Bariatric and metabolic surgery during and after the COVID-19 pandemic.

In The Lancet Diabetes & Endocrinology, Francesco Rubino and colleagues discussed the prioritisation of bariatric and metabolic surgery during and after the COVID-19 pandemic. We congratulate the authors for bringing up this important discussion, since difficulties around future care of obesity and type 2 diabetes might be a major problem within this context.We would like to point out, however, our disagreement with the algorithm for prioritisation for bariatric and metabolic surgery in patients with type 2 diabetes. Many diabetes characteristics the authors suggest be prioritised are associated with reduced long-term benefits (which we previously discussed in a review), but we would like to focus on one point here: established cardiovascular disease. This suggestion goes against current evidence.

Although many good-quality observational data suggest that cardiovascular disease risk and mortality are reduced after bariatric and metabolic surgery, the number of patients evaluated that already had cardiovascular disease is very small, and even smaller if we consider those with type 2 diabetes. In the large Swedish Obese Subjects study, although similar benefits were suggested, only 1·5% of patients had a history of cardiovascular disease, and only 21 patients with cardiovascular disease were submitted to surgery.

In randomised controlled trials of bariatric and metabolic surgery in diabetes, there are few mentions of patients with established cardiovascular disease, and in some of these studies, such as the large and highly cited STAMPEDE, previous cardiovascular disease was an exclusion criterion, according the details registered on ClinicalTrials.gov (NCT 00432809). Early this year, in a retrospective study of nearly 7000 patients who had bariatric and metabolic surgery for obesity, only 3·6% had a history of cardiovascular disease, and the rates of post-operative complications in those patients were significantly higher than in patients without previous cardiovascular disease. The authors concluded that additional research is necessary to define the benefits of bariatric and metabolic surgery in this population. The exact number of patients with type 2 diabetes and a history of cardiovascular disease who have been submitted to bariatric and metabolic surgery and whose outcomes have been studied is unknown, yet is probably too small to draw any definitive conclusion to put such patients on a priority list.

Moreover, we should bear in mind that, on the contrary, this particular population with type 2 diabetes and a history of cardiovascular disease is the most studied regarding long-term safety and benefits in cardiovascular outcome trials with drugs (with more than 50 000 patients studied), and the known cardiovascular and renal benefits of both SGLT2 inhibitors and glucagon-like peptide-1 receptor agonists are clear.

Therefore, we agree with most of Rubino and colleagues’ work and that much effort will have to be made regarding evidenced-based therapies, including bariatric and metabolic surgery for obesity and type 2 diabetes following the COVID-19 pandemic, but it is still unwise and incorrect to prioritise this procedure over drug therapy in a population in whom almost no studies exists about the former treatment and several investigations do exist concerning the latter.