Table 1.
Baseline Characteristics of Included Patients (n = 46 722)
| Age, mean (SD), y | 54 (18) |
|---|---|
| Sex, male | 24 657 (52) |
| Race | |
| White | 35 646 (74.3) |
| Black or African American | 5746 (12.3) |
| Other | 5330 (11.4) |
| Charlson Comorbidity Index, median (IQR) | 0 (0–1) |
| Myocardial infarction | 1510 (3.2) |
| Congestive heart failure | 2384 (5.1) |
| Peripheral vascular disease | 618 (1.3) |
| Dementia | 874 (1.9) |
| Cerebrovascular disease | 489 (1.0) |
| Chronic lung disease | 6042 (12.9) |
| Connective tissue disease | 827 (1.8) |
| Ulcer | 3685 (7.9) |
| Chronic liver disease | 2353 (5.0) |
| Hemiplegia | 205 (0.4) |
| Moderate or severe kidney disease | 2838 (6.1) |
| Diabetes without complications | 6232 (13.2) |
| Diabetes with complications | 1433 (3.1) |
| Tumor | 2849 6.1) |
| Malignant tumor, metastasis | 1287 (2.8) |
| AIDS | 97 (0.2) |
| Complicated intra-abdominal infection diagnosis | |
| Acute appendicitis with peritonitis | 28 004 (59.7) |
| Peritoneal abscess | 4624 (9.9) |
| Perforated intestine | 4142 (8.9) |
| Fistula of intestine | 2406 (5.1) |
| Peritonitis (unspecified) | 1901 (5.1) |
| Hospital-level covariates | |
| Hospital region | |
| South | 19 481 (41.7) |
| West | 10 670 (22.8) |
| Midwest | 9072 (19.4) |
| Northeast | 7499 (16.1) |
| Population served | |
| Urban | 41 304 (88.4) |
| Rural | 5418 (11.6) |
| Teaching hospital | 29 315 (62.7) |
| Nonteaching hospital | 17 407 (37.3) |
| No. of hospital beds | |
| 000–099 | 3092 (6.6) |
| 100–199 | 7428 (15.9) |
| 200–299 | 9228 (19.8) |
| 300–399 | 8060 (17.3) |
| 400–499 | 5263 (11.3) |
| 500+ | 13 651 (29.2) |
Data are presented as No. (%) unless otherwise indicated.
Abbreviation: IQR, interquartile range.