Keeping Tabs on Vitamin B Advised with Metformin
The association of metformin treatment with vitamin B12 deficiency was confirmed in a long-term trial, suggesting that diabetic patients receiving the popular drug would benefit from vitamin monitoring and perhaps B12 supplementation.
With 4.3 years of treatment in a randomized, placebo-controlled trial, the hazard ratio for developing vitamin B12 deficiency while on metformin was 5.5 relative to placebo (95% CI 1.6 to 19.1), reported Coen Stehouwer, MD, of Maastricht University in the Netherlands, and colleagues online in BMJ.
"Our study shows that this decrease is not a transitory phenomenon, but persists and grows over time," the researchers wrote.
From a mean of about 355 pmol/L at the end of the run-in phase, B12 levels dropped to about 305 pmol/L after four months, and from there to 280 pmol/L over the next four years.