Table 7.
Cox regression analysis of survival according to categorisation of variables < vs. > the median value
| Explanatory Variable | HR (95 % CI) | *p |
|---|---|---|
| Univariate analysis | ||
| PHQ-stress | 4.92 (1.06-22.85) | 0.042 |
| Leucocytes | 2.97 (1.06-8.36) | 0.038 |
| 6-MWD (%) | 2.07 (0.6-7.07) | 0.248 |
| BMI | 0.77 (0.30-1.95) | 0.58 |
| FEV1, % predicted | 1.51 (0.59-3.89) | 0.395 |
| Multivariate analyses | ||
| Model I | ||
| 6-MWD (%) | 19.58 (1.01-380.75) | 0.049 |
| BMI | 48.73 (1.21-1969.65) | 0.039 |
| FEV1, % predicted | 3.37 (0.35-32.55) | 0.295 |
| PHQ-stress | 45.63 (1.72-1,208.48) | 0.022 |
| Model 2 | ||
| 6-MWD (%) | 2.6 (0.71-9.57) | 0.151 |
| BMI | 1.34 (0.38-4.79) | 0.650 |
| FEV1, % predicted | 1.03 (0.25-4.18) | 0.970 |
| Leucocytes | 3.41 (0.91-12.85) | 0.069 |
*Only the significant (p ≤ 0.05) univariate variables for physical function, demographic data and biomarkers are shown. Model 1 and 2: Cox proportional hazard model (method: stepwise backward likelihood ratio) including known risk factors for survival in COPD (6-MWD, body mass index, FEV1, (% predicted)) as well as PHQ-stress (model 1) and leucocytes (model 2)
PHQ Patient Health Questionnaire, &-MWD six-minute walk test, BMI body mass index, FEV1 forced expiratory volume in 1 s
Highlighted in bold: p ≤ 0.05