Validity: correlation with related constructs and alternative measures
| E-RS scale† | |||||
|---|---|---|---|---|---|
| Measure | n* | Total score | Breathlessness | Cough & Sputum | Chest Symptoms |
| SGRQ total | 181 | 0.75*** | 0.69*** | 0.58*** | 0.52*** |
| Symptoms | 188 | 0.66*** | 0.44*** | 0.69*** | 0.60*** |
| Activity | 184 | 0.57*** | 0.68*** | 0.31*** | 0.26*** |
| Impact | 181 | 0.70*** | 0.61*** | 0.55*** | 0.54*** |
| mMRC | 188 | 0.33*** | 0.38*** | 0.24** | 0.16* |
| Rescue medication use | 188 | 0.32*** | 0.34*** | 0.26** | 0.17* |
| FEV1% predicted | 188 | −0.10 | −0.17* | −0.05 | 0.01 |
†Sample sizes are a function of missing item-level data.
‡Day 1, Spearman's rank-order correlation.
Bold coefficients identify related constructs with strongest expected value.
*p<0.05; **p<0.001; ***p<0.0001.
E-RS, Exacerbations of Chronic Pulmonary Disease Tool-Respiratory Symptoms; FEV1, forced expiratory volume in 1 s; mMRC, modified Medical Research Council; SGRQ, St George's Respiratory Questionnaire.