Table 2.
Multivariate regression analysis for CAT score variance
| Variable | Model 1 | Model 2 | Model 3 |
|---|---|---|---|
| BDI score | 0.73 (0.04)*** | 0.65 (0.04)*** | 0.68 (0.05)*** |
| MMSE score | −0.23 (0.06)*** | −0.14 (0.06) | −0.13 (0.07)* |
| Age | 0.006 (0.02) | −0.07 (0.03)** | |
| Sex | −0.31 (0.66) | ||
| Post-bronchodilator | NA | −0.06 (0.02)*** | |
| FVC (%) | |||
| Post-bronchodilator | −0.03 (0.02) | ||
| FEV1 (%) | |||
| Post-bronchodilator | NA | −0.9 (0.02)*** | |
| FEV1/FVC | |||
| Dyspnea | −6.90 (1.35)*** | −6.60 (1.44)*** | |
| Previous exacerbations | −1.20 (0.72) | ||
| Charlson index | 0.66 (0.18)** | 0.60 (0.20)** | |
| r2 | 0.40 | 0.43 | 0.45 |
| p-value | <0.001 | <0.001 | <0.001 |
Notes: Data are presented as beta value (SE).
*
p<0.05,
**
p<0.01,
***
p<0.001. Model 1 only includes BDI and MMSE scores; Model 2 includes the whole set of variables, except FVC and FEV1/FVC due to collinearity; Model 3 stepwise automatic selection of variables with a p-value <0.15.
Abbreviations: BDI, Beck Depression Inventory; CAT, COPD assessment test; FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; MMSE, Mini-Mental State Examination; NA, not assessed; SE, standard error.