Table 4. Significant univariable and multivariable Cox regression analyses for the prediction of 30-day mortality.
| Variable | Univariablea | Multivariableb | ||||
|---|---|---|---|---|---|---|
| HR | 95% CI | P-value | HR | 95% CI | P-value | |
| Period of admissionc | 0.12 | 0.12 | ||||
| 1997–2001 | 1.00 | – | – | 1.00 | – | – |
| 2002–2006 | 0.54 | 0.29 to 1.02 | 0.060 | 1.67 | 0.15 to 18.95 | 0.68 |
| 2007–2011 | 0.97 | 0.55 to 1.71 | 0.93 | 4.03 | 0.20 to 81.23 | 0.36 |
| 2012–2016 | 1.17 | 0.65 to 2.12 | 0.60 | 3.09 | 0.46 to 20.97 | 0.25 |
| Age ≥65 years | 2.83 | 1.62 to 4.95 | <0.001 | 2.93 | 1.63 to 5.27 | <0.001 |
| Previous systemic corticosteroids | 1.51 | 0.94 to 2.42 | 0.090 | – | – | – |
| Chronic renal disease | 2.58 | 1.43 to 4.67 | 0.002 | – | – | – |
| Chronic liver disease | 2.10 | 1.14 to 3.87 | 0.017 | – | – | – |
| Neurologic disease | 1.61 | 1.00 to 2.60 | 0.052 | – | – | – |
| Diabetes mellitus | 2.07 | 1.26 to 3.39 | 0.004 | 1.68 | 0.99 to 2.85 | 0.054 |
| SOFA score ≥5d | 7.22 | 4.70 to 11.08 | <0.001 | 3.91 | 2.17 to 7.03 | <0.001 |
| Invasive pneumococcal pneumonia | 1.63 | 1.04 to 2.55 | 0.034 | – | – | – |
| Empiric antibiotic therapye | 0.001 | 0.11 | ||||
| Beta-lactams monotherapy | 1.14 | 0.49 to 2.63 | 0.76 | 1.08 | 0.44 to 2.63 | 0.87 |
| Fluoroquinolones monotherapy | 0.51 | 0.22 to 1.19 | 0.12 | 1.52 | 0.59 to 3.94 | 0.38 |
| Beta-lactams plus fluoroquinolones | 0.96 | 0.51 to 1.81 | 0.90 | 1.32 | 0.62 to 2.81 | 0.48 |
| Beta-lactams plus macrolides | 0.35 | 0.18 to 0.68 | 0.002 | 0.59 | 0.29 to 1.21 | 0.15 |
| Other | 1.00 | – | – | 1.00 | – | – |
| Adequate empiric antibiotic therapy | 0.22 | 0.11 to 0.45 | <0.001 | – | – | – |
| ICU admission | 5.17 | 3.31 to 8.02 | <0.001 | – | – | – |
| Mechanical ventilationf | <0.001 | <0.001 | ||||
| Not ventilated | 1.00 | – | – | 1.00 | – | – |
| Non-invasive | 5.86 | 2.69 to 12.78 | <0.001 | 2.95 | 1.22 to 7.16 | 0.017 |
| Invasive | 8.85 | 5.58 to 14.02 | <0.001 | 4.07 | 2.40 to 6.88 | <0.001 |
Abbreviations: CI indicates confidence interval; HR, hazard ratio; ICU, intensive care unit; SOFA, sequential organ failure assessment. Data are shown as estimated HRs (95% CIs) of the explanatory variables in the 30-day mortality group. The HR is the ratio of hazards (probability of death) in two groups, given that the patient has survived up to a specific time. The P-value is based on the null hypothesis that all HRs relating to an explanatory variable equal unity (no effect).
a The variables analyzed in the univariable analysis were: age, gender, tobacco use, alcohol consumption, influenza and pneumococcal vaccination, previous systemic and inhaled corticosteroids, prior antibiotic treatment, chronic pulmonary disease, chronic cardiovascular disease, chronic renal disease, chronic liver disease, diabetes mellitus, neurological disease, SOFA score, invasive disease pneumonia, adequate empiric antibiotic therapy, ICU admission, and mechanical ventilation.
b Adjusted for the propensity score.
c The p-value corresponds to differences between the four groups (1997–2001, 2002–2006, 2007–2011, or 2012–2016).
d Optimal cut-off value to predict 30-day mortality using ROC curves.
e The p-value corresponds to differences between the five groups (beta-lactams monotherapy, fluoroquinolones monotherapy, beta-lactams plus fluoroquinolones, beta-lactams plus macrolides, or other).
f The p-value corresponds to differences between the three groups (not ventilated, non-invasive, or invasive).