Table 1. Characteristics of the study patients at intensive care unit admission.
| Characteristic | AKI according to serum creatinine (n = 18) | AKI according to urine output alone (n = 38) | No AKI (n = 24) | P |
|---|---|---|---|---|
| Age (years) | 63.8 ± 13.3 | 56.6 ± 17.1 | 52.2 ± 13.5 | 0.06 |
| Sex (%) | 0.35 | |||
| Male | 10/18 (55.6) | 23/38 (60.5) | 10/24 (41.7) | |
| Female | 8/18 (44.4) | 15/38 (39.5) | 14/24 (58.3) | |
| Race (%) | 0.51 | |||
| White | 10/18 (55.6) | 26/38 (68.4) | 15/24 (62.5) | |
| Black | 4/18 (22.2) | 4/38 (10.5) | 6/24 (25.0) | |
| Hispanic | 2/18 (11.1) | 5/38 (13.2) | 3/24 (12.5) | |
| Other/unknown | 2/18 (11.1) | 3/38 (7.9) | 0 | |
| Weight (kg) | 75.1 (IQR 63.0–86.6) | 77.0 (IQR 64.8–90.9) | 67.9 (IQR 65.4–77.3) | 0.46 |
| CKD status | 4/17 (23.5) | 0/38 (0) | 3/24 (12.5) | 0.11 |
| Baseline eGFR (ml/min/1.73 m2) | 60.1 (IQR 45.4–82.1) | 85.9 (IQR 59.1–105.2) | 89.7 (IQR 72.1–104.0) | 0.04 |
| Hypertension | 12/18 (66.7) | 18/38 (47.4) | 10/24 (41.7) | 0.26 |
| Diabetes | 11/18 (61.1) | 8/38 (21.1) | 6/24 (25.0) | 0.007 |
| CHF | 9/18 (50.0) | 3/37 (8.1) | 2/22 (9.1) | <0.001 |
| Cirrhosis | 2/18 (11.1) | 2/38 (5.3) | 1/23 (4.3) | 0.43 |
| Creatinine* (μmol/l) | 110 (IQR 95–143) | 79 (IQR 62–97) | 75 (IQR 64–88) | <0.001 |
| BUN (mmol/l)** | 8.4 (IQR 5.4–12.3) | 5.1 (IQR 3.0–7.6) | 4.0 (IQR 2.9–5.1) | <0.001 |
| Urine output (ml/24 hrs) | 722 (IQR 393–1523) | 758 (IQR 444–1151) | 1440 (IQR 875–2282) | 0.001 |
| Sepsis | 2/18 (11.1) | 1/38 (2.6) | 3/24 (12.5) | 0.18 |
| On vasopressors | 3/18 (16.7) | 4/38 (10.5) | 1/24 (4.2) | 0.42 |
| On mechanical ventilation | 5/18 (27.8) | 14/38 (36.8) | 9/23 (39.1) | 0.77 |
| SOFA score | 3.5 (IQR 1.75–5.25) | 3.5 (IQR 0–6) | 6 (IQR 2-) | 0.72 |
| APACHE III score | 38.0 (IQR 18.5–43.5) | 23.0 (IQR 15.0–59.0) | 13.0 (IQR 13-) | 0.69 |
| Site | 0.02 | |||
| UCSD | 8/18 (44.4) | 26/38 (68.4) | 15/24 (62.5) | |
| University of Alabama | 10/18 (55.6) | 7/38 (18.4) | 9/24 (37.5) | |
| Université de Montréal | 0/18 (0) | 5/38 (13.2) | 0/24 (0) | |
| Type of ICU | 0.02 | |||
| Medical | 15/18 (83.3) | 17/38 (44.7) | 13/24 (54.2) | |
| Surgical | 3/18 (16.7) | 21/38 (55.3) | 11/24 (45.8) |
AKI: acute kidney injury; ICU: intensive care unit; CKD: chronic kidney disease; eGFR: estimated glomerular filtration rate; CHF: cardiac heart failure; BUN: blood urea nitrogen; SOFA: Sequential Organ Failure Assessment; APACHE: Acute Physiology and Chronic Health Evaluation
AKI according to serum creatinine is defined as an increase in serum creatinine level of more than 27 μmol/l or more than 50% from a reference creatinine within 48 hours with or without urine output less than 0.5 ml/kg/hour for at least 6 hours (AKIN criteria)
AKI according to urine output alone was defined as urine output less than 0.5 ml/kg/hour for at least 6 hours without significant changes in serum creatinine
No AKI was defined as no significant changes in serum creatinine or urine output
*to convert from μmol/l to mg/dl, divide by 88.4
**to convert from mmol/l to mg/dl, multiply by 2.81