Link between obesity and kidney transplant may sideline applicable patients from surgery

Researchers from Saint Louis University (SLU) have connected the dots between stomach, kidneys and obesity to find that the resulting outlook does not bode well for patients with all three.

After multiple studies were scoured and analyzed, the adverse relationship became clear — although some outcomes are mystifying and inconsistent, the evidence suggests that patients with obesity predominantly do not fare as well after surgery. The authors of the study reported that those battling the condition tend to later reappear after surgery with more wound infections, delayed graft function, graft failure and cardiac disease. What’s more, the increase in costs is considerable.

With the burdens mounting, it’s important for physicians and other healthcare professionals to not only voice the added risks obesity can have in the surgical forum, but encourage lifestyle changes, if possible, well before said patient is required to go under the knife. 

“Lifestyle alterations that seem reasonable to improve health outcomes should be encouraged,” Betsy Tuttle-Newhall, MD, director of abdominal transplant at SLU and one of the leaders of the study, said in a news release. “Just as we require patients with alcoholic liver disease to stop drinking prior to transplant, it is reasonable to ask kidney transplant candidates to lose excess body fat and attempt to increase lean muscle mass by becoming more physically active and modifying their diet.”

The researchers did cross paths with what is referred to as the “obesity paradox” regarding patients of the sort on dialysis; patients with obesity on dialysis were found to have better long-term survival following a surgery than they would have staying on dialysis. It is posited that the extra fat coupled dialysis function to encourage a protective benefit, although it is believed that this benefit does not unionize as effectively with transplant scenarios.  

Other study frontrunner Krista Lentine, MD, associate professor of internal medicine in nephrology, hopes that the study will tow the line and serve as spackle for the empty spaces in knowledge regarding the affects of weight on kidney transplants.

“Current guidelines from the American Society of Transplantation (AST) recommend a supervised weight loss regimen including a low-calorie diet, behavioral therapy, and a physical activity plan to achieve a body mass index (BMI) of less than 30 prior to kidney transplantation,” Lentine said in the news release. “But, these guidelines also note that we don’t have enough data to determine if some obese patients aren’t appropriate candidates to receive kidney transplants at all.”

For the authors, the BMI measure must be reassessed in further study and a new upper limit established so that patients with obesity, who stand to inherit more negative outcomes than positive from kidney transplantation, will undergo alternative procedures or a lifestyle alteration as to be able to weather the surgery more safely.

The authors referenced the need for “more study to determine whether intentional weight loss before surgery, including diet, exercise and bariatric surgery, does, in fact, improve outcomes.” The bearing that bariatric surgery may or may not have on these patients should also be investigated further, they said.

“This review showed us where there are gaps in the existing research and where current data is too light to be able to draw solid conclusions,” said Lentine. “These gaps are what ‘outcomes research’ is designed to remedy. We’ve figured out some key questions to ask so that we can help our patients have successful transplants and healthy lives.”

The key take-home points for physicians were listed as follows:

  • Obesity appears to affect kidney transplant patients in a negative way, leading to complications during their recovery.
  • Kidney patients should know that their weight may affect the success of a transplant and should work with their doctor to manage it in a healthy way.
  • Doctors need future studies to examine the upper BMI limit at which kidney transplantation should not be recommended for obese patients, to refine ways of measuring obesity, and to define the benefits of losing weight prior to a kidney transplant.

The AST Kidney-Pancreas Committee also encourages primary care providers to establish the following surveillance post-surgery for all patients:

  • Management plan for renal function monitoring.
  • Management plan for monitoring of urinary protein excretion.
  • Management plan for monitoring of blood pressure control, calcium and phosphorus abnormalities, anemia, hypoalbuminemia, acidosis and lipid abnormalities.