Bariatric surgery versus lifestyle modification for decreasing glycated haemoglobin in obese persons living with type 2 diabetes : a review

Abstract

Introduction: Type 2 diabetes mellitus is a chronic disease characterized by high blood sugar levels; it develops due to insulin secretory defects or insulin resistance. Obesity plays a key role in the aetiology of type 2 diabetes; this is being referred to by the term “diabesity”. Treating type 2 diabetes in obese individuals is challenging but a reduction of just 5% body weight is associated with better glycaemic control and a reduced the risk of morbidity and mortality. Methods: This review sought to answer the following question: Is bariatric surgery more effective than lifestyle modification in reducing HbA1c serum levels to a normal range in obese individuals with type 2 diabetes mellitus? The review included papers published between January 2012 and October 2017. The search was carried out using the keywords type 2 diabetes, metabolic surgery, bariatric surgery and HbA1c in Academic Search Complete via EBSCO, Cumulative Index of Nursing and Allied Health Literature (CINAHL) via EBSCO, and Medline via ProQuest. To be included papers had to focus on adults with type 2 diabetes who had undergone bariatric surgery or lifestyle modification. Eight articles met the criteria and were included. The CASP and AMSTAR critical appraisal tools were used to appraise the studies. Results: Results revealed that bariatric surgery is more effective than lifestyle modification in achieving reduced HbA1c serum levels to a normal range. Results also revealed that it was not just the weight reduction that contributed to the diabetes control and remission, but also endocrine changes. Of the different bariatric surgeries available, the best result in terms of remission of diabetes was achieved by duodenal switch with biliopancreatic diversion. Individuals with a lesser magnitude of obesity (a BMI that range from 30 to 35 kg/m²), and an early diagnosis of type 2 diabetes, had a greater chance of achieving type 2 diabetes remission following bariatric surgery. Conclusion: Bariatric surgery is recommended in achieving remission of diabetes in persons who are in the lower obesity range and above, and who have been living with diabetes for less than 8 years. The more complex duodenal switch with biliopancreatic diversion achieves a higher rate of type 2 diabetes remission. This implies that in view of the growing prevalence of type 2 diabetes and obesity, investment in human and other resources is required to meet the future demand for bariatric surgery.