Bariatric Surgery Beats Diet and Exercise in a Head-to-Head Comparison

Gastric bypass surgery vs intensive lifestyle and medical intervention for type 2 diabetes: the CROSSROADS randomised controlled trial (Diabetologia 2016;59:945–953. DOI: 10.1007/s00125-016-3903-x)

What is the problem and what is known about it so far?

Roux-en-Y gastric bypass (RYGB) is a surgery in which the stomach is made smaller and digestion bypasses part of the intestine. Evidence has shown that RYGB can dramatically improve blood glucose control in people with type 2 diabetes, and even lead to diabetes remission (a state in which all signs and symptoms of diabetes disappear). Diets very low in calories paired with intense exercise routines have also been shown to dramatically improve blood glucose control and in certain cases also to lead to diabetes remission. However, there have not been many studies directly comparing RYGB with aggressive diet and exercise.

Why did the researchers do this particular study?

Despite medications and diet/exercise regimens, most people with type 2 diabetes are not able to sustain weight loss for long periods of time without surgery. Diabetes remission requires keeping the weight off. It is also important to meet long-term blood glucose goals in order to prevent complications from diabetes. The researchers wanted to compare directly medicine with diet/exercise treatment plans with surgical approaches to discover the full range of benefits and risks.

Who was studied?

A total of 43 patients with type 2 diabetes were randomly assigned to either the RYGB group (15 patients) or the diet and exercise group (17 patients). All the participants were 25–64 years old and were considered obese according to their BMI (body mass index, a measurement of body weight relative to height).

How was the study done?

Before surgery, the patients in RYGB group participated in weekly telephone-based appointments and attended 2–3 surgery support groups. After surgery, the patients continued to have telephone-based appointments for 10 months. Patients in the diet and exercise group participated in at least 45 min of aerobic exercise 5 days per week, followed a diet designed for weight loss and lowering blood glucose levels, and received standard diabetes medical treatment for 1 year. The researchers then compared the groups after 1 year.

What did the researchers find?

Benefits were seen in both groups in terms of weight and blood glucose control. However, compared with the diet and exercise group, 1 year after the study those in the RYGB group had lost much more weight (about a quarter of their starting weight). They had a much higher rate of type 2 diabetes remission (more than half of the group experienced remission). And they had a larger drop in A1C (average glucose level over 2-3 months). Also, the RYGB group was taking significantly fewer or no diabetes medications after surgery.

What were the limitations of the study?

Although longer follow-up by the researchers is underway, the observation period of 1 year was short. Also, the number of participants was small and the study was based in a single center and therefore may not be applicable to a larger population.

What are the implications of the study?

According to the findings of this study, compared with aggressive diet and exercise, RYGB surgery results in greater weight loss, leads to type 2 diabetes remission more often, and offers tighter blood glucose control, in addition to improvements in other risk factors for heart disease, in patients who are mild-to-moderately obese.