Risk of lactic acidosis in type 2 diabetes patients using metformin: A case control study

Optimizing metformin therapy in practice: Tailoring therapy in specific patient groups to improve tolerability, efficacy and outcomes

Metformin is the first-line medication for type 2 diabetes. It is effective and safe, provided some caution is taken in specific populations. In patients with chronic kidney disease, metformin may provide long-term benefits, and it is a first-line therapy for diabetes, but the estimated glomerular filtration rate (eGFR) must be assessed regularly, to minimize the risk for metformin accumulation. When eGFR is 30-60 mL/min/1.73m2, the dose should be reconsidered, and sick-days education provided. Metformin should be discontinued when eGFR falls below 30 mL/min/1.73m2. Metformin accumulation may increase the risk for lactic acidosis if concomitant risk factors for hyperlactataemia (liver or respiratory insufficiency, sepsis, acute heart failure) are present; in these conditions, metformin is contraindicated, even although the available evidence is reassuring. Patients on metformin often complain of gastrointestinal side effects (mainly diarrhoea and nausea) during therapy initiation, but they may sometimes occur after years of stable therapy. These usually resolve if the dose is carefully titrated, or by switching to the extended-release formulation. Patients with obesity may benefit from the significant, although modest, metformin-associated weight loss and appetite reduction. During pregnancy, metformin is associated with a reduction of pregnancy complications, especially in obese women, but some concern remains, because metformin crosses the placenta, and it is associated with a significantly lower mean birth weight than insulin. In the elderly, gastrointestinal tolerability and renal function must be reassessed more often. Vitamin B-12 should be screened regularly in long-time metformin users because metformin may induce clinical vitamin B-12 deficiency.

Empowering mitochondrial metabolism: Exploring L-lactate supplementation as a promising therapeutic approach for metabolic syndrome

Mitochondrial dysfunction plays a critical role in the pathogenesis of metabolic syndrome (MetS), affecting various cell types and organs. In MetS animal models, mitochondria exhibit decreased quality control, characterized by abnormal morphological structure, impaired metabolic activity, reduced energy production, disrupted signaling cascades, and oxidative stress. The aberrant changes in mitochondrial function exacerbate the progression of metabolic syndrome, setting in motion a pernicious cycle. From this perspective, reversing mitochondrial dysfunction is likely to become a novel and powerful approach for treating MetS. Unfortunately, there are currently no effective drugs available in clinical practice to improve mitochondrial function. Recently, L-lactate has garnered significant attention as a valuable metabolite due to its ability to regulate mitochondrial metabolic processes and function. It is highly likely that treating MetS and its related complications can be achieved by correcting mitochondrial homeostasis disorders. In this review, we comprehensively discuss the complex relationship between mitochondrial function and MetS and the involvement of L-lactate in regulating mitochondrial metabolism and associated signaling pathways. Furthermore, it highlights recent findings on the involvement of L-lactate in common pathologies of MetS and explores its potential clinical application and further prospects, thus providing new insights into treatment possibilities for MetS.

Expanding the evidence for managing metformin poisoning to support decision-making

INTRODUCTION

Metformin-associated lactic acidosis is a well-described and commonly encountered condition associated with significant morbidity and mortality. Patients with metformin-associated lactic acidosis are frequently managed in the intensive care unit with supportive care, including volume resuscitation and consideration of an extracorporeal treatment to correct metabolic acidemia and remove metformin and lactate.

EXTRACORPOREAL TREATMENTS IN POISONING WORKGROUP

The Extracorporeal Treatments in Poisoning Workgroup published evidence-based consensus recommendations in 2015 regarding the use of extracorporeal treatment in metformin toxicity. These recommendations list both clinical and biochemical indications, and they outline the rationale and evidence supporting each recommendation.

NEW RESEARCH SINCE RECOMMENDATIONS WERE PUBLISHED

Subsequent publications have provided new information regarding metformin-associated lactic acidosis and its treatment. A retrospective study showed that patients who did not meet the Extracorporeal Treatments in Poisoning Workgroup criteria for initiation of an extracorporeal treatment had a 100% survival. In patients who met the criteria, survival was approximately 75%; only 66% of these patients received an extracorporeal treatment, and this treatment did not appear to impact survival. Two other retrospective studies in patients diagnosed with metformin-associated lactic acidosis noted that extracorporeal treatments did not improve survival. However, those who received an extracorporeal treatment were more severely ill, potentially supporting a benefit from this intervention. A systematic review of patients receiving continuous kidney replacement therapy identified an overall survival that was higher than the overall survival in patients included in the Workgroup publication. This led the authors to suggest that intermittent hemodialysis may not be the preferred treatment for metformin toxicity. However, a closer look at the Workgroup data identified improved survival with each decade since the initial reports in the 1970s. Furthermore, there are multiple reports of persistent metformin-associated lactic acidosis that did not improve with standard continuous kidney replacement therapy, prompting an increase in the dosage of the extracorporeal treatment. The data supporting these observations are largely derived from retrospective studies, which have inherent biases, so prospective studies are required.

PRESCRIBING EXTRACORPOREAL TREATMENTS FOR PATIENTS WITH METFORMIN POISONING

Case-based decision-making is always necessary, but in general, we continue to follow the Extracorporeal Treatments in Poisoning Workgroup criteria because a convincing reason for changing these has not yet been presented. This includes the use of intermittent hemodialysis where possible, particularly in cases of severe poisoning. For patients with less severe poisoning or when intermittent hemodialysis is not readily available, it is reasonable to trial continuous modalities with careful observation for deterioration.

Risk of Lactic Acidosis in Hospitalized Diabetic Patients Prescribed Biguanides in Japan: A Retrospective Total-Population Cohort Study

Patient data from the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) are used to assess the effect of biguanide administration on rates of lactic acidosis (LA) in hospitalized diabetes mellitus (DM) patients. In this retrospective cohort study (from April 2013 to March 2016), we compare DM inpatients prescribed biguanides to DM inpatients who were not prescribed biguanides to quantify the association between biguanides and incidence of LA. In total, 8,111,848 DM patient records are retrieved from the NDB. Of the 528,768 inpatients prescribed biguanides, 782 develop LA. Of the 1,967,982 inpatients not prescribed biguanides, 1310 develop LA. The rate ratio of inpatients who develop LA and are administered biguanides to those who developed LA without receiving biguanides is 1.44 (95% CI, 1.32-1.58). Incidence rates and rate ratios for both sexes are elevated in the group prescribed biguanides for patients aged 70 years and older, markedly in those 80 years and older: 40.12 and 6.31 (95% CI, 4.75-8.39), respectively, for men and 34.96 and 5.40 (95% CI, 3.91-7.46), respectively, for women. Biguanides should be used conservatively in patients older than 70 years, particularly for those with comorbidities, and with caution in patients 80 years and older.

Ultrafast Measurement of Metformin in the Clinical Setting Using Probe Electrospray Ionization Mass Spectrometry

Metformin (MtF) is a treatment used for type 2 diabetes. Lactic acidosis (LA) is a frequent complication that can be either induced by or associated with elevated MtF plasma concentrations. When coupled with a mass spectrometry (MS) system, the probe electrospray ionization (PESI) method allows direct and rapid analysis of different types of matrices without pretreatment. In this study, we developed a PESI-MS method for the determination of MtF in plasma. We used a tandem mass spectrometer equipped with a PESI source in the reaction monitoring mode for the quantitation of MtF. MtF-d6 was chosen as the internal standard (IS), following an isotope dilution (ID) approach. The method was fully validated with six concentration levels (0.5-50 mg/L). The matrix effect was evaluated for each level, and the specificity was tested with a mix of potential co-medications. Using patient samples, the performance was compared with two classical LC-MS-MS and LC-diode array detector (DAD) methods used in external labs. Sample preparation consisted in mixing 10 µL plasma in 1,000 µL ethanol/ammonium formate buffer including MtF-d6 at a fixed concentration of 5 mg/L. The total run time was 0.31 min. ID gave satisfactory results of accuracy and precision (min-max: -12.1 to 15.8% and 1.0-17.1%, respectively). The matrix effect was fully corrected by the internal standard (bias < 1%). The specificity study also reported satisfactory results. Finally, in a representative group of 29 patients (55% with a concentration <5 mg/L, 38% with a concentration >5 mg/L and 7% not detected), we observed almost identical results when comparing LC-DAD and LC-MS-MS to PESI-MS (r2 > 0.99). We propose a specific, sensitive, accurate and ultrafast solution for the measurement of MtF in patient plasma, with no sample preparation or calibration curve building. This could be helpful in a core lab when rapid diagnosis of LA is needed.

Insights into the regulation of podocyte and glomerular function by lactate and its metabolic sensor G-protein-coupled receptor 81

Podocytes and their foot processes are an important cellular layer of the renal filtration barrier that is involved in regulating glomerular permeability. Disturbances of podocyte function play a central role in the development of proteinuria in diabetic nephropathy. The retraction and effacement of podocyte foot processes that form slit diaphragms are a common feature of proteinuria. Correlations between the retraction of foot processes and the development of proteinuria are not well understood. Unraveling peculiarities of podocyte energy metabolism notably under diabetic conditions will provide insights into the pathogenesis of diabetic nephropathy. Intracellular metabolism in the cortical area of podocytes is regulated by glycolysis, whereas energy balance in the central area is controlled by oxidative phosphorylation and glycolysis. High glucose concentrations were recently reported to force podocytes to switch from mitochondrial oxidative phosphorylation to glycolysis, resulting in lactic acidosis. In this review, we hypothesize that the lactate receptor G-protein-coupled receptor 81 (also known as hydroxycarboxylic acid receptor 81) may contribute to the control of podocyte function in both health and disease.

Investigation of the mechanism of Shen Qi Wan prescription in the treatment of T2DM via network pharmacology and molecular docking

Shen Qi Wan (SQW) prescription has been used to treat type 2 diabetes mellitus (T2DM) for thousands of years, but its pharmacological mechanism is still unclear. The network pharmacology method was used to reveal the potential pharmacological mechanism of SQW in the treatment of T2DM in this study. Nine core targets were identified through protein-protein interaction (PPI) network analysis and KEGG pathway enrichment analysis, which were AKT1, INSR, SLC2A1, EGFR, PPARG, PPARA, GCK, NOS3, and PTPN1. Besides, this study found that SQW treated the T2DM through insulin resistance (has04931), insulin signaling pathway (has04910), adipocytokine signaling pathway (has04920), AMPK signaling pathway (has04152) and FoxO signaling pathway (has04068) via ingredient-hub target-pathway network analysis. Finally, molecular docking was used to verify the drug-target interaction network in this research. This study provides a certain explanation for treating T2DM by SQW prescription, and provides a certain angle and method for researchers to study the mechanism of TCM in the treatment of complex diseases.

Supplementary information

The online version contains supplementary material available at 10.1007/s40203-022-00124-2.

Metformin's Mechanism of Action Is Stimulation of the Biosynthesis of the Natural Cyclic AMP Antagonist Prostaglandylinositol Cyclic Phosphate (Cyclic PIP)

Metformin is the leading drug for treating type 2 diabetics, but the mechanism of action of metformin, despite some suggested mechanisms such as the activation of the AMP-kinase, is largely unknown. Among its many positive effects are the reduction of blood glucose levels, the inhibition of cyclic AMP synthesis, gluconeogenesis and an increase in sensitivity to insulin. Recent studies have described the natural antagonist of cyclic AMP, prostaglandylinositol cyclic phosphate. Synthesis of cyclic PIP is stimulated in all organs by hormones such as insulin and also by drugs such as metformin. Its primary action is to trigger the dephosphorylation of proteins/enzymes, phosphorylated on serine/threonine residues. Cyclic PIP triggers many of the regulations requested by insulin. The parallels between the beneficial effects of metformin and the regulations triggered by cyclic PIP suggest that the mechanism of action of this key drug may well be explained by its stimulation of the synthesis of cyclic PIP.

A Comparative Study of Acidosis in Diabetic Advanced Chronic Kidney Disease Patients on and off Metformin

Aim

The aim of the study is to assess the risk of acidosis in diabetic advanced chronic kidney disease (CKD) patients on and off metformin.

Methods

This retrospective descriptive study was conducted in the nephrology department in The Kidney Centre Post Graduate Training Institute (TKC PGTI) Karachi from February to April 2020. We reviewed the records of all patients over 18 years old who visited the nephrology outpatient department in three months in 2020 (from February 2020 to April 2020), who had CKD (stage 2-5), are not on dialysis, and had type 2 diabetes. These were divided into two groups: those on metformin for more than one year and those not on metformin. We looked at hospitalizations due to acidosis in the previous one-year period.

Results

A total of 524 CKD patients had diabetes; out of those, 268 patients were on metformin, and 256 were not on metformin. The male vs. female distribution was 52.1% vs. 47.9%. A total of 114 (21.8%) patients required admission in the previous one-year period, and only 12 hospitalized patients had acidosis, seven (58.3%) were on metformin, and five (41.7%) were not on metformin, which was statistically insignificant.

Conclusion

Biguanides, especially metformin, is a known oral hypoglycemic drug used for decades to treat type 2 diabetes mellitus (DM). Metformin use is related to a rare but serious adverse event, metformin-associated lactic acidosis (MALA), especially in renal failure patients. In our study, metformin use in CKD diabetic patients did not result in more admissions due to acidosis than non-metformin users.

Randomised clinical study: acute effects of metformin versus placebo on portal pressure in patients with cirrhosis and portal hypertension

BACKGROUND

Portal hypertension is the main determinant of clinical decompensation in patients with liver cirrhosis. In preclinical data metformin lowers portal pressure, but there are no clinical data for this beneficial effect.

AIMS

To investigate the acute effects of metformin on hepatic venous pressure gradient (HVPG) and liver perfusion.

METHODS

In a randomised, double-blinded study design, we investigated 32 patients with cirrhosis before and 90 minutes after ingestion of 1000-mg metformin (n = 16) or placebo (n = 16). Liver vein catherisation was performed to evaluate HVPG and indocyanine green (ICG) infusion for investigation of hepatic blood flow.

RESULTS

The mean relative change in HVPG was -16% (95% CI: -28% to -4%) in the metformin group compared with 4% (95% CI: -6% to 14%) in the placebo group (time × group interaction, P = 0.008). In patients with baseline HVPG ≥12 mm Hg clinically significant improvements in HVPG (HVPG <12 mm Hg or a >20% reduction in HVPG) were observed in 46% (6/13) of metformin-treated and in 8% (1/13) of placebo-treated patients (P = 0.07). There were no changes or differences in systemic blood pressure, heart rate, hepatic plasma and blood flow, hepatic ICG clearance, hepatic O₂ uptake or inflammation markers between groups.

CONCLUSIONS

A single oral metformin dose acutely reduces HVPG in patients with portal hypertension without affecting systemic or liver hemodynamics or inflammatory biomarkers. This offers a promising perspective of a safe and inexpensive treatment option that should be investigated in larger-scale clinical studies with long-term outcomes in patients with cirrhosis and portal hypertension.

[Treatment of diabetes mellitus in perioperative medicine-an update]

Patients with diabetes who undergo a surgical intervention have an increased risk of metabolic derailment, anesthesiological complications, postoperative infections and cardiovascular events. The treatment of diabetes mellitus is subject to a continuous further development due to pharmaceutical and technical innovations. This article presents the implications of the current concepts of diabetes treatment for perioperative medicine, particularly the changes due to new oral antidiabetic agents and insulin pump treatment. Some of the currently available guidelines are discussed with respect to the care of diabetes patients in childhood and adulthood in connection with an operation. Finally, possible perspectives in the field of monitoring and treatment of diabetes patients are discussed.

Tolerability, safety, pharmacokinetics and pharmacodynamics of SHR0534, a potent G protein-coupled receptor 40 (GPR40) agonist, at single- and multiple-ascending oral doses in healthy Chinese subjects

SHR0534 is being developed for type-2 diabetes mellitus. Herein the tolerability, safety, pharmacokinetics and pharmacodynamics of SHR0534 in healthy Chinese subjects were assessed in a phase-I, randomized, double-blind, placebo-controlled, single- and multiple-ascending dose study. Forty subjects were randomized 4:1 to receive SHR0534 at the dose of 10, 25, 50 or 100 mg, or placebo, and another eleven subjects were allocated to either the 5 mg group or the placebo group at an 8:3 ratio. All subjects received a single dose on day 1, followed by a 9-day washout and once-daily administrations for 14 consecutive days. Serial samples were collected, and vital signs, electrocardiograms, laboratory tests, urinalysis and adverse events (AEs) were recorded. All doses of SHR0534 were safe and well tolerated with infrequent, generally mild-to-moderate AEs and no serious AEs in the study. SHR0534 was absorbed with a T _max of approximately 4 hours, and systemic exposure increased with dose. Accumulation was minimal (2- to 3-fold) and steady state was reached after seven days of dosing. For pharmacodynamics, no significant hypoglycaemic effects were seen in healthy adults. Good pharmacokinetics and safety were demonstrated but no obvious effect was found.

Metformin Biodistribution: A Key to Mechanisms of Action?

Metformin has undisputed glucose-lowering effects in diabetes and an impressive safety record. It has also shown promising effects beyond diabetes, and several hundred clinical trials involving metformin are currently planned or active. Metformin targets intracellular effectors, but exactly which remain to be established, and in an era of precision medicine, an incomplete understanding of mechanisms of action may limit the use of metformin. Distribution of metformin depends on specific organic cation transporter proteins that are organ- and species-specific. Therefore, target tissues of metformin can be identified by cellular uptake of the drug, and exploring the biodistribution of the drug in humans becomes an attractive strategy to assist the many investigations into the mechanisms of action of metformin performed in animals. In this review, we combine the emerging evidence from the use of 11C-labeled metformin in humans to discuss metformin action in liver, intestines, and kidney, which are the organs with the most avid uptake of the drug.

Integrated Analysis of the Mechanisms of Da-Chai-Hu Decoction in Type 2 Diabetes Mellitus by a Network Pharmacology Approach

Background

The incidence of type 2 diabetes mellitus (T2DM) has increased year by year, which not only seriously affects people's quality of life, but also imposes a heavy economic burden on the family, society, and country. Currently, the pathogenesis, diagnosis, and treatment of T2DM are still unclear. Therefore, exploration of a precise multitarget treatment strategy is urgent. Here, we attempt to screen out the active components, effective targets, and functional pathways of therapeutic drugs through network pharmacology with taking advantages of traditional Chinese medicine (TCM) formulas for multitarget holistic treatment of diseases to clarify the potential therapeutic mechanism of TCM formulas and provide a systematic and clear thought for T2DM treatment.

Methods

First, we screened the active components of Da-Chai-Hu Decoction (DCHD) by absorption, distribution, metabolism, excretion, and toxicity (ADME/T) calculation. Second, we predicted and screened the active components of DCHD and its therapeutic targets for T2DM relying on the Traditional Chinese Medicine Systems Pharmacology Analysis Platform (TCMSP database) and Text Mining Tool (GoPubMed database), while using the Database for Annotation, Visualization, and Integrated Discovery (DAVID) to obtain T2DM targets. Third, we constructed a network of the active component-target, target-pathway of DCHD using Cytoscape software (http://cytoscape.org/,ver.3.5.1) and then analyzed gene function, related biological processes, and signal pathways through the DAVID database.

Results

We screened 77 active components from 1278 DCHD components and 116 effective targets from 253 ones. After matching the targets of T2DM, we obtained 38 important targets and 7 core targets were selected through further analysis. Through enrichment analysis, we found that these important targets were mainly involved in many biological processes such as oxidative stress, inflammatory reaction, and apoptosis. After analyzing the relevant pathways, the synthetic pathway for the treatment of T2DM was obtained, which provided a diagnosis-treatment idea for DCHD in the treatment of T2DM.

Conclusions

This article reveals the mechanism of DCHD in the treatment of T2DM related to inflammatory response and apoptosis through network pharmacology, which lays a foundation for further elucidation of drugs effective targets.

Metformin Associated Lactic Acidosis in Clinical Practice - A Case Series

AIMS

The aim of this case report is to specify the frequency and mortality of Metformin-Associated Lactic Acidosis (MALA) in emergency medicine, as the diagnosis seems to occur more often than estimated.

METHODS

To identify the subjects, we developed screening criteria for MALA. We measured the serum metformin concentration to confirm the diagnosis in all patients fulfilling these criteria. Retrospectively the patients were grouped according to individual risk (according to a defined risk score) and the application of renal replacement therapy.

RESULTS

From 2013 until 2018 we were able to identify 11 MALA patients revealing a frequency of 1:4,000 emergency patients. Six patients survived and five died in the follow-up. All three patients in the high-risk group died although all of them received renal replacement therapy. In the low-risk group (three patients, one with renal replacement therapy), all patients survived, while in the intermediate-risk group (five patients, one with renal replacement therapy) three patients survived and two died. Additional severe comorbidities also contributed to mortality.

CONCLUSIONS

Every patient matching the screening criteria of acute renal failure, lactic acidosis and continued intake of metformin can be considered a potential MALA case. A risk score assessment which includes severe comorbidities may help to identify high-risk individuals and should be evaluated in larger studies.To prevent MALA, patients should be trained to immediately interrupt their own metformin use when showing signs of volume depletion. Physicians should be aware of the additional risk factors such as co-medication with diuretics, ACE (angiotensin converting enzyme) ACE inhibitors and NSAIDs (non steroidal anti inflammatory drugs).

Effect of continuous use of metformin on kidney function in diabetes patients with acute myocardial infarction undergoing primary percutaneous coronary intervention

BACKGROUND

Diabetes patients presenting with ST-segment elevation myocardial infarction (STEMI) scheduled for primary percutaneous coronary intervention (PCI) have an increased risk of contrast induced-acute kidney injury (CI-AKI). The effects of continuous use of metformin on kidney function are still controversial in patients submitted to primary PCI. This study aimed to assess continuous metformin therapy on kidney function in diabetic patients undergoing coronary intervention.

METHODS

Two hundred eighty-four patients with metformin-treated diabetes, who underwent coronary intervention within 24 h for STEMI, were enrolled in the retrospective study. All the patients had estimated glomerular filtration rate (eGFR) of > 30 mL/min/1.73 m2. According to the physicians' decisions after admission, 119 patients continued metformin treatment after primary PCI, while 165 patients discontinued it > 48 h after the procedure. Serum creatinine was collected at admission and within 48 h post primary PCI to evaluate the incidence of CI-AKI. We performed a multiple logistic regression analysis to examine the determinants of CI-AKI.

RESULTS

No statistical difference in CI-AKI incidence between the continuous and the discontinuous metformin group (12.6%vs10.3%, p = 0.545). Multivariable logistic regression analysis indicated eGFR ≤60 ml/min/1.73 m2[p = 0.025, OR: 3.131; 95% CI (1.156-8.482)] and contrast volume [p = 0.002, OR: 1.010; 95% CI (1.004-1.016)] were predictive factors of CI-AKI. Metformin therapy was irrelevant to CI-AKI [p = 0.365, OR: 0.698; 95% CI (0.320-1.521)]. No case of lactic acidosis was found in this study. Besides, the study supported discontinuation of metformin was not beneficial for patients' blood glucose control after admission.

CONCLUSIONS

The study indicated that the metformin continuation after primary PCI for STEMI in diabetic patients with eGFR > 30 ml/min / 1.73 m2 did not increase the risk of CI-AKI.

Metformin treatment for patients with diabetes and chronic kidney disease: A Korean Diabetes Association and Korean Society of Nephrology consensus statement

The safety of metformin use for patients with type 2 diabetes mellitus (T2DM) and advanced kidney disease is controversial, and more recent guidelines have suggested that metformin be used cautiously in this group until more definitive evidence concerning its safety is available. The Korean Diabetes Association and the Korean Society of Nephrology have agreed on consensus statements concerning metformin use for patients with T2DM and renal dysfunction, particularly when these patients undergo imaging studies using iodinated contrast media (ICM). Metformin can be used safely when the estimated glomerular filtration rate (eGFR) is ≥ 45 mL/min/1.73 m². If the eGFR is between 30 and 44 mL/min/1.73 m², metformin treatment should not be started. If metformin is already in use, a daily dose of ≤ 1,000 mg is recommended. Metformin is contraindicated when the eGFR is < 30 mL/min/1.73 m². Renal function should be evaluated prior to any ICM-related procedures. During procedures involving intravenous administration of ICM, metformin should be discontinued starting the day of the procedures and up to 48 hours post-procedures if the eGFR is < 60 mL/min/1.73 m².

Metformin Treatment for Patients with Diabetes and Chronic Kidney Disease: A Korean Diabetes Association and Korean Society of Nephrology Consensus Statement

The safety of metformin use for patients with type 2 diabetes mellitus (T2DM) and advanced kidney disease is controversial, and more recent guidelines have suggested that metformin be used cautiously in this group until more definitive evidence concerning its safety is available. The Korean Diabetes Association and the Korean Society of Nephrology have agreed on consensus statements concerning metformin use for patients with T2DM and renal dysfunction, particularly when these patients undergo imaging studies using iodinated contrast media (ICM). Metformin can be used safely when the estimated glomerular filtration rate (eGFR) is ≥45 mL/min/1.73 m². If the eGFR is between 30 and 44 mL/min/1.73 m², metformin treatment should not be started. If metformin is already in use, a daily dose of ≤1,000 mg is recommended. Metformin is contraindicated when the eGFR is <30 mL/min/1.73 m². Renal function should be evaluated prior to any ICM-related procedures. During procedures involving intravenous administration of ICM, metformin should be discontinued starting the day of the procedures and up to 48 hours post-procedures if the eGFR is <60 mL/min/1.73 m².

Metformin lactic acidosis: Should we still be afraid?

Metformin, the first choice drug for type 2 diabetes treatment in all stages of therapy, and one of the most widely prescribed anti-hyperglycemic agents worldwide, represents a rare example of an old drug which continues to display new beneficial effects in various fields. However, lactic acidosis (LA) persists as a serious adverse effect. LA incidence is low and is not necessarily determined by the administration of metformin. Unfortunately, the concern for this complication has negatively affected the drug use, particularly in chronic kidney disease, which may impair drug excretion, and in congestive heart failure and chronic liver disease, which may promote lactate accumulation. This review describes how not only these historical contraindications have been considerably scaled back, though rather a recent large body of evidence supports a protective effect of biguanide on kidney, heart and liver and, maybe, against lactic acidosis itself. It is worthy to slow down both contraindications and precautions to metformin use, not to deprive a significant number of diabetic patients, as those with kidney, heart and liver comorbidities, from its potential benefits, and not to hamper in the near future the putative advantages in a wide spectrum of conditions outside of diabetes.

Use of Medicines that May Exacerbate Heart Failure in Older Adults: Therapeutic Complexity of Multimorbidity

BACKGROUND

Multimorbidity is common in older patients with heart failure (HF), complicating therapeutic management and increasing the risk of harm.

OBJECTIVE

This study sought to examine the prevalence of medicines for the treatment of comorbid conditions potentially associated with harm in older people, before and after HF hospitalization.

METHODS

A retrospective cohort study of older people hospitalized with a primary diagnosis of HF over a 12-month period was conducted using administrative health claims data from the Department of Veterans' Affairs (DVA) Australia. We examined the prevalence of medicines that may exacerbate or worsen HF as defined by the American Heart Association (AHA) and Australian HF clinical guidelines, in the 30 days prior and 120 days before and after discharge for HF.

RESULTS

A total of 4069 older adults were hospitalized for HF during the study period; almost 60% (n = 2435) received at least one medicine associated with an increased risk of harm before hospitalization, with the majority (66.7%, n = 1623) dispensed in the 30 days prior. A small but significant reduction after hospitalization was observed, but 56% (n = 1638) received at least one of these medicines after hospitalization (p = 0.001). Over one-quarter received two or more medicines before hospitalization, and this only reduced to 22% post-hospitalization (p < 0.0001).

CONCLUSIONS

Little change in the prescribing of potentially harmful medicines for HF was observed; 56% of older adults received at least one following hospitalization for HF, highlighting the therapeutic complexity of multimorbidity in HF. Use of the AHA list to facilitate identification of potentially harmful medicines, followed by prioritization of treatment goals and appropriate risk mitigation are needed to facilitate reduction in hospitalization for patients with HF with multimorbidity.

Lactic acidosis associated with metformin in patients with moderate to severe chronic kidney disease: study protocol for a multicenter population-based case-control study using health databases

BACKGROUND

The use of metformin in patients with type 2 diabetes mellitus has been associated with lactic acidosis. However, the information available in patients with moderate-severe chronic kidney disease is scarce.

METHODS

The ALIMAR-C2 study is a case-control study to assess the association between metformin and lactic acidosis in patients with type 2 diabetes mellitus and moderate-severe chronic kidney disease. The study will be performed with computerized registered electronic health records from eight Spanish hospitals linked to their corresponding primary care health areas from 2010 to 2016, comprising approximately 22.1 million person-years of follow-up. Logistic regression will be used to assess the crude and adjusted risk of lactic acidosis associated with metformin use overall and stratifying by use and dose categories, and chronic kidney disease stage. The overall case fatality rate of lactic acidosis, as well as the case fatality rate stratified by chronic kidney disease stage, will be calculated.

DISCUSSION

The ALIMAR-C2 study will provide useful information about the risk of lactic acidosis in type 2 diabetes mellitus patients with renal impairment using metformin.

Metformin inhibits IL-6 signaling by decreasing IL-6R expression on multiple myeloma cells

IL-6 signaling plays a crucial role in the pathogenesis of a number of diseases, including multiple myeloma, primary amyloidosis, cytokine release syndrome and other inflammatory conditions. It is central for the growth and survival of malignant plasma cells. IL-6R and IL-6ST receptors transduce IL-6 signaling. Molecular mechanisms regulating expression of IL-6R are not well understood and current therapies are based on monoclonal antibody to target IL-6 signaling. Small molecule inhibitors targeting IL-6 signaling are highly desirable. Metformin specifically decreased IL-6R expression which is mediated via AMPK, mTOR, and miR34a. This is a novel finding and adds to existing therapies targeting IL-6 signaling.

The antineoplastic drug metformin downregulates YAP by interfering with IRF-1 binding to the YAP promoter in NSCLC

Background

Activation of the oncogene YAP has been shown to be related to lung cancer progression and associates with poor prognosis and metastasis. Metformin is a drug commonly used in the treatment of diabetes and with anticancer activity. However, the mechanism through which metformin inhibits tumorigenesis via YAP is poorly understood.

Methods

The mRNA and protein expressions were analyzed by RT-PCR and western blot. The cellular proliferation was detected by CCK8 and MTT. The cell migration and invasion growth were analyzed by wound healing assay and transwell assay. The activities of promoter were analyzed by luciferase reporter assay. Chromatin immunoprecipitation detected the combining ability of IRF-1 and 5′UTR-YAP.

Findings

Our immunohistochemistry staining and RT-PCR assays showed that the expression of YAP was higher in lung carcinoma samples. Interestingly, metformin was able to downregulate YAP mRNA and protein expression in lung cancer cells. Mechanistically, we found that metformin depressed YAP promoter by competing with the binding of the transcription factor IRF-1 in lung cancer cells. Moreover, combination of metformin and verteporfin synergistically inhibits cell proliferation, promotes apoptosis and suppresses cell migration/invasion by downregulating YAP, therefore reduces the side effects caused by their single use and improve the quality of life for patients with lung cancer.

Interpretation

we concluded that metformin depresses YAP promoter by interfering with the binding of the transcription factor IRF-1. Importantly, verteporfin sensitizes metformin-induced the depression of YAP and inhibition of cell growth and invasion in lung cancer cells.

Fund

This work was supported by National Natural Science Foundation of China (No.31801085), the Science and Technology Development Foundation of Yantai (2015ZH082), Natural Science Foundation of Shandong Province (ZR2018QH004, ZR2016HB55, ZR2017PH067 and ZR2017MH125), and Research Foundation of Binzhou Medical University (BY2015KYQD29 and BY2015KJ14).