Kidney Week

Abstract: SA-PO831

Indexing Glomerular Filtration Rate by Body Surface Area in Live Kidney Donors: Is It Really Necessary?

Session Information

• Transplantation: Clinical - Pretransplant Assessment and Living Donors
  November 05, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
  Abstract Time: 10:00 AM - 12:00 PM

Category: Transplantation

• 2002 Transplantation: Clinical

Authors

• Gandhi, Nisarg, Houston Methodist, Houston, Texas, United States

Nisarg Gandhi,

• Hebert, Sean, Houston Methodist, Houston, Texas, United States

Sean Hebert,

• Nguyen, Duc T., Houston Methodist, Houston, Texas, United States

Duc T. Nguyen,

• Graviss, Edward A., Houston Methodist, Houston, Texas, United States

Edward A. Graviss,

• Ibrahim, Hassan N., Memorial Hermann Health System, Houston, Texas, United States

Hassan N. Ibrahim,

Background

Glomerular filtration rate (GFR) is proportional to both kidney and body size. It is commonly expressed as estimated (e)GFR as ml/min/1.73m², which represents the adjustment to a standard body surface area (BSA). However, a compelling rationale for this recommendation is lacking. In the case of kidney donor candidates, eGFR adjustment by BSA may result in wider acceptance of those with BSA <1.73 m² and restrict access for those with a BSA >1.73 m² as adjusted eGFR will be higher in the former and lower in the latter. Long term outcomes of kidney donors who have adjusted eGFR are higher, lower, or equal to their raw eGFR has not been studied.

Methods

Using the publicly available data from The Renal and Lung Living Donor Evaluation Study (RELIVE), we compared the development of hypertension, proteinuria, reduced eGFR, and kidney failure in 8578 donors with: 1) raw and adjusted eGFR ≥ 80 ml/min/1.73m²; 2) only adjusted eGFR ≥ 80 ml/min/1.73m²; 3) only raw eGFR ≥ 80 ml/min; and 4) both raw and adjusted eGFR < 80 ml/min/1.73m².

Results

5504 donors had both adjusted and raw eGFR ≥ 80 ml/min, 258 donors had only adjusted eGFR ≥ 80 ml/min/1.73m², 1086 donors had only raw eGFR > 80 ml/min, and 1730 had both adjusted and raw eGFR < 80 ml/min. The median age of the entire cohort was 39 years, 43.7% were male, 85.1% were non-Hispanic white, median BMI was 25.8 kg/m², and mean BSA at donation was 1.88 ± 0.22 m². Other than the development of eGFR < 45 ml/min/1.73m², no statistical difference was noted in post-donation mortality, CVD, diabetes, hypertension, proteinuria, eGFR < 30 ml/min/1.73m², and ESKD (Figure 1).

Conclusion

Raw and adjusted pre-donation eGFR were highly comparable in predicting long-term outcomes of kidney donors and perhaps the practice of adjusting for BSA should be reconsidered.

Figure 1: C-statistic comparisons between adjusted and raw eGFR, multivariate Cox regression