Anxiety		0.0889	0.0995	0.0331	0.0542	0.0169	0.0090
Cardiovascular comorbidities		0.0072	0.00043	0.0019	0.0167	0.0101	0.0068
Chronic bronchitis							0.0498
R^2	0.38	0.60	0.62	0.56	0.58	0.54	0.54

Abbreviations: CASA-Q, cough and sputum assessment questionnaire; FEV₁, forced expiratory volume in 1 second; mMRC, modified Medical Research Council dyspnea score from 0 to 4 with higher score indicating more severe dyspnea; NS, not significant; SGRQ, Saint George’s Respiratory Questionnaire ranging from 0 to 100 with lower score indicating more severe health-related quality of life impairment.

Table S1 Cough and sputum assessment questionnaire (CASA-Q)

Question
Over the last 7 days:
1. How much did you cough when you woke up in the morning?
2. How often did you cough during the day?
3. How often did you have coughing bouts?
4. How often were you tired after coughing?
5. How often did coughing make you short of breath?
6. How annoyed were you by your cough?
7. How often did you avoid going to public places because of your cough (eg, movie theaters, restaurants, etc)?
8. How often were your usual activities interrupted by your cough (eg, driving, hobbies, working around the house)?
9. How often did your cough interrupt your conversations with others (eg, phone conversations and face-to-face)?
10. How often did your cough wake you up, prevent you from falling asleep or falling back to sleep?
11. How often were you uncomfortable about bothering other people while coughing?
12. How thick was your phlegm?
13. How often did you bring up phlegm?
14. How often did your phlegm make it difficult for you to breathe?
15. How difficult was it for you to bring up phlegm?
16. How often did you feel uncomfortable about bothering other people while bringing up phlegm?
17. How annoyed were you by your phlegm?
18. How often did your phlegm interfere with your ability to speak?
19. How often did your phlegm prevent you from going to public places (eg, movie theaters, restaurants, etc)?
20. How often did you have to interrupt your usual activities to get rid of your phlegm (eg, driving, hobbies, working around the house)?

Note: Each item is answered ranging from “never” to “always” or from “not at all” to “a lot/extremely”, as applicable; each type is answered using five categories.