Bariatric surgery improves kidney function in severely obese patients with CKD

Severely obese patients with chronic kidney disease (CKD) saw significant improvements in kidney function within one year of bariatric surgery, according to a new study presented here at the 29th Annual Meeting of the American Society for Metabolic & Bariatric Surgery (ASMBS). The study found patients went from having either moderate disease to mild or mild disease to normal, within a span of one year.

"With bariatric surgery we are attacking the two main culprits of chronic kidney disease - high blood sugar and high blood pressure," said study co-author Wei-Jei Lee, MD, PhD from Min-Sheng General Hospital and National Taiwan University Hospital. "However, this study suggests the earlier we treat CKD in the disease process with bariatric surgery, the more favorable the impact on the kidney."

The study, conducted by researchers from Min-Sheng General Hospital and National Taiwan University Hospital, included 233 patients who, on average, were 33-years-old and had a body mass index (BMI) of 39.5 (about 80 pounds overweight). About 20 percent had mild to moderate CKD and another 25 percent of patients had a precursor to the disease. More than 90 percent had Type 2 diabetes and nearly half had hypertension.

According to the National Kidney Foundation (NKF), the two main causes of CKD are diabetes and high blood pressure, which are responsible for up to two-thirds of the 26 million CKD cases in the United States.

After undergoing bariatric surgery, patients lost more than 60 percent of their excess weight, and their glomerular filtration rate (GFR), a test used to check how well the kidneys are working, improved no matter which stage of CKD the patient had. GFR went from 81.0 to 98.6 ml/min in the mild disease group, and from 49.3 to 66.8 ml/min in the moderate disease group. Type 2 diabetes went into remission for nearly 60 percent of patients in these groups.

The NKF says normal GFR ranges from 90 to 120 ml/min.1 Those with hyperfiltration, an early sign of potential kidney disease where the kidneys filter larger than normal quantities of blood, saw rates drop from 146.5 to 133 ml/min. This group saw a diabetes remission rate of more than 83 percent. Those with normal kidney function before surgery remained that way and diabetes improved in nearly three out of four patients.