Table 2

Participant characteristics at the time of acute kidney injury by estimated acute interstitial nephritis status

VariablesEstimated acute interstitial nephritis (eAIN; n=34)Not eAIN (n=321)P value
Demographics and comorbidities
 Age66.4 (57.8,75.5)64.6 (56.7,73.1)0.52
 Female sex12 (35.3%)158 (49.1%)0.13
 Black race1 (2.9%)20 (6.2%)0.44
 Diabetes10 (29.4%)80 (24.8%)0.56
 Hypertension28 (82.4%)217 (67.4%)0.07
 Cirrhosis0 (0%)7 (2.2%)0.39
 Chronic kidney disease7 (20.6%)42 (13%)0.22
Cancer and stage
 Lung9 (26.5%)102 (31.7%)0.53
 Melanoma5 (14.7%)46 (14.3%)0.95
 Kidney10 (29.4%)57 (17.7%)0.10
 Digestive1 (2.9%)34 (10.6%)0.16
 Head and neck4 (11.8%)18 (5.6%)0.16
 Breast0 (0%)7 (2.2%)0.39
 Other5 (14.7%)58 (18%)0.63
 Stage 4 cancer30 (88.2%)275 (85.4%)0.65
Laboratory findings at AKI
 Creatinine3.3 (2.1, 6.1)1.4 (1.2, 1.9)<0.001
 Estimated glomerular filtration rate19.2 (9.3, 26.5)45.2 (31.8, 59.5)<0.001
 Blood urea nitrogen (BUN)39 (25, 60)25 (18, 37)0.004
 BUN:creatinine ratio11.2 (8.7, 13.9)16.8 (13.3, 23)<0.001
 Hemoglobin11.2 (9.6, 12.7)10.9 (9.2, 12.7)0.42
 Platelet count237 (173, 360)238 (172, 317)0.75
 Bicarbonate22.5 (19, 25)23 (20, 25)0.52
 Anion gap16 (14, 19)15 (12, 17)0.06
 Urine proteinuria2 (5.9%)57 (17.7%)0.13
 Urine-specific gravity1.012 (1.009,1.02)1.019 (1.013,1.024)0.002
Diagnostic evaluation of AKI
 Urinalysis34 (100%)322 (100%)N/A
Clostridium difficile testing6 (17.6%)67 (20.8%)0.66
 Ultrasound16 (47.1%)54 (16.8%)<0.001
Medication use before AKI
 PPI11 (32.4%)123 (38.2%)0.50
 NSAID4 (11.8%)113 (35.1%)0.006
 Antibiotic21 (61.8%)237 (73.6%)0.14
Medication use after AKI (30 days)
 Steroid use15 (44.1%)87 (27%)0.04
 Steroid use (excluding prior use)13 (40.6%)62 (22.5%)0.02
 Received ICI after AKI16 (47.1%)120 (37.3%)0.26
 Time to next ICI dose, days20.3 (10.2, 123.9)10.5 (0.1, 20.4)0.01
Predicted probability of AIN0.49 (0.44, 0.56)0.15 (0.10, 0.25)<0.001
Immune-related adverse events
 Dermatitis9 (26.5%)51 (15.8%)0.14
 Colitis8 (23.5%)48 (14.9%)0.21
 Hypophysitis4 (11.8%)24 (7.5%)0.33
 Pneumonitis3 (8.8%)32 (9.9%)0.99
 Adrenalitis2 (5.9%)60 (18.6%)0.09
 Thyroiditis2 (5.9%)25 (7.8%)0.99
 Hepatitis2 (5.9%)20 (6.2%)0.99
 Interstitial nephritis6 (17%)16 (5%)0.006
  • Only includes those with AKI and with complete data on components (n=356). Values obtained at AKI.

  • AIN, acute interstitial nephritis; AKI, acute kidney injury; eAIN, estimated acute interstitial nephritis; ICI, immune checkpoint inhibitor; NSAID, non-steroidal anti-inflammatory drug; PPI, proton pump inhibitor.