BOSTON — In adults with obesity and type 2 diabetes who underwent bariatric surgery, acute, first-year weight loss was associated with improved HbA1c at 5 years even if the patient experienced weight regain during follow-up, according to a post hoc analysis of the STAMPEDE trial presented at the American Association of Clinical Endocrinologists annual meeting.
“What we were aiming to do was to look at how weight changes after bariatric surgery impact 5-year HbA1c,” Keren Zhou, MD, endocrinology fellow at Cleveland Clinic, told Endocrine Today. “The question was, is it acute weight loss or chronic weight regain or weight trajectory that is more important in these particular patients? This is an important question, because there has been a lot of information focusing on baseline variables and how they predict the outcome of HbA1c after bariatric surgery, but less data exists about dynamic changes after surgery and how that might impact long-term outcomes.”
Zhou and colleagues analyzed data from 96 adults with type 2 diabetes and a BMI of 27 kg/m² to 43 kg/m² who were randomly assigned to undergo Roux-en-Y gastric bypass (n = 49) or sleeve gastrectomy (n = 47) as part of STAMPEDE, a large, randomized controlled trial that also included adults assigned to receive medical therapy alone (66% women; mean age, 48 years; mean BMI, 36.5 kg/m²; mean HbA1c, 9.4%). The cohort was followed for 5 years, with percent weight loss defined as the percent decrease from baseline body weight to lowest weight in the first year. Percent weight regain was defined as the percent change from lowest body weight in the first year to weight at 5 years. Researchers used Spearman rank correlations to assess the relationship between percent weight change and baseline type 2 diabetes duration with HbA1c at 5 years.
In the first year after surgery, mean percent weight loss was 27.2% in the Roux-en-Y arm and 25.1% in the sleeve gastrectomy arm. Mean percent regain for the from the first year to 5 years was 8.2% in the Roux-en-Y arm and 9.4% in the sleeve gastrectomy arm.
In patients who underwent Roux-en-Y gastric bypass, researchers found that less weight loss in the first year after surgery was positively correlated with higher HbA1c at 5 years (r = 0.5; P = .003). In patients who underwent sleeve gastrectomy, greater weight regain from nadir was positively correlated with higher HbA1c at 5 years (r = 0.43; P = .003). In the Roux-en-Y arm, type 2 diabetes duration was positively correlated with higher HbA1c.
Researchers also found that, in the sleeve gastrectomy arm, patients who lost more weight during the first year after surgery had a longer duration of type 2 diabetes, whereas those with less weight loss tended to have a shorter type 2 diabetes duration.
“Despite some of these patients regaining 10% of their weight or more, that really didn’t impact their 5-year HbA1c,” Zhou said in an interview. “It was acute weight loss, in both the Roux-en-Y and the sleeve gastrectomy groups, which greatly influenced their 5-year HbA1c.”
Zhou said the relationship between first-year weight loss after surgery and 5-year HbA1c is correlational; however, she noted that it is possible that visceral and truncal adipose tissue are harbingers of poor outcomes.
“It’s possible in the first year of acute weight loss that patients are losing more of that visceral adipose, and when they start to regain weight, it’s more diffusely distributed,” Zhou said. “As a consequence, you don’t see that bad outcome because of weight regain.”
“This data provides for clinicians a window for optimal intervention, specifically in that first year after surgery, when you really want to drive the weight down to achieve the best long-term outcomes,” Zhou said. – by Regina Schaffer
Zhou K, et al. Poster #240. Presented at: AACE Annual Scientific and Clinical Congress; May 16-20, 2018; Boston.
Disclosure: Zhou reports no relevant financial disclosures.