CORRECTED-Gastric bypass bests medication for lowering albuminuria in early kidney disease

Last Updated: 2020-06-11

(Corrects researcher's gender in paras 12, 13 and 14, in story originally posted June 10.)

By Marilynn Larkin

NEW YORK (Reuters Health) - Roux-en-Y gastric bypass (RYGB) was more effective than best medical treatment in achieving albuminuria remission in patients with type 2 diabetes and obesity in an intermediate analysis of a randomized controlled trial.

"This is a new treatment paradigm to slow or arrest chronic kidney progression in patients with diabetes and obesity," Dr. Ricardo Vitor Cohen of Oswaldo Cruz German Hospital in Sao Paulo, Brazil, told Reuters Health by email. "It can lead to practice-change."

Coauthor Dr. Carel le Roux from University College Dublin, in Ireland, added, "This will have far-reaching implications not only to alleviate the suffering of patients or potentially preventing early death, but it will also reduce the direct healthcare cost for patients themselves or for private and public payers, because end-stage kidney disease treatment is one of the most expensive treatments any health system undertakes."

For the two-year interim analysis of the Microvascular Outcomes after Metabolic Surgery trial, Drs. Cohen, le Roux and colleagues studied 100 patients (mean age, 51; 55% men) with type 2 diabetes, obesity (body mass indexes of 30 to 35) and early-stage chronic kidney disease (CKD) who had been randomly assigned to best medical treatment or RYGB. The primary outcome was albuminuria remission.

Drugs with a beneficial effect on microvascular and macrovascular outcomes were given soon after the trial started if patients were not already taking these medications. Use of the drugs was continued in the best medical treatment group even if metabolic targets were met or albuminuria remission occurred.

Angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, and statins were continued in the RYGB group regardless of whether albuminuria remitted. Glucose-lowering drugs, including insulin, were dose adjusted. All participants continued on metformin unless the HbA1c level fell below 5.7% (39 mmol/mol) or the fasting glucose level was less than 100 mg/dL.

As reported in JAMA Surgery, albuminuria remission occurred in 55% of patients after best medical treatment and 82% after RYGB, resulting in CKD remission rates of 48% after best medical treatment and 82% after RYGB.

Geometric mean urinary albumin-creatinine ratios were 55% lower after RYGB (10.7 mg/g of creatinine) than after best medical treatment (23.6 mg/g). Rates of serious adverse events were similar.

Dr. Paulina Salminen of Turku University in Finland, coauthor of a related editorial, commented in an email to Reuters Health, "We need to consider bariatric surgery as an effective and safe treatment option for these (higher risk) patients, as it provides superior results for both remission of albuminuria and early CKD compared with best medical therapy."

"This result could perhaps also be achieved after sleeve gastrectomy," she added, "as the long-term outcomes of these two most common bariatric procedures are quite similar."

Dr. Priyamvada Singh, a transplant nephrologist at The Ohio State University Wexner Medical Center in Columbus, commented by email, "Although remission of albuminuria and CKD was significantly lower in the RYGB group and there was no difference in the rate of serious adverse events, the (rates of) wound infection, kidney injury, and oxalate nephropathy were lower than previously reported RYGB studies, which could be due to biases from an open-label design and shorter duration of follow-up."

She also noted that in the bypass group, patients "are continuing ACEI/ARB, calcium channel blockers, and GLP1" to a greater extent than the best treatment group. "For that reason," she said, "the study should instead be reported as 'medical treatment only' versus 'bypass plus medical treatment.' Also, 45% of the bypass group is on GLP1 analogs (compared to 26% in the medical group), which have proven benefit for obesity, diabetes, and albuminuria, and might (confer) a favorable bias to the bypass group."

Further, she added, "there are two black patients (both in the best medical treatment group) in a population of 100 participants, which will decrease the generalizability of the study in this patient population."

"I think the study is hypothesis-generating, but I will refrain from saying that it is practice-changing at this point," she said. "I still will recommend that my patients go through a conservative route like a dietitian and exercise before choosing this option."

Dr. Rohit Soans, Medical Director of Bariatric Surgery at Temple University Hospital in Philadelphia "absolutely agrees" with the study findings, but notes that "patient compliance with the program and willingness to undergo surgery will be major barriers."

"At this point," he said, "the surgery is safe even in the most high-risk patients at centers that are equipped to handle them."

The study was funded in part by a research grant from Johnson and Johnson Brasil. Dr. Cohen and five coauthors received fees from the company.

SOURCE: https://bit.ly/2Yt7gJc and https://bit.ly/3hbJI3U JAMA Surgery, online June 3, 2020.