Endocrine Abstracts

Introduction: Metformin is the first line treatment of type 2 diabetes, but now has been reported to cause a decrease in level of Vitamin B12.

The aim of the study is to describe the prevalence of vitamin B12 deficiency in adults with type 2 Diabetes Mellitus who were in treatment with metformin compared in those without diabetes.

Material and Methods: Total number of patients were 130 between 16–84 years old. Mean age 54.2 ± 16.4 years. Female were 56.9% (74 patients) and males 43.1% (56 patients). Serum B12 concentrations were quantified by chemiluminescent enzyme immunoassay. Patients were considered vitamin B12 deficiency if the level was less than 200 pg/ml and borderline-low B12 (≤ 300 pg/mL) they were in treatment with metformin over one year.

Results: The mean vitamin B12 level in all patients was 337.1 ± 155.5 pg/ml. A total of 16.1% (21 patients) showed vitamin B12 deficiency with mean vitamin B12 level of 145.3 ± 30.4 pg/m; and 48.4% (63 patients) showed borderline-low B12 with mean vitamin B12 level of 214 ± 56.9 pg/ml. The mean concentration of B12 was significantly lower in the metformin treated group (264 pg/ml) compared to those without diabetes (409 pg/ml) (P = 0.06). About 21.5% of persons with diabetes receiving metformin were vitamin B12 deficient (< 200 pg/ml) compared to 4% of persons without diabetes.

Conclusions: Uses of metformin was associated with Vitamin B12 deficiency. Routine testing of vitamin B12 levels in metformin-treated patients should be considered and the clinician must be aware of the possibility of metformin-related B12 deficiency.

Keywords: Vitamin B12, metformin.