Table 1.
Clinical characteristics and postoperative outcomes for all patients stratified by RIFLE-AKI stages.
| No AKI (n=17,613) | All AKI (n=10,228) | P1 | RIFLE-R (n=5959) | RIFLE-I (n=2578) | RIFLE-F (n=1691) | P2 | |
|---|---|---|---|---|---|---|---|
|
| |||||||
| AKI by NSQIP definition, n (%) | 701 (7) | 0 (0) | 3 (0.1) | 698 (41) | <0.001 | ||
|
| |||||||
| ARF diagnostic code1 in discharge summary, n (%) | 1021 (10) | 114 (2) | 166 (6) | 741 (44) | <0.001 | ||
|
| |||||||
| Renal replacement therapy, n (%) | 332 (3) | 0 (0) | 0 (0) | 332 (20) | <0.001 | ||
|
| |||||||
| AKI onset in the first 72 hours postoperatively, n (%) | 7330 (72) | 4197 (70) | 1948 (76) | 1185 (70) | <0.001 | ||
| AKI onset between day 3-7 postoperatively, n (%) | 2515 (25) | 1666 (28) | 511 (20) | 338 (20) | |||
| AKI onset after postoperative day 7, n (%) | 383 (3) | 96 (3) | 119 (5) | 168 (10) | |||
|
| |||||||
| Complete Renal Recovery, n (%) | 7491 (73) | 5107 (86) | 1707 (66) | 677 (40) | <0.001 | ||
| Partial or No Renal Recovery, n (%) | 2735 (27) | 852 (14) | 871 (34) | 1012 (60) | |||
|
| |||||||
| Baseline Characteristics | |||||||
|
| |||||||
| Age (years), Mean (SD) | 54 (15) | 56 (15) | <0.001 | 55 (15) | 56 (15) | 56 (15) | NS |
|
| |||||||
| Female sex, n (%) | 9017 (51) | 5094 (50) | 0.03 | 3081 (52) | 1300 (50) | 713 (42) | <0.001 |
|
| |||||||
| African-American ethnicity, n (%) | 2174 (12) | 1473 (14) | <0.001 | 794 (13) | 390 (15) | 289 (17) | <0.001 |
|
| |||||||
| Rural area residency | 5411 (33) | 3132 (33) | NS | 1843 (33) | 794 (33) | 495 (32) | NS |
|
| |||||||
| Annual Income (1000$), Median (25th, 75th) | 35 (30, 41) | 34 (29, 41) | NS | 34 (29, 41) | 34 (28, 41) | 33 (28, 41) | NS |
|
| |||||||
| Primary Insurance | <0.001 | 0.003 | |||||
| Medicare | 6740 (38) | 4632 (45) | 2655 (45) | 1195 (46) | 782 (46) | ||
| Medicaid | 1808 (10) | 1360 (14) | 746 (13) | 368 (14) | 246 (15) | ||
| Private | 7993 (45) | 3709 (36) | 2222 (37) | 895 (35) | 592 (35) | ||
| No insurance | 1072 (6) | 527 (5) | 336 (5) | 120 (5) | 71 (4) | ||
|
| |||||||
| Weekend admission | 1568 (9) | 1484 (15) | <0.001 | 804 (13) | 414 (16) | 266 (16) | 0.002 |
|
| |||||||
| Weekend discharge | 4026 (23) | 1685 (16) | <0.001 | 1028 (17) | 403 (16) | 254 (15) | 0.04 |
|
| |||||||
| Emergency admission | 5247 (30) | 5135 (50) | <0.001 | 2677 (45) | 1412 (55) | 1046 (62) | <0.001 |
|
| |||||||
| Initial admission to medicine service | 1154 (7) | 2093 (20) | <0.001 | 889 (15) | 568 (22) | 636 (38) | <0.001 |
|
| |||||||
| Charlson’s Comorbidity Score, Median (25th, 75th) | 1 (0, 2) | 2 (1, 3) | <0.001 | 1 (0, 3) | 2 (1, 3) | 2 (1, 3) | 0.05 |
| 0 | 7226 (41) | 2474 (24) | <0.001 | 1642 (28) | 568 (22) | 264 (16) | <0.001 |
| 1-2 | 6920 (39) | 4804 (47) | 2748 (46) | 1234 (48) | 822 (48) | ||
| 3-4 | 1734 (10) | 1771 (17) | 879 (15) | 501 (19) | 391 (23) | ||
| ≥ 5 | 1715 (10) | 1170 (12) | 685 (11) | 271 (11) | 214 (13) | ||
|
| |||||||
| Postoperative Outcomes | |||||||
|
| |||||||
| Hospital mortality, n (%) | 98 (0.6) | 771 (8) | <0.001 | 162 (3) | 168 (7) | 441 (26) | <0.001 |
|
| |||||||
| 90-day mortality, n (%) | 457 (3) | 1103 (11) | <0.001 | 343 (6) | 273 (11) | 487 (29) | <0.001 |
|
| |||||||
| Sepsis, n (%) | 91 (0.5) | 929 (9) | <0.001 | 156 (3) | 260 (10) | 513 (30) | <0.001 |
|
| |||||||
| Severe Sepsis, n (%) | 42 (0.2) | 830 (8) | <0.001 | 117 (2) | 216 (8) | 497 (29) | <0.001 |
|
| |||||||
| Postoperative surgical infections, n (%) | 639 (4) | 805 (8) | 0.001 | 380 (6) | 250 (10) | 175 (10) | 0.001 |
|
| |||||||
| Mechanical wound complications, n (%) | 700 (4) | 981 (10) | <0.001 | 486 (8) | 276 (11) | 219 (13) | <0.001 |
|
| |||||||
| Procedural complications, n (%) | 782 (4) | 1102 (11) | <0.001 | 532 (9) | 297 (12) | 273 (16) | <0.001 |
|
| |||||||
| Mechanical ventilation, n (%) | 2251 (13) | 4393 (43) | <0.001 | 2045 (34) | 1247 (48) | 1101 (65) | <0.001 |
|
| |||||||
| Days on mechanical ventilation, | 2 (1,2) | 4 (2, 14) | <0.001 | 2 (2, 7) | 6 (2, 16) | 12 (3, 29) | <0.001 |
|
| |||||||
| Long-term mechanical ventilation, n (%) | 367 (2) | 1431 (14) | <0.001 | 423 (7) | 446 (17) | 562 (33) | <0.001 |
|
| |||||||
| Pulmonary complications, n (%) | 729 (4) | 1584 (15) | <0.001 | 668 (11) | 475 (18) | 441 (26) | <0.001 |
|
| |||||||
| Cardiovascular complications, n (%) | 512 (3) | 775 (8) | <0.001 | 356 (6) | 237 (9) | 182 (11) | <0.001 |
|
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| Neurological complications, n (%) | 294 (2) | 369 (4) | <0.001 | 186 (3) | 117 (5) | 66 (4) | 0.004 |
|
| |||||||
| Gastrointestinal complications, n (%) | 407 (2) | 513 (5) | 0.05 | 268 (5) | 147 (6) | 98 (6) | 0.02 |
1
International Classification of Diseases, Ninth Revision, Clinical Modification diagnostic codes 584.XX or 997.5.
P1 Comparing no RIFLE-AKI versus all RIFLE-AKI patients.
P2 Comparing RIFLE-AKI classes to each other.