Kidney Week

Abstract: PUB530

Paradoxical Association of Predonation Urine Protein with Kidney Function in Living Kidney Donors without Obesity

Session Information

• Publication Only

Category: Transplantation

• 2102 Transplantation: Clinical

Authors

• Tantisattamo, Ekamol, University of California Irvine School of Medicine, Orange, California, United States

Ekamol Tantisattamo, MD, MPH, FASN

• Kookanok, Chutawat, University of California Irvine School of Medicine, Orange, United States

Chutawat Kookanok, MD

• Rodsom, Kamonluk, University of California Irvine School of Medicine, Orange, United States

Kamonluk Rodsom, MD

• Rochanaroon, Voramol, University of California Irvine School of Medicine, Orange, California, United States

Voramol Rochanaroon, MD

• Kanthajan, Tatchaya, University of California Irvine School of Medicine, Orange, California, United States

Tatchaya Kanthajan, MD

• Prasitsumrit, Vitchapong, University of California Irvine School of Medicine, Orange, California, United States

Vitchapong Prasitsumrit, MD

• Sodsri, Tulaton, University of California Irvine School of Medicine, Orange, California, United States

Tulaton Sodsri, MD

• Sripusanapan, Adivitch, University of California Irvine School of Medicine, Orange, California, United States

Adivitch Sripusanapan, MD

• Siramongkholkarn, Smuch, University of California Irvine School of Medicine, Orange, United States

Smuch Siramongkholkarn, MD

• Wattanachayakul, Phuuwadith, University of California Irvine School of Medicine, Orange, California, United States

Phuuwadith Wattanachayakul, MD

Background

Clinical significance of pre-donation proteinuria in living kidney donors (LKD) is unknown. We aim to examine the association between pre-donation urinary protein:creatinine ratio (UPCR) and the risk of kidney function decline in LKD.

Methods

A retrospective cohort study using OPTN/SRTR included adult LKD undergoing donation between 6/1972 and 9/2022. The association between pre-donation UPCR and time-to-event of ≥35% decline in post-donation eGFR from pre-donation eGFR was examined by multiple Cox regression.

Results

Of 174,311 adult LKD, the mean±SD age was 41±12 years and 60% were female. Mean pre-donation UPCR was 2.12 ±9.23 mg/g of Cr and UPCR at immediate post-donation, 6-, 12-, and 24-months post-donation were 1.23±6.54, 1.44±8.26, 1.72±9.26, and 1.37±7.96 mg/g of Cr, respectively. The median (IQR) pre-donation eGFR was 91 (75, 111) mL/min/1.73 m². Median eGFR at immediate post-donation, 6-, 12-, and 24-months post-donation were 50 (40, 62), 54 (44, 67), 55 (45, 68), and 57 (47, 70) mL/min/1.73 m², respectively. Out of 38,780 LKD with post-donation eGFR data at 6, 12, or 24 months, 31,054 LKD had the event of ≥35% decline in post-donation eGFR from pre-donation eGFR with a median time to follow-up of 6.77 months (IQR 5.93, 12.67). The incidence rate of the event was 0.08 person-months. After adjusting for age, race/ethnicity, U.S. citizenship, education level, history of pre-donation BMI, hypertension, diabetes, and pre-donation SBP and DBP, every 1 mg/g of Cr increase in pre-donation UPCR was associated with a 0.8% lower risk for the event (HR 0.992, 95%CI 0.985, 0.998). Obesity status was an effect measured modifier with a decreased risk of a decline in eGFR ≥35% observed in LKD with pre-donation normal weight and overweight, but not obesity (HR_{normal weight} 0.988, 95%CI 0.977, 0.999; HR_overweight 0.989, 95%CI 0.978, 0.999; and HR_obesity 1.003, 95%CI 0.991, 1.014).

Conclusion

Pre-donation UPCR is inversely associated with the risk for a significant decline in post-donation eGFR in LKD with normal weight and overweight. Relatively less glomerular hyperfiltration in non-obese LKD may contribute to a reno-protective effect regardless of the degree of pre-donation proteinuria.