‘First do no harm’: Implications of mandating weight loss pre-transplant
There is no substantial evidence that losing weight before a kidney transplant improves the survival of transplant candidates with obesity, and some research suggests the opposite may be true. Yet, many patients with ESKD and obesity are getting turned away by transplant programs unless they lose weight.
“Abdominal obesity certainly makes transplant surgery and recovery from surgery more challenging and some studies have suggested that graft survival is lower (among transplant recipients with obesity),” Meera Nair Harhay, MD, MSCE, FASN, told Nephrology News & Issues. “That doesn’t mean dialysis patients with obesity who are losing weight are necessarily getting healthier with that weight loss, especially if they are losing muscle mass.”
In the general population, WHO defines overweight as a BMI of 25 kg/m2 to 29.9kg/m2 and obesity as a BMI of at least 30kg/m2. Harhay cited prior research showing most kidney transplant programs in the United States use a BMI cutoff value between 35 kg/m2 to 45 kg/m2 to determine transplant evaluation eligibility.
“Some programs won’t even evaluate a person for transplant if they don’t meet that goal first,” Harhay said, noting “BMI is not a good surrogate for body composition.”
Based on the prevalence of obesity in the patient population, a BMI cutoff of 35 kg/m2 would exclude about one in five incident dialysis patients in the United States from kidney transplant, whereas a BMI cutoff of 40 kg/m2 would exclude one in 10, Harhay said.
Transplant program discretion about BMI cutoffs may present extra challenges for prospective transplant recipients with obesity who live in rural areas, she said. “In areas where patients have multiple choices for transplant programs, they might be able to find a program without weight restrictions. For patients in smaller cities or rural areas where there is only one hospital that performs transplants nearby, you might be out of luck,” she said.
There is evidence that higher body mass may offer some benefits to dialysis patients, Harhay said. These include a lower risk of cachexia and energy dysmetabolism; higher nutritional stores and hemodynamic stability. She also cited several studies that suggested that weight loss was a risk factor for death in patients with ESKD, regardless of BMI. However, Harhay agrees that morbid obesity, either pre- or post-transplant, poses its own health risks and should not be ignored. “In our survey of renal dietitians across the United States, several factors emerged as barriers to healthy weight loss among dialysis patients with obesity, including limited time for dietitians to do nutrition and exercise counseling and patients’ lack of energy and access to healthy foods. We need real solutions for these challenges,” Harhay said.
After transplant, maintaining a healthy weight can be difficult for many patients, as there are far fewer dietary restrictions than when they were on dialysis. “People who lost a lot of weight before transplant tend to gain it back and then some after transplant,” Harhay said. “It is important for our transplant recipients to know the importance of healthy food choices and exercise,” she said.
Ultimately, health care providers need to learn more about the long-term risks and benefits of different weight loss interventions in ESKD, Harhay said.
“Just like any other recommendation we make, before we mandate weight loss for transplant, we should ask ourselves: ‘Is this in the best interest of the patient?’” – by Mark E. Neumann
- Harhay M. Should patients be required to lose weight before transplant? Let’s weigh the risks first. Presented at: National Kidney Foundation Spring Clinical Meetings; March 25-29, 2020 (virtual meeting).
- WHO. Obesity: preventing and managing the global epidemic. World Health Org Tech Rep Ser. 2000; 894: i–xii, 1–253.
- Aditi S. et al. J Ren Nutr. 2020;doi:10.1053/j.jrn.2020.01.021.
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- Meera Nair Harhay, MD, MSCE, FASN, is an associate professor of medicine at Drexel University College of Medicine and associate professor of epidemiology & biostatistics at Drexel University Dornsife School of Public Health. She can be reached at firstname.lastname@example.org.
Disclosure: Harhay reports no relevant financial disclosures.