Background: :
Drug-induced Acute Kidney Injury (AKI) develops in 10-15% of patients who receive nephrotoxic
medications. Urinary biomarkers of renal tubular dysfunction may detect nephrotoxicity early and predict
AKI.
Methods::
We prospectively studied patients who received aminoglycosides, vancomycin, amphotericin, or calcineurin
inhibitors, and collected their serial urine while on therapy. Patients who developed drug-induced AKI (fulfilling
KDIGO criteria) were matched with non-AKI controls in a 1:2 ratio. Their urine samples were batch-analyzed
at time-intervals leading up to AKI onset; the latter benchmarked against the final day of nephrotoxic therapy in non-
AKI controls. Biomarkers examined include clusterin, beta-2-microglobulin, KIM1, MCP1, cystatin-C, trefoil-factor-
3, NGAL, interleukin-18, GST-Pi, calbindin, and osteopontin; biomarkers were normalized with corresponding urine
creatinine.
Results::
Nine of 84 (11%) patients developed drug-induced AKI. Biomarkers from 7 AKI cases with pre-AKI samples
were compared with those from 14 non-AKI controls. Corresponding mean ages were 55(±17) and 52(±16)
years; baseline eGFR were 99(±21) and 101(±24) mL/min/1.73m2 (all p=NS). Most biomarker levels peaked before
the onset of AKI. Median levels of 5 biomarkers were significantly higher in AKI cases than controls at 1-3 days
before AKI onset (all µg/mmol): clusterin [58(8-411) versus 7(3-17)], beta-2-microglobulin [1632(913-3823) versus
253(61-791)], KIM1 [0.16(0.13-0.76) versus 0.07(0.05-0.15)], MCP1 [0.40(0.16-1.90) versus 0.07(0.04-0.17)], and
cystatin-C [33(27-2990) versus 11(7-19)], all p<0.05; their AUROC for AKI prediction were >0.80 (confidence
intervals >0.50), with average accuracy highest for clusterin (86%), followed by beta-2-microglobulin, cystatin-C,
MCP1, and KIM1 (57%) after cross-validation.
Conclusion: :
Serial surveillance of these biomarkers could improve the lead time for nephrotoxicity detection by
days.
Using the newer Kidney Disease: Improving Global Outcomes criteria, beta-2-microglobulin levels associate with severity of acute kidney injury
