OBESITY AND KIDNEY TRANSPLANTATION


Obesity in the general population is a growing problem in the US and is especially problematic when viewed from the standpoint of a patient who has chronic kidney disease and is awaiting a kidney transplant. Research has shown that there is a higher chance of death while on dialysis – almost 20 % per year, with this rate almost 9 times higher if you are also obese. This is probably because obese patients with kidney disease happen to be older, have a higher incidence of diabetes and are more likely to be African American. It is estimated that more than 60 % of kidney transplant recipients today are obese or overweight, a number that has almost doubled since 1990.

Obese patients also tend to wait longer for a kidney on the waiting list. Compared to a person who has normal BMI (25 kg/m2), an obese patient (> 30 kg/m2), at an average waits almost a year and a half longer for a transplant. This no doubt increases the chance that he may never get a kidney in time and likely die on the waiting list.

Let’s look at what happens after an obese patient gets a kidney transplant. There is a higher chance that the transplanted kidney may not work right away, a phenomenon known as delayed graft function or DGF. This is especially true for recipients of a kidney donated by a brain dead donor. This in turn decreases the life span of the transplant in the long term. Obese patients are more likely to suffer from wound infections as well. Because of pre-existing diabetes and hypertension, obese patients also tend to have higher rates of cardiovascular problems such as heart disease and stroke. All these together combine to significantly shorten an obese person’s chances of having a functioning kidney transplant long term. Obesity has also shown to have a direct adverse effect on the functioning of the kidney.

Approximately 50 % of recipients will gain weight after a kidney transplant. This happens because dietary restrictions are no longer in place, there is improvement in a person’s appetite and also due to some post-transplant medications such as steroids that play a role in this weight gain.

Dietary interventions with regular and aggressive follow up have shown to be helpful in the first few months after a kidney transplant in controlling weight. Physical activity is also highly encouraged and has been found to be beneficial in preventing excessive weight gain and increasing the sense of well-being. Some transplant programs have also encouraged pre-transplant bariatric or weight loss surgery which has had beneficial results.