Table 4.
Stepwise multiple linear regression analysis for D6MWT
| Variables | Coefficient (95% CI) | Standardized β | P-value | VIF |
|---|---|---|---|---|
|
| ||||
| Intercept | 741.063 (651.726–830.400) | |||
| mMRC grade | −17.986 (−34.754 to −1.218) | −0.288 | 0.036* | 2.245 |
| Age (years) | −2.328 (−3.516 to −1.140) | −0.357 | <0.001* | 1.036 |
| CAT score | −4.069 (−7.602 to −0.536) | −0.306 | 0.025* | 2.198 |
| Adjusted R2=0.445 | ||||
*
Notes: Statistical significance. Variables: age, FVC, FEV1, DLCO, RV/TLC, R20, 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; D6MWT, distance of 6-minute walk test; DLCO, diffusing capacity of the lungs for carbon monoxide; mMRC, modified Medical Research Council dyspnea scale; R20, reactance at 20 Hz; RV, residual volume; SGRQ, St George’s Respiratory Questionnaire; TLC, total lung capacity; VIF, variance inflation factor; X5, reactance at 5 Hz.