Weight Loss Helps Kidney Function in Chronic Kidney Disease
Weight loss can greatly benefit obese individuals who have chronic kidney disease, according to a review study conducted by researchers at the Cleveland Clinic. The benefit was seen regardless of whether the weight loss was achieved through bariatric surgery or diet and exercise.
According to the National Kidney Foundation, Institute of Diabetes and Digestive and Kidney Diseases, 26 million Americans have chronic kidney disease. The disease includes conditions that damage the kidneys and decreases their ability to remove waste, toxins, and fluid from the body, regulate blood pressure, and manufacture red blood cells. Glomerular (capillaries in the kidneys) filtration rate reveals how much kidney function a person has, and it is the best estimate of kidney failure. In the current study, weight loss had a significant impact on glomerular filtration rate.
The investigators reviewed the findings of thirteen studies, six that used nonsurgical means to achieve weight loss and seven that involved bariatric surgery. In the nonsurgical intervention studies, weight loss was associated with reductions in proteinuria. Proteinuria is a condition in which large amounts of protein are present in the urine as a result of damage to the filtering system in the kidneys called the glomeruli. A decrease in proteinuria indicated an improvement in the glomerular filtration rate and thus improved kidney function.
Review of the studies that involved bariatric surgery in morbidly obese patients showed that weight loss resulted in normalization of the glomerular filtration rate. In both the surgical and nonsurgical studies, the patients experienced significant weight loss and improvements in systolic blood pressure as well. Since heart disease is the major cause of death for people who have chronic kidney disease, the improvement in blood pressure associated with weight loss is a significant feature as well.
At this point, researchers do not know whether the normalization of glomerular filtration rate brought on by weight loss will result in long-term benefits to the kidneys in people with chronic kidney disease. They note that larger, long-terms studies are needed to evaluate the effect of weight loss on renal outcomes, including whether the disease progresses to the more serious phase of end-stage renal disease.
National Institute of Diabetes and Digestive and Kidney Disease
Navaneethan S et al. Clinical Journal of the American Society of Nephrology 2009; DOI: 10.2215/CJN.02250409.