Table 1.
Baseline characteristics of participants.
| Covariates | All patients | Preadmission metformin use | P-value | |
|---|---|---|---|---|
| (n = 2,383) | No (n = 1,907) | Yes (n = 476) | ||
| Age(years) | 70.2 ± 13.1 | 69.5 ± 12.6 | 70.1 ± 12.4 | 0.263 |
| Female, sex, n (%) | 1,145 (48.0) | 915 (48.0) | 230 (48.3) | 0.895 |
| Ethnicity, white, n (%) | 1,649 (69.2) | 1,303 (68.3) | 346 (72.7) | 0.065 |
| Marital status, n (%) | 0.212 | |||
| Single/divorced | 658 (27.6) | 525 (27.5) | 133 (27.9) | |
| Married | 1,109 (46.5) | 871 (45.7) | 238 (50.0) | |
| Other | 616 (25.8) | 511 (26.8) | 105 (22.1) | |
| Insurance, n (%) | 0.013 | |||
| Medicaid | 1,810 (76.0) | 1,464 (76.8) | 346 (72.7) | |
| Private | 524 (22.0) | 399 (20.9) | 125 (26.3) | |
| Other | 49 (2.1) | 44 (2.3) | 5 (1.1) | |
| Admission type, n (%) | 0.044 | |||
| Elective | 183 (7.7) | 136 (7.1) | 47 (9.9) | |
| Emergency | 2,200 (92.3) | 1,771 (92.9) | 429 (90.1) | |
| Service unit, n (%) | 0.166 | |||
| CCU | 332 (13.9) | 266 (13.9) | 66 (13.9) | |
| CSRU | 288 (12.1) | 217 (11.4) | 71 (14.9) | |
| MICU | 1,157 (48.6) | 937 (49.1) | 220 (46.2) | |
| SICU | 384 (16.1) | 315 (16.5) | 69 (14.5) | |
| TSICU | 222 (9.3) | 172 (9.0) | 50 (10.5) | |
| Heart rate (bpm) | 87.1 ± 16.1 | 86.9 ± 16.2 | 88.2 ± 16.0 | 0.109 |
| MAP (mmHg) | 75.7 ± 10.5 | 75.8 ± 10.6 | 75.3 ± 10.0 | 0.405 |
| Respiratory rate (bpm) | 20.0 ± 4.3 | 19.7 ± 4.2 | 20.4 ± 4.2 | 0.128 |
| SPO2 (%) | 96.9 ± 2.7 | 96.9 ± 2.8 | 96.9 ± 2.0 | 0.935 |
| Glucose (mg/dL) | 165.8 ± 54.2 | 165.2 ± 54.8 | 168.4 ± 52.0 | 0.245 |
| WBC (×109) | 13.7 (9.9–18.7) | 13.7 (9.9–18.8) | 13.6 (9.9–18.4) | 0.822 |
| SCr (mg/dL) | 1.2 (0.9–1.8) | 1.3 (0.9–1.9) | 1.2 (0.9–1.7) | 0.488 |
| Hemoglobin (g/L) | 10.0 ± 2.1 | 9.8 ± 2.0 | 9.9 ± 2.0 | 0.240 |
| Platelet (×1012) | 188.0 (127.0–257.0) | 188.0 (125.0–260.0) | 187.0 (137.0–246.2) | 0.764 |
| Lactate (mmol/L) | 2.4 (1.6–4.0) | 2.4 (1.5–4.0) | 2.4 (1.6–3.9) | 0.676 |
| HBA1C (%) | 7.2 ± 2.0 | 7.1 ± 2.0 | 7.3 ± 1.7 | 0.007 |
| Tested HBA1C, n(%) | 780 (32.7%) | 610 (32.0%) | 170 (35.7%) | 0.121 |
| SAPS II score | 41.6 ± 14.1 | 41.9 ± 14.2 | 40.5 ± 13.4 | 0.057 |
| Infection site | ||||
| Respiratory system | 602 (25.4%) | 493 (26.0%) | 109 (22.9%) | 0.326 |
| Cardiovascular system | 808 (34.1%) | 641 (33.8%) | 167 (35.2%) | |
| Digestive system | 185 (7.8%) | 149 (7.9%) | 36 (7.6%) | |
| Urogenital system | 443 (18.7%) | 341 (18.0%) | 102 (21.5%) | |
| Other | 331 (14.0%) | 270 (14.3%) | 61 (12.8%) | |
| Preadmission medications | ||||
| Statin | 945 (39.7%) | 658 (34.5%) | 287 (60.3%) | <0.001 |
| Insulin | 629 (26.4%) | 539 (28.3%) | 90 (18.9%) | <0.001 |
| Aspirin | 551 (23.1%) | 423 (22.2%) | 128 (26.9%) | 0.029 |
| Ventilator use, n (%) | 1,205 (50.6) | 1,007 (52.8) | 259 (54.4) | 0.530 |
| Vasopressor use, n (%) | 1,037 (43.5) | 832 (43.6) | 205 (43.1) | 0.825 |
| RRT, n (%) | 78 (3.3) | 65 (3.4) | 13 (2.7) | 0.457 |
| Comorbidity disease, n (%) | ||||
| Congestive heart failure | 628 (26.4) | 536 (28.1) | 92 (19.3) | <0.001 |
| Liver disease | 220 (9.2) | 189 (9.9) | 31 (6.5) | 0.220 |
| Malignancy | 228 (9.6) | 176 (9.2) | 52 (10.9) | 0.261 |
| Neurological disease | 308 (12.9) | 259 (13.6) | 49 (10.3) | 0.056 |
| Chronic pulmonary disease | 573 (24.0) | 462 (24.2) | 111 (23.3) | 0.679 |
| Hypertension | 41 (1.7) | 35 (1.8) | 6 (1.3) | 0.533 |
| 30-day mortality, n (%) | 480 (20.1) | 418 (21.9) | 62 (13.0) | <0.001 |
Bpm, beat per minute; CCU, coronary care unit; CSRU, cardiac surgery recovery unit; LOS, length of stay; MICU, medical intensive care unit; MAP, mean arterial pressure; RRT, renal replace treatment; SICU, surgical intensive care unit; SAPS, simplified acute physiology score; TSICU, trauma and surgical intensive care unit; WBC, white blood count; SCr, serum creatinine; HBA1C, glycated hemoglobin.