Table 1. Patient Characteristics and Outcomes.
| Full cohort analysis | Propensity score-based analysis | |||||
|---|---|---|---|---|---|---|
| AKI patients (n = 66) |
Non-AKI patients (n = 2152) |
P value | AKI patients (n = 35) |
Non-AKI patients (n = 1269) |
P value | |
| Patient characteristics | ||||||
| Age (yr) | 68.7 ± 12.3 | 66.2 ± 12.0 | 0.09 | 65.6 ± 14.0 | 64.9 ± 12.6 | 0.73 |
| Male, no. (%) | 48 (72.7) | 1274 (59.2) | 0.03 | 23 (65.7) | 731 (57.6) | 0.34 |
| Body mass index (kg/m2) | 21.1 ± 8.2 | 22.4 ± 24.7 | 0.67 | 19.6 ± 9.5 | 22.1 ± 5.5 | 0.14 |
| CKD stage, no. (%) | < 0.01 | 0.06 | ||||
| 1 (90 ≤ eGFR) | 16 (24.2) | 435 (20.2) | 15 (42.9) | 778 (61.3) | ||
| 2 (60 ≤ eGFR < 90) | 26 (39.4) | 1289 (59.9) | 11 (31.4) | 264 (20.8) | ||
| 3 (30 ≤ eGFR < 60) | 20 (30.3) | 394 (18.3) | 7 (20.0) | 207 (16.3) | ||
| 4 (15 ≤ eGFR < 30) | 4 (6.1) | 34 (1.6) | 2 (5.7) | 20 (1.6) | ||
| Preoperative eGFR (ml/min/1.73 m2) | 77.9 ± 44.8 | 75.5 ± 21.8 | 0.67 | 87.4 ± 49.5 | 76.4 ± 21.6 | 0.20 |
| Comorbidity | ||||||
| Hypertension | 35 (53.0) | 918 (42.7) | 0.15 | 14 (40) | 517 (40.7) | 0.93 |
| Peripheral vascular disease | 10 (15.2) | 189 (8.8) | 0.17 | 6 (17.1) | 102 (8.0) | 0.06 |
| Preoperative medication | ||||||
| Non-steroidal anti-inflammatory drugs | 6 (9.1) | 199 (9.2) | 0.71 | 4 (11.4) | 108 (8.5) | 0.54 |
| Angiotensin converting enzyme inhibitor | 4 (6.1) | 65 (3.0) | 0.15 | 1 (2.9) | 36 (2.8) | 0.99 |
| Angiotensin II receptor blockers | 13 (19.7) | 380 (17.7) | 0.67 | 4 (11.4) | 212 (16.7) | 0.41 |
| Diuretics | 6 (9.1) | 103 (4.8) | 0.04 | 2 (5.7) | 59 (4.6) | 0.77 |
| ASA–PS classification, no. (%) | < 0.001 | < 0.001 | ||||
| 1 | 2 (3.0) | 316 (14.7) | 1 (2.9) | 194 (15.3) | ||
| 2 | 37 (56.1) | 1607 (74.7) | 20 (57.1) | 949 (74.8) | ||
| 3 | 21 (31.8) | 217 (10.1) | 11 (31.4) | 121 (9.5) | ||
| 4 | 6 (9.1) | 12 (0.6) | 3 (8.6) | 5 (0.4) | ||
| Emergency surgery, no. (%) | 18 (27.3) | 140 (6.5) | < 0.001 | 10 (28.6) | 91 (7.2) | < 0.001 |
| Surgical site, no. (%) | < 0.001 | 0.57 | ||||
| Laparoscopic upper abdominal surgery | 21 (31.8) | 794 (36.9) | 11 (31.4) | 490 (38.6) | ||
| Open upper abdominal surgery | 27 (40.9) | 710 (33.0) | 13 (37.1) | 400 (35.1) | ||
| Laparoscopic colorectal surgery | 12 (18.2) | 373 (17.3) | 7 (20.0) | 221 (17.4) | ||
| Open colorectal surgery | 4 (6.1) | 152 (7.1) | 2 (5.7) | 86 (6.8) | ||
| Combination of abdominal and intrathoracic surgery | 0 (0) | 74 (3.4) | 0 (0) | 43 (3.4) | ||
| Superficial surgery | 2 (3.0) | 49 (2.3) | 2 (5.7) | 29 (2.3) | ||
| Intraoperative measures | ||||||
| Operation time (min) | 270.0 ± 206.9 | 218.9 ± 143.4 | 0.05 | 251.5 ± 248.2 | 197.6 ± 156.0 | 0.21 |
| Estimated blood loss, no. (%) | < 0.001 | 0.04 | ||||
| < 500 ml | 34 (51.5) | 1610 (74.8) | 20 (57.1) | 930 (73.3) | ||
| 500–999 ml | 13 (19.7) | 298 (13.8) | 4 (11.4) | 142 (11.2) | ||
| ≥ 1000 ml | 19 (28.8) | 244 (11.3) | 11 (31.4) | 197 (15.5) | ||
| Total infused HES, no. (%) | 0.83 | 0.11 | ||||
| 0 ml | 33 (50.0) | 1002 (46.6) | 23 (65.7) | 903 (71.2) | ||
| 1–999 ml | 17 (25.8) | 618 (28.7) | 0 (0) | 80 (6.3) | ||
| ≥ 1000 ml | 16 (24.2) | 532 (24.7) | 12 (34.3) | 286 (22.5) | ||
| Use of non-steroidal anti-inflammatory drugs during surgery | 6 (9.1) | 199 (9.2) | 0.71 | 4 (11.4) | 370 (29.2) | 0.02 |
| Urine output (ml) | 618.2 ± 732.9 | 679.1 ± 737.0 | 0.51 | 662.0 ± 868.8 | 559.6 ± 697.8 | 0.40 |
| Total crystalloids infusion (ml) | 4848.5 ± 4029.5 | 3488.8 ± 2540.0 | 0.01 | 4315.7 ± 4448.4 | 3226.2 ± 2841.3 | 0.16 |
| Total red blood cell transfusion (ml) | 715.5 ± 1325.7 | 184.6 ± 1305.5 | < 0.01 | 729.7 ± 1553.8 | 216.6 ± 1662.8 | 0.06 |
| Total albumin infusion (ml) | 340.9 ± 724.1 | 34.3 ± 178.4 | 0.001 | 357.1 ± 816.4 | 40.9 ± 183.5 | 0.03 |
| Outcome measure | ||||||
| Serum creatinine (mg/dl) | < 0.01 | 0.04 | ||||
| Preoperative | 0.88 ± 0.58 | 0.78 ± 0.28 | 0.83 ± 0.55 | 0.77 ± 0.28 | ||
| Postoperative day 1 | 1.43 ± 1.63 | 0.71 ± 0.27 | 1.17 ± 1.25 | 0.71 ± 0.28 | ||
| Postoperative day 2 | 4.1 ± 18.9 | 0.74 ± 0.31 | 1.08 ± 0.67 | 0.74 ± 0.30 | ||
| Postoperative day 3 | 1.5 ± 1.71 | 0.68 ± 0.26 | 1.40 ± 1.42 | 0.67 ± 0.27 | ||
| Postoperative day 4 | 3.57 ± 14.73 | 0.72 ± 0.27 | 5.53 ± 20.60 | 0.72 ± 0.27 | ||
| Postoperative day 5 | 1.24 ± 1.07 | 0.70 ± 0.30 | 1.08 ± 0.79 | 0.70 ± 0.30 | ||
| Postoperative day 6 | 1.26 ± 1.44 | 0.72 ± 0.32 | 1.38 ± 1.98 | 0.71 ± 0.29 | ||
| Postoperative day 7 | 1.36 ± 1.29 | 0.74 ± 0.28 | 1.08 ± 0.65 | 0.73 ± 0.28 | ||
| RIFLE criteria, no. (%) | - | - | ||||
| Risk | 40 (60.6) | 22 (62.9) | ||||
| Injury | 15 (22.7) | 8 (22.9) | ||||
| Failure | 11 (16.7) | 5 (14.3) | ||||
Values are presented as means ± SD for continuous variables, and as the number (percentage) for categorical variables. AKI: acute kidney injury, CKD: chronic kidney disease, eGFR: estimated glomerular filtration rate, ASA-PS: American Society of Anesthesiologists Physical Status, HES: hydroxyethyl starch, RIFLE: Risk, Injury, Failure, Loss, or End-stage kidney disease.