Comparison Between Different Intramuscular Vitamin B12 Supplementation Regimes: a Retrospective Matched Cohort Study.

Abstract

The incidence of vitamin B12 deficiency after bariatric surgery can range from 26 to 70%. There is no consensus on optimal vitamin B12 supplementation in postbariatric patients. The objective of this study was to compare three different regimes. In this retrospective matched cohort study, we included 63 patients with methylmalonic acid (MMA) levels ≥300nmol/L. Group A (n = 21) received 6 intramuscular (im) vitamin B12 injections including a loading dose, group B (n = 21) received 3 im vitamin B12 injections without loading dose and group C (n = 21) received no im vitamin B12 injections. The total post-bariatric patient population consisted of 14 males (22.2%) and 49 women (77.8%) with a mean current body mass index of 30.6 ± 8.0kg/m2. There was no significant difference in vitamin B12 and MMA levels between 3 groups at baseline. There was a significant difference in follow-up vitamin B12 levels of group A compared to group B (p = 0.02) and group A compared to group C (p = 0.03). In the follow-up results, there is also a significant decrease in MMA levels of group A compared to group B (p = 0.02), group A compared to group C (p < 0.001), and group B compared to group C (p < 0.01). In this study, a shorter injection regime is probably not sufficient to treat a vitamin B12 deficiency. An injection regime with 6 injections recovered all vitamin B12 deficiencies biochemically. MMA levels cannot recover spontaneously over time without additional im injection regime.