A recent meta-analysis claims that high BMI (30 and above) does not affect the short-term results of living kidney donation (live donor nephrectomy).
I took a look at the study, since it was being lauded in an online living donor group, and I want to copy/paste what I said there, here:
Like so many other published articles regarding living donation, I suspect the conclusions drawn by the researchers are not as iron-clad as some might want to believe.
The meta-analysis clearly says higher BMI results in longer surgical time, higher rate of conversions from lap to open, and a longer ischemic time for the donated kidney. These things are not incidental. Remember, that there is a steep operator learning curve for the lap procedure, meaning that the more inexperienced surgeon has a higher risk of complications, so it’s important to ask a prospective surgeon how many of the lap live donor nephrectomy procedures s/he has done.
The results also show a higher creatinine level in high BMI donors as well as a lower GFR. I pulled up the studies to see when the measures were taken.
Kuo – 1 wk
Mateo – at discharge from the hospital
Heimbach – 6-12 months
Rea – median of 340 days
Espinoza – 50.8 ± 28.5 months <- showed lower GFR in high BMI donors
Rook – 2 months
Tavakol – 11 ± 7 yrs <- (some of the LKDs in this study were low BMI at the time of donation, but were high BMI at the time of this study, which altered the comparison results)
Reese – 6 months. <- But they used the OPTN database, which was deemed “useless” for research or analysis for anything after 6 weeks.
As the researchers were clear to point out, they were only looking at the SHORT term risks of high BMI. Because the average living kidney donor in the U.S. is 41, we have a whole lot of LONG term to worry about, and no valid or reliable data to rely on. High BMI (obesity) puts strain on the kidneys and the heart. Reduced kidney function also increases the risk of cardiovascular disease and death.
So while I understand that the certain facets of the transplant industry are always looking for ways to justify more living kidney donors, we’d all be better off if we concentrated on preventing and treating diabetes and hypertension, which account for the majority end-stage renal disease diagnosis in the U.S.
Addendum: Researchers conducting meta-analysis always have the option of making a conclusion equivalent to – hey, the results are mixed, we really need to do more research on the subject. Such a declaration would’ve been appropriate here. The fact the authors chose to say there were no short term risks to a high BMI person donating a kidney reflects their preference.
Lafranca JA, Hagen SM, Dols LF, Arends LR, Weimar W, Ijzermans JN, & Dor FJ (2013). Systematic review and meta-analysis of the relation between body mass index and short-term donor outcome of laparoscopic donor nephrectomy. Kidney international PMID: 23344469