Table 1. Patient characteristics and univariable comparison between patients with and without documentation of AKI. Continuous variables are expressed as mean ± standard deviation or median (IQR). Categorical variables are expressed as percentages.
| AKI not documented (n = 3,192) |
AKI documented (n = 2,927) |
Total (n = 6,119) |
p-value (documented vs. not documented) | |
|---|---|---|---|---|
| Demographics | ||||
| Male | 47.7 | 57.8 | 52.1 | < 0.001 |
| Age, years | 61.2 ± 16.7 | 61 ± 15.9 | 61.1 ± 16.4 | 0.64 |
| Race | ||||
| Black | 30.1 | 27.7 | 29 | 0.05 |
| White | 53.7 | 56.8 | 55 | |
| Other | 16.2 | 15.5 | 15.9 | |
| Service | ||||
| Surgical | 47.9 | 41 | 44.9 | < 0.001 |
| Medical | 52.1 | 59 | 55.1 | |
| Hospital course | ||||
| Length of Stay, days | 12 (7 – 21) | 17 (10 – 29) | 14 (8 – 24) | < 0.001 |
| Length of stay prior to AKI onset, days | 3 (1 – 7) | 4 (2 – 9) | 3 (2 – 8) | < 0.001 |
| Duration of AKI, days | 6 (3 – 11) | 9 (5 – 16) | 7 (4 – 13) | < 0.001 |
| ICU stay, days | 2 (0 – 6) | 4 (0 – 10) | 2.5 (0 – 8) | < 0.001 |
| Ever in an ICU | 64.4 | 73.9 | 68.5 | < 0.001 |
| Ever ventilated | 37.7 | 47.1 | 41.7 | < 0.001 |
| Comorbidities | ||||
| HIV | 2.5 | 2.4 | 2.5 | 0.82 |
| Malignancy | 10.4 | 13 | 11.5 | 0.003 |
| Congestive heart failure | 31.7 | 39.5 | 35 | < 0.001 |
| Cardiovascular disease | 10 | 9.6 | 9.8 | 0.65 |
| Dementia | 1.2 | 0.9 | 1.1 | 0.26 |
| Diabetes mellitus | 26.2 | 28.8 | 27.3 | 0.04 |
| Hemiplegia | 2.3 | 2.8 | 2.5 | 0.30 |
| Metastatic solid tumor | 9.2 | 10 | 9.5 | 0.31 |
| Myocardial infarction | 13.6 | 14.2 | 13.8 | 0.50 |
| Liver disease | 11.3 | 19.7 | 14.9 | < 0.001 |
| Pulmonary disease | 16.6 | 13.8 | 15.4 | 0.004 |
| Peripheral vascular disease | 13.4 | 13.6 | 13.5 | 0.81 |
| Rheumatic disease | 3.3 | 3.3 | 3.3 | 0.943 |
| Peptic ulcer disease | 1.7 | 2.6 | 2.1 | 0.02 |
| Creatinine kinetics | ||||
| Baseline creatinine, mg/dl | 0.73 ± 0.26 | 0.88 ± 0.24 | 0.79 ± 0.26 | < 0.001 |
| Time from onset to doubling, days* | 1 (0 – 2) | 1 (0 – 2) | 1 (0 – 2) | < 0.001 |
| Peak creatinine, mg/dl | 1.97 ± 0.93 | 2.87 ± 1.17 | 2.36 ± 1.13 | < 0.001 |
| Nadir-to-Peak creatinine, mg/dl | 1.25 ± 0.77 | 1.99 ± 1.11 | 1.57 ± 1 | < 0.001 |
| Other labs | ||||
| Nadir bicarbonate, meq/l | 18.9 ± 5 | 17.3 ± 4.9 | 18.2 ± 5 | < 0.001 |
| Peak potassium, meq/l | 5.2 ± 0.9 | 5.4 ± 0.9 | 5.3 ± 0.9 | < 0.001 |
| Peak BUN, mg/dl | 42 ± 26 | 61 ± 35 | 50 ± 31 | < 0.001 |
| Peak WBC count, thousands/ul | 19.3 ± 15.3 | 22.3 ± 22.2 | 20.6 ± 18.6 | < 0.001 |
| Nadir hemoglobin, mg/dl | 8.3 ± 2 | 7.8 ± 1.8 | 8.1 ± 1.9 | < 0.001 |
| Nadir sodium, meq/l | 132.1 ± 4.7 | 131.3 ± 4.8 | 131.8 ± 4.8 | < 0.001 |
| Acuity of illness | ||||
| Peak SOFA score | 5.1 ± 3.5 | 7.1 ± 3.9 | 6 ± 3.8 | < 0.001 |
*Patients with documentation had longer time from start of AKI to doubling of creatinine, though not reflected in the median (IQR). ICU = intensive care unit; HIV = human immunodeficiency virus infection; BUN = blood urea nitrogen; WBC = white blood cell; SOFA = sequential organ failure assessment.