(817.7) Association of Pre-Living Kidney Donation Body Mass Index with Post-Donation Estimated Glomerular Filtration Rate Decline

Poster Board Number: A407

Ekamol Tantisattamo (University of California Irvine School of Medicine, University of California Irvine School of Medicine, University of California Irvine School of Medicine), Manasawee Tanariyakul (University of California Irvine School of Medicine, University of California Irvine School of Medicine), Natchaya Polpichai (Prince of Songkla University), Pornthira Mutirangura (University of California Irvine School of Medicine, University of California Irvine School of Medicine)

Introduction:  Obesity is one of the risk factors for chronic kidney disease (CKD). Whether body mass index (BMI) at pre-living kidney donation is associated with worsening kidney function of the remaining kidney after donation is unclear. We aim to examine the association between pre-donation BMI and change in post-donation estimated glomerular filtration rate (eGFR) in living kidney donors.

Methods:  A single-center retrospective cohort study included 14 living kidney donors. Associations between pre-donation BMI and percentage of eGFR decline at 2 and 7 days post-donation were examined by multiple linear regression.

Results:  Of all 14 living kidney donors, mean age±SD was 52.64±13.46 years old and 50% was female. Mean BMI was 26.90±2.66 kg/m2. The majority were overweight (72%) followed by normal weight (21%) and obese (7%). eGFR at 2- and 7-day post-donation were significantly lower than pre-donation eGFR (55.59±12.48 vs. 55.29±11.33 vs. 93.39±14.62, p lt;0.001; Figure 1). Every 1 kg/m2 increase in pre-donation BMI was associated with 0.1% greater decline in eGFR at 2-day post-donation, while eGFR decline was up to 1.4% at 7-day post-donation (β2day±SE 0.149±0.716, p 0.861, 95%CI -1.668, 1.966; Figure 2A and β7day ±SE 1.368±0.834, p 0.080, 95%CI -0.191, 2.928; Figure 2B). After adjusted for age, gender, ethnicity, pre-donation eGFR, and interaction term between age and pre-donation eGFR, the magnitude of eGFR decline post-donation were greater for both 2- and 7-day post-donation; however, only the 7-day post-donation eGFR decline was statistically significant without the interaction between age and pre-donation eGFR (β2day±SE 0.653±0.977, p 0.525, 95%CI -1.657, 2.963, pinteraction 0.045 and β7day±SE 2.068±0.800, p 0.036, 95%CI 0.176, 3.959, pinteraction 0.541).

 

Conclusions:  Higher pre-donation BMI is associated with greater eGFR decline at 7-day, but not 2-day, post-donation. Pathological glomerular hyperfiltration from overweight or obesity may counteract with physiological glomerular hyperfiltration from acquired solitary kidney post-donation leading to worsening post-donation eGFR decline.





Figure 1: Mean estimated glomerular filtration rate over time from pre- to 7-day post-donation categorized by body mass index                                             eGFR, estimated glomerular filtration rate; Figure 2: Scatter plots demonstrating relationship between pre-donation body mass index and percentage of post-donation estimated glomerular filtration rate decline at 2 days (A) and 7 days (B)                                       eGFR, estimated glomerular filtration rate, CI, confidence interval