Table 5.
Stepwise multiple linear regression analysis for S6MWT
| Variable | Coefficient (95% CI) | Standardized β | P-value | VIF |
|---|---|---|---|---|
|
| ||||
| Intercept | 699.972 (634.661–765.283) | |||
| DLCO (% predicted) | 1.126 (0.576–1.677) | 0.429 | <0.001* | 1.306 |
| CAT score | −3.571 (−5.812 to −1.329) | −0.334 | 0.002* | 1.306 |
| Adjusted R2=0.417 | ||||
*
Notes: Statistical significance; r: correlation coefficient. Variables: IC, FVC, FEV1, SpO2, DLCO, RV/TLC, X5, mMRC grade, SGRQ score, CAT score and CCQ score.
Abbreviations: β, regression coefficient; CAT, Chronic Obstructive Pulmonary Disease Assessment Test; CCQ, Clinical Chronic Obstructive Pulmonary Questionnaire; DLCO, diffusing capacity of the lungs for carbon monoxide; IC, inspiratory capacity; mMRC, modified Medical Research Council dyspnea scale; RV, residual volume; S6MWT, steps of 6-minute walk test; SGRQ, St George’s Respiratory Questionnaire; TLC, total lung capacity; VIF, variance inflation factor.