Weight Loss Surgery & Kidney Disease: Study Details continued...
"About 20[%] to 40% of all patients with type 2 diabetes will develop diabetic nephropathy," Heneghan says.
How to treat that is still evolving, she says.
Compared to before the surgery, the patients also had improvements in blood sugar levels and in HbA1c, an indicator of blood sugar control over the previous three months.
Overall, Heneghan says, the surgery had good effects on the kidney problems as well as the diabetes. "We believe bariatric surgery can induce a significant and sustained improvement in type 2 diabetes and prevent complications such as diabetic nephropathy," Heneghan says.
About 200,000 U.S. adults have bariatric surgery annually, according to the American Society for Metabolic and Bariatric Surgery. The risk of death is about 0.1%. The major complication rate is about 4%.
Bariatric Surgery & Kidney Problems: Perspective
The study has good points and limitations, says Benjamin Canales, MD, MPH, assistant professor of urology at the University of Florida in Gainesville. He reviewed the study.
He conducts bariatric surgery research on animals. He believes the Cleveland Clinic study is the longest follow-up to date to look at how bariatric surgery might improve kidney problems.
"This is a very promising long-term study in a group of diabetic patients who typically progress in their kidney disease over a course of five to 20 years," he says.
One limitation, however, he says, is the lack of a comparison group. In this case, it would be obese patients with diabetes who did not have the surgery.
"The author's conclusion that bariatric surgery 'may improve or even prevent long-term nephropathy' may be true, there's just no way to make this assumption based on the small number of positive results presented here," Canales tells WebMD.
More study is needed, he says.
These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.