Table 3.
Mortality risks estimates using univariate and multivariate regression analysis on possible mortality confounders
| Confounders | Univariate analysis; HR (95% CI) | P-value | Multivariate analysis; adjusted HR (95% CI) | P-value |
|---|---|---|---|---|
| BMI <21 kg·m−2 | 1.36 (1.02–1.80) | 0.0327 | – | – |
| Presence of two or more comorbidities | 1.24 (1.05–1.47) | 0.0114 | – | – |
| Age (per 5 years of increase) | 1.16 (1.07–1.25) | 0.0001 | 1.18 (1.06–1.31) | 0.0017 |
| Quadriceps force, as function of weight (per 10 units of increase) | 0.97 (0.94–0.99) | 0.0217 | – | – |
| FEV1, % predicted (per 10 units of increase) | 0.82 (0.75–0.89) | <0.0001 | – | – |
| Oxygen uptake, % predicted (per 10 units of increase) | 0.79 (0.73–0.85) | <0.0001 | 0.80 (0.72–0.89) | 0.0010 |
| DLCO, % predicted (per 10 units of increase) | 0.78 (0.71–0.85) | <0.0001 | – | – |
| Change in FEV1, % predicted after training (per unit of increase) | 0.98 (0.96–0.99) | 0.0080 | 0.98 (0.96–0.99) | 0.0258 |
| Change in quadriceps force after training (per 10 units of increase) | 0.90 (0.84–0.98) | 0.0139 | 0.90 (0.82–0.99) | 0.0326 |
| Change in BMI after training, per unit of increase | 0.88 (0.78–0.99) | 0.0391 | – | – |
| Change in oxygen uptake, % predicted after training (per 10 units of increase) | 0.85 (0.76–0.94) | 0.0026 | 0.83 (0.70–0.98) | <0.0001 |
| Change in Wmax after training (per 10 units of increase) | 0.79 (0.70–0.88) | <0.0001 | – | – |
| Change in 6MWD ≥30 m | 0.66 (0.51–0.85) | 0.0013 | 0.68 (0.49–0.94) | 0.0214 |
| Enrolling in the maintenance program (months 3–6) | 0.62 (0.44–0.86) | 0.0052 | – | – |
| Initial 6MWD ≥350 m | 0.39 (0.30–0.50) | <0.0001 | 0.46 (0.32–0.65) | <0.0001 |
Notes: Only variables that remained in the model are reported in the multivariate regression analysis. Bold font denotes statistical significance (P<0.05). –, indicates that the variable was not included in the multivariate model.
Abbreviations: 6MWD, 6-minute walk distance; BMI, body mass index; CI, confidence interval; DLco, diffusion capacity for carbon monoxide; FEV1, forced expiratory volume in the first second; HR, hazard ratio; Wmax, maximal workload during cycling exercise test.