Peter Benotti

Iron is an essential nutrient in living organisms with multiple vital functions. Iron deficiency (ID) can cause long term health consequences beyond iron deficiency anemia (IDA). The high prevalence of ID and its long-term effects in patients with obesity and after metabolic and bariatric surgery (MBS) is recognized. Nevertheless, there is limited knowledge of the optimal route or dose for treatment of patients with obesity and post-MBS, and an evidence-based universal guideline for prevention and treatment of ID in short- and long-term post-MBS (PMBS) is not yet available. ID in the general population is currently treated with oral or parenteral iron, where oral iron treatment is considered the preferred option with parenteral iron as a second-line treatment in case there is intolerance or lack of response to oral iron. In patients with obesity with chronic low-grade inflammation and PMBS patients with altered gut anatomy and function, there are also alterations in the bioavailability and higher risks of side effects of available oral irons. The conclusions of current studies exploring effective treatment of iron deficiency in this population have been inconsistent and further well-planned randomized and prospective studies are needed. This is a narrative review of the literature on the available treatment options and strategies for treatment of ID in PMBS patients to recognize the knowledge gaps and provides topics of future research.

Objective We sought to validate an algorithm designed to identify patients with post-gastric bypass hypoglycemia (PGBH) using clinician chart review. Methods We conducted a chart review study of non-diabetic patients who underwent Roux-en-Y gastric bypass (RYGB) at our institution from 2004 to 2013. The electronic medical record (EMR) algorithm was based on any post-operative glucose <60 mg/dl, diagnosis of hypoglycemia, or medication use for treatment of PGBH and identified 158 charts as PGBH and 1048 charts without PGBH. Two clinicians independently reviewed a random selection of 80 cases and 80 control charts and determined the presence or absence of PGBH by searching the chart using keywords and reviewing laboratory results, medications, and clinic notes. Results Of the 160 charts reviewed, the EMR algorithm agreed with the chart review for 130 (accuracy = 80%, 95% CI = 75–87%) with sensitivity of 89% (95% CI = 83–96%) and specificity of 86% (95% CI = 78–93%). We improved the algorithm’s accuracy to 90% by limiting the search to data obtained 3 months or more following RYGB. Conclusion The EMR algorithm has high sensitivity, specificity, and accuracy to identify post-gastric bypass hypoglycemia within our patient cohort. The use EMR-based algorithms may be a useful tool for future research to improve our understanding of epidemiology and risk factors for post-bariatric surgery hypoglycemia.