medwireNews: Almost three-quarters of patients who undergo Roux-en-Y gastric bypass (RYGB) experience diabetes remission within 1 year of surgery, but nearly one-third subsequently relapse, population-based study data show.
Importantly, “those who underwent RYGB surgery had substantially decreased risk of subsequent microvascular complications and a (not statistically significant) decreased risk of subsequent macrovascular complications as compared with non-operated individuals with type 2 diabetes; successful diabetes remission at 1 year was a clear predictor of fewer microvascular complications,” say Lene Madsen and colleagues from Aarhus University Hospital in Denmark.
After 6 months of follow-up, 65% of 1111 obese individuals (BMI ≥35 kg/m2) with type 2 diabetes who underwent RYGB surgery at hospitals in northern Denmark between 2006 and 2015 were in diabetes remission. This was defined as a glycated hemoglobin level (HbA1c) below 48 mmol/mol (<6.5%) with no glucose-lowering drug use or a level below 42 mmol/mol (<6.0%) with metformin monotherapy, as “it is clinical practice in Denmark to continue metformin despite observed diabetes remission,” the researchers explain.
The remission rate increased to 74% at 1 year and remained above 70% for each 6 month period in the first 5 years post-surgery. In spite of this, 6% of patients in remission at year 1 had relapsed by year 2, increasing to 12%, 18%, and 27% by years 3, 4, and 5, respectively.
In line with findings from previous randomized controlled trials, older age (>50 years), longer diabetes duration (>5 years), higher baseline HbA1c (>53 mmol/mol; >7.0%), and the use of glucose-lowering drugs other than metformin were all associated with a reduced likelihood for achieving remission at all. The strongest predictor of no remission was insulin use, at a risk ratio of 0.57.
Madsen and team also found that, during the median 5.3-year follow-up period, the individuals who underwent RYGB had a significant 47% lower risk for microvascular complications than a matched cohort of 1074 obese patients with type 2 diabetes who did not undergo surgery, with crude incidence rates of 21.5 versus 38.7 events per 1000 person–years.
The incidence of macrovascular complications was also lower with than without RYGB, at 11.7 versus 15.0 events per 1000 person–years but the difference did not reach statistical significance.
Patients who achieved diabetes remission had a 57% lower risk for microvascular complications than those who did not achieve remission, but no significantly reduced risk for macrovascular complications.
Writing in Diabetologia, Madsen et al conclude that their findings “add evidence to the importance of regular check-ups following RYGB, despite initial diabetes remission, and also suggest that timing of RYGB is important (i.e. consider RYGB while there are still functional pancreatic beta cells).”
They also stress that the “substantial risk of relapsing into type 2 diabetes […] should be accounted for when advising patients and planning post-surgery care.”
By Laura Cowen
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