British Obesity and Metabolic Surgery Society Guidelines on perioperative and postoperative biochemical monitoring and micronutrient replacement for patients undergoing bariatric surgery—2020 update

Abstract

Bariatric surgery is recognized as the most clinically and cost-effective treatment for people with severe and complex obesity. Many people presenting for surgery have pre-existing low vitamin and mineral concentrations. The incidence of these may increase after bariatric surgery as all procedures potentially cause clinically significant micronutrient deficiencies. Therefore, preparation for surgery and long-term nutritional monitoring and follow-up are essential components of bariatric surgical care. These guidelines update the 2014 British Obesity and Metabolic Surgery Society nutritional guidelines. Since the 2014 guidelines, the working group has been expanded to include healthcare professionals working in specialist and non-specialist care as well as patient representatives. In addition, in these updated guidelines, the current evidence has been systematically reviewed for adults and adolescents undergoing the following procedures: adjustable gastric band, sleeve gastrectomy, Rouxen-Y gastric bypass and biliopancreatic diversion/duodenal switch. Using methods based on Scottish Intercollegiate Guidelines Network methodology, the levels of evidence and recommendations have been graded. These guidelines are comprehensive,

Changes in Anthropometric Measures, Nutritional Indices and Gastrointestinal Symptoms Following One Anastomosis Gastric Bypass (OAGB) Compared with Roux-en-y Gastric Bypass (RYGB)

“…Previous literature has reported vitamin B12 deficiency in 20% of the RYGB patients [ 8 ]. The potential causes of this may be bypassing the gastric fundus, the primary site for intrinsic factor production, which aids in B12 complex absorption [ 5 ], malabsorption related to common medications (metformin and proton pump inhibitors) as well as dietary restrictions induced by the surgery, which may result in food intolerances and suboptimal protein intake in longer term [ 30 ]. Hence supplementation and ongoing monitoring is required.…”

“…Serum B12 may not be adequate to identify metabolic deficiencies of vitamin B12 [ 5 ] and hence active B12 level and Hcy were also measured. We observed lower disorder levels of 15.8% at 12 months and 21.0% at 24 months post OAGB compared to the literature and no difference in between the groups.…”

“…Metabolic bone health is one area that is still under investigation and data on best management continues to emerge. Prior to and post bariatric procedures, Vitamin D and iPTH deficiencies are common and need close attention long term [ 5 ]. There are limited studies reporting on these nutrients post OAGB [ 3 , 18 ], while a reduction in bone mass has reported [ 31 ].…”

Micronutrient Deficiencies in Laparoscopic Sleeve Gastrectomy

“…Current micronutrient supplementation guidelines published by the British Obesity and Metabolic Surgery Society and the American Society for Metabolic & Bariatric Surgery in 2020 and 2019, respectively, will be augmented by this comprehensive review of micronutrient deficiencies in SG patients [51,52]. Between these sets of guidelines, only the latter focuses on recommendations specifically for SG patients and notes weakness in evidence of vitamin recommendations for these patients when compared to other procedures.…”

Common Pitfalls in the Management of Patients with Micronutrient Deficiency: Keep in Mind the Stomach

“…In the case of total gastrectomy, the complete absence of the gastric mucosa and thus gastric acid and intrinsic factor secretion leads over time to impaired iron and vitamin B 12 absorption, once body stores are depleted. Addtionally, in the case of partial gastrectomy due to the loss of the gastrin-producing antral mucosa (Billroth I, II, Roux-en-Y gastric bypass, biliopancreatic diversion) or the loss of part of the oxyntic mucosa (sleeve gastrectomy), the regular absorption of the hematopoietic micronutrients iron and vitamin B 12 is impaired [ 123 ]. In these patients, when not regularly monitored with blood tests, chronic anemia may develop.…”