Measured GFR in oncological solitary kidney: a critical parameter for precision management in onconephrology
- Maulinkumar Patel
- 5 days ago
- 2 min read
Abstract
Background and Aims
Chronic kidney disease (CKD) and acute kidney injury (AKI) are among the most significant long-term complications following radical nephrectomy (RN) for renal masses. In clinical practice, precise renal function assessment is crucial to minimize these risks, particularly for patients with an oncological solitary kidney (SK), where management largely depends on glomerular filtration rate (GFR) values. While estimated GFR (eGFR) is the most commonly used method to assess renal function, it carries a notable margin of error compared to the gold standard, measured GFR (mGFR). This study aimed to quantify the discrepancy between eGFR most used formulas and mGFR in a cohort of patients with oncological solitary kidneys to enhance accuracy in clinical decision-making and postoperative care.
Method
We retrospectively analyzed a cohort of 170 patients with a solitary kidney (SK), of whom 79.4% (n = 135) had an oncological SK. Renal function was assessed using measured GFR (mGFR) via Iohexol clearance, considered the gold standard, and compared with estimated GFR (eGFR) calculated using multiple formulas.
To evaluate the agreement between mGFR and eGFR methods, we computed the Concordance Correlation Coefficient (CCC), Total Deviation Index (TDI), and Coverage Probability (CP). Histograms were generated to visualize the distribution of absolute differences between Iohexol clearance and eGFR, while scatter plots were used to compare individual eGFR methods against mGFR.
All statistical analyses and visualizations were performed using R (version 4.4.2). The following packages were used: ggplot2 for scatter plots, epiR for CCC, TDI, and CP calculations, and dplyr/tidyr for data preprocessing.
Results
Descriptive analysis is shown in Table 1. Agreement between mGFR and eGFR varied across formulas (Tables 2, 3). EKFC showed the highest concordance, while CKD-EPI 2012 (cystatin C) and Cockcroft-Gault performed worst (Fig. 1). Histograms (Fig. 2) and scatter plots confirmed these discrepancies.
Conclusion
In daily clinical practice, a tailored nephrological follow-up based on measured GFR (mGFR) is essential for radical nephrectomy (RN) patients with a solitary kidney. Reliance on estimated GFR (eGFR) alone can lead to significant clinical errors, either underestimating or overestimating actual renal function, potentially resulting in critical medical consequences.
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