Screening and diagnosis of micronutrient deficiencies before and after bariatric surgery

Background: Micronutrient deficiencies are key concerns after bariatric surgery. We describe the prevalence of perioperative testing and diagnosis of micronutrient deficiencies among a cohort of insured bariatric surgery patients. Methods: We used claims data from seven health insurers to identify bariatric surgery patients from 2002-2008. Our outcomes were perioperative claims for vitamin D, B12, folate, and iron testing and diagnosed deficiencies. We analyzed results by bariatric surgery type: Roux-en-Y gastric bypass (RYGB), restrictive, and malabsorptive. We calculated the prevalence of testing and deficiency diagnosis, and performed multivariate logistic regression to determine the association with surgery type. Results: Of 21,345 eligible patients, 84 % underwent RYGB. The pre-surgical testing prevalence for all micronutrients was <25 %. The testing prevalence during the first 12 months after surgery varied: vitamin D (12 %), vitamin B12 (60 %), folate (47 %) and iron (49 %), and declined during 13-24 and 25-36 months. The deficiency prevalence during 0-12 months post-survey varied: vitamin D (34 %), vitamin B12 (20 %), folate (13 %), and iron (10 %). The odds of vitamin B12, folate, and iron deficiency during 0-12 months were significantly lower for restrictive as compared to RYGB, but were not different during 13-24 and 25-36 months post-surgery. The odds of vitamin D deficiency were significantly greater for malabsorptive as compared to RYGB during all post-surgical periods. Conclusion: Many patients did not receive micronutrient testing pre- or post-surgery, yet deficiencies were relatively common among those tested. These results highlight the need for surgeons and primary care providers to test all bariatric surgery patients for micronutrient deficiencies.