Table 1.
Distribution of baseline covariates in the study sample
| Variable | Median (IQR) or Percent With Condition |
|---|---|
| Continuous covariates | |
| Age (years) | 70 (70‐84) |
| Systolic blood pressure (mmHg) | 145 (125‐168) |
| Respiratory rate (breaths per minute) | 24 (20‐28) |
| Serum urea nitrogen (mmol/L) | 8.2 (6.1‐11.7) |
| Binary covariates | |
| Low sodium serum concentration (<136 mEq/L) | 20.9% |
| Low serum hemoglobin (<10.0 g/dL) | 12.8% |
| Cancer | 11.3% |
| Chronic obstructive pulmonary disease (COPD) | 27.1% |
| Cerebrovascular disease | 17.9% |
| Hepatic cirrhosis | 0.7% |
| Dementia | 9.3% |
Continuous covariates are summarized using the median (25th–75th percentiles), while binary covariates are summarized using the percentage of subjects in whom the condition is present. The sample consists of 7162 patients treated at 96 hospitals.