Clinical Outcomes of Metformin Use in Populations With Chronic Kidney Disease, Congestive Heart Failure, or Chronic Liver Disease: A Systematic Review

Metformin increases urinary sodium excretion by reducing phosphorylation of the sodium-chloride cotransporter

OBJECTIVE

Metformin is an antidiabetic drug that is widely used to treat patients with diabetes mellitus. Recent studies have reported that treatment with metformin not only improved blood glucose levels but also reduced blood pressure. However, it remains unclear how metformin reduces blood pressure. We hypothesized that metformin affects sodium reabsorption in the kidneys.

METHODS

Urinary sodium excretion and expression of renal sodium transporters were examined in 8-week-old male C57BL/6 mice with acute and chronic treatment of metformin. In addition, we examined metformin effects using ex vivo preparations of mice kidney slices.

RESULTS

In this study, we demonstrated that metformin increased urinary sodium excretion by reducing phosphorylation of the thiazide-sensitive Na-Cl cotransporter (NCC) in acute and chronic metformin administration. We also confirmed reduction of phosphorylated NCC in an ex vivo study. The activity of other renal sodium transporters, such as NKCC2, ENaC, and NHE3 did not show significant changes. WNK-OSR1/SPAK kinase signals were not involved in this inactivation effect of metformin on NCC.

CONCLUSION

Metformin increased urinary sodium excretion by reducing phosphorylation of NCC, suggesting its role in improving hypertension.

Deleting Death and Dialysis: Conservative Care of Cardio-Vascular Risk and Kidney Function Loss in Chronic Kidney Disease (CKD)

The uremic syndrome, which is the clinical expression of chronic kidney disease (CKD), is a complex amalgam of accelerated aging and organ dysfunctions, whereby cardio-vascular disease plays a capital role. In this narrative review, we offer a summary of the current conservative (medical) treatment options for cardio-vascular and overall morbidity and mortality risk in CKD. Since the progression of CKD is also associated with a higher cardio-vascular risk, we summarize the interventions that may prevent the progression of CKD as well. We pay attention to established therapies, as well as to novel promising options. Approaches that have been considered are not limited to pharmacological approaches but take into account lifestyle measures and diet as well. We took as many randomized controlled hard endpoint outcome trials as possible into account, although observational studies and post hoc analyses were included where appropriate. We also considered health economic aspects. Based on this information, we constructed comprehensive tables summarizing the available therapeutic options and the number and kind of studies (controlled or not, contradictory outcomes or not) with regard to each approach. Our review underscores the scarcity of well-designed large controlled trials in CKD. Nevertheless, based on the controlled and observational data, a therapeutic algorithm can be developed for this complex and multifactorial condition. It is likely that interventions should be aimed at targeting several modifiable factors simultaneously.

Chronic Kidney Disease-Induced Insulin Resistance: Current State of the Field

PURPOSE OF REVIEW

Insulin resistance is an early complication of chronic kidney disease (CKD) associated with worsening cardiovascular outcomes. This review will evaluate mechanisms responsible for CKD-induced insulin resistance and therapies currently available.

RECENT FINDINGS

Recent mechanisms have been identified including SIRPα and specific E3 ubiquitin ligases causing insulin resistance in CKD. The hallmark finding in these mechanisms is degradation of the insulin receptor substrate 1 (IRS1) which impairs intracellular insulin signaling and ultimately metabolism. The mechanisms responsible for insulin resistance in CKD include inflammation, oxidative stress, elevations in aldosterone, angiotensin II, uremic toxins, and metabolic acidosis. Potential treatments currently available for CKD-induced insulin resistance include lifestyle modification and metformin. Potential future treatments may include glucagon-like peptide agonists, SGLT2 inhibitors, and thiazolidinediones. Investigations into molecular mechanisms responsible for insulin resistance in CKD may provide new therapeutic targets while current therapies may prevent the catabolic sequelae of CKD and ameliorate its cardiovascular consequences.

Perspective Review: Type 2 Diabetes and Readmission for Heart Failure

Heart failure is a leading cause for hospitalisation and for readmission, especially in patients over the age of 65. Diabetes is an increasingly common companion to heart failure. The presence of diabetes and its associated comorbidity increases the risk of adverse outcomes and premature mortality in patients with heart failure. In particular, patients with diabetes are more likely to be readmitted to hospital soon after discharge. This may partly reflect the greater severity of heart disease in these patients. In addition, agents that reduce the chances of readmission such as β-blockers, renin-angiotensin-aldosterone system blockers, and mineralocorticoid receptor antagonists are underutilised because of the perceived increased risks of adverse drug reactions and other limitations. In some cases, readmission to hospital is precipitated by acute decompensation of heart failure (re-exacerbation) leading to pulmonary congestion and/or refractory oedema. However, it appears that for most of the patients admitted and then discharged with a primary diagnosis of heart failure, most readmissions are not due to heart failure, but rather due to comorbidity including arrhythmia, infection, adverse drug reactions, and renal impairment/reduced hydration. All of these are more common in patients who also have diabetes, and all may be partly preventable. The many different reasons for readmission underline the critical value of multidisciplinary comprehensive care in patients admitted with heart failure, especially those with diabetes. A number of new strategies are also being developed to address this area of need, including the use of SGLT2 inhibitors, novel nonsteroidal mineralocorticoid antagonists, and neprilysin inhibitors.

Is metformin poised for a second career as an antimicrobial?

Metformin, a widely used antihyperglycaemic, has a good safety profile, reasonably manageable side-effects, is inexpensive, and causes a desirable amount of weight loss. In 4 studies of patients with tuberculosis (1 prospective and 3 retrospective), metformin administration resulted in better outcomes. In mice with several models of endotoxemia, metformin diminished levels of proinflammatory cytokines and improved survival. Laboratory studies showed effectiveness of the drug on multiple pathogens, including Trichinella spiralis, Staphylococcus aureus, Pseudomonas aeruginosa, hepatitis B virus, hepatitis C virus, and human immunodeficiency virus. Metformin administration in humans and mice produced major changes in the composition of the gut microbiota. These recently discovered microbe-modulating properties of the drug have led investigators to predict wide therapeutic utility for metformin. The recent easing in United States Food and Drug Administration (FDA) guidelines regarding administration of metformin to patients with kidney disease, and reduced anxiety about patient safety in terms of lactic acidosis, increase the probability of broadening of metformin's usage as a treatment of infectious agents. In this text we review articles pertinent to metformin's effects on microorganisms, both pathogens and commensals. We highlight the possible role of metformin in a wide range of infectious diseases and a possible expansion of its therapeutic profile in this field. A systematic review was done of PubMed indexed articles that examined the effects of metformin on a wide range of pathogens. Metformin was found to have efficacy as an antimicrobial agent in patients with tuberculosis. Mice infected with Trypanosomiasis cruzi had higher survival when also treated with metformin. The drug in vitro was active against T. spiralis, S. aureus, P. aeruginosa, and hepatitis B virus. In addition there is emerging literature on its role in sepsis. We conclude that metformin may have a potential role in the therapy for multiple infectious diseases. Metformin, in addition to its traditional effects on glucose metabolism, provides anti-microbial benefits in patients with tuberculosis and in a very wide range of other infections encounters in vitro and in vivo.

Drug repurposing in kidney disease

Drug repurposing, is the re-tasking of known medications for new clinical indications. Advantages, compared to de novo drug development, include reduced cost and time to market plus the added benefit of a known pharmacokinetic and safety profiles. Suitable drug candidates are identified through serendipitous observations, data mining, or increased understanding of disease mechanisms. This review highlights drugs suited for repurposing in kidney disease. The main cause of mortality in patients with chronic kidney disease is cardiovascular disease. Hence, we have included CV endpoints for the drugs. This review begins with candidates in acute kidney injury: vasodilators levosimendan and vitamin D, followed by candidates in CKD, with particular focus on diabetic kidney disease, autosomal dominant polycystic kidney disease, and focal segmental glomerulosclerosis. Examples include glucose-lowering drugs (sodium glucose co-transporter 2 inhibitors, glucagon-like peptide 1 agonists, and metformin), which have mechanistic potential for cardiac and/or renal protection beyond glucose lowering, with broader applicability to the nondiabetic population; xanthine oxidase inhibitors (allopurinol, febuxostat), selective endothelin receptor A antagonist (atrasentan), Janus kinase inhibitor (baricitinib), selective costimulation modulator (abatacept), pentoxyfylline, and the DNA demethylating agent/vasodilator (hydralazine).

Metformin use and health care utilization in patients with coexisting chronic obstructive pulmonary disease and diabetes mellitus

Background

Chronic obstructive pulmonary disease (COPD) is associated with persistent systemic inflammation. Anti-inflammatory therapies have been shown to decrease acute exacerbations of COPD. The antidiabetic medication metformin decreases oxidative stress and inflammation and may benefit patients with COPD. We aimed at investigating the effect of metformin on health care utilizations in patients with coexisting COPD and diabetes mellitus (DM).

Methods

We studied 5% Medicare beneficiaries with coexisting COPD and DM prescribed metformin or other antidiabetics during the period 2007-2010. The primary outcome was COPD-specific emergency room (ER) visits and hospitalizations; the secondary outcome was all-cause ER visits and hospitalizations over the 2-year follow-up after the index antidiabetic prescription. The effects of metformin were examined by COPD complexity and compared with the effects of other antidiabetic medications.

Results

Among 11,260 patients, 3,193 were metformin users and 8,067 were nonusers. Metformin users were younger, were less sick, were less likely to be on oxygen, and had fewer hospitalizations in the prior year compared with the nonusers. Over a 2-year period, metformin users had lower COPD-specific and all-cause ER visits and hospitalizations (7.11% vs 9.61%, p<0.0001; and 61.63% vs 71.27%, p<0.0001, respectively). In a stratified multivariable analysis, the odds of COPD-specific ER visits and hospitalizations were lower in patients with low-complexity COPD (adjusted odds ratio =0.66, 95% confidence interval =0.52-0.85). However, patients with all COPD complexities get benefits of metformin on all-cause ER visits and hospitalizations.

Conclusion

The use of metformin in patients with coexisting COPD and DM was associated with fewer COPD-specific ER visits and hospitalizations, especially in low-complexity COPD.

Management of diabetes in older adults

Type 2 diabetes prevalence is high in older adults and is expected to rise in the next decades. Diabetes in the population of frail older adults is accompanied by functional disability, several comorbidities, and premature mortality. A comprehensive geriatric assessment, including functional, cognitive, mental and social status, is advisable for identifying the glycemic targets and glucose-lowering therapies, focused on patient preferences, needs, and risks. The therapeutic options for older adults with diabetes are like those for the adult population. However, the pharmacological treatments must be carefully prescribed and monitored, taking into consideration the patient cognitive capacities, the potentially life-threatening drug-drug interactions, the cardiovascular risk, and with the main goal of avoiding hypoglycemia. Also, a careful nutritional evaluation with appropriate tools, as well as a balanced and periodically monitored physical activity, contribute to an effective tailored care plan, as needed by older adults with diabetes. This review evaluates the currently available hypoglycemic drugs and the current indications to the Italian diabetology community, specifically with regard to the treatment of adults aged 75 years or older with diabetes, including the unmet needs by the guidelines.

Mortality Associated with Metformin Versus Sulfonylurea Initiation: A Cohort Study of Veterans with Diabetes and Chronic Kidney Disease

BACKGROUND

For patients with type 2 diabetes and chronic kidney disease (CKD), high-quality evidence about the relative benefits and harms of oral glucose-lowering drugs is limited.

OBJECTIVE

To evaluate whether mortality risk differs after the initiation of monotherapy with either metformin or a sulfonylurea in Veterans with type 2 diabetes and CKD.

DESIGN

Observational, national cohort study in the Veterans Health Administration (VHA).

PARTICIPANTS

Veterans who received care from the VHA for at least 1 year prior to initiating monotherapy treatment for type 2 diabetes with either metformin or a sulfonylurea between 2004 and 2009.

MAIN MEASURES

Metformin and sulfonylurea use was assessed from VHA electronic pharmacy records. The CKD-EPI equation was used to estimate glomerular filtration rate (eGFR). The outcome of death from January 1, 2004, through December 31, 2009, was assessed from VHA Vital Status files.

KEY RESULTS

Among 175,296 new users of metformin or a sulfonylurea monotherapy, 5121 deaths were observed. In primary analyses adjusted for all measured potential confounding factors, metformin monotherapy was associated with a lower mortality hazard ratio (HR) compared with sulfonylurea monotherapy across all ranges of eGFR evaluated (HR ranging from 0.59 to 0.80). A secondary analysis of mortality risk differences favored metformin across all eGFR ranges; the greatest risk difference was observed in the eGFR category 30-44 mL/min/1.73m² (12.1 fewer deaths/1000 person-years, 95% CI 5.2-19.0).

CONCLUSIONS

Initiation of metformin versus a sulfonylurea among individuals with type 2 diabetes and CKD was associated with a substantial reduction in mortality, in terms of both relative and absolute risk reduction. The largest absolute risk reduction was observed among individuals with moderately-severely reduced eGFR (30-44 mL/min/1.73m²).

Monitoring Patients on Metformin: Recent Changes and Rationales

Objective: The Food and Drug Administration recently updated metformin prescribing recommendations for patients with diabetes and renal disease. The American Diabetes Association as well as the American Association of Clinical Endocrinologists and American Clinical Endocrinologists also recommend periodic monitoring of vitamin B12 levels for patients using metformin. A review of the literature was conducted to assess data to evaluate the recent updates to metformin usage and provide rationales for these recommendations. Data Sources: PubMed MESH terms "Diabetes Mellitus, Type 2" and "Renal Insufficiency, Chronic" and "Metformin" were searched with an English limitation from 1990 to May 2017. A MEDLINE search was conducted using the terms "metformin" and "renal disease" from 1990 to May 2017. A PubMed search was conducted using the MESH terms "vitamin b12 deficiency" and "metformin" from 1970 to May 2017. A MEDLINE search was conducted using terms "metformin" and "vitamin B12 deficiency" with an English limitation from 1970 to May 2017. Study Selection and Data Extraction: Retrospective and prospective clinical trials, meta-analyses, and systematic reviews were considered for inclusion. Citations from identified articles were also reviewed for inclusion. Data Synthesis: The incidence of metformin-associated lactic acidosis is minimal. Data indicate metformin-treated patients with an estimated glomerular filtration rate above 30 mL/min/1.73 m2 have a reduction in mortality. Additionally, data suggest metformin may lead to vitamin B12 deficiency. Conclusion: Data support recommendations for metformin use in patients with diabetes and renal insufficiency with an estimated glomerular filtration rate above 30 mL/min/1.73 m2. Data also suggest that baseline and periodic testing of vitamin B12 levels are warranted and supported by clinical guidelines due to the risk of vitamin B12 deficiency in metformin-treated patients.

Exploring heart failure events in contemporary cardiovascular outcomes trials in type 2 diabetes mellitus

INTRODUCTION

Type 2 diabetes mellitus (DM) and heart failure (HF) are closely related, with the onset of one serving as an independent risk factor for the development or progression of the other. The true impact of their relationship is poorly understood. Since various classes of glucose-lowering therapies have been shown to have differing impact on cardiovascular outcomes, cardiovascular effects of such therapies have been increasingly formally evaluated. Areas covered: With the increasing prevalence of concomitant HF and type 2 DM, HF outcomes serve as important endpoints in trials of glucose-lowering therapies. A thorough literature search of recent cardiovascular outcome trials of glucose-lowering therapies was performed. The authors focus on the availability and extent of ascertainment of data related to HF outcomes in these contemporary clinical trial experiences. Expert commentary: Although early cardiovascular outcome trials did not focus on HF events, these outcomes have been increasingly recognized as meaningful end points in cardiovascular outcome trials. The ascertainment of HF end point data needs to become routine and standardized.

SIRT2 Acts as a Cardioprotective Deacetylase in Pathological Cardiac Hypertrophy

BACKGROUND

Pathological cardiac hypertrophy induced by stresses such as aging and neurohumoral activation is an independent risk factor for heart failure and is considered a target for the treatment of heart failure. However, the mechanisms underlying pathological cardiac hypertrophy remain largely unknown. We aimed to investigate the roles of SIRT2 in aging-related and angiotensin II (Ang II)-induced pathological cardiac hypertrophy.

METHODS

Male C57BL/6J wild-type and Sirt2 knockout mice were subjected to the investigation of aging-related cardiac hypertrophy. Cardiac hypertrophy was also induced by Ang II (1.3 mg/kg/d for 4 weeks) in male C57BL/6J Sirt2 knockout mice, cardiac-specific SIRT2 transgenic (SIRT2-Tg) mice, and their respective littermates (8 to ≈12 weeks old). Metformin (200 mg/kg/d) was used to treat wild-type and Sirt2 knockout mice infused with Ang II. Cardiac hypertrophy, fibrosis, and cardiac function were examined in these mice.

RESULTS

SIRT2 protein expression levels were downregulated in hypertrophic hearts from mice. Sirt2 knockout markedly exaggerated cardiac hypertrophy and fibrosis and decreased cardiac ejection fraction and fractional shortening in aged (24-month-old) mice and Ang II-infused mice. Conversely, cardiac-specific SIRT2 overexpression protected the hearts against Ang II-induced cardiac hypertrophy and fibrosis and rescued cardiac function. Mechanistically, SIRT2 maintained the activity of AMP-activated protein kinase (AMPK) in aged and Ang II-induced hypertrophic hearts in vivo as well as in cardiomyocytes in vitro. We identified the liver kinase B1 (LKB1), the major upstream kinase of AMPK, as the direct target of SIRT2. SIRT2 bound to LKB1 and deacetylated it at lysine 48, which promoted the phosphorylation of LKB1 and the subsequent activation of LKB1-AMPK signaling. Remarkably, the loss of SIRT2 blunted the response of AMPK to metformin treatment in mice infused with Ang II and repressed the metformin-mediated reduction of cardiac hypertrophy and protection of cardiac function.

CONCLUSIONS

SIRT2 promotes AMPK activation by deacetylating the kinase LKB1. Loss of SIRT2 reduces AMPK activation, promotes aging-related and Ang II-induced cardiac hypertrophy, and blunts metformin-mediated cardioprotective effects. These findings indicate that SIRT2 will be a potential target for therapeutic interventions in aging- and stress-induced cardiac hypertrophy.

Pharmacological management of type 2 diabetes: what's new in 2017?

INTRODUCTION

Novelties in the management of type 2 diabetes are dominated by the commercialisation of new glucose-lowering agents, which offer alternatives to older antidiabetic medications, and by the publication of several prospective placebo-controlled outcome trials, which demonstrated not only cardiovascular safety but also cardiovascular and renal protection with some new medications. Areas covered: Updates regarding the use of glucose-lowering agents are discussed from a clinical point of view. Some new viewpoints concern older antidiabetic agents such as metformin, sulfonylureas and glitazones whose benefit-risk balance has been revisited, especially in high risk patients. The recent data regarding DPP-4 inhibitors (gliptins) focused on the safety profile of this pharmacological class, including in patients with impaired renal function. The highlight concerns the cardiovascular (and renal) protection by some GLP-1 receptor agonists (liraglutide, semaglutide) and SGLT2 inhibitors (empagliflozin, canagliflozin) in patients with high cardiovascular risk. Finally, efficacy and safety of new combinations and advances in insulin therapy will be briefly discussed. Expert commentary: The recent data from randomized controlled trials, meta-analyses and observational real-life studies should trigger a revision of the algorithm for the treatment of hyperglycemia in type 2 diabetes, especially in patients with high cardiovascular and/or renal risk.

Metformin, the aspirin of the 21st century: its role in gestational diabetes mellitus, prevention of preeclampsia and cancer, and the promotion of longevity

Metformin is everywhere. Originally introduced in clinical practice as an antidiabetic agent, its role as a therapeutic agent is expanding to include treatment of prediabetes mellitus, gestational diabetes mellitus, and polycystic ovarian disease; more recently, experimental studies and observations in randomized clinical trials suggest that metformin could have a place in the treatment or prevention of preeclampsia. This article provides a brief overview of the history of metformin in the treatment of diabetes mellitus and reviews the results of metaanalyses of metformin in gestational diabetes mellitus as well as the treatment of obese, non-diabetic, pregnant women to prevent macrosomia. We highlight the results of a randomized clinical trial in which metformin administration in early pregnancy did not reduce the frequency of large-for-gestational-age infants (the primary endpoint) but did decrease the frequency of preeclampsia (a secondary endpoint). The mechanisms by which metformin may prevent preeclampsia include a reduction in the production of antiangiogenic factors (soluble vascular endothelial growth factor receptor-1 and soluble endoglin) and the improvement of endothelial dysfunction, probably through an effect on the mitochondria. Another potential mechanism whereby metformin may play a role in the prevention of preeclampsia is its ability to modify cellular homeostasis and energy disposition, mediated by rapamycin, a mechanistic target. Metformin has a molecular weight of 129 Daltons and therefore readily crosses the placenta. There is considerable evidence to suggest that this agent is safe during pregnancy. New literature on the role of metformin as a chemotherapeutic adjuvant in the prevention of cancer and in prolonging life and protecting against aging is reviewed briefly. Herein, we discuss the mechanisms of action and potential benefits of metformin.

Therapeutic Considerations for Antihyperglycemic Agents in Diabetic Kidney Disease

Diabetic kidney disease is among the most frequent complications of diabetes, with approximately 50% of patients with ESRD attributed to diabetes in developed countries. Although intensive glycemic management has been shown to delay the onset and progression of increased urinary albumin excretion and reduced GFR in patients with diabetes, conservative dose selection and adjustment of antihyperglycemic medications are necessary to balance glycemic control with safety. A growing body of literature is providing valuable insight into the cardiovascular and renal safety and efficacy of newer antihyperglycemic medications in the dipeptidyl peptidase-4 inhibitor, glucagon-like peptide-1 receptor agonist, and sodium-glucose cotransporter 2 inhibitor classes of medications. Ongoing studies will continue to inform future use of these agents in patients with diabetic kidney disease.

Diabetes Mellitus and Heart Failure

Epidemiologic and clinical data from the last 2 decades have shown that the prevalence of heart failure in diabetes is very high, and the prognosis for patients with heart failure is worse in those with diabetes than in those without diabetes. Experimental data suggest that various mechanisms contribute to the impairment in systolic and diastolic function in patients with diabetes, and there is an increased recognition that these patients develop heart failure independent of the presence of coronary artery disease or its associated risk factors. In addition, current clinical data demonstrated that treatment with the sodium glucose cotransporter 2 inhibitor empagliflozin reduced hospitalization for heart failure in patients with type 2 diabetes mellitus and high cardiovascular risk. This review article summarizes recent data on the prevalence, prognosis, pathophysiology, and therapeutic strategies to treat patients with diabetes and heart failure.

Antihyperglycemic treatment in patients with type 2 diabetes in Italy: the impact of age and kidney function

We describe AHA utilization pattern according to age and renal function in type 2 diabetes mellitus (T2DM), in real-life conditions.

The analysis was performed using the data set of electronic medical records collected between 1 January and 31 December, 2011 in 207 Italian diabetes centers. The study population consisted of 157,595 individuals with T2DM. The AHA treatment regimens was evaluated. Kidney function was assessed by eGFR, estimated using the CKD-EPI formula. Other determinations: HbA1c, blood pressure (BP), low- density lipoprotein (LDL-c), total and high density lipoprotein cholesterol (TC and HDL-c), triglycerides (TG) and serum uric acid (SUA). Quality of care was assessed through Q score.

The proportion of subjects taking metformin declined progressively across age quartiles along with eGFR values, but remained high in oldest subjects (i.e. 54.5 %). On the other hand, the proportion of patients on secretagogues or insulin increased with aging (i.e. 54.7% and 37% in the fourth age quartile, respectively). The percentage of patients with low eGFR (i.e. <30 ml/min/1.73m2) taking either metformin or sulphonilureas/repaglinide was particularly high (i.e. 15.3% and 34.3% respectively).

In a large real-life cohort of T2DM, metformin or sulphonylureas/repaglinide, although not recommended, are frequently prescribed to elderly subjects with severe kidney disease.

Diabetes-Related Cardiac Dysfunction

The proposal that diabetes plays a role in the development of heart failure is supported by the increased risk associated with this disease, even after correcting for all other known risk factors. However, the precise mechanisms contributing to the condition referred to as diabetic cardiomyopathy have remained elusive, as does defining the disease itself. Decades of study have defined numerous potential factors that each contribute to disease susceptibility, progression, and severity. Many recent detailed reviews have been published on mechanisms involving insulin resistance, dysregulation of microRNAs, and increased reactive oxygen species, as well as causes including both modifiable and non-modifiable risk factors. As such, the focus of the current review is to highlight aspects of each of these topics and to provide specific examples of recent advances in each area.

Diabetes Mellitus and Heart Failure

Epidemiologic and clinical data from the last 2 decades have shown that the prevalence of heart failure in diabetes is very high, and the prognosis for patients with heart failure is worse in those with diabetes than in those without diabetes. Experimental data suggest that various mechanisms contribute to the impairment in systolic and diastolic function in patients with diabetes, and there is an increased recognition that these patients develop heart failure independent of the presence of coronary artery disease or its associated risk factors. In addition, current clinical data demonstrated that treatment with the sodium glucose cotransporter 2 inhibitor empagliflozin reduced hospitalization for heart failure in patients with type 2 diabetes mellitus and high cardiovascular risk. This review article summarizes recent data on the prevalence, prognosis, pathophysiology, and therapeutic strategies to treat patients with diabetes and heart failure.

Metformin in heart failure patients

The use of metformin was considered a contraindication in heart failure patients because of the potential risk of lactic acidosis; however, more recent evidence has shown that this should no longer be the case. We reviewed the current literature and the recent guideline to correct the misconception.

Comparative Safety of Sulfonylurea and Metformin Monotherapy on the Risk of Heart Failure: A Cohort Study

BACKGROUND

Medications that impact insulin sensitivity or cause weight gain may increase heart failure risk. Our aim was to compare heart failure and cardiovascular death outcomes among patients initiating sulfonylureas for diabetes mellitus treatment versus metformin.

METHODS AND RESULTS

National Veterans Health Administration databases were linked to Medicare, Medicaid, and National Death Index data. Veterans aged ≥18 years who initiated metformin or sulfonylureas between 2001 and 2011 and whose creatinine was <1.4 (females) or 1.5 mg/dL (males) were included. Each metformin patient was propensity score-matched to a sulfonylurea initiator. The outcome was hospitalization for acute decompensated heart failure as the primary reason for admission or a cardiovascular death. There were 126 867 and 79 192 new users of metformin and sulfonylurea, respectively. Propensity score matching yielded 65 986 per group. Median age was 66 years, and 97% of patients were male; hemoglobin A1c 6.9% (6.3, 7.7); body mass index 30.7 kg/m2 (27.4, 34.6); and 6% had heart failure history. There were 1236 events (1184 heart failure hospitalizations and 52 cardiovascular deaths) among sulfonylurea initiators and 1078 events (1043 heart failure hospitalizations and 35 cardiovascular deaths) among metformin initiators. There were 12.4 versus 8.9 events per 1000 person-years of use (adjusted hazard ratio 1.32, 95%CI 1.21, 1.43). The rate difference was 4 heart failure hospitalizations or cardiovascular deaths per 1000 users of sulfonylureas versus metformin annually.

CONCLUSIONS

Predominantly male patients initiating treatment for diabetes mellitus with sulfonylurea had a higher risk of heart failure and cardiovascular death compared to similar patients initiating metformin.