Table 1.

General characteristics of patients according to AKI stage

CharacteristicAll Patients(n=18,410)No AKI (n=8157)AKI Stage 1 (n=7367)AKI Stage 2 (n=1634)AKI Stage 3 
(n=1252)P
Age (yr)63.9±17.661.7±17.866.6±17.263.6±17.762.4±16.1<0.001
Men10,434 (56.7)4829 (59.2)4148 (56.3)786 (48.1)671 (53.6)<0.001
Hypertension6103 (33.2)2936 (36.0)2440 (33.1)477 (29.2)250 (20.0)<0.001
Diabetes mellitus3587 (19.5)1501 (18.4)1534 (20.8)307 (18.8)245 (19.6)0.002
Congestive heart failure3622 (19.7)1058 (13.0)1730 (23.5)438 (26.8)396 (31.6)<0.001
COPD3096 (16.8)1208 (14.8)1368 (18.6)303 (18.5)217 (17.3)<0.001
Liver disease900 (4.9)293 (3.6)354 (4.8)113 (6.9)140 (11.2)<0.001
Solid tumors2780 (15.1)1117 (13.7)1262 (17.1)248 (15.2)153 (12.2)<0.001
Lymphoma290 (1.6)104 (1.3)141 (1.9)25 (1.5)20 (1.6)0.01
Metastatic cancer823 (4.5)301 (3.7)408 (5.5)67 (4.1)47 (3.8)<0.001
Sepsis2087 (11.3)399 (4.9)855 (11.6)355 (21.7)478 (38.2)<0.001
ICU first service<0.001
 Medical6701 (36.4)2592 (31.8)2853 (38.7)671 (41.1)585 (46.7)
 Surgical979 (5.3)465 (5.7)393 (5.3)83 (5.1)38 (3.0)
 Cardiac care3974 (21.6)1733 (21.2)1629 (22.1)352 (21.5)260 (20.8)
 Cardiac surgery6.756 (36.7)3367 (41.3)2492 (33.8)528 (32.3)369 (29.5)
SAPS on ICU admission14 (10–18)12 (8–16)14 (10–18)16 (13–20)18 (13–21)<0.001
SOFA on ICU admission6 (2–9)4 (1–7)6 (3–9)8 (5–11)9 (6–13)<0.001
Hyperkalemia 1604 (8.7)276 (3.4)647 (8.8)278 (17.0)403 (32.2)<0.001
Azotemia (BUN >60 mg/dl)1775 (9.6)98 (1.2)734 (10.0)331 (20.3)612 (48.9)<0.001
Cumulative fluid balance >5% body wt7359 (54.2)2359 (40.9)3157 (57.5)1007 (77.0)836 (82.8)<0.001
Hyponatremia5252 (28.5%)1570 (19.2)2179 (29.6)756 (46.3)747 (59.7)<0.001
Metabolic acidosis12,828 (69.7)4843 (59.4)5442 (73.9)1409 (86.2)1134 (90.6)<0.001
Alkali therapy1137 (6.2)161 (2.0)434 (5.9)196 (12.0)346 (27.6)<0.001
Diuretic use during ICU stay7722 (41.9)2549 (31.2)3439 (46.7)1009 (61.8)725 (57.9)<0.001
Need for vasoactive drugs6001 (32.6)2266 (27,8)2304 (31.3)778 (47.6)653 (52.2)<0.001
Need for mechanical ventilation10,483 (56.9)3840 (47.1)4290 (58.2)1325 (81.1)1028 (82.1)<0.001
ICU LOS, d 5.6±3.62.6±1.74.9±2.811.7±7.718.9±8.8<0.001
ICU mortality1394 (7.6)205 (2.5)657 (8.9)238 (14,6)294 (23.5)<0.001
In-hospital mortality2046 (11.1)385 (4.7)978 (13.3)303 (18.5)380 (30.4)<0.001
  • Data are expressed as the mean±SD, n (%), or median (interquartile range). Alkali and diuretic therapy were considered only if administered before RRT. COPD, chronic pulmonary obstructive disease; ICU, intensive care unit; SOFA, sequential organ failure assesment; SAPS, simplified acute physiology score; LOS, length of stay.