A case for bariatric surgery among obese renal transplant candidates
By Maria Frisch

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Approximately 1 in 3 U.S. adults are obese or have a body mass index of 30 or higher.1 England and Canada aren't far behind at every 1 in 4.2,3 This is unfortunate, given the common association between obesity and excess morbidity and mortality.4-6 This association is particularly true in renal transplant surgery.


Should obese patients undergo bariatric surgery before renal transplant surgery?
  • 1. Yes
  • 2. No

Pischon and Sharma compared outcomes in 2,791 obese and nonobese renal transplant patients and found that five-year mortality in obese patients ranged from 23 percent to 45 percent, but in nonobese patients it ranged from 10 percent to 11 percent.7

Meier-Kriesche and colleagues analyzed data from 51,927 adult transplant recipients from the United States Renal Data System database.8 In their study, the relative risk ratio for graft loss was approximately 1.4 in patients with a BMI >36 kg/m2. Similar risk ratios were found for death-censored graft loss (graft loss not including patients who die with functioning grafts; RR = 1.45 for BMI 36 kg/m2), death with a functioning graft (RR?=?1.36), and for cardiovascular-related complications (RR = 1.4). The best overall results were found in patients with a BMI of 2224 kg/m2.

Obesity is linked with significant comorbidity that results in damage to end organ function.9 Higher BMI is associated with an increased risk of wound complications, early nephrectomy, delayed graft function, cardiac disease and increased costs.10-13 Obese recipients with a BMI of >35 are in a particularly high-risk category.14

As a result of these risk factors, obesity is often considered a contraindication to renal transplantation. Thus, consideration of presurgical bariatric surgery may be warranted in cases where prescribed dietary therapy and physical activity has failed.

Between 1991 and 2004, at least 188 Medicare patients on a renal allograft weight list chose bariatric surgery to either improve rental transplant outcomes or to gain eligibility to a wait list.15 Median excess weight loss was about 30-60 percent, with laparoscopic Roux-en-Y (LRYBG) gastric bypass the most common procedure. Takata and colleagues described successful LRYGB in seven end-stage renal disease patients.16 At 1.5-year follow-up, mean excess body-weight loss was 61 percent, and all were listed for transplant.

Marszalek and colleagues presented a case study of a 55-year old female with end-stage renal disease.17 She had previously been disqualified for renal transplant due to a BMI of 41.5. The patient underwent a vertical-banded gastroplasty with no postoperative complications. Ten months following the bariatric surgery, the patient's BMI was down to 29, and she was selected as a kidney transplant recipient from a deceased donor. There were no surgical complications after transplantation, but delayed graft function was observed.

A case series of obese females at an average BMI of 52 also showed that bariatric surgery resulted in favorable outcomes, but this population underwent bariatric surgery following renal transplant.18 At two years, all patients had lost at least 50 percent of body weight. There were no complications following surgery, and no alteration to immunosuppressant drugs were necessitated after bariatric surgery.

In another case study, a 34-year old man with a BMI of 36.7 underwent renal transplantation in 2008.19 He was previously diagnosed with noninsulin-dependent diabetes mellitus in 1997 and hypertension in 2001. Both conditions were attributed to obesity. As a result, he received LRYGB in 2010. In the month that followed, he lost 10 kilograms. His serum creatinine decreased to 1.11 mg/dL (1.4 mg/dL, preoperative) and his hemoglobin A1c decreased to 8.5 percent (10.4 percent, preoperative). These changes resulted in improved renal function.

Currently, there are no large trials showing benefit of surgery-assisted weight loss before or after transplant on subsequent patient or transplant survival.20 However, this review suggests study of this area is warranted.

Maria Frisch is a healthcare consultant and clinical research scientist. She received her medical training from St. George's Medical School and graduate training in public health from the University of Minnesota.


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