Table 2.
Baseline characteristics of study cohort, by AKI status
| Variables | No AKI (n = 3456) | AKI (n = 1993) | Stages of AKI |
P valuea (no AKI vs. all AKI | P valueb (trend) | ||
|---|---|---|---|---|---|---|---|
| 1 (n = 927) | 2 (n = 447) | 3 (n = 619) | |||||
| Age (yr) | 61.0 (50.0, 72.0) | 69.0 (58.0, 78.0) | 69.0 (58.0, 79.0) | 71.0 (58.5, 79.0) | 67.0 (58.0, 76.0) | <0.001 | <0.001 |
| Male | 2047 (59.2) | 1270 (63.7) | 556 (60.0) | 266 (59.5) | 448 (72.4) | 0.001 | <0.001 |
| Race | 0.04 | 0.04 | |||||
| Asian | 304 (8.8) | 162 (8.1) | 72 (7.8) | 35 (7.8) | 55 (8.9) | ||
| Black | 708 (20.5) | 415 (20.8) | 190 (20.5) | 106 (23.7) | 119 (19.2) | ||
| White | 1294 (37.4) | 818 (41.0) | 393 (42.4) | 191 (42.7) | 234 (37.8) | ||
| Other/multiracial | 988 (28.6) | 506 (25.4) | 232 (25.0) | 92 (20.6) | 182 (29.4) | ||
| Other/unknown | 138 (4.0) | 84 (4.2) | 38 (4.1) | 21 (4.7) | 25 (4.0) | ||
| Declined | 24 (0.7) | 8 (0.4) | 2 (0.2) | 2 (0.4) | 4 (0.6) | ||
| Ethnicity | 0.03 | 0.03 | |||||
| Hispanic/Latino | 765 (22.1) | 380 (19.1) | 159 (17.2) | 85 (19.0) | 136 (22.0) | ||
| Not Hispanic/Latino | 2474 (71.6) | 1479 (74.2) | 711 (76.7) | 330 (73.8) | 438 (70.8) | ||
| Other/unknown | 217 (6.3) | 134 (6.7) | 57 (6.1) | 32 (7.2) | 45 (7.3) | ||
| Language | 0.52 | 0.12 | |||||
| English | 2825 (81.7) | 1608 (80.7) | 764 (82.4) | 353 (79.0) | 491 (79.3) | ||
| Spanish | 402 (11.6) | 238 (11.9) | 96 (10.4) | 53 (11.9) | 89 (14.4) | ||
| Other | 229 (6.6) | 147 (7.4) | 67 (7.2) | 41 (9.2) | 39 (6.3) | ||
| Insurance status | <0.001 | <0.001 | |||||
| Commercial | 1329 (38.5) | 527 (26.4) | 247 (26.6) | 98 (21.9) | 182 (29.4) | ||
| Medicaid | 792 (22.9) | 349 (17.5) | 159 (17.2) | 78 (17.4) | 112 (18.1) | ||
| Medicare | 1238 (35.8) | 1054 (52.9) | 495 (53.4) | 260 (58.2) | 299 (48.3) | ||
| Self-pay | 67 (1.9) | 47 (2.4) | 19 (2.0) | 8 (1.8) | 20 (3.2) | ||
| Other | 30 (0.9) | 16 (0.8) | 7 (0.8) | 3 (0.7) | 6 (1.0) | ||
| Hospital type | 0.06 | 0.04 | |||||
| Tertiary | 2420 (70.0) | 1345 (67.5) | 635 (68.5) | 312 (69.8) | 398 (64.3) | ||
| Community | 1036 (30.0) | 648 (32.5) | 292 (31.5) | 135 (30.2) | 221 (35.7) | ||
| Comorbid conditionsc | |||||||
| HTN | 1745 (50.5) | 1292 (64.8) | 624 (67.3) | 287 (64.2) | 381 (61.6) | <0.001 | <0.001 |
| CAD | 311 (9.0) | 289 (14.5) | 136 (14.7) | 72 (16.1) | 81 (13.1) | <0.001 | <0.001 |
| HF | 141 (4.1) | 208 (10.4) | 112 (12.1) | 47 (10.5) | 49 (7.9) | <0.001 | <0.001 |
| PVD | 37 (1.1) | 61 (3.1) | 22 (2.4) | 18 (4.0) | 21 (3.4) | <0.001 | <0.001 |
| Diabetes | 967 (28.0) | 830 (41.6) | 368 (39.7) | 193 (43.2) | 269 (43.5) | <0.001 | <0.001 |
| HIV | 25 (0.7) | 10 (0.5) | 5 (0.5) | 4 (0.9) | 1 (0.2) | 0.42 | 0.36 |
| Chronic liver disease | 72 (2.1) | 42 (2.1) | 27 (2.9) | 8 (1.8) | 7 (1.1) | 1.00 | 0.11 |
| COPD | 149 (4.3) | 147 (7.4) | 74 (8.0) | 36 (8.1) | 37 (6.0) | <0.001 | <0.001 |
| Asthma | 317 (9.2) | 143 (7.2) | 74 (8.0) | 35 (7.8) | 34 (5.5) | 0.012 | 0.02 |
| OSA | 99 (2.9) | 65 (3.3) | 27 (2.9) | 20 (4.5) | 18 (2.9) | 0.46 | 0.31 |
| Cancer | 194 (5.6) | 133 (6.7) | 65 (7.0) | 25 (5.6) | 43 (6.9) | 0.13 | 0.30 |
| Obesity | 916 (26.5) | 559 (28.0) | 244 (26.3) | 132 (29.5) | 183 (29.6) | 0.23 | 0.25 |
| Morbid obesity | 276 (8.0) | 180 (9.0) | 81 (8.7) | 42 (9.4) | 57 (9.2) | 0.20 | 0.57 |
| BMI (kg/m2) | 28.4 (25.3, 32.8) | 29.0 (25.4, 33.5) | 28.7 (25.5, 33.2) | 28.7 (24.7, 33.6) | 29.5 (25.9, 34.0) | 0.09 | 0.04 |
| Kidney function | |||||||
| Admission SCr (mg/dl) | 0.95 (0.77, 1.16) | 1.24 (0.91, 1.82) | 1.26 (0.91, 1.83) | 1.30 (0.95, 1.86) | 1.19 (0.90, 1.79) | <0.001 | <0.001 |
| Discharge SCr (mg/dl) | 0.80 (0.66, 0.98) | 1.42 (0.84, 3.16) | 1.02 (0.72, 1.57) | 1.38 (0.80, 2.26) | 4.00 (2.21, 6.12) | <0.001 | <0.001 |
| Peak SCr (mg/dl) | 0.98 (0.80, 1.20) | 2.23 (1.40, 4.12) | 1.50 (1.10, 2.16) | 2.13 (1.59, 2.91) | 5.20 (3.40, 7.24) | <0.001 | <0.001 |
| Median SCr (mg/dl) | 0.86 (0.70, 1.03) | 1.20 (0.82, 2.00) | 1.04 (0.75, 1.53) | 1.10 (0.80, 1.53) | 2.05 (1.11, 3.55) | <0.001 | <0.001 |
| Admission eGFR (ml/min/1.73 m2) | 82.5 (62.0, 98.0) | 56.0 (34.0, 80.0) | 54.0 (33.0, 81.0) | 53.0 (32.0, 79.0) | 62.0 (37.0, 81.0) | <0.001 | <0.001 |
| Discharge eGFR (ml/min/1.73 m2) | 94.0 (77.0, 107.0) | 45.0 (17.0, 86.0) | 69.0 (39.0, 97.0) | 50.0 (27.0, 89.0) | 14.0 (8.0, 27.0) | <0.001 | <0.001 |
| Medications | |||||||
| No. of medications | 3 (1, 7) | 6 (2, 10) | 6 (2, 10) | 6 (2, 10) | 5 (1, 9) | <0.001 | <0.001 |
| ACE-I | 385 (11.9) | 269 (15.9) | 119 (14.4) | 51 (13.4) | 99 (20.2) | <0.001 | <0.001 |
| ARB | 516 (16.0) | 386 (22.8) | 184 (22.3) | 84 (22.1) | 118 (24.0) | <0.001 | <0.001 |
| ICU | 335 (9.7) | 1060 (53.2) | 320 (34.5) | 244 (54.6) | 496 (80.1) | <0.001 | <0.001 |
| Mechanical ventilator | 122 (3.5) | 1068 (53.6) | 288 (31.1) | 262 (58.6) | 518 (83.7) | <0.001 | <0.001 |
| ECMO | 0 (0.0) | 10 (0.5) | 3 (0.3) | 5 (1.1) | 2 (0.3) | <0.001 | <0.001 |
| Inotropesd | 3 (0.1) | 51 (2.6) | 10 (1.1) | 12 (2.7) | 29 (4.7) | <0.001 | <0.001 |
| Vasopressore | 119 (3.4) | 1049 (52.6) | 278 (30.0) | 252 (56.4) | 519 (83.8) | <0.001 | <0.001 |
| CCI | 3.0 (1.0, 5.0) | 5.0 (3.0, 7.0) | 5.0 (3.0, 7.0) | 5.0 (3.0, 7.5) | 4.0 (3.0, 6.0) | <0.001 | <0.001 |
| Length of stay (d) | |||||||
| Discharged/ expired | 4.9 (3.0, 7.6) | 7.8 (5.0, 11.6) | 7.4 (4.8, 10.9) | 7.2 (4.2, 12.1) | 8.6 (5.8, 12.3) | <0.001 | <0.001 |
| Currently hospitalized | 10.3 (8.5, 13.0) | 13.2 (10.2, 17.3) | 12.2 (9.4, 16.2) | 14.0 (11.0, 18.1) | 14.0 (11.0, 18.23) | <0.001 | <0.001 |
| Disposition | <0.001 | <0.001 | |||||
| Discharged | 2761 (79.9) | 519 (26.0) | 397 (42.8) | 87 (19.5) | 35 (5.7) | ||
| Expired | 194 (5.6) | 694 (34.8) | 208 (22.4) | 152 (34.0) | 334 (54.0) | ||
| Currently hospitalized | 501 (14.5) | 780 (39.1) | 322 (34.7) | 208 (46.5) | 250 (40.4) | ||
ACE-I, angiotensin-converting enzyme inhibitor; AKI, acute kidney injury; ARB, angiotensin II receptor blocker; BMI, body mass index; CAD, coronary artery disease; CCI, Charleson Comorbidity Index; COPD, chronic obstructive pulmonary disease; ECMO, extracorporeal membrane oxygenation; eGFR, estimated glomerular filtration rate; HF, heart failure; HTN, hypertension; ICU, intensive care unit; OSA, obstructive sleep apnea; PVD, peripheral vascular disease, SCr, serum creatinine.
Values are median (interquartile range) or n (%).
a
Comparisons are made between no AKI and AKI using Fisher exact test for categorical variables and or nonparametric Kruskal-Wallis test for continuous variables.
b
Comparisons are made across the stages of AKI using Kruskal-Wallis rank sum test.
c
Chronic kidney disease was not included as a comorbid condition because prehospitalization estimated glomerular filtration rate was only available in 15% of patients.
d
Inotropes include dobutamine and milrinone.
e
Vasopressors include norepinephrine, epinephrine, vasopressin, dopamine, angiotensin-2 infusion.