Table 1.

The primary COPD-EQ questionnaire obtained by the Delphi method

Response choices by item questions	Choice id
How old are you?
Aged 25–49	Item-1: age_0
Aged 50–59	Item-1: age_1
Aged 60–69	Item-1: age_2
Aged ≥70	Item-1: age_3
How many cigarettes have you smoked? (packs per year)
0	Item-2: smoking_amount_0
0–10	Item-2: smoking_amount_1
10–20	Item-2: smoking_amount_2
>20	Item-2: smoking_amount_3
Have you been exposed to biomass smoke for more than half a year?
No	Item-3: bio_fuel_0
Yes	Item-3: bio_fuel_1
During the past year, how much of time did you feel short of breath?
None of the time	Item-4: short_breathe_0
A little of the time	Item-4: short_breathe_1
Some of the time	Item-4: short_breathe_2
Most of the time	Item-4: short_breathe_3
All the time	Item-4: short_breathe_4
When do you have dyspnoea?
No dyspnoea	Item-5: dyspnoea_0
During strenuous activities	Item-5: dyspnoea_1
During walking quickly on the flat ground or climbing a small slope	Item-5: dyspnoea_2
Slower than peers when walking on the flat ground, or needs to rest	Item-5: dyspnoea_3
Severe dyspnoea leads to inability to leave home, or dyspnoea when wearing and undressing	Item-5: dyspnoea_4
Do you often cough when you don't have a cold?
No	Item-6: cough_0
Yes	Item-6: cough_1
Have you ever coughed up something, such as mucus or sputum?
Never	Item-7: cough_up_0
Yes, cough occasionally when having a cold or chest infection	Item-7: cough_up_1
Yes, cough for a few days every month	Item-7: cough_up_2
Yes, cough for most days	Item-7: cough_up_3
Yes, cough every day	Item-7: cough_up_4
Did you suffer from chronic respiratory disease as a child?
No	Item-8: childhood_ resp_disease_0
Yes	Item-8: childhood_ resp_disease_1
Whether your first-degree relatives (parents, children, siblings) have a history of respiratory disease (such as chronic bronchitis, emphysema, asthma)?
No	Item-9: relatives_medical_history_0
Yes	Item-9: relatives_medical_history_1