Weight Loss Surgery May Improve Kidney Health

Bariatric surgery tied to better kidney function among obese patients

/ Author:  / Reviewed by: Robert Carlson, M.D Beth Bolt, RPh

(RxWiki News) Obese patients sometimes choose weight loss surgery to improve their heart health and drop pounds more quickly. And new research suggests the surgery may improve kidney function.

A new study examined how weight loss surgery affected patients' kidneys.

The researchers found that the average weight loss surgery patient lost a significant amount of weight and had improved kidney function.

"Our findings suggest a beneficial impact on kidney function in patients with and without baseline kidney disease," said lead study author Alex R. Chang, MD, of Geisinger Health System.

According to the study authors, people who are morbidly obese face a higher risk of kidney failure.

For the study, researchers recruited 3,134 obese patients who underwent weight loss, or bariatric, surgery. They followed up with the weight loss surgery patients for more than two years after surgery.

There are many types of weight loss surgery. One of the most common is gastric bypass, in which the surgeon reduces the size of the patient's stomach to reduce food intake.

One year after surgery, the patients had lost an average of 86.4 pounds.

The patients' average body mass index (BMI) had decreased from 46.8 to 32.6. BMI is a height- and weight-based measure of body fat. A BMI of 30 or more is commonly considered obese.

The patients also underwent an eGFR test, which shows how well the kidney is filtering waste from the blood.

Dr. Chang and team found that the patients' kidneys had a 4.5 percent higher filtration rate than before they underwent weight loss surgery. The patients with chronic kidney disease prior to surgery saw the most benefit, the researchers noted.

Some patients had a condition called albuminuria, which is a sign of kidney damage. Patients with this condition have a substance called albumin in their urine. Patients who lost weight had decreased albuminuria, Dr. Chang and colleagues found.

The researchers concluded that weight loss after bariatric surgery could improve kidney health in obese patients.

The study was presented Nov. 14 at the American Society of Nephrology Kidney Week 2014. Research presented at conferences may not have been peer-reviewed.

The researchers disclosed no funding sources or conflicts of interest.

Review Date: 
November 13, 2014
Last Updated:
November 17, 2014