Examining the Beneficial Effect of Micronutrient Monitoring for Bariatric Surgical Patients: A Retrospective Observational Study

Background: Despite the excellent weight loss and comorbidity remission outcomes, bariatric surgery can predispose to malnutrition. Before 2018, patients undergoing bariatric surgery at a large bariatric center in the South East of England would have had their first blood tests at their preoperative appointment, approximately 6 weeks before surgery. Since 2018, all patients seeking bariatric surgery have had blood tests upon entry into the tier 4 service at the multidisciplinary team (MDT) appointment. If deficiencies were detected, advice was given regarding treatment to the patient and the general practitioner. The aim of this study was to assess the effectiveness of implementing an additional blood test at MDT assessment on the patient's longer-term vitamin and mineral deficiencies. Patients and Methods: A retrospective study was conducted using data from medical records of patients who underwent surgery from October 2016 to December 2016 (group A) and October 2018 to December 2018 (group B). Several parameters, such as vitamin D, vitamin B12, and ferritin levels at the entry to the tier 4 service (group B only), preoperatively and 1-year postoperatively, were obtained. Results: The comparison of the mean levels of the studied nutrients in the two groups showed that there were significantly higher mean preoperative (p = 0.031) and postoperative (p = 0.004) vitamin D levels in group B than in group A. No statistically significant difference was found in either of the other studied nutrients (p > 0.05). Only the preoperative levels of vitamin D were significant predictors of the postoperative levels (p < 0.001). Conclusion: Our findings provide preliminary evidence concerning the value of early biochemical monitoring and management of nutrient deficiencies. Intervention to correct micronutrient deficiencies at the point of MDT assessment yielded significantly improved vitamin D levels in our patients. Other micronutrient parameters were unaffected.