Table 1. Baseline patient characteristics.
Baseline patient characteristics in the training and validation sets. Data is in count (%) or median (IQR). There is significant difference across the data sets for all variables listed here at P < 0.001. Missing data is provided as a percentage of total time points included in the model (N = 22,743,165).
| YNHH Training Set (N = 60,701) | YNHH Validation Set (N = 30,599) | SRH (N = 43,534) | BH (N = 35,025) | Missing Data (%) | |
|---|---|---|---|---|---|
| Demographics | |||||
| Age, y | 61 (47–74) | 60 (47–74) | 68 (55–81) | 65 (50–79) | 0 |
| Sex, male | 29,649 (48.8%) | 15,013 (49.1%) | 19,478 (44.7%) | 16,212 (46.3%) | 0 |
| Race, black | 10,173 (16.8%) | 5,066 (16.6%) | 7,694 (17.7%) | 6,973 (19.9%) | 0 |
| Surgical admission | 17,265 (28.4%) | 8,809 (28.8%) | 11,197 (25.7%) | 8,214 (23.5%) | 0 |
| Laboratory | |||||
| Bicarbonate, mmol/L | 22.7 (20.6–24.9) | 22.6 (20.5–24.8) | 24 (22–26) | 25 (23–28) | 9.1 |
| BUN, mg/dL | 16 (11–24) | 16 (11–24) | 17 (12–25) | 17 (12–25) | 9.2 |
| Chloride, mmol/L | 102 (99–105) | 102 (99–105) | 102 (99–105) | 103 (100–106) | 9.8 |
| Creatinine, mg/dL | 0.9 (0.7–1.2) | 0.9 (0.7–1.2) | 0.9 (0.7–1.2) | 0.9 (0.7–1.2) | 8.9 |
| Hemoglobin, g/dL | 12.6 (10.8–14.1) | 12.5 (10.8–14.1) | 12.4 (10.9–13.8) | 12.2 (10.6–13.6) | 8.6 |
| Platelets (x 109/L) | 232 (176–298) | 232 (175–297) | 227 (179–287) | 224 (174–282) | 8.7 |
| Potassium, mmol/L | 4 (3.7–4.4) | 4 (3.7–4.4) | 4.1 (3.7–4.4) | 4.2 (3.9–4.6) | 9.2 |
| Sodium, mmol/L | 138 (136–141) | 138 (136–141) | 139 (136–141) | 139 (136–141) | 9.1 |
| White blood cells (cells/mm3) | 9.1 (6.7–12.3) | 9.1 (6.7–12.4) | 9 (6.8–12.2) | 9.1 (6.8–12.3) | 8.7 |
| Medical History | |||||
| CHF | 9,038 (14.9%) | 4,474 (14.6%) | 7,806 (17.9%) | 5,216 (14.9%) | 0 |
| Diabetes | 13,124 (21.6%) | 6,650 (21.7%) | 10,599 (24.3%) | 7,175 (20.5%) | 0 |
| Hypertension | 5,369 (8.8%) | 2,675 (8.7%) | 4,989 (11.5%) | 3,001 (8.6%) | 0 |
| Liver disease | 4,556 (7.5%) | 2,288 (7.5%) | 2,348 (5.4%) | 1,580 (4.5%) | 0 |
| Elixhauser score | 3 (1–5) | 3 (1–5) | 3 (1–5) | 2 (0–4) | 0 |
| Medical Procedures | |||||
| BiPAP use | 1,991 (3.3%) | 1,054 (3.4%) | 1,999 (4.6%) | 1,009 (2.9%) | 0 |
| Contrast study | 14,267 (23.5%) | 6,947 (22.7%) | 6,177 (14.2%) | 7,203 (20.6%) | 0 |
| Ventilation requirement | 5,064 (8.3%) | 2,473 (8.1%) | 1,305 (3%) | 1,642 (4.7%) | 0 |
| ICU | 14,059 (23.2%) | 6,911 (22.6%) | 5,198 (11.9%) | 4,429 (12.6%) | 0 |
| Cardiac catheterization | 2,954 (4.9%) | 1,548 (5.1%) | 1,130 (2.6%) | 1,106 (3.2%) | 0 |
| RBC transfusion | 8,390 (13.8%) | 4,128 (13.5%) | 4,355 (10%) | 3,099 (8.8%) | 0 |
| Medications | |||||
| ACE or ARB | 12,427 (20.5%) | 6,298 (20.6%) | 11,699 (26.9%) | 8,452 (24.1%) | 0 |
| Antibiotic | 37,041 (61%) | 18,558 (60.6%) | 29,321 (67.4%) | 17,227 (49.2%) | 0 |
| Chemotherapy | 1,481 (2.4%) | 708 (2.3%) | 160 (0.4%) | 312 (0.9%) | 0 |
| Diuretic | 16,707 (27.5%) | 8,467 (27.7%) | 13,949 (32%) | 8,373 (23.9%) | 0 |
| Narcotic | 38,046 (62.7%) | 19,152 (62.6%) | 26,506 (60.9%) | 16,487 (47.1%) | 0 |
| NSAID | 5,928 (9.8%) | 3,020 (9.9%) | 6,678 (15.3%) | 3,407 (9.7%) | 0 |
| Vasopressor | 11,091 (18.3%) | 5,497 (18%) | 7,955 (18.3%) | 3,798 (10.8%) | 0 |
| Proton pump inhibitor | 23,967 (39.5%) | 11,852 (38.7%) | 20,421 (46.9%) | 11,864 (33.9%) | 0 |
| Statin | 11,637 (19.2%) | 5,854 (19.1%) | 10,250 (23.5%) | 5,967 (17.0%) | 0 |
Abbreviations: ACE, angiotensin converting enzyme inhibitor; ARB, angiotensin II receptor blockers; AKI, acute kidney injury; BH, Bridgeport Hospital; BiPAP, Bilevel Positive Airway Pressure; BUN, blood urea nitrogen; CHF, congestive heart failure; ICU, intensive care unit; IQR, interquartile range; NSAID, nonsteroidal anti-inflammatory drug; SRH, Saint Raphael's Hospital; RBC, red blood cell; YNHH, Yale New Haven Hospital.