Vitamin B12 Deficiency in Relation to Metformin Use in Adults with Type-2 Diabetes Mellitus

Objective: To find the correlation between serum vitamin B12 levels in metformin users among type-2 diabetics.Study Design: Cross-sectional Study.Place and Duration of Study: The study was carried out at the Department of Medicine of Combined Military Hospital, Peshawar, Pakistan from April 2021 to September 2021.Materials and Methods: Using a consecutive sampling technique, patients were selected from both outdoor and indoor medical health facility Blood tests were performed on all patients and serum vitamin B12 level was assessed, a level less than 200 pg/ml was considered deficient. The comparison was made among patients taking metformin and those not on metformin.Results: 148 patients were enrolled, consisting of an equal proportion of cases and controls i.e. 74 patients in each group, with a mean age of 44.09± 10.61 and 46.15± 10.64 respectively. Vitamin B12 deficiency was found more in metformin user group 34 (45.94%) than in patients not on metformin 11 (14.86%) (p<0.001). The odd ratio was 4.87 (95% CI is 2.22 – 10.69).Conclusion: Metformin users taking at least 1000mg daily of minimum one-year duration experienced significant reductions in blood vitamin B12 levels as compared to patients not using metformin. A serum vitamin B12 test needs to be performed on regular basis after every three months in type-2 diabetic patients taking metformin of more than 1 gram daily for more than a year.