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10-16-2018 | Metabolic surgery | medwireNews | News

Marked reduction in vascular events in diabetes patients after bariatric surgery

medwireNews: An observational study published in JAMA demonstrates a substantial reduction in the risk for hard cardiovascular endpoints in obese patients with type 2 diabetes who have undergone bariatric surgery.

And another study in the same journal addresses the issue of which definition of weight regain is most closely associated with progression of diabetes and deterioration in quality of life.

The first study, from David Arterburn (Kaiser Permanente Washington Health Research Institute, Seattle, USA) and colleagues, compared outcomes of 5301 obese people with type 2 diabetes who had undergone surgery (mostly Roux-en-Y gastric bypass) with those of 14,934 people, matched for age, sex, study site, BMI, glycated hemoglobin level, and insulin use, who had not undergone surgery.

Over a median follow-up of 4.7 and 4.6 years, respectively, macrovascular outcomes (coronary heart disease or cerebrovascular disease) were significantly less frequent in patients who underwent surgery than those who did not. The 5-year cumulative event rates were 2.1% versus 4.3% for macrovascular outcomes and 1.3% versus 4.5% for mortality (the latter being an exploratory post-hoc analysis).

After further adjustment for variables such as ethnicity, diabetes duration, and medication use, this equated to a significant reduction of 40% for macrovascular events and 67% for mortality with bariatric surgery. There was a significant reduction in the risk for coronary events and a nonsignificant reduction in that of cerebrovascular events, of which there were fewer.

Although the findings are based on observational data, the researchers’ sensitivity analysis indicated that the protective effect of surgery could be explained by unmeasured confounding only if the confounders had an effect far larger than any known risk factors, such as hypertension.

It is therefore “implausible that an unmeasured confounder exists that can overcome the effect of bariatric surgery observed in the current analysis study,” they say, although they stress that the benefits should be confirmed by randomized trials.

The second study, by Wendy King (University of Pittsburgh, Pennsylvania, USA) and co-researchers, drew on data from 1406 patients (around a third with diabetes) who underwent Roux-en-Y gastric bypass and had at least 5 years of follow-up in the prospective LABS-2 study.

At their lowest post-surgery bodyweight, the participants had lost a median 37.4% of their presurgery bodyweight and their median BMI was 28.8 kg/m2. At the most recent assessment, these were a corresponding 28.0% and 33.2 kg/m2.

The team looked at five measures of weight regain: kg regained; change in BMI; percentage of presurgery weight; percentage of lowest achieved weight; and percentage of maximum weight lost. All of these measures significantly correlated with progression of diabetes, satisfaction with surgery, and physical health-related quality of life, and most correlated with mental health-related quality of life.

But the strongest associations were seen for weight regain as a percentage of maximum weight lost, with each 18.9% increase associated with a 51% increased risk for diabetes deterioration and 28%, 11%, and 56% increases in the risk for a clinically important deterioration in physical and mental health-related quality of life and satisfaction with surgery, respectively.

In a linked editorial, Amir Ghaferi and Oliver Varban (both from University of Michigan, Ann Arbor, USA) say that the study “highlights the importance of setting appropriate expectations about weight loss and comorbidity resolution after bariatric surgery and also reinforces the concept that obesity is a chronic disease demanding long-term multidisciplinary care.”

They add that “[t]he weight regain and return of comorbidity highlights the need for careful follow-up and counseling of these patients and early intervention when weight regain occurs” and call for improved cooperation and communication between surgical and primary care providers to achieve this.

By Eleanor McDermid

medwireNews is an independent medical news service provided by Springer Healthcare. © 2018 Springer Healthcare part of the Springer Nature group

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