Prevalence of Vitamin B12 Deficiency Among Diabetic Patients Taking Metformin in Jordan.

Background Type 2 diabetes mellitus prevalence in Jordan is high and increasing, leading to an increase in the use of metformin, which is considered the first-line treatment. Metformin, which belongs to the biguanides family of anti-diabetic medication, is known for its low cost, bodyweight neutrality, effectiveness, and good safety profile. In addition, it showed that it improves body lipid profile, inflammatory markers, and decreases cardiovascular events. In spite of that, a reduction in vitamin B12 levels was reported as a possible long-term side effect of metformin. Vitamin B12 deficiency can result in macrocytic, megaloblastic anemia, it can also cause neuropathies, including subacute combined degeneration, neuropsychiatric symptoms, peripheral neuropathy, and optic neuropathy. Aims The current study aimed to identify the level of serum vitamin B12 among patients who use metformin. Additionally, the study aimed to explore associations between serum vitamin B12 levels and patients' age, gender, duration, and dosage of metformin use, and concurrent medications. Moreover, the study summarizes participants' socio-demographical and pharmacological data and presents the statistical analysis methods used to answer the research questions. Methods A cross-sectional study was conducted on a sample that included 435 patients suffering from type 2 diabetes mellitus at the internal medicine clinics at Al-Mahabba Hospital, Madaba, Jordan. After applying the inclusion and exclusion criteria that we have designed, information regarding their age, gender, metformin dosage, treatment duration, and other medications in use was precisely collected, followed by ordering serum vitamin B12 level and obtaining the results as soon as they were available. We diagnosed vitamin B12 deficiency depending on a cut-off value for serum vitamin B12 level of less than 200 pg/ml. The collected data were entered into an Microsoft Excel 16 (Microsoft Corp., Redmond, WA) sheet and then transferred to the statistical software, IBM SPSS Statistics for Windows, Version 28.0 (IBM Corp., Armonk, NY) to analyze the data. Results A total of 435 patients on metformin were participated, the majority of patients were male with sample mean age of 59 years, most of patients use metformin three times a day with 13.9 years of metformin duration of treatment, the serum vitamin B12 level was found to be 188.9 pg/ml which considers deficient with a prevalence of 66%. The patients' age, metformin dose, and duration were negatively correlated with serum B12. The patients' gender did not show an impact on vitamin B12 levels. The type of medications in use with metformin demonstrated a significant impact on B12 level, as evident by the post hoc test. Conclusion According to the findings, we concluded that patients who have used metformin are likely to be more vulnerable to vitamin B12 deficiency than those who have not used metformin. There is an obvious link between the patient's age, dosage, and length of metformin usage and the vitamin B12 deficiency. The patients' gender did not show an impact on vitamin B12 levels. Also, other medications in use with metformin, such as insulin, vildagliptin, histamine 2 blockers, and proton pump inhibitors, have an impact on vitamin B12 levels.