Association of biochemical B₁₂ deficiency with metformin therapy and vitamin B₁₂ supplements: the National Health and Nutrition Examination Survey, 1999-2006

Association between vitamin B12 deficiency and metformin use in type 2 diabetic patients: a cross-sectional study in a South Vietnam tertiary hospital

OBJECTIVES

Vitamin B12 deficiency is a common and neglected adverse effect experienced by type 2 diabetic patients treated with metformin. A lack of vitamin B12 may have severe consequences, such as fatigue, macrocytic anaemia and worsened peripheral diabetic neuropathy. This study aims to identify the rate of vitamin B12 deficiency and the associated factors in type 2 diabetic patients treated with metformin.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

This study involved 145 type 2 diabetic patients treated with metformin in Cho Ray hospital, a tertiary healthcare centre in South Vietnam. The levels of vitamin B12 and associated clinical and paraclinical parameters were measured and collected.

RESULTS

The study population's mean age was 61.5 years, of which 51.7% were women. The median duration of metformin use was 10 years, and the median metformin dose was 1700 mg. The vitamin B12 deficiency rate was 22.1%. HbA1c, duration of metformin use and metformin dose were independent factors statistically associated with vitamin B12 deficiency.

CONCLUSIONS

This study identified the rate of vitamin B12 deficiency and associated factors in type 2 diabetic patients treated with metformin. These findings can be helpful in screening patients and replacing vitamin B12 in high-risk populations with vitamin B12 deficiency.

TRIAL REGISTRATION NUMBER

Ethical Committee of Cho Ray Hospital (approval number 1711/CN-HĐĐĐ).

Prevalence of Functional Cobalamin Deficiency and Relevant Mortality Risk in the General Population: An Unheeded Phenotype Distinct from Cobalamin Deficiency

BACKGROUND

Current guidelines prioritize monitoring and managing cobalamin (Cbl) deficiency but insufficiently address the issue of functional Cbl deficiency (decreased Cbl sensitivity). This study aims to investigate the prevalence burden of functional Cbl deficiency and to examine its prospective association with mortality risk, compared to Cbl deficiency, among United States (US) adults.

METHOD

The cohort study included 22,513 US participants aged ≥20 years from 1999 to 2014 and was followed up through December 31, 2019. Cbl sensitivity was assessed using a combination of binary classifications for Cbl and methylmalonic acid (MMA) levels, with cutoff values set at 400 pg/mL for Cbl and 250 nmol/L for MMA. Functional Cbl deficiency was defined as elevated MMA and Cbl levels. Serum Cbl levels <148 pmol/L (200 pg/mL) were classified as Cbl deficiency.

RESULTS

In this study, approximately 2.1% of US adults had Cbl deficiency, while the age-adjusted prevalence of functional Cbl deficiency was 4.5%, corresponding to an estimated 10 million US adults. Over a median follow-up period of 10.7 years, there were 4636 recorded deaths. Compared to the MMAlowCbllow group (MMA ≤250 nmol/L, Cbl ≤400 pg/mL), the multivariable-adjusted hazard ratios for all-cause, cardiovascular, and cancer-related mortality in the MMAhighCblhigh group were 1.76 (95% confidence interval [CI]: 1.53-2.02, p < 0.001), 2.17 (95% CI: 1.78-2.67, p < 0.001), and 1.38 (95% CI: 0.95-2.00, p = 0.089). In contrast, the mortality risk associated with Cbl deficiency became insignificant after adjusting for similar confounders. While Cbl supplementation or dietary intake above recommended levels might alleviate Cbl deficiency, they do not appear to reduce the prevalence of functional Cbl deficiency or its associated mortality risk.

CONCLUSION

Compared with Cbl deficiency, functional Cbl deficiency is more frequent and is significantly associated with increased mortality risk in the general population.

Anemia in diabetes mellitus: Pathogenetic aspects and the value of early erythropoietin therapy

Anemia is a frequent, yet increasingly recognized, comorbidity in diabetes mellitus (DM), with prevalence often driven by multifactorial mechanisms. Hematinic deficiencies, common in this population, may arise from associated comorbidities or medications, such as metformin, as well as other drugs commonly employed for DM-related conditions. Among contributing factors, diabetic kidney disease (DKD) plays a pivotal role, with anemia developing more frequently and being more pronounced in earlier stages, than in CKD of other causes. This enhanced susceptibility stems primarily from the combined impact of impaired renal oxygen sensing and deficient erythropoietin (EPO) production linked to tubulointerstitial fibrosis. Additional mechanisms comprise glomerular dysfunction, shortened erythrocyte lifespan, uremia-induced bone marrow suppression, and increased bleeding risk. DM is also recognized as a chronic low-grade inflammatory condition, with its inflammatory burden driving iron maldistribution, suppression of erythropoiesis, and resistance to EPO. The diagnostic approach of anemia in DM mirrors that in the general population. Addressing modifiable causes such as hematinic deficiencies, and other chronic conditions, such as DKD and bone marrow disorders, is paramount. In total, the underlying pathophysiology of anemia in DM primarily reflects a state of absolute or relative EPO deficiency and/or diminished bone marrow responsiveness, effectively corresponding to 'anemia of chronic disease. Early initiation of EPO therapy, even in DM patients without overt DKD, may mitigate disease progression and improve outcomes. Future research should focus on diabetes-specific strategies integrating optimal EPO use, potentially implementing targeted management of renal and inflammatory contributors to anemia.

Metformin in gestational diabetes: physiological actions and clinical applications

Metformin is an effective oral hypoglycaemic agent used in the treatment of type 2 diabetes mellitus; however, its use in pregnancy for the treatment of gestational diabetes mellitus (GDM) remains controversial owing to concerns around safety and efficacy. This comprehensive review outlines the physiological metabolic functions of metformin and synthesizes existing literature and key knowledge gaps pertaining to the use of metformin in pregnancy across various end points in women with GDM. On the basis of current evidence, metformin reduces gestational weight gain, neonatal hypoglycaemia and macrosomia and increases insulin sensitivity. However, considerable heterogeneity between existing studies and the grouping of aggregate and often inharmonious data within meta-analyses has led to disparate findings regarding the efficacy of metformin in treating hyperglycaemia in GDM. Innovative analytical approaches with stratification by individual-level characteristics (for example, obesity, ethnicity, GDM severity and so on) and treatment regimens (diagnostic criteria, treatment timing and follow-up duration) are needed to establish efficacy across a range of end points and to identify which, if any, subgroups might benefit from metformin treatment during pregnancy.

The Effectiveness of Steroid Versus Vitamin Therapy in the Improvement of Extraocular Movements in Patients With Diabetic Cranial Nerve Palsy: A Comparative Study

BACKGROUND

 Diabetic mononeuropathies, which are focal neuropathies, are less common than peripheral neuropathy in diabetes. They are frequently underreported or misdiagnosed due to mild or unnoticed cases. Early detection and treatment are crucial to prevent worsening nerve damage and complications.

OBJECTIVES

This study aims to compare the effectiveness of conventional treatment with vitamin therapy for improving these neuropathies.

METHODS

Fifty cases of diabetic ocular nerve palsy were stratified into two groups, 25 in each. Group A received steroids, while group B received vitamin B12 injections. Ocular movements were assessed before and after treatment initiation at 3, 6, and 10 days using the Kestenbaum limbus test. Inferential statistics were done using the chi-square test and the student t-test.

RESULTS

The average age of the participants in the study was 60.5 ± 6.3 years. Thirty-eight patients had sixth nerve palsy, and 12 patients had associated third nerve palsy. Thirty-eight subjects had poorly controlled diabetes. The mean enhancement in movements was 0.75 ± 0.3 in group A and 1.04 ± 0.5 in group B, with a p value of 0.026, demonstrating the statistically significant difference between both groups.

CONCLUSION

This study infers that the ocular movements were significantly improved with vitamin therapy. Treating diabetic neuropathy solely with vitamin supplementation indirectly addresses nutritional deficiencies, potentially accelerating diabetes-related complications and enhancing quality of life.

Low concentration of serum vitamin B12 may be a strong predictor of large-artery atherosclerosis stroke: A case-control study

INTRODUCTION

Identifying controllable risk factors for large-artery atherosclerosis (LAA) stroke is crucial due to its significant role as a leading cause of ischemic stroke. We aimed to validate the correlation of serum vitamin B12 with LAA stroke.

METHODS

Inpatients with LAA stroke and healthy controls were retrospectively collected for a case-control study from January 2020 to May 2022. Serum vitamin B12 concentration and other blood indicators, demographic, lifestyle factors and comorbidities were investigated. Logistic regression analysis was used to identify the correlation of serum vitamin B12 concentrations with LAA stroke, meanwhile adjusted for confounding factors.

RESULTS

Patients with LAA stroke had significantly lower serum vitamin B12 concentrations in comparison to those of controls. In the fully adjusted model, vitamin B12 (per 1 interquartile range increase, odds ratio [OR] = 0.84, 95 % confidence interval [CI]: 0.77-0.91), vitamin B12 < 200 pg/mL (OR=7.70, 95 %CI: 2.19-27.03) and vitamin B12 < 300 pg/mL (OR=4.19, 95 %CI: 1.82-9.66) were independently factors for LAA stroke. Furthermore, the optimal cut-off values for vitamin B12 to predict LAA stroke were 305.25 pg/mL (area under the curve [AUC] = 0.71) when unadjusted and 308.25 pg/mL when adjusted for age and sex (AUC=0.68). Lower vitamin B12 concentrations were significantly associated with male sex, smoking, older age, higher neutrophil count, higher creatinine, lower folate and higher total homocysteine.

CONCLUSION

Results indicate that low concentration of serum vitamin B12 may be a strong predictor for the risk of LAA stroke.

Vitamin B12 Deficiency in Patients Taking Metformin: Pathogenesis and Recommendations

Metformin is a cornerstone therapy for type 2 diabetes mellitus due to its glucose-lowering efficacy and additional benefits such as reducing cardiovascular mortality. However, accumulating evidence suggests an association between long-term metformin use and vitamin B12 deficiency, which can lead to serious clinical consequences. This review aims to synthesize current knowledge on the pathogenesis, prevalence, clinical implications, and management of metformin-induced vitamin B12 deficiency. Given the significant clinical implications, it is crucial to monitor and manage vitamin B12 levels in patients using metformin. This review emphasizes the importance of early detection and supplementation to prevent adverse outcomes. By analyzing the current evidence, the review aims to inform healthcare professionals about best practices for managing vitamin B12 deficiency in patients on metformin, offering insights to guide future clinical practices and research directions.

Vitamin B12 deficiency in diabetic patients treated with metformin: A narrative review

Metformin is the most prescribed oral hypoglycemic drug and is considered by many health practitioners as the first-line treatment for non-insulin-dependent diabetes mellitus (T2DM). It is used either as a monotherapy or adjuvant to other anti-hyperglycemic agents. Most of its side effects are usually mild and self-limiting. However, several studies have shown an association between the use of metformin and low vitamin B12 levels in diabetic patients. The current review aimed to provide a literature review of the current published reports on the association, the possible mechanisms, and the related individualized risk factors that might lead to this incidence. The most accepted mechanism of the effect of metformin on vitamin B12 level is related to the absorption process where metformin antagonism of the calcium cation and interference with the calcium-dependent IF-vitamin B12 complex binding to the ileal cubilin receptor. In addition, many risk factors have been associated with the impact of metformin on vitamin B12 levels in diabetic patients such as dose and duration where longer durations showed a greater prevalence of developing vitamin B12 deficiency. Male patients showed lower levels of vitamin B12 compared to females. Black race showed a lower prevalence of vitamin B12 deficiency in metformin-treated patients. Moreover, chronic diseases including T2DM, hyperlipidemia, coronary artery disease, polycystic ovary disease (PCOD), obesity, and metformin therapy were significantly associated with increased risk of vitamin B12 deficiency.

Vitamin B12 deficiency in diabetic patients treated with metformin: A cross-sectional study

Metformin is a cornerstone medication in the management of type 2 diabetes. Metformin is safe, effective, and inexpensive; however, it is associated with vitamin B12 deficiency. This study set out to evaluate the rate of vitamin B12 deficiency in Vietnamese patients with type 2 diabetes who were treated with metformin and to investigate factors associated with vitamin B12 deficiency. This is a cross-sectional study that was conducted in Vinmec Central Park Hospital from February to June 2023. The clinical and paraclinical characteristics of the participants were recorded, and the levels of vitamin B12 and folate were measured. The rate of vitamin B12 deficiency in patients treated with metformin was found to be 18.6%. Further, the duration of diabetes, duration of metformin use, metformin dose, and hemoglobin levels were statistically associated with vitamin B12 deficiency with OR (95% CI) = 1.12 (1.03-1.19), 1.01 (1.00-1.02), 1.002 (1.001-1.002), 0.74 (0.55-0.99), respectively. After adjusting for covariates, a metformin dose greater than the median dose remained the only parameter associated with vitamin B12 deficiency, with OR (95% CI) = 4.10 (1.62-10.36). Moreover, when combining both long-term use of metformin and a metformin dose greater than the median dose, the OR increased to 5.25 (95% CI: 2.11-13.15). These results demonstrate that vitamin B12 deficiency in patients treated with metformin is quite prevalent in Vietnam and that those with long-term use of metformin (48 months or more) and high metformin dose (1000 mg/day or more) are at high risk of experiencing this adverse effect and so require screening.

Expert consensus guidelines for community pharmacists in the management of diabetic peripheral neuropathy with a combination of neurotropic B vitamins

This consensus guidance is for community pharmacists in diabetic peripheral neuropathy (DPN) management with a combination of neurotropic B vitamins. A multidisciplinary team including endocrinology, neurology, and pharmacy from Thailand discussed and aligned the practical scheme of DPN management in the community pharmacy setting, using the literature review and having face-to-face meeting. Five major statements have been endorsed as consensus recommendations for DPN care with strong acknowledgment. The aims of DPN management included reducing symptoms and the risk of complications, minimising adverse reactions from treatment regimens, and improving patients' knowledge and adherence to the treatment strategies. An initial screening process using a 7 items interview of Douleur Neuropathique 4 (DN4) questionnaire should be implemented to identify patients at risk of developing DPN. Subsequently, pharmacologic, and non-pharmacologic treatment should be employed based on patient-centered care. An interesting approach is combination of neurotropic B vitamins, which may be used as monotherapy or combination therapy to control DPN symptoms. The combined therapy potentially exhibits a synergistic effect and improves patient adherence. The consensus would be further considered in context of harmonisation of routine practice and country requirements.

Neuroprotective role of vitamin B12 in streptozotocin-induced type 1 diabetic rats

Chronic hyperglycemia-induced neuropathological changes include neuronal apoptosis, astrogliosis, decrease in neurotrophic support, impaired synaptic plasticity, and impaired protein quality control (PQC) system. Vitamin B12 is indispensable for neuronal development and brain function. Several studies reported the neuroprotective effect of B12 supplementation in diabetic patients. However, the underlying molecular basis for the neuroprotective effect of B12 supplementation in diabetes needs to be thoroughly investigated. Two-month-old Sprague-Dawley rats were randomly assigned into three groups: Control (CN), diabetes (D; induced with streptozotocin; STZ), and diabetic rats supplemented with vitamin B12 (DBS; vitamin B12; 50 μg/kg) for four months. At the end of 4 months of experimentation, the brain was dissected to collect the cerebral cortex (CC). The morphology of CC was investigated with H&E and Nissl body staining. Neuronal apoptosis was determined with TUNEL assay. The components of neurotrophic support, astrogliosis, synaptic plasticity, and PQC processes were investigated by immunoblotting and immunostaining methods. H& E, Nissl body, and TUNEL staining revealed that diabetes-induced neuronal apoptosis and degeneration. However, B12 supplementation ameliorated the diabetes-induced neuronal apoptosis. Further, B12 supplementation restored the markers of neurotrophic support (BDNF, NGF, and GDNF), and synaptic plasticity (SYP, and PSD-95) in diabetic rats. Interestingly, B12 supplementation also attenuated astrogliosis, ER stress, and ameliorated autophagy-related proteins in diabetic rats. Overall, these findings suggest that B12 acts as a neuroprotective agent by inhibiting the neuropathological changes in STZ-induced type 1 diabetes. Thus, B12 supplementation could produce beneficial outcomes including neuroprotective effects in diabetic patients.

Vitamin B12 insufficiency and deficiency: a review of nondisease risk factors

Vitamin B12 deficiency and insufficiency can lead to both hematological and neurological impairments. This review examines nondisease causes and risk factors associated with dietary availability, such as eating habits, food processing, cooking techniques, and bioavailability, as well as increased physiological needs and iatrogenic factors linked to medication use or surgical procedures. As a result of these nondisease influences, groups at higher risk include vegans, vegetarians, older adults, individuals with limited diets, breastfed and preterm infants, and those who primarily consume foods prepared or cooked in ways that reduce vitamin B12 content, as well as individuals on certain medications or who have undergone specific surgeries. Recognizing these diverse risk factors helps develop strategies for prevention and intervention to minimize the adverse health effects related to B12 deficiency and insufficiency.

Vitamin B12 Deficiency among Metformin Treated Type 2 Diabetic Mellitus Patients Visiting the Department of Medicine of a Tertiary Care Centre

Introduction

About 424.9 million people worldwide are affected by Diabetes mellitus. Prevalence among people 20-79 years old in Nepal was 4% in 2017. It is associated with microvascular and macrovascular complications such as peripheral neuropathy leading to risk of foot ulcers and amputation, and impaired sensation in their feet. The study aimed to find the prevalence of vitamin B12 deficiency among metformin-treated type 2 diabetic patients visiting the Department of Medicine of a tertiary care centre.

Methods

A descriptive cross-sectional study was conducted in a tertiary care centre between 24 May 2021 to 24 May 2022 after obtaining ethical approval from the Institutional Review Committee. Patients who visited the Department of Medicine and gave informed consent were included in the study. Patients with underlying comorbidities were excluded from the study. A convenience sampling method was used. The point estimate was calculated at a 95% Confidence Interval.

Results

Among 330 patients, vitamin B12 deficiency was seen in 33 (10%) (6.76-13.24, 95% Confidence Interval). Among them, 27 (81.82%) were male and 6 (18.18%) were female.

Conclusions

The prevalence of vitamin B12 deficiency was found to be higher than other studies done in similar settings.

Keywords

diabetic neuropathy; metformin; type 2 diabetes; vitamin B12.

Metformin-Induced Vitamin B12 Deficiency in Patients With Type-2 Diabetes Mellitus

Diabetes mellitus (DM) is the most common metabolic disease worldwide. Hence, the prevalence of the disease continues to increase across the globe. Metformin is used as a first-line oral hypoglycemic drug to keep control of type-2 DM (T2DM) in adults. Diabetic patients on metformin have been largely seen to be suffering from a deficiency of vitamin B12. It is a water-soluble vitamin mainly obtained from animal food like meat. At the basic cell level, it acts as a cofactor for enzymes essential for DNA synthesis and neuroprotection. As a result, vitamin B12 deficiency can show clinical effects such as progressive demyelination, peripheral neuropathy and haematological abnormalities (such as macrocytic anaemia and neutrophil hypersegmentation). Various studies also show a relation between vitamin B12 insufficiency and metformin-treated T2DM patients as decreased absorption of vitamin B12. There could be a severe complication of vitamin B12 deficiency in T2DM patients. The use of proton pump inhibitors, gastric bypass surgery, older patients and patients with a higher red blood cell turnover are factors that hasten the depletion of vitamin B12 reserves in the liver. Methylmalonic acid and homocysteine levels can be measured to identify vitamin B12 insufficiency at its early stage if blood vitamin B12 levels are borderline. The action of metformin on vitamin B12 absorption and its potential mechanisms of inhibition will be the main topics of discussion in this review. The review will also discuss how vitamin B12 deficiencies in T2DM patients using metformin affect their clinical results.

Relationship of Vitamin B12 Levels With Different Degrees of Obesity and Diabetes Mellitus

INTRODUCTION

The potential influence of micronutrient status on obesity should be considered. Nevertheless, previous research examining the relationship between serum vitamin B12 levels and obesity has yielded inconclusive results. The objective of this study was to investigate the associations between serum vitamin B12 levels and obesity and diabetes mellitus (DM) in a population consisting of persons aged 18 years and older.

METHODS

A retrospective case-control research was undertaken on a sample of 1024 individuals aged 18 years and older who were admitted to a tertiary healthcare facility (Recep Tayyip Erdoğan University Education and Research Hospital, Rize) for either overweight-related issues or routine check-ups. The primary objective of this study was to assess the B12 levels of these individuals. The researcher recorded the body mass index (BMI) and history of DM for all subjects.

RESULTS

The study comprised a total of 1024 participants, consisting of 834 females and 190 males. The levels of vitamin B12 in women were found to be 308±113 pg/mL, while in men, the levels were 304±125 pg/mL. The results of the statistical analysis indicate that there is no statistically significant disparity in vitamin B12 levels between males and females (p=0.748). There was a statistically significant positive correlation seen between age and B12 levels; however, the magnitude of this connection was found to be minor (p=0.000, R2=0.017). The study findings revealed that out of the 1,024 individuals evaluated, 179 individuals exhibited B12 levels below 200, while 845 individuals displayed vitamin B12 levels above 200. The study findings indicated that there was no statistically significant distinction observed in the occurrence of obesity and DM in relation to vitamin B12 deficiency (p = 0.938, p = 0.08, respectively).

CONCLUSION

The results of this study offer empirical support for the notion that there is no significant difference in vitamin B12 levels between individuals afflicted with obesity and diabetes and those unaffected by these conditions. Interestingly, it was shown that serum B12 levels exhibited a modest increase with advancing age.

Bidirectional association between diabetic peripheral neuropathy and vitamin B12 deficiency: Two longitudinal 9-year follow-up studies using a national sample cohort

AIM

This study aims to investigate the association among metformin use, vit B12 deficiency, and DPN occurrence in diabetes.

METHODS

This retrospective, propensity-matched cohort study was performed using National Health Insurance Service database - National Sample Cohort in South Korea. Study 1 analyzed DPN incidence according to vit B12 deficiency and study 2 analyzed vit B12 deficiency incidence according to the presence/absence of DPN. Moreover, we compared the results with respect to metformin use.

RESULTS

In study 1, DPN incidence per 10000 person-year (PY) was 179.7 and 76.6 in the vit B12 and non-vit B12 deficiency groups, respectively. The adjusted HR was 1.32 (95% CI; 1.21-1.44, P < 0.05) and metformin use elicited a more significant effect of DPN occurrence in patient with vit B12 deficiency (HR: 5.76 (95% CI; 5.28-6.29). In study 2, vit B12 deficiency incidence per 10000 PY was 250.6 and 129.4 in the DPN and non-DPN groups, respectively. The adjusted HR was 2.44 (95% CI; 2.24-2.66, P < 0.05), however, metformin prescription was associated with the reduced incidence of vit B12 deficiency in DPN patients (HR 0.68 (95% CI; 0.62-0.74, P < 0.05).

CONCLUSION

DPN occurrence increased in diabetes with vit B12 deficiency and the incidence of vit B12 deficiency was also high in DPN patients. However, metformin showed opposite effects in both cohorts. Further studies clarifying the causal relationship among DPN occurrence, vit B12 deficiency, and metformin use are warranted.

Prevalence of vitamin B12 deficiency in type 2 diabetic patients taking metformin, a cross-sectional study in primary healthcare

Background

Several studies documented that metformin use contributes to vitamin B12 deficiency in patients with type 2 diabetes mellitus (T2DM). However, there has been a lack of data assessing this issue in Jordan.

Aims

Assess the vitamin B12 serum levels, frequency of vitamin B12 deficiency, and related factors among Jordanian patients with T2DM patients treated with metformin.

Methods

a total of 447 subjects attending a primary health care center were included in this cross-sectional study consisting of T2DM patients who use metformin and a control group of non-diabetics. Serum B12 levels were evaluated and B12 deficiency was defined as serum B12 levels ≤ 200 pmol/L. Associations of B12 serum levels or B12 deficiency with other factors like gender, age, and duration of T2DM were analyzed.

Results

There was no significant difference in serum B12 levels nor the frequency of vitamin B12 deficiency between T2DM metformin-treated patients and control groups. Among metformin-treated patients there was no difference relating to age, type 2 diabetes mellitus duration, proton pump inhibitors use, and metformin use (duration, dose) between patients with or without B12 deficiency.

Conclusion

The prevalence of vitamin B12 deficiency among T2DM patients on metformin treatment in this study was high (48.9%). However, the treatment with metformin and the dose of metformin use was not associated with vitamin B12 deficiency.

The effects of daily dose and treatment duration of metformin on the prevalence of vitamin B12 deficiency and peripheral neuropathy in Chinese patients with type 2 diabetes mellitus: A multicenter cross-sectional study

AIMS

To evaluate the prevalence of vitamin B12 deficiency in Chinese patients with type 2 diabetes mellitus receiving metformin treatment and to investigate the effects of metformin daily dose and treatment duration on the prevalence of vitamin B12 deficiency and peripheral neuropathy (PN).

MATERIALS AND METHODS

In this multicenter cross-sectional study, 1027 Chinese patients who had been taking ≥1000 mg/day metformin for ≥1 year were enrolled using proportionate stratified random sampling based on daily dose and treatment duration. Primary measures included the prevalence of vitamin B12 deficiency (<148 pmol/L), borderline B12 deficiency (148 pmol/L-211 pmol/L), and PN.

RESULTS

The prevalence of vitamin B12 deficiency, borderline deficiency, and PN were 2.15%, 13.66%, and 11.59%, respectively. Patients receiving ≥1500 mg/day metformin had significantly higher prevalence of borderline vitamin B12 deficiency (16.76% vs. 9.91%, p = .0015) and serum B12 ≤221 pmol/L (19.25% vs. 11.64%, p < .001) than patients receiving <1500 mg/day metformin. No difference was found in prevalence of borderline vitamin B12 deficiency (12.58% vs. 15.49%, p = .1902) and serum B12 ≤221 pmol/L (14.91% vs. 17.32%, p = .3055) between patients receiving metformin for ≥3 and <3 years. Patients with vitamin B12 deficiency had numerically higher PN prevalence (18.18% vs. 11.27%, p = .3192) than patients without it. Multiple logistic analyses revealed that HbA1c and metformin daily dose were associated with the prevalence of borderline B12 deficiency and B12 ≤221 pmol/L.

CONCLUSIONS

High daily dosage (≥1500 mg/day) played an important role in metformin-associated vitamin B12 deficiency while not contributing to the risk of PN.

Association between Acid-Lowering Agents, Metformin, and Vitamin B12 among Boston-Area Puerto Ricans

BACKGROUND

Vitamin B12 involves several physiological functions, and malabsorption is reported with medication use.

OBJECTIVES

Studies have reported an inverse association between the use of metformin or acid-lowering agents (ALAs), such as proton pump inhibitors, histamine 2 receptor antagonists, and blood vitamin B12 concentration, because of malabsorption. The concomitant use of these medications is underreported. We sought to examine these associations in a cohort of Boston-area Puerto Rican adults.

METHODS

This analysis was conducted within the Boston Puerto Rican Health Study (BPRHS), an ongoing longitudinal cohort that enrolled 1499 Puerto Rican adults aged 45-75 y at baseline. Our study comprised 1428, 1155, and 782 participants at baseline, wave2 (2.2 y from baseline), and wave3 (6.2 y from baseline), respectively. Covariate-adjusted linear and logistic regression was used to examine the association between baseline medication use and vitamin B12 concentration or deficiency (vitamin B12 <148 pmol/L or methylmalonic acid >271 nmol/L), and long-term medication use (continuous use for ∼6.2 y) and wave3 vitamin B12 concentration and deficiency. Sensitivity analyses were done to examine these associations in vitamin B12 supplement users.

RESULTS

At baseline, we observed an association between metformin use (β = -0.069; P = 0.03) and concomitant ALA and metformin use (β = -0.112; P = 0.02) and vitamin B12 concentration, but not a deficiency. We did not observe associations between ALA, proton pump inhibitors, or histamine 2 receptor antagonists, individually, with vitamin B12 concentration or deficiency.

CONCLUSIONS

These results suggest an inverse relationship between metformin, concomitant ALA, metformin use, and serum vitamin B12 concentration.

The correlation between vitamin B12 and folate levels and bone mineral density among the Saudi population in a primary care setting

Purpose

Bone health and osteoporosis are significant health problems in Saudi Arabia. Approximately 40%-50% of women and 25%-33% of men sustain osteoporotic fractures in their lifetimes. Hence, identifying the risk factors for osteoporosis is crucial in reducing the incidence of fractures.

Materials and Methods

We retrospectively reviewed the electronic medical records of 557 patients (female 60%, male 40%) aged ≥18 years (mean age, 66.53 years [standard deviation ± 14.169]) who underwent bone mineral density (BMD) scans at the Department of Family Medicine & Polyclinics, King Faisal Specialist Hospital and Research Centre (KFSH&RC) between January 2004 and June 2019. Data collected included demographics, BMD values, vitamin B12 levels, and folate levels.

Results

This study indicated that the prevalence rates of vitamin B12 and folate deficiencies among the study population were 8.4% and 1.3%, respectively. There was a statistically significant association between vitamin B12 levels and fracture risk (P =0.044). However, no statistically significant correlation was observed between BMD at either site (lumbar spine or femoral neck) and vitamin B12 (P =0.926.,070) and folate levels (P =.683.,79). BMD showed a significant positive correlation with body mass index at the lumbar spine and femoral neck (P = 0.000). There was no statistically significant association between vitamin B12 levels and the use of metformin (P =.26).

Conclusion

Vitamin B12 is associated with fracture risk; however, vitamin B12 and folate levels are not correlated to BMD (femoral neck and lumbar spine).

The Correlation between Metformin Use and Incident Dementia in Patients with New-Onset Diabetes Mellitus: A Population-Based Study

The evidence of metformin's effect on dementia is conflicting. This study investigates the association between metformin use and the risk of dementia among patients with diabetes mellitus (DM). This study included patients with new-onset DM between 2002 and 2013. We divided the patients into patients who used metformin and patients who did not. Two models were used to assess metformin use: the cumulative defined daily dose (cDDD) of metformin use and the intensity of metformin use. This study with 3-year and 5-year follow-ups investigated the risk of dementia among patients with DM who used metformin. At the 3-year follow-up, patients who received cDDD < 300 had an odds ratio (OR) of developing dementia of 0.92 (95% confidence interval [CI] = 0.89-0.96); patients who used metformin at intensities <10 and 10-25 DDD/month had ORs of 0.92 (95% CI: 0.87-0.97) and 0.92 (95% CI: 0.85-1.00), respectively. Metformin use at cDDD 300-500 (OR = 0.80, 95% CI = 0.56-1.15) or >500 (OR = 1.48, 95% CI = 0.48-4.60) or at an intensity >25 DDD/month (OR = 0.84, 95% CI = 0.60-1.18) were not associated with an incident of dementia. There were similar results at the 5-year follow-up. Patients with a low intensity of metformin use had a lower risk of dementia. However, higher doses of metformin with higher intensity exhibited no protective role in dementia. Prospective clinical trials are warranted to evaluate the actual underlying mechanisms between metformin dosage and the risk of dementia.

Determinants of vitamin B12 deficiency in patients with type-2 diabetes mellitus - A primary-care retrospective cohort study

BACKGROUND

Like many developed nations, the prevalence of both older people and type-2 diabetes mellitus (T2DM) in Singapore is rising. This demographic shift predisposes the population to greater risks of both frailty and its complications that can be further aggravated by vitamin B12 deficiency -a highly prevalent associated variable that is potentially modifiable. Indeed, B12 deficiency adversely impacts the neuro-cognitive, haematological, and even the immune systems; jeopardizing our aspirations for successful aging. Despite this, many patients with T2DM in primary care remain unscreened due to a lack of clear guidelines for regular B12 screening. We therefore investigated the determinants of B12 deficiency in community-dwelling patients with T2DM, with the aim of profiling patients most in need of B12-deficiency screening.

METHODS

B12 deficiency was evaluated using a retrospective cross-sectional cohort of 592 primary-care patients with T2DM, recruited from 2008 to 2011 from a Polyclinic in Singapore.

RESULTS

B12 deficiency (serum B12 < 150 pmol/L) was present in 164 (27.7%) patients and was associated with a higher "metformin daily dose" (OR = 2.79; 95% CI, 2.22-3.48, P < 0.001); "age ≥ 80 years" (OR = 2.86; 95% CI, 1.31-6.25, P = 0.008); "vegetarianism" (OR = 21.61; 95% CI, 4.47-104.44, P < 0.001); and "folate deficiency" (OR = 2.04; 95% CI, 1.27-3.28, P = 0.003). Conversely, "Prescribed B12 supplementation" was associated with a lower odds of B12 deficiency (OR = 0.37; 95% CI: 0.22-0.61, P < 0.001). The area under the receiver operating characteristic curve was 0.803 (95% CI: 0.765-0.842). "Metformin daily dose" correlated interchangeably with "Metformin 1-year cumulative dose" (r = 0.960; P < 0.01), and also associated linearly with "duration of diabetes" (B = 0.113, P < 0.0001). Independent of the duration of T2DM, 29.3% of the B12-deficient patients needed > 1 screening test before the detection of B12 deficiency.

CONCLUSIONS

Primary-care screening for B12 deficiency should be part of the annual laboratory review of patients with T2DM regardless of the duration of T2DM -especially when they are prescribed ≥ 1.5 g/day of metformin; ≥ 80 years old; vegetarian; and not prescribed B12 supplementation. Concurrent evaluation for associated folate (vitamin B9) deficiency is essential when addressing T2DM-associated B12 deficiencies. Current "Metformin daily dose" is an accurate proxy of both cumulative metformin exposure and duration of T2DM.

Vitamin B12 levels in type 2 diabetic patients on Metformin compared to those never on Metformin: a cross sectional study in Tunisia

INTRODUCTION

Recent studies suggest that long-term use of metformin may decrease the plasma level of Vitamin B12.

AIM

To assess the Vitamin B12 status in Tunisian patients treated with metformin and to study its association with the dose, the duration of metformin use, and the clinical and biological parameters.

METHODS

It was a cross-sectional, comparative study on 200 type 2 diabetic (T2D) patients. A vitamin B12 assay was performed with a neurological examination and a Complete blood count.

RESULTS

The mean level of Vitamin B12 assayed in our population was 398.5±188.3 pg/ml. The serum Vitamin B12 levels were 356.9±153.5 pg/ml in the metformin group and 460.9±218.6 pg/ml in the no metformin group (p <0.01). Metformin intake was associated with an increased prevalence of Vitamin B12 deficiency and borderline level. The level of Vitamin B12 was correlated with the duration and the dose of metformin. Vitamin B12 deficiency was significantly associated with anemia, macrocytosis, and diabetic neuropathy. Multivariate analysis concluded that Vitamin B12 deficiency was significantly associated with the duration, cumulative metformin dose, clinical neuropathy, anemia, and macrocytosis.

CONCLUSION

Our study showed an association of Vitamin B12 deficiency with the dose and duration of metformin intake in Tunisian T2D patients, with hematological and neurological repercussions.

The potential of tailoring the gut microbiome to prevent and treat cardiometabolic disease

Despite milestones in preventive measures and treatment, cardiovascular disease (CVD) remains associated with a high burden of morbidity and mortality. The protracted nature of the development and progression of CVD motivates the identification of early and complementary targets that might explain and alleviate any residual risk in treated patients. The gut microbiota has emerged as a sentinel between our inner milieu and outer environment and relays a modified risk associated with these factors to the host. Accordingly, numerous mechanistic studies in animal models support a causal role of the gut microbiome in CVD via specific microbial or shared microbiota-host metabolites and have identified converging mammalian targets for these signals. Similarly, large-scale cohort studies have repeatedly reported perturbations of the gut microbial community in CVD, supporting the translational potential of targeting this ecological niche, but the move from bench to bedside has not been smooth. In this Review, we provide an overview of the current evidence on the interconnectedness of the gut microbiome and CVD against the noisy backdrop of highly prevalent confounders in advanced CVD, such as increased metabolic burden and polypharmacy. We further aim to conceptualize the molecular mechanisms at the centre of these associations and identify actionable gut microbiome-based targets, while contextualizing the current knowledge within the clinical scenario and emphasizing the limitations of the field that need to be overcome.

Prevalence of Vitamin B12 Deficiency in Type 2 Diabetes Mellitus Patients on Metformin Therapy

Background Long-term metformin treatment in individuals with type 2 diabetes mellitus causes vitamin B12 insufficiency, which is typically neglected, undetected, and under-treated. A severe deficit may cause life-threatening neurological problems. This study assessed the prevalence of vitamin B12 deficiencies among T2DM patients and its factors at a tertiary hospital in the Tamil Nadu district of Salem. Materials and Methods This is an analytical cross-sectional study conducted in a tertiary care hospital in the Salem district, Tamil Nadu, India. Patients with type 2 diabetes mellitus who were prescribed metformin at the outpatient department of general medicine took part in the trial. Our research instrument was a structured questionnaire. We used a questionnaire containing information on sociodemographic characteristics, metformin use among diabetic mellitus patients, diabetes mellitus history, lifestyle behaviors, anthropometric measurement, examination findings, and biochemical markers. Prior to administering the interview schedule, each participant's parents provided written informed consent. A thorough medical history, physical exam, and anthropometric examination were performed. Data were entered in Microsoft Excel (Microsoft Corporation, Redmond, WA) and analyzed using SPSS version 23 (IBM Corp., Armonk, NY). Results Among the study participants, we diagnosed nearly 43% of diabetes cases in participants between the ages of 40-50 years, while we diagnosed 39% aged under 40 years. Nearly 51% had diabetes for 5-10 years, while only 14% had diabetes for over 10 years. In addition, 25% of the study sample had a positive family history of type 2 diabetes. Nearly 48% and 13% of the study group had been on metformin for 5-10 years and >10 years, respectively. The majority, 45%, were found to take 1000 mg of metformin per day, whereas just 15% take 2 g per day. In our study, the prevalence of vitamin B12 insufficiency was 27%, and nearly 18% had borderline levels. The duration of diabetes mellitus, the duration of metformin intake, and the dose of metformin were statistically significant (p-value = 0.05) among the variables associated with diabetes mellitus and vitamin B12 deficiency. Conclusion The results of the study show that a deficiency in vitamin B12 increases the likelihood that diabetic neuropathy would worsen. Therefore, individuals with diabetes who take larger dosages of metformin (more than 1000mg) for an extended period must have their vitamin B12 levels monitored often. Preventative or therapeutic vitamin B12 supplementation can mitigate this issue.

Metformin treatment and risk of diabetic peripheral neuropathy in patients with type 2 diabetes mellitus in Beijing, China

BACKGROUND

Metformin treatment is associated with vitamin B12 deficiency, which is a risk factor for neuropathy. However, few studies have examined the relationship between metformin treatment and diabetic peripheral neuropathy (DPN), and the available findings are contradictory. We aimed to assess whether metformin treatment is associated with DPN in patients with type 2 diabetes mellitus (T2DM) in Beijing, China.

METHODS

All patients with newly diagnosed T2DM between January 2010 and September 2012 in the Medical Claim Data for Employees database were included. Metformin treatment was defined as any record of metformin prescription. The average daily dose of metformin during follow-up was calculated. DPN was defined as DPN admissions occurring after a diagnosis of T2DM in the database. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards models.

RESULTS

Among 49,705 T2DM patients, 1,933 DPN events were recorded during a median follow-up of 6.36 years. The crude incidence rates were 7.12 and 3.91 per 1000 person-years for patients treated with metformin (N=37,052) versus those not treated (N=12,653). Patients treated with metformin had an 84% increased risk of DPN compared with patients not using metformin (HR, 1.84; 95% CI, 1.62, 2.10). The daily dose was positively associated with DPN risk (HR, 1.48; 95% CI, 1.46, 1.51; P for trend <0.001). The risk of DPN was 1.53-fold (1.30, 1.81) and 4.31-fold (3.76, 4.94) higher in patients with daily doses of 1.0-2.0 g and >2.0 g, respectively, than in patients who did not receive treatment. Patients aged less than 60 years had a higher risk of DPN (P<0.05 for interaction test). Among patients taking vitamin B12 at baseline, there was no increased risk of DPN in the metformin group (1.92: 0.79, 4.69).

CONCLUSIONS

In Chinese patients with T2DM, metformin treatment was associated with an increased risk of DPN admission and this risk responds positively to the daily dose of metformin. In particular, metformin use was a major risk factor for DPN in younger patients. Concomitant use of vitamin B12 may avoid the increased risk of DPN associated with metformin use.

Metformin in therapeutic applications in human diseases: its mechanism of action and clinical study

Metformin, a biguanide drug, is the most commonly used first-line medication for type 2 diabetes mellites due to its outstanding glucose-lowering ability. After oral administration of 1 g, metformin peaked plasma concentration of approximately 20-30 μM in 3 h, and then it mainly accumulated in the gastrointestinal tract, liver and kidney. Substantial studies have indicated that metformin exerts its beneficial or deleterious effect by multiple mechanisms, apart from AMPK-dependent mechanism, also including several AMPK-independent mechanisms, such as restoring of redox balance, affecting mitochondrial function, modulating gut microbiome and regulating several other signals, such as FBP1, PP2A, FGF21, SIRT1 and mTOR. On the basis of these multiple mechanisms, researchers tried to repurpose this old drug and further explored the possible indications and adverse effects of metformin. Through investigating with clinical studies, researchers concluded that in addition to decreasing cardiovascular events and anti-obesity, metformin is also beneficial for neurodegenerative disease, polycystic ovary syndrome, aging, cancer and COVID-19, however, it also induces some adverse effects, such as gastrointestinal complaints, lactic acidosis, vitamin B12 deficiency, neurodegenerative disease and offspring impairment. Of note, the dose of metformin used in most studies is much higher than its clinically relevant dose, which may cast doubt on the actual effects of metformin on these disease in the clinic. This review summarizes these research developments on the mechanism of action and clinical evidence of metformin and discusses its therapeutic potential and clinical safety.

[Cross-Sectional Study on Adverse Effects of Metformin Hydrochloride on 130 Patients Type 2 Diabetic Admitted to Medical Center and Diabetes Home of Sidi Bel-Abbès]

INTRODUCTION

MetforminHydrochloride is an antidiabetic used for many years, currently; it considered the first choice in treatment of type 2 diabetes (T2D). It decreases insulin resistance, does not induce hypoglycaemia, increases glucose utilization in the liver and skeletal muscle, and decreases hepatic glucose production. Its adverse effects (AE) are gastrointestinal, decrease in vitamin B12 absorption, abnormalities of hemogram and rarely skin reactions. The objective of this study was to report the type and frequency of AEs of MetforminHydrochloride used in the therapeutic management of T2D patients admitted to the medical center and the diabetes home of Sidi Bel-Abbès in Algeria.

MATERIALS AND METHODS

A cross-sectional descriptive study was carried out over a period of four months, from January 1st, 2017 to April 30th, 2017, involving 130 patients treated with MetforminHydrochloride consulting at Mimoun City Diabetes Home and Gambetta Diabetes Center in the town of Sidi Bel-Abbès. The primary outcome measure was the determination of the type and frequency of AEs related to normal dosages or overdose use of MetforminHydrochloride in T2D. Data were collected from patient records, using a questionnaire, and analyzed using Statistical Package for the Social Sciences, version 20 software.

RESULTS

130 patients were included, including 82 women, with a mean age of 51.08±8.85 years (30-66). One hundred and ninety-eight (198) AEs were reported, an average of 1.52 AEs per patient. Among them, 95 (47.98%) AEs are digestive disorders (30.77% of patients suffered from diarrhea, 10.77% had nausea and vomiting, 8.46% suffered from abdominal pain and bloating, 3.85% lost their taste, 7.69% complained of epigastric cramps and 11.54% of anorexia), 29 (14.65%) AEs are hypoglycaemia, 73 (36.87%) AEs are other symptoms and 1 (0.50%) EI is vitamin B12 deficiency and no cases of lactic acidosis or allergic reaction were reported. Five (3.85%) patients had a total and lasting intolerance to MetforminHydrochloride leading to its discontinuation following persistent diarrhoea.

CONCLUSION

AEs of MetforminHydrochloride used in the management of T2D patients consulting at the medical center and the Diabetes home of Sidi Bel-Abbès are frequent. Digestive disorders were the most frequent, diarrhea was very frequent and led to discontinuation of treatment in 3.85% of T2D patients, followed by nausea and vomiting, then abdominal pain, bloating and epigastric cramps, and rarely taste metallic. Hypoglycaemia was frequent following its association with insulin, the onset of headaches and fatigue were frequent, but no case of lactic acidosis or allergic reaction was reported. Due to a lack of means, the dosage of homocysteine and methylmalonic acid had not been carried out to confirm the vitamin B12 deficiency in the patient whose level was less than 200ng/mL. A precise assessment of the imputability of reported AEs is necessary.

Effect of Metformin on Vitamin B12 Deficiency in Patients With Type 2 Diabetes Mellitus and Factors Associated With It: A Meta-Analysis

The current meta-analysis aims to explore the effect of metformin use on vitamin B12 deficiency in patients with type 2 diabetes mellitus (T2DM) and the factors associated with it. This meta-analysis followed the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines and the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines. We searched PubMed and EMBASE from January 1, 2010, to October 31, 2022, to collect the studies that reported the effect of metformin on the deficiency of vitamin B12 in patients with T2DM and the factors associated with it. A total of 17 studies were included in the current meta-analysis. Among all the included studies, 13 were cross-sectional studies, 3 were retrospective cohorts, and one was a case-control study. The pooled rate of deficiency of vitamin B12 in patients receiving metformin (23.16%) was significantly higher compared to patients who were not on metformin (17.4%) (OR: 2.95, 95% CI: 2.18-4.00, p-value: 0.001). Factors significantly associated with vitamin B12 deficiency in patients with T2DM and receiving metformin include the duration of metformin use and a greater dose of metformin. In conclusion, our meta-analysis found that the prevalence of vitamin B12 deficiency is greater in patients receiving metformin compared to patients who did not receive metformin. Given the importance of vitamin B12 in nutrition, metformin-induced B12 decrease may be harmful to patients with T2DM. Supplemental vitamin B12 may be advantageous for those on metformin.

Metformin: Is it a drug for all reasons and diseases?

Metformin was first used to treat type 2 diabetes in the late 1950s and in 2022 remains the first-choice drug used daily by approximately 150 million people. An accumulation of positive pre-clinical and clinical data has stimulated interest in re-purposing metformin to treat a variety of diseases including COVID-19. In polycystic ovary syndrome metformin improves insulin sensitivity. In type 1 diabetes metformin may help reduce the insulin dose. Meta-analysis and data from pre-clinical and clinical studies link metformin to a reduction in the incidence of cancer. Clinical trials, including MILES (Metformin In Longevity Study), and TAME (Targeting Aging with Metformin), have been designed to determine if metformin can offset aging and extend lifespan. Pre-clinical and clinical data suggest that metformin, via suppression of pro-inflammatory pathways, protection of mitochondria and vascular function, and direct actions on neuronal stem cells, may protect against neurodegenerative diseases. Metformin has also been studied for its anti-bacterial, -viral, -malaria efficacy. Collectively, these data raise the question: Is metformin a drug for all diseases? It remains unclear as to whether all of these putative beneficial effects are secondary to its actions as an anti-hyperglycemic and insulin-sensitizing drug, or result from other cellular actions, including inhibition of mTOR (mammalian target for rapamycin), or direct anti-viral actions. Clarification is also sought as to whether data from ex vivo studies based on the use of high concentrations of metformin can be translated into clinical benefits, or whether they reflect a 'Paracelsus' effect. The environmental impact of metformin, a drug with no known metabolites, is another emerging issue that has been linked to endocrine disruption in fish, and extensive use in T2D has also raised concerns over effects on human reproduction. The objectives for this review are to: 1) evaluate the putative mechanism(s) of action of metformin; 2) analyze the controversial evidence for metformin's effectiveness in the treatment of diseases other than type 2 diabetes; 3) assess the reproducibility of the data, and finally 4) reach an informed conclusion as to whether metformin is a drug for all diseases and reasons. We conclude that the primary clinical benefits of metformin result from its insulin-sensitizing and antihyperglycaemic effects that secondarily contribute to a reduced risk of a number of diseases and thereby enhancing healthspan. However, benefits like improving vascular endothelial function that are independent of effects on glucose homeostasis add to metformin's therapeutic actions.

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

Background

Vitamin B12 malabsorption is one of the side effects of long-term metformin intake. Prolonged vitamin B12 deficiency 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 deficiency 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 significant difference, p value < 0.001. There was a significant difference between study groups regarding HbA1c level (p value = 0.03). Peripheral neuropathy was significantly 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 significant deficiency. Peripheral neuropathy was significantly associated with poor glycemic control and female gender, but was not associated with vitamin B12 deficiency.

KDOQI US Commentary on the KDIGO 2020 Clinical Practice Guideline for Diabetes Management in CKD

In October 2020, KDIGO (Kidney Disease: Improving Global Outcomes) published its first clinical practice guideline directed specifically to the care of patients with diabetes and chronic kidney disease (CKD). This commentary presents the views of the KDOQI (Kidney Disease Outcomes Quality Initiative) work group for diabetes in CKD, convened by the National Kidney Foundation to provide an independent expert perspective on the new guideline. The KDOQI work group believes that the KDIGO guideline takes a major step forward in clarifying glycemic targets and use of specific antihyperglycemic agents in diabetes and CKD. The purpose of this commentary is to carry forward the conversation regarding optimization of care for patients with diabetes and CKD. Recent developments for prevention of CKD progression and cardiovascular events in people with diabetes and CKD, particularly related to sodium/glucose cotransporter 2 (SGLT2) inhibitors, have filled a longstanding gap in nephrology's approach to the care of persons with diabetes and CKD. The multifaceted benefits of SGLT2 inhibitors have facilitated interactions between nephrology, cardiology, endocrinology, and primary care, underscoring the need for innovative approaches to multidisciplinary care in these patients. We now have more interventions to slow kidney disease progression and prevent or delay kidney failure in patients with diabetes and kidney disease, but methods to streamline their implementation and overcome barriers in access to care, particularly cost, are essential to ensuring all patients may benefit.

RJX Improves Wound Healing in Diabetic Rats

BACKGROUND

We recently reported the clinical safety profile of RJX, a well-defined intravenous GMP-grade pharmaceutical formulation of anti-oxidant and anti-inflammatory vitamins as active ingredients, in a Phase 1 study in healthy volunteers (ClinicalTrials.gov Identifier: NCT03680105) (Uckun et al., Front. Pharmacol. 11, 594321. 10.3389/fphar.2020.594321). The primary objective of the present study was to examine the effects of GMP-grade RJX on wound and burn injury healing in diabetic rats.

METHODS

In the present study, a rat model of T2DM was used that employs HFD in combination with a single injection of STZ intraperitoneally (i.p) at a moderate dose level (45 mg/kg). Anesthetized diabetic rats underwent full-thickness skin excision on the back or were subjected to burn injury via a heated brass probe and then started on treatments with normal saline (NS = vehicle) or RJX administered via intraperitoneal injections for three weeks.

FINDINGS

Notably, diabetic rats treated with the 1.25 mL/kg or 2.5 mL/kg RJX (DM+RJX groups) rapidly healed their wounds as fast as non-diabetic control rats. Inflammatory cell infiltration in the dermis along with fibrin and cell debris on the epithelial layer persisted for up to 14 days in the DM+NS group but not in RJX-treated groups. The histopathological score of wound healing on days 7 and 14 was better in diabetic rats treated with RJX than diabetic rats treated with NS and comparable to the scores for non-diabetic healthy rats consistent with an accelerated healing process. The residual wound area of RJX-treated rats was significantly smaller than that of NS-treated diabetic rats at each evaluation time point (P<0.001). The accelerating effect of RJX on diabetic wound healing was dose-dependent. We obtained similar results in the burn injury model. Our results demonstrate that RJX - at a dose level >10-fold lower than its clinical maximum tolerated dose (MTD) - accelerates the healing of excision wounds as well burn injury in diabetic rats.

Evolving Concepts of Type 2 Diabetes Management

With the concept of patient-centered care in mind, this article outlines the current diabetes medications available for glucose lowering and the characteristics of each of these medications that need to be considered in shared decision-making for durable and effective therapy. Important patient characteristics such as weight, risk for hypoglycemia, cost, social determinants of health, and medical literacy need to be considered. The evidence-base informing the use of antihyperglycemic agents has changed dramatically due to 2008 FDA guidance for cardiovascular safety and cardiorenal protection with antihyperglycemic agents. New evidence supports an approach to diabetes management that addresses pre-existing cardiorenal disease.

AMPK activators for the prevention and treatment of neurodegenerative diseases

INTRODUCTION

As the global population ages at an unprecedented rate, the burden of neurodegenerative diseases is expected to grow. Given the profound impact illness like dementia exert on individuals and society writ large, researchers, physicians, and scientific organizations have called for increased investigation into their treatment and prevention. Both metformin and aspirin have been associated with improved cognitive outcomes. These agents are related in their ability to stimulate AMP kinase (AMPK). Momordica charantia, another AMPK activator, is a component of traditional medicines and a novel agent for the treatment of cancer. It is also being evaluated as a nootropic agent.

AREAS COVERED

This article is a comprehensive review which examines the role of AMPK activation in neuroprotection and the role that AMPK activators may have in the management of dementia and cognitive impairment. It evaluates the interaction of metformin, aspirin, and Momordica charantia, with AMPK, and reviews the literature characterizing these agents' impact on neurodegeneration.

EXPERT OPINION

We suggest that AMPK activators should be considered for the treatment and prevention of neurodegenerative diseases. We identify multiple areas of future investigation which may have a profound impact on patients worldwide.

Adverse Effects of Medications on Micronutrient Status: From Evidence to Guidelines

Recent dietary reference intake workshops focusing on nutrient requirements in chronic disease populations have called attention to the potential adverse effects of chronic medication use on micronutrient status. Although this topic is mostly ill defined in the literature, several noteworthy drug-nutrient interactions (DNIs) are of clinical and public health significance. The purpose of this narrative review is to showcase classic examples of DNIs and their impact on micronutrient status, including those related to antidiabetic, anticoagulant, antihypertensive, antirheumatic, and gastric acid-suppressing medications. Purported DNIs related to other drug families, while relevant and worthy of discussion, are not included. Unlike previous publications, this review is primarily focused on DNIs that have sufficient evidence supporting their inclusion in US Food and Drug Administration labeling materials and/or professional guidelines. While the evidence is compelling, more high-quality research is needed to establish clear and quantitative relationships between chronic medication use and micronutrient status. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Serum vitamin B12 status of patients with type 2 diabetes mellitus on metformin: A single-center cross-sectional study from Bangladesh

BACKGROUND

Metformin use is a known cause of B12 deficiency in patients with type 2 DM (T2DM). Diabetic peripheral neuropathy (DPN) often has clinically indistinguishable clinical features of B12 deficiency-induced peripheral neuropathy (PN).

OBJECTIVE

The present study aims to assess serum vitamin B12 levels in patients with T2DM on metformin.

SUBJECTS AND METHODS

This cross-sectional study was conducted at a specialized endocrine outpatient clinic in Cumilla, Bangladesh, over six months from January 2020 to June 2020. Non-pregnant adults (≥18 years age) receiving metformin for T2DM for at least six months were evaluated for PN and assessed for serum B12 levels.

RESULTS

Among 90 subjects evaluated, 28 (31.1%) had B12 deficiency and 6 (6.7%) had borderline B12 deficiency; 56 (62.2%) had normal B12 levels. Study subjects with subnormal B12 used metformin for a longer duration [8.5 (7.0-14.0) vs. 5.0 (2.25-10.0) years, median (IQR), P = 0.006], gram-years of metformin use was higher in them [12.0 (7.9-14.0) vs. 5.75 (2.0-13.6) years, median (IQR), P = 0.005] and they had a higher mean corpuscular volume [85.9±7.2 vs. 82.4±6.4 fL, mean±SD, P = 0.020] compared to those having normal B12 levels. Serum B12 levels had a strong negative correlation with duration of metformin use and gram-years of metformin use. B12 status did not influence the presence and severity of PN.

CONCLUSIONS

A considerable number of patients with T2DM have subnormal B12 levels. Periodic screening for serum vitamin B12 level may be of clinical benefit in such patients.

Interaction between Metformin, Folate and Vitamin B12 and the Potential Impact on Fetal Growth and Long-Term Metabolic Health in Diabetic Pregnancies

Metformin is the first-line treatment for many people with type 2 diabetes mellitus (T2DM) and gestational diabetes mellitus (GDM) to maintain glycaemic control. Recent evidence suggests metformin can cross the placenta during pregnancy, thereby exposing the fetus to high concentrations of metformin and potentially restricting placental and fetal growth. Offspring exposed to metformin during gestation are at increased risk of being born small for gestational age (SGA) and show signs of ‘catch up’ growth and obesity during childhood which increases their risk of future cardiometabolic diseases. The mechanisms by which metformin impacts on the fetal growth and long-term health of the offspring remain to be established. Metformin is associated with maternal vitamin B₁₂ deficiency and antifolate like activity. Vitamin B₁₂ and folate balance is vital for one carbon metabolism, which is essential for DNA methylation and purine/pyrimidine synthesis of nucleic acids. Folate:vitamin B₁₂ imbalance induced by metformin may lead to genomic instability and aberrant gene expression, thus promoting fetal programming. Mitochondrial aerobic respiration may also be affected, thereby inhibiting placental and fetal growth, and suppressing mammalian target of rapamycin (mTOR) activity for cellular nutrient transport. Vitamin supplementation, before or during metformin treatment in pregnancy, could be a promising strategy to improve maternal vitamin B₁₂ and folate levels and reduce the incidence of SGA births and childhood obesity. Heterogeneous diagnostic and screening criteria for GDM and the transient nature of nutrient biomarkers have led to inconsistencies in clinical study designs to investigate the effects of metformin on folate:vitamin B₁₂ balance and child development. As rates of diabetes in pregnancy continue to escalate, more women are likely to be prescribed metformin; thus, it is of paramount importance to improve our understanding of metformin’s transgenerational effects to develop prophylactic strategies for the prevention of adverse fetal outcomes.

Long-Acting Metformin Vs. Metformin Immediate Release in Patients With Type 2 Diabetes: A Systematic Review

Background: Metformin, a commonly used antidiabetic medication, is available in both an immediate-release (IR) formulation and a long-acting formulation (metformin extended-release; XR). Objective: We performed a systematic review to compare the effectiveness, safety, and patient compliance and satisfaction between the metformin IR and XR formulations. Method: We searched for randomized control trials (RCTs) and observational studies comparing the effectiveness, safety, or patient compliance and satisfaction of metformin XR with metformin IR using the MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases. Following report screening, data collection, and risk of bias assessment, we separately pooled data from RCTs and observational studies using the Grading of Recommendation Assessment, Development, and Evaluation approach to rate the quality of evidence. Result: We included five RCTs, comprising a total of 1,662 patients, and one observational study, comprising 10,909 patients. In the meta-analyses, no differences were identified in outcomes of effectiveness and safety between the two forms of metformin (including change in HbA1c: mean difference (MD), 0.04%, 95% confidence interval [CI], -0.05-0.13%, fasting blood glucose: MD, -0.03 mmol/L, 95% CI, -0.22-0.15 mmol/L, postprandial blood glucose: MD, 0.50 mmol/L, 95% CI, -0.71-1.72 mmol/L, adverse events of abdominal pain: relative risk (RR), 1.15, 95% CI, 0.57-2.33, all-cause death (RR, 3.02, 95% CI 0.12-73.85), any adverse events (RR, 1.14, 95% CI 0.97-1.34), any adverse events leading to treatment discontinuation: RR, 1.51, 95% CI, 0.82-2.8, any gastrointestinal adverse events: RR, 1.09, 95% CI, 0.93-1.29, diarrhea: RR, 0.82, 95% CI, 0.53-1.27, flatulence: RR, 0.43, 95% CI, 0.15-1.23, nausea: RR, 0.97, 95% CI, 0.64-1.47, severe adverse events: RR, 0.64, 95% CI, 0.28-1.42, and vomiting: RR, 1.46, 95% CI, 0.6-3.56). Data from both the RCTs and the observational study indicate mildly superior patient compliance with metformin XR use compared with metformin IR use; this result was attributable to the preference for once-daily administration with metformin XR. Conclusion: Our systematic review indicates that metformin XR and IR formulations have similar effectiveness and safety, but that metformin XR is associated with improved compliance to treatment.

The Current and Potential Therapeutic Use of Metformin-The Good Old Drug

Metformin, one of the oldest oral antidiabetic agents and still recommended by almost all current guidelines as the first-line treatment for type 2 diabetes mellitus (T2DM), has become the medication with steadily increasing potential therapeutic indications. A broad spectrum of experimental and clinical studies showed that metformin has a pleiotropic activity and favorable effect in different pathological conditions, including prediabetes, type 1 diabetes mellitus (T1DM) and gestational diabetes mellitus (GDM). Moreover, there are numerous studies, meta-analyses and population studies indicating that metformin is safe and well tolerated and may be associated with cardioprotective and nephroprotective effect. Recently, it has also been reported in some studies, but not all, that metformin, besides improvement of glucose homeostasis, may possibly reduce the risk of cancer development, inhibit the incidence of neurodegenerative disease and prolong the lifespan. This paper presents some arguments supporting the initiation of metformin in patients with newly diagnosed T2DM, especially those without cardiovascular risk factors or without established cardiovascular disease or advanced kidney insufficiency at the time of new guidelines favoring new drugs with pleotropic effects complimentary to glucose control. Moreover, it focuses on the potential beneficial effects of metformin in patients with T2DM and coexisting chronic diseases.

Assessment of vitamin B12 deficiency and B12 screening trends for patients on metformin: a retrospective cohort case review

OBJECTIVES

Our study investigated the use of vitamin B12 testing in a large cohort of patients on metformin and assesses appropriateness and benefits of screening recommendations for vitamin B12 deficiency.

DESIGN

This retrospective cohort study included insured adult patients who had more than 1 year of metformin use between 1 January 2010 and 1 October 2016 and who filled at least two consecutive prescriptions of metformin to establish compliance. The comparison group was not exposed to metformin. Primary outcome was incidence of B12 deficiency diagnosed in patients on metformin. Secondary outcome was occurrence of B12 testing in the patient population on metformin. Records dated through 31 December 2018 were analysed.

SETTING

Large hospital system consisting of inpatient and outpatient data base.

PARTICIPANTS

A diverse, adult, insured population of patients who had more than 1 year of metformin use between 1 January 2010 and 1 October 2016 and who filled at least two consecutive prescriptions of metformin.

RESULTS

Of 13 489 patients on metformin, 6051 (44.9%) were tested for vitamin B12 deficiency, of which 202 (3.3%) tested positive (vs 2.2% of comparisons). Average time to test was 990 days. Average time to test positive for deficiency was 1926 days. Factors associated with testing were linked to sex (female, 47.8%), older age (62.79% in patients over 80 years old), race (48.98% white) and causes of malabsorption (7.11%). Multivariable logistic regression showed older age as the only factor associated with vitamin B12 deficiency, whereas African-American ethnicity approached significance as a protective factor.

CONCLUSIONS

Based on our study's findings of vitamin B12 deficiency in patients on metformin who are greater than 65 years old and have been using it for over 5 years, we recommend that physicians consider screening in these populations.

A Critical Review of the Evidence That Metformin Is a Putative Anti-Aging Drug That Enhances Healthspan and Extends Lifespan

The numerous beneficial health outcomes associated with the use of metformin to treat patients with type 2 diabetes (T2DM), together with data from pre-clinical studies in animals including the nematode, C. elegans, and mice have prompted investigations into whether metformin has therapeutic utility as an anti-aging drug that may also extend lifespan. Indeed, clinical trials, including the MILES (Metformin In Longevity Study) and TAME (Targeting Aging with Metformin), have been designed to assess the potential benefits of metformin as an anti-aging drug. Preliminary analysis of results from MILES indicate that metformin may induce anti-aging transcriptional changes; however it remains controversial as to whether metformin is protective in those subjects free of disease. Furthermore, despite clinical use for over 60 years as an anti-diabetic drug, the cellular mechanisms by which metformin exerts either its actions remain unclear. In this review, we have critically evaluated the literature that has investigated the effects of metformin on aging, healthspan and lifespan in humans as well as other species. In preparing this review, particular attention has been placed on the strength and reproducibility of data and quality of the study protocols with respect to the pharmacokinetic and pharmacodynamic properties of metformin. We conclude that despite data in support of anti-aging benefits, the evidence that metformin increases lifespan remains controversial. However, via its ability to reduce early mortality associated with various diseases, including diabetes, cardiovascular disease, cognitive decline and cancer, metformin can improve healthspan thereby extending the period of life spent in good health. Based on the available evidence we conclude that the beneficial effects of metformin on aging and healthspan are primarily indirect via its effects on cellular metabolism and result from its anti-hyperglycemic action, enhancing insulin sensitivity, reduction of oxidative stress and protective effects on the endothelium and vascular function.

Long-term metformin treatment and risk of peripheral neuropathy in older Veterans

AIM

Our objective was to assess whether increased duration of metformin therapy is associated with incident peripheral neuropathy (PN) in older Veterans with diabetes.

METHODS

Using national Veterans Affairs registry data from 2002 to 2015, we examined Veterans (50 + years) with diabetes. Long-term metformin therapy was defined as prescription ≥ 500 mg/day, filled for ≥ 6 consecutive months. Metformin therapy duration was examined both as continuous and categorical measures. Incident PN was defined by medical chart review. We estimated unadjusted and adjusted (variables selecteda priori)odds ratios (OR) and 95% confidence intervals (CI) using logistic regression.

RESULTS

The study included n = 210,004 individuals (mean ± SD: age: 66.2 ± 8.4 yrs, 96% male) prescribed metformin for 47.0 ± 34.0 months. Nineteen percent developed PN during follow-up. After adjusting for age, body mass index, duration of time receiving health care within the VA, smoking status, alcohol abuse, and vitamin B12 testing and treatment, the number of months of metformin treatment was associated with elevated odds for incident PN (aOR (metformin treatment - continuous) = 1.009 (95% CI = 1.009, 1.010); aOR (metformin treatment - categorical (ref: 6-<18 months): 18-<44.1 months = 1.57 (1.51-1.63), 44.1-<61 months = 2.05 (1.97-2.14), 61 + months = 2.69 (2.58-2.79), all p-values < 0.0001).

CONCLUSION

Our study suggests that Veterans treated for at least 18 months with metformin are approximately 2-3 times more likely to develop PN than those treated at least six, but<18 months. Future studies are needed to determine whether the association we found may be due to a decline in vitamin B12 status following metformin initiation.

Folic acid and vitamin B12 supplementation in subjects with type 2 diabetes mellitus: A multi-arm randomized controlled clinical trial

OBJECTIVE

This study was conducted to investigate and compare the effects of add-on folic acid and vitamin B12 supplementation on glycaemic control, insulin resistance and serum lipid profile in subjects with type 2 diabetes mellitus.

STUDY DESIGN & INTERVENTION

This study was a randomized, multi-arm, open-label clinical trial. 80 patients with type 2 diabetes and on stable oral antidiabetics were enrolled and 20 patients each were randomly allocated to one of the four groups - Group A: add-on Folic acid (5 mg/day); Group B: add-on Methylcobalamin (500 mcg/day); Group C: add-on Folic acid (5 mg/day) + Methylcobalamin (500 mcg/day) and Group D: Standard oral anti-diabetic drugs. The patients were followed up after 8 weeks.

RESULTS

HbA1c improved significantly in Groups B and C [median changes from baseline - 1.2 % (- 13 mmol/mol) and - 1.5 % (- 16 mmol/mol) respectively, p values 0.04 and 0.02 respectively] compared to Group D. Groups B and C also showed significant improvements in plasma insulin, insulin resistance and serum adiponectin compared to Group D. Serum homocysteine declined significantly in all three groups with add-on supplementation compared to standard treatment. No improvement in the lipid profile was noted in any of the groups.

CONCLUSIONS

Add-on supplementation with vitamin B12 improved glycaemic control and insulin resistance in patients with type 2 diabetes mellitus.