Table 4

Patient baseline characteristics and the Risk, Injury, Failure, Loss of Kidney Function, End-stage Kidney Disease (RIFLE) criteria
Variable
 No acute kidney injury (n = 372)
 Risk (n = 97)
 Injury (n = 73)
 Failure (n = 120)
 P value
Mean age (years)
 55 ± 19
 64 ± 18
 63 ± 15
 61 ± 16
 < 0.0001
Male (%)
 55.6
 65.9
 63
 62.5
 0.252
Caucasian (%)
 93
 91.7
 91.8
 92.5
 1.000
History of cardiovascular diseasea (%)
 48.4
 63.9
 61.6
 54.2
 0.023
Medical admission (%)
 71.8
 78.4
 80.8
 86.7
 0.008
Sepsisb (%)
 26.6
 39.2
 61.6
 74.2
 < 0.0001
Baseline serum creatinine (μmol/l)c
 86 ± 24
 100 ± 42
 107 ± 26
 123 ± 50
 < 0.0001
Simplified Acute Physiology Score version IId
 40 ± 15
 48 ± 15
 51 ± 18
 62 ± 21
 < 0.0001
Vasopressors (%)
 21.5
 48.5
 63
 76.7
 < 0.0001
Need for mechanical ventilation (%)
 83.6
 85.6
 86.3
 86.7
 1.000
Urine output (l)e
 2.2 ± 0.9
 0.5 ± 0.2
 0.9 ± 0.5
 1.4 ± 1.1
Serum creatinine at maximum RIFLE
162 ± 35
 235 ± 32
 395 ± 54
Need for renal replacement therapy




     % of patients
2
 12.3
 56.7
 < 0.0001
     Mean time (days)
 5 ± 2
 10 ± 8
 9 ± 7
 0.599
Mean length of stay (days)
 7 ± 8
 8 ± 6
 9 ± 10
 11 ± 12
 0.009
Mortality
 11
 30.9
 32.8
 55
 < 0.0001
Complete renal function recoveryf
 74.6
 73.5
 55.6
 0.053

aAangina pectoris, myocardial infarction, cerebrovascular disease, and diabetes mellitus. bDefined in accordance with the American College of Chest Physicians and the Society of Critical Care Medicine consensus [15]. cEstimated by the Modification of Diet in Renal Disease equation [14], assuming a lower limit of the normal baseline glomerular filtration rate of 75 ml/min/1.73 m2. dCalculated based on the worst variables recorded during the first 24 hours of admission [16]. eAt maximum RIFLE (6-hour urine output for risk, 12-hour urine output for injury, and 24-hour urine output for failure). fIf the patient returned to their baseline classification within the RIFLE criteria [2].

Lopes et al. Critical Care 2008 12:R110   doi:10.1186/cc6997