Kidney Week

Abstract: SA-PO612

A Novel Nomogram to Predict the Reliability of Estimated Glomerular Filtration Rate Formula in Oncology Patients

Session Information

• Pharmacology
  October 27, 2018 | Location: Exhibit Hall, San Diego Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Pharmacology (PharmacoKinetics, -Dynamics, -Genomics)

• 1700 Pharmacology (PharmacoKinetics, -Dynamics, -Genomics)

Authors

• Cheng, Yichun, Department of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China

Yichun Cheng,

• Huang, Liu, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China

Liu Huang,

• Han, Yunfeng, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China

Yunfeng Han,

• Xu, Gang, Tongji hospital affiliated to Tongji medical college, Huazhong University of Science and Technology, Wuhan, China

Gang Xu,

• Ge, Shuwang, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China

Shuwang Ge,

Background

Formulae of estimated glomerular filtration rate (eGFR) based on serum creatinine (Scr) are routinely used for drug dosage in oncology patients, however, they are inaccurate in some populations. Our aim was to identify population characteristics where eGFR formulae performed poorly and thereby build a nomogram to predict the reliability of estimates.

Methods

Measured GFR (mGFR) using isotope from 444 oncology patients were compared with eGFR from four formulae (Cockcroft-Gault, de-indexed MDRD, de-indexed CKD-EPI and Wright). Multivariate logistic regression was applied to identify characteristics associated with inaccurate eGFR and construct a predictive nomogram.

Results

The Cockcroft–Gault formula exhibited estimates with lowest bias and highest precision. Nonetheless, it was still unreliable in a relevant proportion of patients. The percentage of patients within 30%, 20%, and 10% of the accurate percentage error (APE) was seen in only 62.8%, 47.7% and 24.8% of patients respectively. Inaccuracy was found in overweight patients or in patients with BUN/Scr ratio greater than 20 or with eGFR greater than 60 ml/min/1.73m². A novel nomogram was constructed to help oncologists to predict the risk of inaccuracy of eGFR. The calibration curve showed good agreement.

Conclusion

Our results suggest that all eGFR formulae tend to overestimate the eGFR in oncology patients. Our nomogram may assist oncologists in decision-making when mGFR is needed.