Screening and diagnosis of micronutrient deficiencies before and after bariatric surgery

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.

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.

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.

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.