Table 1.
Clinical Characteristics for All Patients Stratified by Kidney Disease
| Variables | Patient Groupsa | ||||
|---|---|---|---|---|---|
| No Known Kidney Disease (n = 1557) | AKI | CKD Without AKI (n = 160) | ESRD (n = 128) | ||
| Without CKD (n = 1465) | With CKD (n = 336) | ||||
| Age, mean (SD), y | 62 (14) | 66 (14)b | 68 (12)b | 69 (12)b | 64 (12) |
| Age ≥65 y, No. (%) | 741 (47.6) | 895 (61.1)b | 234 (69.6)b | 112 (70.0)b | 62 (48.4) |
| Female, No. (%) | 575 (36.9) | 555 (37.9) | 94 (28.0)b | 58 (36.3) | 45 (35.2) |
| African American ethnicity, No. (%) | 116 (7.5) | 157 (10.7)b | 53 (15.8)b | 25 (15.6)b | 33 (25.8)b |
| Emergent surgery, No. (%) | 498 (32.0) | 607 (41.4)b | 156 (46.4)b | 65 (40.6) | 82 (64.1)b |
| Weekend admission, No. (%) | 139 (8.9) | 172 (11.7)b | 39 (11.6) | 16 (10.0) | 25 (19.5)b |
| Charlson-Deyo comorbidity index, No. (%) | |||||
| 0 | 86 (5.5) | 55 (3.8) | 1 (0.3)b | 3 (1.9) | 0b |
| 1 | 591 (38.0) | 540 (36.9) | 56 (16.7)b | 19 (11.9)b | 1 (0.8)b |
| 2 | 484 (31.1) | 458 (31.3) | 54 (16.1)b | 26 (16.3)b | 8 (6.3)b |
| ≥3 | 396 (25.4) | 412 (28.1) | 225 (67.0)b | 112 (70.0)b | 119 (93.0)b |
| Comorbidities, No. (%) | |||||
| Myocardial infarction | 205 (13.2) | 208 (14.2) | 62 (18.5)b | 28 (17.5) | 15 (11.7) |
| Congestive heart failure | 115 (7.4) | 177 (12.1)b | 75 (22.3)b | 39 (24.4)b | 32 (25.0)b |
| Chronic obstructive pulmonary disease | 450 (28.9) | 429 (29.3) | 112 (33.3) | 58 (36.3) | 24 (18.8) |
| Diabetes mellitus | 336 (21.6) | 281 (19.2) | 76 (22.6) | 49 (30.6)b | 54 (42.2)b |
| Surgery type, No. (%) | |||||
| Endovascular thoracic and abdominal | 240 (15.4) | 200 (13.7) | 60 (17.9) | 32 (20.0) | 13 (10.2) |
| Lower extremity amputations | 118 (7.6) | 63 (4.3)b | 20 (6.0) | 20 (12.5) | 25 (19.5)a |
| Open abdominal | 304 (19.5) | 370 (25.3)b | 88 (26.2) | 23 (14.4) | 21 (16.4) |
| Open carotid | 74 (4.8) | 31 (2.1)b | 3 (0.9)b | 11 (6.9) | 1 (0.8) |
| Endovascular peripheral | 111 (7.1) | 99 (6.8) | 24 (7.1) | 24 (15.0)b | 19 (14.8) |
| Open peripheral | 334 (21.5) | 194 (13.2)b | 43 (12.8)b | 25 (15.6) | 33 (25.8) |
| Open thoracic | 376 (24.1) | 508 (34.7)b | 98 (29.2) | 25 (15.6) | 16 (12.5)b |
| Admission hemoglobin level, g/dL, No. (%) | |||||
| Missing | 318 (20.4) | 215 (14.7) | 53 (15.8) | 27 (16.9) | 26 (20.3) |
| <10 | 249 (16.0) | 299 (20.4)b | 76 (22.6)b | 34 (21.3) | 35 (27.3)b |
| 10–12 | 460 (29.5) | 463 (31.6) | 113 (33.6) | 56 (35.0) | 35 (27.3) |
| ≥12 | 530 (34.0) | 488 (33.3) | 94 (28.0) | 43 (26.9) | 32 (25.0) |
| Admission medications, No. (%) | |||||
| Aspirin | 409 (26.3) | 318 (21.7)b | 75 (22.3) | 44 (27.5) | 31 (24.2) |
| Statin | 386 (24.8) | 307 (21.0) | 91 (27.1) | 50 (31.3) | 28 (21.9) |
| Angiotensin-converting enzyme inhibitor | 194 (12.5) | 205 (14.0) | 53 (15.8) | 25 (15.6) | 21 (16.4) |
| β-Blocker | 626 (40.2) | 572 (39.0) | 152 (45.2) | 76 (47.5) | 61 (47.7) |
| Chronic kidney disease, No. (%) | |||||
| Mild to moderatec | NA | NA | 248 (73.8) | 133 (83.1) | NA |
| Severed | NA | NA | 88 (26.2)e | 27 (16.9) | NA |
| AKI, No. (%) | |||||
| Mild to moderatef | NA | 1214 (82.9) | 135 (40.2) | NA | NA |
| Severeg | NA | 251 (17.1) | 201 (59.8)h | NA | NA |
Abbreviations: AKI, acute kidney injury; CKD, chronic kidney disease; ESRD, end-stage renal disease; NA, not applicable.
SI conversion factor: To convert hemoglobin to grams per liter, multiply by 10.0.
Percentages have been rounded and may not total 100.
P < .05 for comparison with respect to the group with no known kidney disease using Bonferroni adjustment for 4 comparisons.
Indicates estimated glomerular filtration rate (eGFR) of 30 mL/min/1.73m2 or higher.
Indicates eGFR lower than 30 mL/min/1.73m2.
P < .05 for association between CKD severity (mild to moderate or severe) and 2 renal groups (AKI with CKD and CKD with no AKI).
Indicates stage 1 (a 50% change in serum creatinine level) or 2 (a doubling in serum creatinine level).
Indicates stage 3 (a tripling or increase in serum creatinine level to 4.0mg/dL or higher [to convert to micromoles per liter, multiply by 88.4] or the initiation of renal replacement therapy).
P < .05 for association between AKI severity (mild to moderate or severe) and 2 renal groups (AKI with no CKD and AKI with CKD).