Do we need to measure vitamin B12 and magnesium in morbidly obese patients with type 2 diabetes mellitus?

Abstract

ObjectiveWe aimed to investigate the prevalence of B12 deficiency in metformin-treated, morbidly obese, type 2 diabetes mellitus (T2DM) patients, compared to morbidly obese controls, as well as to evaluate the magnesium status.DesignRetrospective cross-sectional analysis of plasma vitamin B12, plasma magnesium, glucometabolic status and clinical measurements in all consecutive morbidly obese patients was conducted during 1 year.SettingOutpatient Clinic of Obesity Care.SubjectsOne hundred forty-seven patients were evaluated: 107 morbidly obese controls and 40 metformin-treated, morbidly obese patients with T2DM.Main outcome measuresCirculating plasma concentrations of vitamin B12 (cobalamin), magnesium, clinical measurements and metformin medication.ResultsThere were differences between the two groups regarding age, sagittal diameter, glucose parameters and magnesium concentrations. Longer diabetes duration was associated with lower magnesium. Metformin-treated T2DM patients had lower magnesium (0.76±0.07 mmol/L) than controls (0.82±0.07 mmol/L). A subgroup analysis of 26 non-metformin-treated T2DM patients showed a normal magnesium concentration compared to controls, that is, 0.81±0.06 mmol/L. We found no statistical difference in B12 concentrations between the two groups.ConclusionTo fully benefit from metformin medication, routine testing of B12 as well as magnesium in metformin-treated, morbidly obese patients should be performed, with consideration of substitution to avoid low levels.

Assessment of the effects of metformin and glibenclamide on the concentration of selected trace elements in type 2 diabetic patients

“…By contrast, metformin did not significantly change serum Mg levels, leading to significantly lower levels than the control. Our results are in accordance with the findings of previous studies (Chakraborty et al, 2011, Wahlen et al, 2017. Even though the glibenclamide treated group in the present study had worse glycaemic control, they showed better serum Mg levels than the patients treated with metformin.…”

<p>Metformin and Micronutrient Status in Type 2 Diabetes: Does Polypharmacy Involving Acid-Suppressing Medications Affect Vitamin B12 Levels?</p>

“…Additionally, Swedish researchers recommend that to optimally benefit from medication with metformin, morbidly obese patients should undergo routine assessments of both vitamin B 12 and magnesium levels, with relevant supplementation considered where necessary to maintain optimal status. 190 As detailed earlier in this review, the recommendation that calcium supplementation could potentially prevent metformin-induced deficiency of vitamin B 12 is premature due to the existing paucity of studies. 59…”

Repurposing Metformin for the Treatment of Atrial Fibrillation: Current Insights

“…104,150,151 Patients who are prescribed metformin should therefore be monitored periodically and, if appropriate, provided vitamin B12 supplements, especially if the patients have other co-existing conditions such as renal or hepatic impairment. 151,152 Metformininduced vitamin B12 deficiency has been linked to higher frequencies of autonomic neuropathy and linked to a 3.16 fold increase in cardiovascular events, including cardiac arrhythmias, and a 3.17 fold increase in mortality and therefore of importance when considering the chronic use of metformin in subjects with AF. 149,153 Metformin is predominantly cleared by the kidneys thereby requiring that the dosage should be adjusted if the patient has reduced renal function.…”