By Emma Rose McGlone, RCS-funded research fellow, PhD student and bariatric surgery registrar, department of metabolic medicine, Hammersmith Hospital.
Author of ‘Is bariatric surgery in patients following renal transplantation safe and effective? A best evidence topic’
Many patients undergoing renal transplant are overweight or obese. This is not surprising given that the two most common causes of long-term renal failure in this country are type 2 diabetes and high blood pressure, conditions often associated with obesity. After transplant, many patients gain further weight: on average 8-14kg during the year after transplant. There are several reasons for this, including the immunosuppressant drugs, such as steroids, given to patients after transplant to prevent kidney rejection.
Obesity can cause health problems for people with and without kidney disease, but it is particularly risky for patients that have a renal transplant. Obesity puts people at higher risk of a range of medical problems including type 2 diabetes, cardiac problems, joint problems and breathing problems. Obesity also puts renal transplant patients at higher risk of transplant failure. When this occurs, it is devastating for affected patients.
The most effective and long-term treatment for obesity is bariatric (weight loss) surgery. This involves operations such as gastric bypass, where the stomach is made smaller and the amount of bowel in which nutrients can be digested is shortened. Although these operations are usually very successful, a small proportion of patients will experience a complication. This is more likely when patients are high-risk for an anaesthetic. Unfortunately most patients that have undergone a renal transplant would be considered relatively high-risk.
To find out how safe and effective bariatric surgery is in renal transplant patients, we conducted a review of the medical literature to see what could be learnt by summarising the findings of different researchers studying this topic. We found four papers that were the best designed to answer the question ‘How safe and effective is bariatric surgery following renal transplantation?’ In total, these papers studied 112 patients. In total there were three deaths in the 30 days following surgery. This rate is high, but it is important to note that all were reported in the same study which involved ‘open’ or conventional surgery. These operations took place more than 10 years ago and today almost all bariatric surgery is performed ‘keyhole’ or laparoscopically, which is associated with a much lower rate of complications and mortality.
Weight loss (expressed as a % of the excess weight carried by each patient pre-operatively) ranged from 30-75% at one year post-surgery. Where patients had diabetes before their surgery, most experienced an improvement.
According to this review, bariatric surgery has a reasonable safety profile and results in good short-term weight loss for patients with renal transplant. The evidence available has several limitations including small numbers of patients and study design where there is no group for comparison. Large-scale well designed studies would be useful to give better information regarding the benefits and risks of performing bariatric surgery in transplant patients.