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Table 2 Baseline characteristics of patients classified according to the maximum Risk, Injury, Failure, Loss, and End-stage Kidney (RIFLE) class

From: RIFLE criteria for acute kidney injury are associated with hospital mortality in critically ill patients: a cohort analysis

  No acute kidney injury Risk Injury Failure
n 1,766 (32.8%) 670 (12.4%) 1,436 (26.7%) 1,511 (28.1%)
Sex (male) 988 (55.9%) 372 (55.5%) 841 (58.6%) 570 (57.0%)
Age (years)* 56.6 (18.2) 63.4 (17.0) 62.6 (16.6) 62.1 (16.4)
Race (n = 5,101)**     
   White 1,491 (89.5%) 587 (91.3%) 1,237 (90.7%) 1,255 (87.9%)
   Black 146 (8.8%) 45 (7.0%) 111 (8.1%) 156 (10.9%)
   Other 29 (1.7%) 11 (1.7%) 16 (1.2%) 17 (1.2%)
Chronic kidney insufficiency* 17 (1.0%) 4 (0.6%) 17 (1.2%) 121 (8.0%)
Admission type* (n = 5,375)     
   Medical 778 (44.2%) 277 (41.4%) 566 (39.4%) 545 (36.1%)
   Surgical 984 (55.8%) 392 (58.6%) 870 (60.6%) 963 (63.9%)
Reason for admission according to organ system* (n = 5,375)     
   Cardiovascular disease 446 (25.3%) 236 (35.3%) 446 (31.1%) 513 (34.0%)
   Neurological disease 311 (17.7%) 109 (16.3%) 314 (21.9%) 327 (21.7%)
   Pulmonary disease/infection 226 (12.8%) 101 (15.1%) 232 (16.2%) 291 (19.3%)
   Trauma 317 (18.0%) 85 (12.7%) 203 (14.1%) 163 (10.8%)
   Malignancy 117 (6.6%) 34 (5.1%) 38 (2.6%) 35 (2.3%)
   Gastrointestinal disease 67 (3.8%) 22 (3.3%) 32 (2.2%) 26 (1.7%)
   Other 278 (15.8%) 82 (12.3%) 171 (11.9%) 153 (10.1%)
APACHE III score* (n = 3,400) 36 (26–47) 46 (35–57) 46 (36–58) 56 (41–73)
SOFA score* 5.1 (3.3) 6.3 (4.0) 6.8 (4.1) 7.8 (4.5)
SOFAnonrenal score* 4.5 (3.1) 5.3 (3.5) 5.6 (3.5) 5.9 (3.9)
SOFA RIFLEmax score* (n = 4,994) 3.7 (3.2) 5.3 (3.8) 5.9 (3.8) 6.7 (4.3)
SOFAnonrenal RIFLEmax score* (n = 4,994) 3.2 (2.8) 4.5 (3.5) 5.0 (3.4) 5.0 (3.7)
Inhospital before ICU admission* 527 (29.8%) 243 (36.3%) 476 (33.1%) 592 (39.2%)
Pre-ICU LOS* (days) 1 (1–4) 2 (1–4) 2 (1–5) 2 (1–6)
Time to RIFLEmax* (days)   2 (1–3) 2 (1–4) 2 (1–7)
RIFLE class on glomerular filtration rate criteria*   463 (69.1%) 929 (64.7%) 1,110 (73.5%)
  1. Continuous variables are presented as the mean (standard deviation) when normally distributed or as the median (interquartile interval) when not normally distributed. Categorical variables are presented as percentages. No acute kidney injury is those patients without any occurrence of RIFLE criteria; APACHE III, Acute Physiology and Chronic Health Evaluation, version III; SOFAnonrenal, Sequential Organ Failure Assessment score without points for renal insufficiency, SOFA RIFLEmax, Sequential Organ Failure Assessment score at the time of maximum RIFLE class; pre-ICU LOS, length of hospital stay before intensive care unit admission (only for patients who were in hospital before intensive care unit admission). *P < 0.001, **P = 0.035.