Vitamin B12 deficiency in type two Diabetic patients using metformin at Kenyatta National Hospital

Abstract

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. STUDY 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. STUDY DESIGN: A descriptive cross-sectional study . STUDY METHODS: The study was carried out at the Kenyatta National Hospital diabetic clinic. A total of 190 type 2DM patients on metformin, were recruited after meeting the study criteria. Patients completed a questionnaire form; requiring; information that included demographic history, current duration and mode of therapy. Peripheral neuropathy was assessed using the Neuropathy Disability scores. Blood sample was drawn for measuring serum vitamin B\2, mean cell volume (MCV) and hemoglobin (Hb). Descriptive statistics such as frequency and. means were computed. Chi-square and student's t tests inferential statistics were used to analyze associations between categorical and continuous variables. Also vitamin B12 levels were correlated with other variables using the Pearson productmoment correlation coefficient. Further multivariate logistical regression identified covariates independently associated with B 12 deficiency. RESULTS: Eight percent (n =14) of diabetic patients had confirmed B12 deficiency. With vitamin B 12 levels < 208 pg/ml, 18% (32) of the study population had lower/normal levels 208-300pg/ml and 74%patients had normal levels> 300pg/ml. No significant correlation between vitamin B12' levels and dosage and duration of metformin use, Hb, MCV or peripheral neuropathy was found. SUMMARY: Vitamin B-12 deficiency is rare in diabetics treated with metformin. Key words: Metformin, type 2 diabetes, vitamin B 12.