Abstract
Introduction
Micronutrient deficiencies are common after metabolic bariatric surgery and can lead to serious health complications. The British Obesity and Metabolic Specialist Society recommend routine micronutrient monitoring and supplementation to prevent deficiency, yet real-world adherence to these recommendations is unknown, and multicentre data on postoperative micronutrient status is limited. This study assessed the prevalence of micronutrient deficiencies and adherence to nutritional guidance during the first 12 months after metabolic bariatric surgery in the UK.Methods
A multicentre retrospective cohort study was conducted across 13 bariatric centres across England. Adults undergoing primary metabolic bariatric surgery in 2021 were included. Site-level data were collected on preoperative and 3-, 6- and 12-month postoperative micronutrient levels, clinician blood test requests, and patient-reported adherence to recommended supplementation. The prevalence of each micronutrient deficiency was calculated using patients with available data.Results
Data were available for 669 patients. Early postoperative blood monitoring was inconsistent, with a clinician requesting tests for 33.7% of patients at 3 months, 60.0% at 6 months, and 88.4% at 12 months. Amongst patients tested, low Vitamin D and folate levels were less prevalent at 12 months compared to preoperative values. Low zinc and selenium levels were observed amongst patients who underwent testing during the 12 month follow up period,, with low zinc seen more frequently after sleeve gastrectomy than gastric bypass at all follow-up points - prevalence estimate (95% CI): 16.7% (5.8-39.2) vs. 11.5% (4.0-29.0) at 3 months; 27.6% (14.7-45.7) vs. 10.0% (4.0-23.1) at 6 months; 32.2% (23.2-42.6) vs. 26.0% (18.5-35.1) at 12 months. However, these findings should be interpreted cautiously given the limited availability of trace mineral data and the potential for selective testing. Where recorded, approximately two-thirds of patients self-reported full adherence to supplementation.Conclusion
Among patients with available biochemical testing, micronutrient deficiencies were frequently observed during the first year after MBS. The observed frequency of low zinc and selenium amongst tested patients warrants further prospective investigation to explore clinical implications and to evaluate the earlier and more systematic monitoring of trace minerals after MBS. Inconsistencies in micronutrient blood monitoring and substantial missing postoperative data may suggest that the BOMSS nutritional monitoring guidelines are not being fully implemented in clinical practice across England, limiting the availability of real-world postoperative micronutrient data.