Reliability, validity and responsiveness of E-RS:COPD in patients with spirometric asthma-COPD overlap

Respiratory Research

Table 2 Inter-item correlations^a for E-RS items and wheeze item at Day − 1 for the Overall population (N = 328)

Variable	Chest congested	Cough	Mucus when coughing	Difficulty with mucus	Chest discomfort	Chest tight	Breathless	How breathless	Short of breath with personal care	Short of breath with indoor	Short of breath with outdoor	Wheeze
1. Chest congested	1	0.5	0.5	0.6	0.6	0.6	0.5	0.5	0.5	0.5	0.5	0.5
2. Cough	0.5	1	0.6	0.5	0.5	0.4	0.4	0.3	0.3	0.4	0.4	0.4
3. Mucus when coughing	0.5	0.6	1	0.5	0.3	0.2	0.2	0.2	0.3	0.3	0.2	0.3
4. Difficulty with mucus	0.6	0.5	0.5	1	0.4	0.4	0.4	0.4	0.4	0.5	0.4	0.5
5. Chest discomfort	0.6	0.5	0.3	0.4	1	0.8	0.6	0.5	0.5	0.5	0.5	0.5
6. Chest tight	0.6	0.4	0.2	0.4	0.8	1	0.6	0.5	0.5	0.5	0.5	0.5
7. Breathless	0.5	0.4	0.2	0.4	0.6	0.6	1	0.7	0.5	0.6	0.7	0.5
8. How breathless	0.5	0.3	0.2	0.4	0.5	0.5	0.7	1	0.5	0.5	0.6	0.5
9. Short of breath with personal care	0.5	0.3	0.3	0.4	0.5	0.5	0.5	0.5	1	0.7	0.6	0.4
10. Short of breath (indoor)	0.5	0.4	0.3	0.5	0.5	0.5	0.6	0.5	0.7	1	0.7	0.4
11. Short of breath (outdoor)	0.5	0.4	0.2	0.4	0.5	0.5	0.7	0.6	0.6	0.7	1	0.5
Wheeze	0.5	0.4	0.3	0.5	0.5	0.5	0.5	0.5	0.4	0.4	0.5	1

^aData were analyzed using Spearman’s correlation
Correlations > 0.40 and > 0.70 were defined as moderate and strong, respectively
E-RS Evaluating Respiratory Symptoms in chronic obstructive pulmonary disease

ISSN: 1465-993X