Table 4.
Convergent validity: correlation between variables suspected of being related to cough and LCQ-Sp total score.
| Variables | Rho Spearman | Median LCQ-Sp | Interquartile range (25–75%) LCQ-Sp | p |
|---|---|---|---|---|
| mMRC | <0.001 | |||
| 0 | — | 18.50 | 15.81–19.85 | |
| 1 | — | 16.26 | 13.66–18.89 | |
| 2 | — | 14.96 | 11.89–16.54 | |
| 3 | — | 12.93 | 9.78–15.01 | |
| 4 | — | 0 | 0 | |
| Sputum purulence | 0.070 | |||
| No expectoration/mucous | — | 18.88 | 14.98–20.30 | |
| Mucopurulent | — | 16.62 | 15.07–19.33 | |
| Purulent | — | 16.85 | 13.04–18.94 | |
| Chronic bronchial colonisation | 0.283 | |||
| None | — | 17.07 | 16.20–20.01 | |
| Pseudomonas aeruginosa | — | 16.43 | 13.31–19.07 | |
| Other than Pseudomonas | — | 17.21 | 13.73–19.78 | |
| FEV1% predicted | 0.210 | — | — | 0.016 |
| 24-h sputum volume (mL) | −0.328 | — | — | <0.001 |
| Number of affected lobes | 0.071 | — | — | 0.427 |
FEV1: forced expiratory volume in 1 s; LCQ: Leicester Cough Questionnaire; LCQ-Sp: Spanish version of the LCQ; mMRC: modified Medical Research Council.