Table 1.
Baseline characteristics of patients receiving immune checkpoint inhibitor therapy
| Characteristics | All Patients | No Sustained AKI | Sustained AKI | Immune Checkpoint Inhibitor–Related AKI |
|---|---|---|---|---|
| Mean±SD or n (%) | ||||
| No. of patients | 1016 | 934 | 82 | 30 |
| Age, yr | 63±13 | 63±14 | 63±12 | 65±12 |
| Baseline creatinine, mg/dL | 0.9±0.3 | 0.9±0.4 | 0.9±0.3 | 0.9±0.3 |
| eGFR, ml/min | 82±22 | 82±22 | 85±20 | 83±22 |
| Men | 616 (61) | 566 (61) | 50 (61) | 18 (60) |
| Women | 400 (39) | 368 (39) | 32 (39) | 12 (40) |
| Race | ||||
| White | 920 (91) | 844 (90) | 76 (93) | 27 (90) |
| Black | 19 (2) | 19 (2) | 0 | 0 |
| Hispanic | 16 (1) | 13 (1) | 3 (4) | 2 (7) |
| Asian | 27 (3) | 25 (3) | 2 (2) | 0 |
| Other/unknown | 34 (3) | 33 (4) | 1 (1) | 1 (3) |
| Cirrhosis | 17 (2) | 15 (2) | 2 (2) | 0 |
| Hypertensiona | 513 (50) | 463 (50) | 50 (61)a | 22 (73) |
| Diabetes | 171 (17) | 156 (17) | 15 (18) | 7 (23) |
| Drugs | ||||
| NSAIDs | 358 (35) | 332 (36) | 26 (32) | 13 (43) |
| Allopurinol | 74 (7) | 68 (7) | 6 (7) | 1 (3) |
| PPIsa | 607 (60) | 549 (59) | 58 (71)a | 23 (77) |
| H2 blockers | 396 (39) | 367 (39) | 29 (35) | 12 (40) |
| ACE/ARB | 403 (40) | 364(39) | 39 (48) | 15 (50) |
| Baseline kidney function (eGFR group) | ||||
| <60 ml/min per 1.73 m2 | 169 (17) | 159 (17) | 10 (12) | 4 (15) |
| 60–90 ml/min per 1.73 m2 | 441 (43) | 406 (43) | 35 (43) | 10 (39) |
| ≥90 ml/min per 1.73 m2 | 406 (40) | 369 (40) | 37 (45) | 12 (46) |
| Immune checkpoint inhibitor class | ||||
| PD1 agents | 701 (69) | 650 (69) | 51 (62) | 16 (53) |
| CTLA4 agents | 249 (24) | 223 (24) | 26 (32) | 12 (40) |
| PDL1 agents | 37 (4) | 34 (4) | 3 (4) | 1 (4) |
| Combined therapy | 29 (3) | 27 (3) | 2 (2) | 1 (3) |
| Prior exposure to nephrotoxic chemotherapya | 309 (30) | 276 (30) | 33 (40)a | 10 (33) |
| Malignancy | ||||
| Melanoma | 438 (43) | 396 (42) | 42 (51) | 18 (60) |
| Lung | 310 (30) | 293 (31) | 17 (21) | 6 (20) |
| Head and neck | 58 (6) | 53 (6) | 5 (6) | 3 (10) |
| Luminal | 38 (4) | 34 (4) | 4 (5) | 0 |
| Liquid | 36 (3) | 33 (4) | 3 (4) | 0 |
| Glioblastoma multiforme | 29 (3) | 26 (3) | 3 (4) | 1 (3) |
| Hepatobiliary | 23 (2) | 19 (2) | 4 (5) | 0 |
| Renal cell carcinoma | 26 (3) | 23 (2) | 3 (3) | 2 (7) |
| Other | 58 (6) | 57 (6) | 1 (1) | 0 |
The baseline characteristics for “All patients” are shown as a percentage of the overall cohort n=1016. For the outcomes, sustained AKI and immune checkpoint inhibitor–related AKI, the percentage of events in each subgroup is presented. First sustained AKI event was specified as the outcome in each patient. Comorbid conditions, including hypertension and cirrhosis, were determined by International Classification of Diseases, Ninth or Tenth Revision codes appearing at least twice in the electronic medical record. Diagnosis of diabetes was determined by either a hemoglobin A1c ≥6.5% or by prescription of a glucose-lowering medication and a diagnosis code for diabetes. Other than the race being unknown in a few patients, there were no missing demographic or comorbidities data. NSAIDs, nonsteroidal anti-inflammatory drugs; PPIs, proton pump inhibitors; H2, Histamine H2-receptor Antagonists; ACE/ARB, Angiotensin Converting Enzyme inhibitors/Angiotensin Receptor Blockers; PD1, Programmed cell death protein 1; CTLA4, Cytotoxic T lymphocyte–associated antigen 4; PDL1, programmed death ligand 1; Combined, ipilimumab (CTLA4) and nivolumab (PD1).
In univariable models comparing demographic and clinical characteristics of patients who experienced sustained AKI with those who did not, only baseline proton pump inhibitor exposure (0.03), nephrotoxic chemotherapy exposure (0.04), and hypertension (0.05) were significant to a P value of <0.10. These were included in the multivariable model for sustained AKI along with other clinically important variables that were determined a priori to be exposures of interest. Nephrotoxic chemotherapies included carboplatin, cisplatin, oxaliplatin, gemcitabine, capecitabine, cyclophosphamide, methotrexate, topotecan, irinotecan, vemurafenib, and bortezomib.