Association of Mean Serum Vitamin B-12 levels in Patients with Type II Diabetes Mellitus patients with and without Metformin therapy.

Abdul Mannan Jehangir ,Aamna Asghar ,Ayesha Iftikhar

doi:10.7176/jmpb/62-15

Abstract

Objective: To determine mean serum vitamin B12 levels in patients with type II diabetes mellitus using metformin. Study Design: Prospective Cross sectional Study Location and Duration: Department of Medicine, Nishtar Hospital Multan, from March 2018 to September 2019. Methodology: Ninety two patients were involved after getting informed consent. HbA1 c, body mass index and blood pressure and deficiency for vitamin B12 was assessed by using electro-chem-iluminescence immunoassay method. B12 levels were categorized as normal (>220pg/ml), possibly deficient (150 to 220 pg/ml) and definitely deficient (<150pg/ml). Neuropathy was assessed and was classified by using Toronto clinical scoring system by the researcher himself. All the data was subjected to statistical analysis using computer software SPSS version 23. Continuous variables were analyzed by their mean and standard deviation while quantitative variables were analyzed by frequency and percentages. Chi square test was applied and P value less than or equal to 0.05 was taken as significant. Results: Mean Serum B-12 levels were 378.42±161.27 pg/ml and 488.90±147.02 pg/ml in metformin and non-metformin groups, respectively. The difference was statistically significant (p=0.001). The patients who were possibly deficient and definitely deficient were 15 (28.30%) and 5 (9.43%) in metformin group and were significantly more (p=0.006) than non-metformin group i.e. 4 (10.26%) and 0. The mean Toronto Neuropathy Score was statistically different (p<0.001) between metformin group (6.03±1.73) and non-metformin group (4.13±1.75). The patients who had mild neuropathy and moderate neuropathy were 23 (43.39%) and 5 (9.43%) in metformin group, while 6 (15.38%) and 2 (5.13%) in non-metformin group. Statistically, both the groups were significantly different (p=0.005). Conclusion: At the end of this study conclusion can be made that metformin use for type II diabetes mellitus is strongly associated with vitamin B12 deficiency and worsening of already susceptible neuropathy. Keywords: vitamin B12, Type II diabetes mellitus, neuropathy. DOI : 10.7176/JMPB/62-15 Publication date: December 31 st 2019

Highlights

For almost forty years it has been known that metformin use has a hand in lowering vitamin B12 levels
Vitamin B12 deficiency is basically caused by malabsorption leading to classical condition of pernicious anemia
Two case reports have been found which showed evidence of vitamin B12 deficiency causing peripheral neuropathy 3 and in the light of these reports annual supplementation of vitamin B12 has been recommended for the patient receiving metformin for type II diabetes mellitus

Summary

Introduction

For almost forty years it has been known that metformin use has a hand in lowering vitamin B12 levels. Vitamin B12 deficiency is a common phenomenon among the elderly 1. It may present as hematological disease or neuropsychiatric illness and at times it is difficult to detect in certain scenarios 2. Vitamin B12 deficiency is basically caused by malabsorption leading to classical condition of pernicious anemia. Two case reports have been found which showed evidence of vitamin B12 deficiency causing peripheral neuropathy 3 and in the light of these reports annual supplementation of vitamin B12 has been recommended for the patient receiving metformin for type II diabetes mellitus. In some parts of the world it is considered as an empirical therapy for peripheral neuropathy

Methods

Results

Conclusion