Weight loss and diabetes remission

Weight loss is a cornerstone of the effective management of obese people with type 2 diabetes, but it is difficult to achieve with conventional management. In this issue of Diabetes Digest, two studies extend our knowledge of the effects of bariatric surgery and very-low-energy diets (VLEDs) on potential diabetes remission.

While there is accumulating evidence from randomised controlled trials that bariatric surgery is more effective than conventional medical and lifestyle-based therapies in improving glycaemic control in obese people with type 2 diabetes (e.g. Schauer et al, 2014; Ikramuddin et al, 2015), follow-up in these studies has been limited to 2–3 years, so long-term outcomes and adverse events are not known. In the study summarised alongside, Mingrone and colleagues extend this evidence base, reporting 5-year follow-up data of a randomised controlled trial in which 60 people aged 30–60 years, with BMI ≥35 kg/m², HbA_1c ≥53 mmol/mol (7.0%) and type 2 diabetes of at least 5 years’ duration were randomised to medical treatment, Roux-en-Y gastric bypass or biliopancreatic diversion.

In the 53 people who completed the 5-year follow-up, 50% of the surgery recipients but none of the medically treated participants had maintained diabetes remission. However, among the 34 people who had achieved diabetes remission at 2 years, hyperglycaemia relapse was recorded at least once over the study course in 44%. As expected, the surgery groups had maintained substantially greater weight loss than the medical treatment group (around 40 kg vs 10 kg) at 5 years, but the incidence of adverse metabolic events was higher in the former. Thus, these data indicate that diabetes remission can be durable in a substantial proportion of people following surgery, but that continued long-term monitoring of glycaemia and metabolic complications is essential in all patients post-surgery.

Lim et al (2011) had previously demonstrated that, by restricting dietary energy intake to around 600 kcal/day, diabetes could be reversed – at least for 8 weeks – in people with a diabetes duration of less than 4 years, suggesting that dietary as well as surgical approaches could, in principle, lead to diabetes remission. However, it was not known whether this extended to people with longer-duration disease. In Steven and Taylor’s recent study (summarised in Roger Gadsby’s section on page 14), 15 people with short-duration diabetes (<4 years) and 14 with long-duration diabetes (>8 years) completed an 8-week VLED intervention (approximately 700 kcal/day). Overall, 87% of the short-duration group and 50% of the long-duration group achieved non-diabetic fasting glucose concentrations by the end of the intervention.

These data imply that aggressive dietary intervention can reduce blood glucose concentrations to non-diabetic levels, at least in the short-term, in a substantial proportion of people with long-standing diabetes. Whether this approach will be a viable diabetes treatment strategy in practice will depend on whether weight loss and improved glycaemia can be maintained over the longer term. The ongoing DiRECT study (Diabetes Remission Clinical Trial; available at: www.directclinicaltrial.org.uk), in which people with diabetes undergo a VLED with 2 years of follow-up, should help provide some answers.

To read the article summaries, please download the PDF