Endocrine Abstracts

Background

Metformin is most frequently prescribed first line therapy for individuals with type 2 diabetes. Continuous use of metformin is associated with vitamin B12 deficiency, yet the prevalence of this side effect and subsequent clinical implications has not been estimated.

Objective

To determine the prevalence of vitamin B12 deficiency and the variables associated with it in patients with type 2 DM on metformin at Kenyatta National Hospital.

Design

A cross-sectional, descriptive study.

Setting

Diabetes out-patient clinic of Kenyatta National Hospital, Nairobi, Kenya.

Subjects

A total of 190 patients with type 2 diabetes on metformin for more than one year attending the out- patient clinic, were enrolled into the study.

Results

Of the patients studied the peak age was around 50–59 years, and majority (61%) were women. The mean duration of metformin use was 5.6 years. Eight percent (n =14) of diabetic patients had confirmed B12 deficiency. With vitamin B12 levels < 208 pg/ml, 18% (32) of the study population had lower/normal levels 208–300 pg/ml and 74%patients had normal levels > 300 pg/ml. No significant correlation between vitamin B12 levels and dosage and duration of metformin use, Hb, MCV or peripheral neuropathy was found.

Conclusion

Vitamin B-12 deficiency is rare in diabetics treated with metformin at an average dose of 1gram per day. A possibility that an individual’s diet, duration of exposure to metformin, and dosage may have been responsible for the low prevalence of Vitamin B12 deficiency.

Keywords: metformin, type 2 diabetes, vitamin B12.