Postprandial hypoglycaemia is a complication of bariatric surgery (BS) of unknown aetiology, for which the diagnosis and therapeutic approach are challenging, especially in the most severe cases. Initially described as late dumping syndrome, referring to the accelerated gastric emptying that is one of the pathogenic mechanisms described, today, the term postprandial hyperinsulinaemic hypoglycaemia (PHH) is preferred. However, some authors include only the most severe cases under this heading. Its prevalence in different series varies, depending on the type of surgical technique, severity and diagnostic tool. In general, they appear most frequently after techniques that exclude the pylorus, such as gastric bypass (GBP)1. In a study based on a Swedish national registry, a risk of hospital admission for severe hypoglycaemia or some other condition (epilepsy, confusion, syncope) was observed in people with a history of GBP of 0.2%2, with a prevalence of 0.47% in the multicentre Spanish registry of the Grupo de Obesidad de la Sociedad Española de Endocrinología y Nutrición (GOSEEN) [Obesity Group of the Spanish Society of Endocrinology and Nutrition]3. However, if less severe self-reported hypoglycaemia is included, the prevalence is more variable: between 0.1% after GBP and 0.02% after vertical sleeve gastrectomy (VSG)1, to 30%4 and up to 75% if continuous glucose monitoring (CGM) is used5.

This paper reviews the aetiopathogenesis, diagnostic methods and nutritional, pharmacological and surgical treatment of postprandial hypoglycaemia after BS. GOSEEN has agreed on these recommendations as a group of experts.