Bariatric Surgery Tied to Lower All-Cause Mortality With Obesity, Kidney Failure

By Lisa Rappaport

June 08, 2020

(Reuters Health) - People with obesity and end stage kidney disease (ESKD) who get bariatric surgery have lower all-cause mortality rates than counterparts who don't get these operations, a new study suggests.

Researchers examined data on 1,597 people with obesity and ESKD who got bariatric surgery - including sleeve gastrectomy, Roux-en-Y gastric bypass, gastric banding, or duodenal switch - as well as 4,750 matched controls who received usual care.

At five years, bariatric surgery was associated with lower all-cause mortality compared with usual care (cumulative incidence 25.6% vs 39.8%; adjusted hazard ratio 0.69).

"This study suggests that we should strongly consider doing more bariatric surgery in patients with ESKD," said study coauthor Dr. Kyle Sheetz of the department of surgery and the Center for Healthcare Outcomes and Policy at the University of Michigan School of Medicine, in Ann Arbor.

"We should be working with surgeons, nephrologists, and primary care doctors to encourage greater use of bariatric surgery in managing the growing number of patients on dialysis with obesity," Dr. Sheetz said by email. "Bariatric surgery may also be a strategy to increase access to kidney transplantation - where obesity may not only limit access, but also lead to worse outcomes after transplant."

Lower mortality from cardiovascular causes at five years contributed to the reduced all-cause mortality for people who underwent bariatric surgery, the researchers report in JAMA Surgery.

The cumulative incidence of cardiovascular mortality at five years was 8.4% in the bariatric surgery group and 17.2% among nonsurgical controls (aHR 0.51).

"The impact of bariatric surgery on weight, diabetes, lipids, and perhaps blood pressure decreases overall cardiovascular risk," Dr. Sheetz said.

With surgery, patients were also more likely to receive kidney transplants at five years, with a cumulative incidence of 33% in this group compared with 20.4% for nonsurgical controls (aHR 1.82).

Initially, however, the effect of surgery on mortality looked different. At one year, bariatric surgery was associated with higher all-cause mortality than usual care, with a cumulative incidence of 8.6% compared with 7.7% among nonsurgical controls (aHR 1.45). This might be due to some short-term risks associated with treatment or with an imperfect selection of patients for surgery, the study team writes.

"Concern for short-term surgical complications in this perceived higher-risk patient population should not deter bariatric surgeons from offering potentially life-altering and life-sustaining treatment," said Dr. Anita Courcoulas, chief of Minimally Invasive Bariatric and General Surgery at the University of Pittsburgh Medical Center. Dr. Courcoulas wasn't involved in the study.

It's still possible that results based on administrative data for Medicare patients on dialysis may be explained by some factors that weren't measured in the analysis, the authors acknowledge.

The people who did not undergo bariatric surgery may have been very different than those who did, said Dr. Jordana Cohen, an assistant professor in the Renal-Electrolyte and Hypertension Division at the Perelman School of Medicine at the University of Pennsylvania, in Philadelphia.

"They may have had greater disability, inadequate access to bariatric surgery, have different health behaviors than those who did not undergo bariatric surgery, or other risk factors not captured in the dataset that could have made them both poor surgical candidates and at higher risk of death," Dr. Cohen, who wasn't involved in the study, said by email.

Even so, the results suggest that more doctors should consider bariatric surgery for patients with obesity who are on dialysis, said Dr. Alex Chang, an assistant professor at the Kidney Health Research Institute at Geisinger in Danville, Pennsylvania.

"A lot of doctors may be afraid to have a patient on dialysis go through bariatric surgery since patients on dialysis with severe obesity often have many medical problems and are at some higher risk for surgical complications," Dr. Chang, who wasn't involved in the study, said by email. "Given encouraging findings from this study, I would say that if a patient with severe obesity on dialysis is potentially eligible for a kidney transplant (besides severe obesity), they should be referred for bariatric surgery."

SOURCE: and JAMA Surgery, online May 27, 2020.