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Endocrine Abstracts (2019) 63 P989 | DOI: 10.1530/endoabs.63.P989

ECE2019 Poster Presentations Diabetes, Obesity and Metabolism 3 (112 abstracts)

Metformin and Vitamin B12 deficiency: evaluation of vitamin B12, homocysteine and methylmalonic acid levels in type 2 diabetics

Isabel Inácio 1 , Teresa Azevedo 1 , Márcia Alves 1 , Rosa Dantas 1 , Ana Margarida Balsa 2 , Sara Ferreira 1 , Patrícia Rosinha 1 , Fernanda Gomes 1 , Catarina Fonseca 1 , Ana Garret 1 , Andreia Jesus 1 & Joana Guimarães 1,

1Endocrinology Department, Centro Hospitalar Baixo Vouga, Aveiro, Portugal; 2Endocrinology Department, Centro Hospitalar de Trás-os-Montes e Alto Douro, Vila Real, Portugal; 3Faculty of Health Sciences of the University of Beira Interior, Covilhã, Portugal; 4Department of Medical Sciences of the University of Aveiro, Aveiro, Portugal.

Introduction: The American Diabetes Association guideline states that the long-term use of metformin may be associated with biochemical vitamin B12 (B12) deficiency and periodic measurement should be considered, although isolated serum B12 measurement has low sensitivity and specificity. Homocysteine (Hcy) and methylmalonic acid (MMA) are more sensitive biomarkers, the latter being more specific.

Objectives: To estimate B12 deficiency in type 2 diabetics (DM2) taking metformin according to the serum levels of B12, Hcy and MMA and correlation with duration of diabetes, exposure and doses of metformin, anemia and neuropathy.

Material and methods: Included DM2 taking metformin (MET) and DM2 control group not taking metformin (nMET). Blood count, B12, Hcy and MMA were measured. Neuropathy was assessed through the Michigan Neuropathy Screening Instrument (MNSI).

Results: A total of 56 patients were studied: 64.3% males, with mean age of 63.6±10.5 (38-83 years) and 13.8±8.4 years of mean duration of diabetes. Acid suppression drugs in 32.1%, A1C 7.7±1.2%. MET group was composed of 40 and NMET by 16 patients. MET patients were under metformin for 10.7±6.5 years, with a current dose of 2073±583 mg. MET patients had sufficient but significantly lower levels of B12 (367.4±166.5 vs 544.0±429.9, P=0.035). The prevalence of B12 deficiency (≤211 pg/mL) was 12.5% in MET and 6.3% in nMET (P=0.662). Combined low and borderline B12 levels (≤246 pg/mL) was 25% in MET and 6.3% in nMET (P=0.150). Although there were no statistically significant differences, MMA elevation (>32 ug/L) was higher in MET (23.1% vs 14.3%), but combined elevation of Hcy (≥15 μmol/L) and MMA was lower (12.1% vs 14.3%). Both in the analysis for all patients and in the subgroup with eGFR >45 mL/min/1.73m2, MMA levels was correlated with duration of DM2 (r=0.439, P=0.010, and r=0.406, P=0.029, respectively) and exposure to metformin (r=0.454, P=0.026, and r=0.406, P=0.026, respectively). No statistically significant correlations were found between B12, Hcy or MMA with age, doses of metformin, A1C, hemoglobin or MNSI scores.

Conclusion: Patients taking metformin had lower levels of B12, as already described in other studies. The results shows that B12 should be monitored in these patients. The absence of significant differences between the groups for Hcy and MMA assays may be due to the limited size of the sample. Further studies are needed to identify the risk factors for B12 deficiency and the real contribution to the development of anemia and neuropathy.

Volume 63

21st European Congress of Endocrinology

Lyon, France
18 May 2019 - 21 May 2019

European Society of Endocrinology 

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