Laparoscopic Sleeve Gastrectomy Versus Conventional Medical Therapy in Patients With Newly Diagnosed Type 2 Diabetes and Body Mass Index 30-42 Kg/m2: a Randomized Clinical Trial

Recent evidence suggests that, in obese patients with type 2 diabetes mellitus of long duration, and / or poorly controlled with conventional therapy, bariatric surgery promises diabetes remission rates significantly higher than those attainable with traditional treatment, irrespective of initial BMI and the loss of body weight of the patients.

This has ensured the growing conviction in the international scientific community that bariatric surgery should not be considered as an alternative to conventional obesity and diabetes therapies only after the failure of traditional treatments, but should be performed with the intent to prevent complications associated with these diseases, and therefore at their onset [23]. Furthermore, the use of BMI as the main parameter to guide the indication of bariatric surgery is increasingly being called into question with regard to the presence of comorbidities such as diabetes, as it is the distribution of obesity, together with the presence of comorbidities such as diabetes, rather than the degree of obesity that predicts the onset of related complications.

Bariatric surgery is currently regarded as a "last resort" for both the treatment of obesity and its associated comorbidities, such as diabetes, particularly in patients with a BMI ≤ 35. Despite this, it is now apparent that initial BMI and body weight loss resulting from bariatric surgery have no connection with the metabolic effects of the procedure, such as on the treatment of diabetes. In fact, according to the current national and international guidelines (which are based on a consensus dated 1991[6]), bariatric surgery may be considered in diabetic patients, with a BMI between 30 and 39.9 Kg/m2, only after the recorded failure of conventional medical therapies for obesity and diabetes.

This wait-and-see policy is due to the fact that bariatric surgery is a surgical procedure that is associated, depending on the procedure, with a certain rate of short and long term potential adverse events, and while in the short-medium term it has been shown to achieve significantly higher rates of remission from diabetes, when compared to medical therapy, there remain uncertainties about the durability of remission of diabetes and weight control after long follow-up periods. Essentially, therefore, the risk-benefit ratio has not allowed for the use of bariatric surgery as a first-line therapy for the treatment of type 2 diabetes in obese patients, and in particular in class 1 and 2 obesity. It can be hypothesized, however, that the performance of LSG at diagnosis of diabetes in obese patients can dramatically improve both the resolution/remission rate and the duration of resolution/remission from diabetes, and thus improve the protection against the development of vascular complications.

In fact, growing evidence suggests that the period of time between the diagnosis of diabetes and bariatric surgery is a determining factor in the achievement and duration of diabetes remission. It has also been observed that bariatric surgery is more effective than medical therapy in preventing diabetes in obese patients.