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Kidney Week

Abstract: SA-PO426

Quest for Simple and Accurate Estimate of Kidney Function for Chemotherapy Dosing: A Comparison of Commonly Used GFR Estimates and Inulin Clearance

Session Information

Category: Chronic Kidney Disease (Non-Dialysis)

  • 302 CKD: Estimating Equations, Incidence, Prevalence, Special Populations

Authors

  • Tanemoto, Fumiaki, St.Luke's International Hospital, Tokyo, Japan
  • Ishii, Taisuke, St.Luke's International Hospital, Tokyo, Japan
  • Nakano, Eriko, St.Luke's International Hospital, Tokyo, Japan
  • Komatsu, Yasuhiro, St.Luke's International Hospital, Tokyo, Japan
Background

The increase in the number of oncology patients with renal impairment demands the accurate estimate of kidney function to avoid unnecessary adverse effects caused by overdose of chemotherapy. However, dose accuracy after renal function assessment calculated using eGFR equations based on creatinine measured by enzymatic assay and/or cystatin C remains unclear.

Methods

In this single-center study, we collected data from all adult patients whose inulin clearance was measured between January 2009 and March 2017. Renal function and consequent dose of renally-excreted chemotherapy, including carboplatin, were calculated by estimated creatinine-based GFR (eGFRcre) developed by the Japanese Society of Nephrology (JSN), estimated cystatin C-based GFR (eGFRcys) developed by JSN, averaged value of eGFRcre and eGFRcys (eGFRave), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), Cockcroft-Gault (CG), Wright, and Jelliffe formulae. Logistic regression analysis was conducted to determine factors associated with overdose.

Results

The concordance of renal function estimates according to the CKD classification with measured inulin clearance (67±32 ml/min/1.73m2) in 187 adults (age 52±16, 58.3% men) for eGFRcre, eGFRcys, eGFRave, CKD-EPI, CG, Wright, and Jelliffe formulae was 53.5%, 56.6%, 58.5%, 52.9%, 49.2%, 52.4%, and 52.9%, respectively. Concordance for recommended dosage of chemotherapy using each respective formulae was 71.1%, 64.8%, 74.8%, 68.9%, 65.2%, 67.9%, and 67.4%. Especially concordance for carboplatin was 64.2%, 57.2%, 69.8%, 57.2%, 43.9%, 40.6%, and 47.6%, respectively. Hypoalbuminemia was an independent factor for overdose (OR 3.14, 95% CI 1.75-5.61).

Conclusion

For accurate chemotherapy dosing, eGFRave appears to be the most appropriate estimate of renal function. Patients with hypoalbuminemia may need actual measurement of inulin clearance.