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Kidney Week

Abstract: TH-PO0175

Relevance of Measured GFR as a Game Changer in the Management of Onconephrological Patients

Session Information

Category: Onconephrology

  • 1700 Onconephrology

Authors

  • Trevisani, Francesco, IRCCS Ospedale San Raffaele, Milan, Lombardy, Italy
  • Paccagnella, Matteo, Fondazione ARCO Cuneo, Cuneo, Italy
  • Bettiga, Arianna, IRCCS Ospedale San Raffaele, Milan, Lombardy, Italy
  • Monti, Agnese, IRCCS Ospedale San Raffaele, Milan, Lombardy, Italy
  • Cinque, Alessandra, IRCCS Ospedale San Raffaele, Milan, Lombardy, Italy
  • Pizzagalli, Giorgio, IRCCS Ospedale San Raffaele, Milan, Lombardy, Italy
  • Floris, Matteo, Azienda Ospedaliera Brotzu, Cagliari, Sardinia, Italy
  • Rosiello, Giuseppe, IRCCS Ospedale San Raffaele, Milan, Lombardy, Italy
  • Capitanio, Umberto, IRCCS Ospedale San Raffaele, Milan, Lombardy, Italy
  • Salonia, Andrea, IRCCS Ospedale San Raffaele, Milan, Lombardy, Italy
  • Briganti, Alberto, IRCCS Ospedale San Raffaele, Milan, Lombardy, Italy
  • Montorsi, Francesco, IRCCS Ospedale San Raffaele, Milan, Lombardy, Italy
Background

Accurate GFR estimation is crucial in both general and oncologic populations, particularly when patients are exposed to nephrotoxic agents or require surgery. While eGFR formulas are commonly used, their accuracy remains debated. We assessed the agreement between eGFR formulas and measured GFR (mGFR) via iohexol clearance, comparing performance in oncologic vs non-oncologic patients.

Methods

We retrospectively analyzed 754 patients (mean age 64.1 ± 14.0 years; 73.9% male), including 366 (48.5%) with active cancer. mGFR was measured by iohexol plasma clearance. eGFR was calculated using MDRD, CKD-EPI (2012, 2021, creatinine/cystatin C), EKFC, Janowitz, and Cockcroft-Gault. Agreement was assessed using Concordance Correlation Coefficient (CCC), Total Deviation Index (TDI), and Coverage Probability (CP).

Results

In the overall population, EKFC showed the best concordance with iohexol (CCC: 0.863; TDI: 20.6; CP: 87.8%), followed by MDRD and CKD-EPI 2021. Formulas based on cystatin C (2021crcys, 2012cys) had lower accuracy. In oncologic patients, all formulas performed slightly worse, but EKFC remained superior (CCC: 0.853; CP: 89.8%). Scatter plot revealed consistent patterns of over- or underestimation. Histograms confirmed wider error distributions for cystatin C–based formulas.

Conclusion

eGFR formulas show clinically relevant discrepancies compared to mGFR, particularly in oncologic patients. EKFC consistently outperformed other equations but did not eliminate misclassification. Whenever feasible, iohexol-based mGFR should be used to ensure accurate renal function assessment, especially in high-risk populations.

Digital Object Identifier (DOI)