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

Background: The incidence of vitamin B deficiency after bariatric surgery can range from 26 to 70 %. There is no consensus on optimal vitamin B supplementation in postbariatric patients. The objective of this study was to compare three different regimes.

Methods: In this retrospective matched cohort study, we included 63 patients with methylmalonic acid (MMA) levels ≥300 nmol/L. Group A (n = 21) received 6 intramuscular (im) vitamin B injections including a loading dose, group B (n = 21) received 3 im vitamin B injections without loading dose and group C (n = 21) received no im vitamin B injections.

Results: 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 ± 8.0 kg/m. There was no significant difference in vitamin B and MMA levels between 3 groups at baseline. There was a significant difference in follow-up vitamin B 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).

Conclusions: In this study, a shorter injection regime is probably not sufficient to treat a vitamin B deficiency. An injection regime with 6 injections recovered all vitamin B deficiencies biochemically. MMA levels cannot recover spontaneously over time without additional im injection regime.