Association between vitamin B12 level and clinical peripheral neuropathy in type 2 diabetic patients on metformin therapy

Association between vitamin B12 level and clinical peripheral neuropathy in type 2 diabetic patients on metformin therapy

 

Nouran Fakkar Hammam Fakkar (1), Diaa Marzouk (1,2), Mohamed Farouk Allam (1), Mohamed Mahmoud Fouad (3), Maram Maher Aboromia (4) Mohsen Gadallah (2)

 

1. Department of Family Medicine, Faculty of Medicine, Ain Shams University, E11566, Cairo, Abbasia, Egypt.

2. Department of Community, Environmental and Occupational Medicine, Faculty of Medicine, Ain Shams University, Cairo, Egypt.

3 Department of Neurology, Faculty of Medicine, Ain Shams University, Cairo, Egypt.

4. Department of Internal Medicine, Faculty of Medicine, Ain Shams University, Cairo, Egypt.

 

https://doi.org/10.1186/s41983-022-00483-9

 

Abstract

Background: Vitamin B12 malabsorption is one of the side efects of long-term metformin intake. Prolonged vitamin B12 defciency can lead to irreversible nervous system damage. So, the current study aimed to determine the association between serum vitamin B12 level and clinical peripheral neuropathy among type 2 DM patients who are on metformin in comparison to those not taking it. It is a cross-sectional study that was conducted in Egypt and recruited 100 type 2 diabetic patients who were divided into 2 groups: metformin treated, and non-metformin treated (50 subjects per group). The collected data included personal history, medical history, dietetic history that included frequency of eating food rich in vitamin B12 and clinical peripheral neuropathy assessment by Toronto Clinical Scoring System (TCSS). Blood samples were collected for assessment of HbA1c and vitamin B12 level.

Results: Vitamin B12 defciency was present in 4% of metformin group and 2% of non-metformin group. The mean value of vitamin B12 between metformin users (624.3±364.1 pg/ml) and non-metformin users (991.0±489.9 pg/ml) showed a high signifcant diference, p value<0.001. There was a signifcant diference between study groups regarding HbA1c level (p value=0.03). Peripheral neuropathy was signifcantly associated with HbA1c (p value=0.04) and female gender (p value=0.001). Conclusions: Vitamin B12 level was lower in type 2 diabetic patients on metformin compared to those on other oral anti-diabetic drugs, but without signifcant defciency. Peripheral neuropathy was signifcantly associated with poor glycemic control and female gender, but was not associated with vitamin B12 defciency. Keywords: Metformin, Peripheral neuropathy, Type 2 diabetes mellitus, Vitamin B12 defciency> <0.001. There was a signifcant diference between study groups regarding HbA1c level (p value=0.03). Peripheral neuropathy was signifcantly associated with HbA1c (p value=0.04) and female gender (p value=0.001)

Conclusions: Vitamin B12 level was lower in type 2 diabetic patients on metformin compared to those on other oral anti-diabetic drugs, but without signifcant defciency. Peripheral neuropathy was signifcantly associated with poor glycemic control and female gender, but was not associated with vitamin B12 defciency.

 

Keywords: Metformin, Peripheral neuropathy, Type 2 diabetes mellitus, Vitamin B12 defciency.

 

The Egyptian Journal of Neurology, Psychiatry and Neurosurgery 2022;58:46. 

https://ejnpn.springeropen.com/articles/10.1186/s41983-022-00483-9