Vascular and metabolic effects of metformin added to insulin therapy in patients with type 1 diabetes: A systematic review and meta-analysis

Effect of metformin adjunct therapy on cardiometabolic parameters in Indian adolescents with type 1 diabetes: a randomized controlled trial

Introduction

Insulin resistance is being increasingly reported in type-1 Diabetes (T1D) and is known to accelerate microvascular complications. The Asian Indian population has a higher risk of double diabetes development compared to Caucasians. Hence, we studied the effect of adding Metformin to standard insulin therapy on glycemic control, insulin sensitivity (IS), cardiometabolic parameters and body composition in Indian adolescents with T1D.

Methods

A Randomized controlled trial was conducted spanning 9 months (Registration number:CTRI/2019/11/022126). Inclusion: Age 10-19 years, T1D duration>1year, HbA1c>8% Exclusion: Uncontrolled vascular complications/comorbidities, Metformin intolerance, concomitant drugs affecting insulin sensitivity. Participants were randomized to Metformin/Placebo (n=41 each) groups and age, sex, duration-matched. Assessments were performed at baseline, 3 and 9 months.

Results

82 participants aged 14.7 ± 3years (40 females) were enrolled, with a mean diabetes duration of 5.2 ± 2.3 years. Over 9 months, HbA1c decreased significantly by 0.8 (95% confidence interval: -1.2 to -0.3) from 9.8 ± 1.8% to 9.1 ± 1.7% on Metformin but remained largely unchanged (difference of 0.2, 95% confidence interval: -0.7 to 0.2) i.e. 9.9 ± 1.6% and 9.7 ± 2.2% on placebo. HbA1c improvement correlated negatively with baseline IS (EGDR:r= -0.3;SEARCH:r = -0.24, p<0.05) implying better HbA1c-lowering in those with decreased initial IS. CGM-based glycemic variability (standard deviation) reduced by 6.3 mg/dL (95% confidence interval: -12.9 to 0.2) from 100.2 ± 19.1 mg/dL to 93.7 ± 19.9 mg/dL in those on Metformin (p=0.05) but not placebo (94.0 ± 20.5; 90.0 ± 22.6 mg/dL). Insulin sensitivity: CACTIexa & SEARCH scores demonstrated no change with Metformin but significant worsening on placebo. Significant increase in LDL-C(42%), total cholesterol(133.6 to 151.1 mg/dL), triglyceride (60.0 to 88.0 mg/dL) and carotid intima-media thickness was noted on placebo but not Metformin. Weight, BMI, fat Z-scores increased significantly on placebo but not Metformin. Adverse events (AE) were minor; AE, compliance and safety parameters were similar between the two groups.

Conclusion

Metformin as an adjunct to insulin in Asian Indian adolescents with T1D demonstrated beneficial effect on glycemic control, glycemic variability, IS, lipid profile, vascular function, weight and body fat, with a good safety profile when administered for 9 months.

Treating obesity in type 1 diabetes mellitus - review of efficacy and safety

PURPOSE OF REVIEW

Obesity is an epidemic in the United States with serious concomitant co-morbid conditions; people living with type 1 diabetes mellitus (T1D) are not immune to the risk either. Weight gain in T1D is likely multifactorial, due to genetic, environmental and treatment-related factors. FDA-approved and other adjunctive weight loss therapies may benefit people living with T1D but there are risks to consider when providing recommendations or prescribing medications.

RECENT FINDINGS

We performed a PubMed search of studies assessing clinical outcomes of both approved and off-label medications used in the treatment of type 1 diabetes. Search terms included 'type 1 diabetes, obesity' and the following: (1) metformin, (2) pramlintide, (3) glucagon-like peptide-1 (GLP-1) receptor agonists, (4) dual GLP-1 and gastric inhibitory polypeptide (GIP) agonists, (5) sodium-glucose cotransporter-2 (SGLT-2) inhibitors, (6) surgical treatment of obesity, (7) insulin pump, (8) insulin, (9) medical nutrition therapy, (10) diabetes self-management education, (11) exercise, (12) naltrexone-buproprion, (13) orlistat, and (14) phentermine-topiramate.

SUMMARY

Weight loss treatments provide a wide-range of benefits in reducing both morbidity and mortality in those who are obese. Treatments also have varying adverse effect profiles which may impact T1D treatment. In this review, we aim to summarize study outcomes in people with T1D, including risks and benefits, of on- and off-label weight loss treatments.

New advances in type 1 diabetes

Type 1 diabetes is an autoimmune condition resulting in insulin deficiency and eventual loss of pancreatic β cell function requiring lifelong insulin therapy. Since the discovery of insulin more than 100 years ago, vast advances in treatments have improved care for many people with type 1 diabetes. Ongoing research on the genetics and immunology of type 1 diabetes and on interventions to modify disease course and preserve β cell function have expanded our broad understanding of this condition. Biomarkers of type 1 diabetes are detectable months to years before development of overt disease, and three stages of diabetes are now recognized. The advent of continuous glucose monitoring and the newer automated insulin delivery systems have changed the landscape of type 1 diabetes management and are associated with improved glycated hemoglobin and decreased hypoglycemia. Adjunctive therapies such as sodium glucose cotransporter-1 inhibitors and glucagon-like peptide 1 receptor agonists may find use in management in the future. Despite these rapid advances in the field, people living in under-resourced parts of the world struggle to obtain necessities such as insulin, syringes, and blood glucose monitoring essential for managing this condition. This review covers recent developments in diagnosis and treatment and future directions in the broad field of type 1 diabetes.

Effects of metformin on glycaemic variability in combination with insulin in overweight/obese patients with type 1 diabetes

BACKGROUND

The prevalence of overweight and obesity in type 1 diabetes mellitus (T1DM) individuals is increasing. Overweight people with T1DM may be insulin resistant. Glycaemic variability (GV) is an emerging measure of glycaemic control. The aim of this study is to investigate whether metformin, in adjunct to insulin, would have any favourable effect on GV.

METHODS

This was a multi-centre, open-label randomised crossover study. Twenty-four overweight/obese T1DM patients aged ⩾18 years old with HbA1c ⩾ 7.0% (53 mmol/mol) were recruited and randomised into two study arms. For first 6-week, one arm remained on standard of care (SOC), the other arm received metformin, adjunctive to SOC. After 2-week washout, patients crossed over and continued for another 6 weeks. Glycaemic variability, other glycaemic parameters and metabolic profile were monitored.

RESULTS

There were significant reduction in metformin group for GV: mean (0.18 ± 1.73 vs -0.95 ± 1.24, p = 0.014), %CV (-15.84 (18.92) vs -19.08 (24.53), p = 0.044), glycemic risk assessment of diabetes equation (-0.69 (3.83) vs -1.61 (3.61), p = 0.047), continuous overlapping net glycaemic action (0.25 ± 1.62 vs -0.85 ± 1.22, p = 0.013), J-index (-0.75 (21.91) vs -7.11 (13.86), p = 0.034), time in range (1.13 ± 14.12% vs 10.83 ± 15.47%, p = 0.032); changes of systolic blood pressure (2.78 ± 11.19 mmHg vs -4.30 ± 9.81 mmHg, p = 0.027) and total daily dose (TDD) insulin (0.0 (3.33) units vs -2.17 (11.45) units, p = 0.012). Hypoglycaemic episodes were not significant in between groups.

CONCLUSION

Metformin showed favourable effect on GV in overweight/obese T1DM patients and reduction in systolic blood pressure, TDD insulin, fasting venous glucose and fructosamine.

The function, mechanisms, and clinical applications of metformin: potential drug, unlimited potentials

Metformin has been used clinically for more than 60 years. As time goes by, more and more miraculous effects of metformin beyond the clinic have been discovered and discussed. In addition to the clinically approved hypoglycemic effect, it also has a positive metabolic regulation effect on the human body that cannot be ignored. Such as anti-cancer, anti-aging, brain repair, cardiovascular protection, gastrointestinal regulation, hair growth and inhibition of thyroid nodules, and other nonclinical effects. Metformin affects almost the entire body in the situation taking it over a long period, and the preventive effects of metformin in addition to treating diabetes are also beginning to be recommended in some guidelines. This review is mainly composed of four parts: the development history of metformin, the progress of clinical efficacy, the nonclinical efficacy of metformin, and the consideration and prospect of its application.

Neuromodulatory effect of the combination of metformin and vitamin D3 triggered by purinergic signaling in type 1 diabetes induced-rats

Several studies have indicated the vitamin D deficiency in the development of macro- and microvascular complications of diabetes mellitus (DM) including DM-related cognitive dysfunction. The purinergic system plays an important role in the modulation of a variety of mechanisms, including neuroinflammation, plasticity, and cell-cell communication. In addition, purines, their receptors, and enzymes can regulate the purinergic axis at different levels in type 1 DM (T1DM). This study evaluated the effects of vitamin D₃ alone or in combination with metformin in the behavioral performance of streptozotocin-induced T1DM rats. The effects of this combination on the metabolism of ATP and ADP were also studied by NTPDase (CD39), AMP by 5'-nucleotidase (CD73), and adenosine by adenosine deaminase (E-ADA) in the brain and peripheral lymphocytes of type 1 diabetic STZ-induced rats. The results showed that anxiety and memory loss from the DM condition reverted after 30 days of vitamin D₃ treatment. Furthermore, the DM state affected systemic enzymes, with no effect on the central enzymes hydrolyzing extracellular nucleotides and nucleosides. Vitamin D₃ treatment positively regulated ectonucleotidase (NTPDase and 5'-nucleotidase) activity, E-ADA, and the purinergic receptors as a mechanism to prevent oxidative damage in the cerebral cortex of T1DM rats. A neuroprotector effect of vitamin D₃ through adenosine signaling was also observed, by regulating A1 and A_2A receptors proteins levels. The present findings suggest that purinergic signaling through vitamin D₃ modulation may be a novel alternative strategy for T1DM treatment, and may compensate for the negative changes in the central nervous system.

Effect and Safety of Adding Metformin to Insulin Therapy in Treating Adolescents With Type 1 Diabetes Mellitus: An Updated Meta-Analysis of 10 Randomized Controlled Trials

BACKGROUND

The role of metformin in the treatment of adolescents with type 1 diabetes mellitus (T1DM) remains controversial. We conducted this updated meta-analysis to generate a comprehensive assessment regarding the effect and safety of metformin in treating adolescents with T1DM.

METHODS

We systematically searched PubMed, Embase, and the Cochrane Central Registry of Controlled Trials (CENTRAL) from their inception to November 2021 to identify randomized controlled trials evaluating the efficacy of metformin in the treatment of adolescents with T1DM. The primary outcome was the HbA1c level, and secondary outcomes included the body mass index (BMI), total insulin daily dose (TIDD) (unit/kg/d), hypoglycemia events, diabetes ketoacidosis (DKA) events, and gastrointestinal adverse events (GIAEs). Statistical analysis was conducted using RevMan 5.4 and STATA 14.0.

RESULTS

Ten studies enrolling 539 T1DM adolescents were included. Results suggested that metformin significantly decreased the HbA1c level at 12 months (mean difference [MD])=-0.50, 95% confidence interval [CI]=-0.61 to -0.39, P < 0.01); BMI (kg/m²) at 3 months (MD=-1.05, 95%CI=-2.05 to -0.05, P=0.04); BMI z-score at 6 months (MD=-0.10, 95%CI=-0.14 to -0.06, P<0.01); and TIDD at 3 (MD=-0.13, 95%CI=-0.20 to -0.06, P<0.01), 6 (MD=-0.18, 95%CI=-0.25 to -0.11, P<0.01), and 12 (MD=-0.42, 95%CI=-0.49 to -0.35, P<0.01) months but significantly increased the risk of hypoglycemia events (risk ratio [RR]=3.13, 95%CI=1.05 to 9.32, P=0.04) and GIAEs (RR=1.64, 95%CI=1.28 to 2.10, P<0.01). For remaining outcomes at other time points, no statistical difference was identified. Sensitivity analysis confirmed the robustness of all pooled results.

CONCLUSIONS

The use of metformin might result in decreased BMI (kg/m²), BMI z-score, and TIDD and increased risk of hypoglycemia events and GIAEs in adolescents with T1DM. However, future studies are required to further confirm the optimal dose and duration of metformin therapy.

Prognostic Factors for COVID-19 Hospitalized Patients with Preexisting Type 2 Diabetes

BACKGROUND

Type 2 diabetes (T2D) as a worldwide chronic disease combined with the COVID-19 pandemic prompts the need for improving the management of hospitalized COVID-19 patients with preexisting T2D to reduce complications and the risk of death. This study aimed to identify clinical factors associated with COVID-19 outcomes specifically targeted at T2D patients and build an individualized risk prediction nomogram for risk stratification and early clinical intervention to reduce mortality.

METHODS

In this retrospective study, the clinical characteristics of 382 confirmed COVID-19 patients, consisting of 108 with and 274 without preexisting T2D, from January 8 to March 7, 2020, in Tianyou Hospital in Wuhan, China, were collected and analyzed. Univariate and multivariate Cox regression models were performed to identify specific clinical factors associated with mortality of COVID-19 patients with T2D. An individualized risk prediction nomogram was developed and evaluated by discrimination and calibration.

RESULTS

Nearly 15% (16/108) of hospitalized COVID-19 patients with T2D died. Twelve risk factors predictive of mortality were identified. Older age (HR = 1.076, 95% CI = 1.014-1.143, p=0.016), elevated glucose level (HR = 1.153, 95% CI = 1.038-1.28, p=0.0079), increased serum amyloid A (SAA) (HR = 1.007, 95% CI = 1.001-1.014, p=0.022), diabetes treatment with only oral diabetes medication (HR = 0.152, 95%CI = 0.032-0.73, p=0.0036), and oral medication plus insulin (HR = 0.095, 95%CI = 0.019-0.462, p=0.019) were independent prognostic factors. A nomogram based on these prognostic factors was built for early prediction of 7-day, 14-day, and 21-day survival of diabetes patients. High concordance index (C-index) was achieved, and the calibration curves showed the model had good prediction ability within three weeks of COVID-19 onset.

CONCLUSIONS

By incorporating specific prognostic factors, this study provided a user-friendly graphical risk prediction tool for clinicians to quickly identify high-risk T2D patients hospitalized for COVID-19.

The management of type 1 diabetes in adults. A consensus report by the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD)

The American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD) convened a writing group to develop a consensus statement on the management of type 1 diabetes in adults. The writing group has considered the rapid development of new treatments and technologies and addressed the following topics: diagnosis, aims of management, schedule of care, diabetes self-management education and support, glucose monitoring, insulin therapy, hypoglycaemia, behavioural considerations, psychosocial care, diabetic ketoacidosis, pancreas and islet transplantation, adjunctive therapies, special populations, inpatient management and future perspectives. Although we discuss the schedule for follow-up examinations and testing, we have not included the evaluation and treatment of the chronic microvascular and macrovascular complications of diabetes as these are well-reviewed and discussed elsewhere. The writing group was aware of both national and international guidance on type 1 diabetes and did not seek to replicate this but rather aimed to highlight the major areas that healthcare professionals should consider when managing adults with type 1 diabetes. Though evidence-based where possible, the recommendations in the report represent the consensus opinion of the authors. Graphical abstract.

The Management of Type 1 Diabetes in Adults. A Consensus Report by the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD)

The American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD) convened a writing group to develop a consensus statement on the management of type 1 diabetes in adults. The writing group has considered the rapid development of new treatments and technologies and addressed the following topics: diagnosis, aims of management, schedule of care, diabetes self-management education and support, glucose monitoring, insulin therapy, hypoglycemia, behavioral considerations, psychosocial care, diabetic ketoacidosis, pancreas and islet transplantation, adjunctive therapies, special populations, inpatient management, and future perspectives. Although we discuss the schedule for follow-up examinations and testing, we have not included the evaluation and treatment of the chronic microvascular and macrovascular complications of diabetes as these are well-reviewed and discussed elsewhere. The writing group was aware of both national and international guidance on type 1 diabetes and did not seek to replicate this but rather aimed to highlight the major areas that health care professionals should consider when managing adults with type 1 diabetes. Though evidence-based where possible, the recommendations in the report represent the consensus opinion of the authors.

Metformin improves glycemic variability in adults with type 1 diabetes mellitus: an open-label randomized control trial

INTRODUCTION

Metformin has been demonstrated to enhance cardioprotective benefits in type 1 diabetes (T1DM). Although glycemic variability (GV) is associated with increased risk of CVD in diabetes, there is a scarcity of research evaluating the effect of metformin on GV in T1DM.

OBJECTIVES

In the present study, the effects of adjuvant metformin therapy on GV and metabolic control in T1DM were explored.

PATIENTS AND METHODS

A total of 65 adults with T1DM were enrolled and subjected to physical examination, fasting laboratory tests, and continuous glucose monitoring, and subsequently randomized 1:1 to 3 months of 1000-2000 mg metformin daily add-on insulin (MET group, n = 34) or insulin (non-MET group, n = 31). After, baseline measurements were repeated.

RESULTS

The mean amplitude of glycemic excursions was substantially reduced in MET group, compared with non-MET group (-1.58 (-3.35, 0.31) mmol/L vs 1.36 (-1.12, 2.24) mmol/L, P = 0.004). In parallel, the largest amplitude of glycemic excursions (-2.83 (-5.47, -0.06) mmol/L vs 0.45 (-1.29, 4.48) mmol/L, P = 0.004), the s.d. of blood glucose (-0.85 (-1.51, 0.01) mmol/L vs -0.14 (-0.68, 1.21) mmol/L, P = 0.015), and the coefficient of variation (-6.66 (-15.00, 1.50)% vs -1.60 (-6.28, 11.71)%, P = 0.012) all demonstrated improvement in the MET group, compared with the non-MET group. Significant reduction in insulin dose, BMI, and body weight was observed in patients in MET, not those in non-MET group.

CONCLUSION

Additional metformin therapy improved GV in adults with T1DM, as well as improving body composition and reducing insulin requirement. Hence, metformin as an adjunctive therapy has potential prospects in reducing the CVD risk in patients with T1DM in the long term.

Adjunctive therapies in type 1 diabetes mellitus

PURPOSE OF REVIEW

Insulin is the mainstay of treatment in people living with type 1 diabetes mellitus due to an immune-mediated loss of beta cells. Yet despite advances in insulin therapy and other technological advances, glycemic control remains difficult to achieve. Therefore, we aim to highlight risks and benefits of adjunctive therapies that may improve type 1 diabetes care.

RECENT FINDINGS

We identified studies assessing clinical outcomes of adjunctive therapies that are both Food and Drug Administration (FDA)-approved and off-label in type 1 diabetes. Adjunctive therapies reviewed included metformin, pramlintide, glucagon-like peptide-1 (GLP-1) receptor agonists and sodium-glucose cotransporter-2 inhibitors.

SUMMARY

Although insulin is required in people living with type 1 diabetes mellitus, adjunctive therapies may positively impact glycemic control, reduce insulin requirements and lead to weight loss. In addition, the risk of hypoglycemia, gastrointestinal side effects and diabetes ketoacidosis may be increased with the use of these adjunctive therapies. Pramlintide is currently the only FDA-approved adjunctive therapy, whereas others require continued research to better understand risk-to-benefit ratio.