Weight gain in kidney transplant recipients: Risks, cardiovascular outcome and management

Abstract

Kidney transplantation (KT), which is by far the most frequently carried out transplantation globally, is generally accepted as the best treatment both for quality of life and cost effectiveness in end stage renal disease patients although other renal replacement therapies are present. In spite of considerable progress in immunosuppressive and supportive treatments, a number of factors still interfere with the complete success of KT. Cardiovascular (CV) disease is the leading cause of death in renal transplant recipients (RTR). They are at an increased CV risk because of advanced age and adverse effects such as weight gain, hypertension, glucose intolerance, diabetes and dyslipidemia. The determinants that lead to atherosclerosis in RTRs are similar to those in the general population. Excessive weight gain that leads to obesity is quite common after KT. This is often attributed to corticosteroids and other immunosuppressive drugs. Average weight gain in 1year posttransplant period have been reported to be 8-14 kgs. Risk factors for weight gain are feeling of well-being, unrestricted diet, increased appetite, ethnicity, age at the time of transplant, sex, pre-existing obesity, dialysis modality, socioeconomic status and donor type. Obesity has long been associated with an increased risk for coronary heart disease. The risk is compounded by the common coexistence of other risk factors associated with obesity. It is uncertain how much of the risk is due to obesity alone. Furthermore, the mechanisms by which obesity, particularly abdominal obesity, cause or accelerate coronary atherogenesis are also uncertain. Abdominal fat is a strong predictor of mortality after adjustment for total-body fat, and waist circumference correlates highly with abdominal fat. Body mass index (BMI) apart, anthropometric measures of abdominal obesity and body fat distribution like waist circumference and waist/hip ratio appear directly, rather than inversely, associated with all-cause and CV mortality in the general population. In a recent study of RTRs, waist-to-hip ratio but not BMI correlated with CV risk factors, suggesting that central adiposity has a major role in determining CV risk. This shows the importance of identifying ideal measures of adiposity in the evaluation of RTRs because most centers rely solely on BMI. Using only BMI as a cut off value for transplant might not be ideal. In the general population, obesity is widely recognized as a major risk factor for the development of kidney disease. Glomerular hyperfiltration and hypertrophy have long been proposed as possible pathogenic mechanisms in obesity related kidney disease. Many important risk factors for chronic allograft nephropathy, shortened graft function and lower recipient life expectancy have a higher incidence in obese patients, including hypertension, dyslipidemia and type 2 diabetes, although there are conflicting reports in the literature. In addition, posttransplant complications, especially new-onset transplant diabetes mellitus, wound complications and weight gain, are more common in obese RTRs (BMI ≥35kg/m²) in early period. The management of obesity is an important factor necessary to ensure long-term patient and graft survival. Nutritional counseling and exercise should be available immediately after KT for all RTRs. In this article, we review the impact of increased BMI on patient and graft survival, risk factors for the development of post-transplant obesity and available intervention options. © 2012 by Nova Science Publishers, Inc. All rights reserved.