Table 4.
Univariate Cox Regression Analysis for Variables Associated With 30-Day Mortality and Independent Predictors of 30-Day Mortality Determined by Multivariable Cox Regression Analysis (n = 1664)a
| Univariate | Multivariable | |||||
|---|---|---|---|---|---|---|
| Variable | HR | 95% CI | P Value | HR | 95% CI | P Value |
| Age ≥80 y | 3.99 | 2.55–6.24 | <.001 | 2.87 | 1.80–4.57 | <.001 |
| Male sex | 1.12 | 0.73–1.73 | .596 | - | - | - |
| Influenza vaccine | 0.89 | 0.59–1.33 | .565 | - | - | - |
| Pneumococcal vaccine | 0.57 | 0.31–1.05 | .071 | 0.49 | 0.27–0.92 | .025 |
| Previous inhaled corticosteroids | 1.31 | 0.83–2.05 | .247 | - | - | - |
| Previous systemic corticosteroids | 0.75 | 0.24–2.36 | .620 | - | - | - |
| Antibiotic use in the last week | 1.21 | 0.77–1.92 | .408 | - | - | - |
| Chronic respiratory disease | 1.00 | 0.67–1.51 | .993 | - | - | - |
| Chronic cardiac disease | 1.57 | 0.97–2.53 | .064 | - | - | - |
| Chronic renal disease | 2.78 | 1.69–4.55 | <.001 | 2.64 | 1.59–4.38 | <.001 |
| Chronic liver disease | 0.97 | 0.36–2.65 | .956 | - | - | - |
| Diabetes mellitus | 0.48 | 0.27–0.85 | .011 | 0.42 | 0.24–0.75 | .003 |
| Chronic neurologic disease | 3.33 | 2.12–5.00 | <.001 | 2.48 | 1.61–3.81 | <.001 |
| Previous pneumonia | 0.88 | 0.49–1.58 | .663 | - | - | - |
| Nursing home resident | 3.56 | 2.21–5.74 | <.001 | 2.17 | 1.31–3.61 | .003 |
| Fever | 0.44 | 0.30–0.67 | <.001 | 0.49 | 0.32–0.73 | .001 |
| Deterioration in sensorium | 1.99 | 1.31–3.02 | .001 | - | - | - |
| C-reactive protein ≥15 mg/dL | 0.72 | 0.48–1.08 | .111 | - | - | - |
| Lymphopenia (<724 lymphocytes/mm3) | 1.73 | 1.15–2.59 | .008 | 1.94 | 1.29–2.93 | .001 |
| Pleural effusion | 1.81 | 1.10–2.97 | .018 | 1.90 | 1.15–3.14 | .013 |
| Acute respiratory distress syndrome | 1.63 | 0.76–3.53 | .211 | - | - | - |
| Acute renal failureb | 2.72 | 1.81–4.09 | <.001 | - | - | - |
| Appropriate empiric antibiotic treatment | 0.99 | 0.36–2.68 | .977 | - | - | - |
| Streptococcus pneumoniae | 1.05 | 0.64–1.74 | .846 | - | - | - |
| Respiratory virus | 0.68 | 0.32–1.48 | .334 | - | - | - |
Data are shown as estimated HRs (95% CIs) of the explanatory variables in the 30-day mortality group. The HR is defined as the ratio of the hazard rates corresponding to the conditions described by 2 levels of an explanatory variable (the hazard rate is the risk of death [ie, the probability of death], 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).
Abbreviation: HR, hazard ratio.
aExcluded 236 patients with septic shock, 34 patients with missing data regarding septic shock, 211 patients who had do-not-resuscitate orders, and 58 with missing data regarding a do-not-resuscitate order.
bVariable highly correlated with another independent variable and therefore not included in the multivariable model.