Mediators of the improvement in heart failure outcomes with empagliflozin in the EMPA-REG OUTCOME trial

The effect of Empagliflozin on echocardiographic parameters in diabetic patients after acute myocardial infarction: A systematic review and meta-analysis with trial sequential analysis

Patients with diabetes mellitus (DM) are at higher risk of cardiovascular events, particularly acute myocardial infarction (MI). Sodium-glucose cotransporter 2 inhibitors (SGLT2i) can improve cardiac outcomes among heart failure individuals, however, the effects on acute myocardial infarction remain unclear. This meta-analysis investigates the impact of empagliflozin in diabetic patients following acute myocardial infarction. We comprehensively searched PubMed, Scopus, Cochrane, and Web of Science through August 10th, 2023. We included studies comparing empagliflozin versus placebo in diabetes patients with acute myocardial infarction. We used Revman to report the data as mean difference (MD) and 95% confidence interval (CI), and our effect size with a random effects model. Additionally, we performed Trial Sequential Analysis (TSA) to test the robustness of the results. The study protocol was published on PROSPERO with ID: CRD42023447733. Five studies with a total of 751 patients were included in our analysis. Empagliflozin was effective to improve LVEF% (MD: 1.80, 95% CI [0.50, 3.10], p = 0.007), left ventricular end-diastolic volume (LVEDV) (MD: -9.93, 95% CI [-16.07, -3.80], p = 0.002), and left ventricular end-systolic volume (LVESV) (MD: -7.91, 95% CI [-11.93, -3.88], p = 0.0001). However, there was no difference between empagliflozin and placebo groups in terms of NT-pro BNP (MD: - 136.59, 95% CI [-293.43, 20.25], p = 0.09), and HbA1c (MD: -0.72, 95% CI [-1.73, 0.29], p = 0.16). Additionally, empagliflozin did not prevent hospitalization due to heart failure (RR: 0.59, 95% CI [0.16, 2.24], p = 0.44, I-squared = 0%), and mortality (RR: 1.34, 95% CI [0.15,11.90], p = 0.79, I-squared = 25%). Empagliflozin initiation in diabetic patients following acute MI may improve echocardiographic parameters. However, empagliflozin might not be effective in heart failure prevention and optimal glycemic control in this patient population. Further large-scale trials are warranted to ascertain our findings.

Mechanisms of heart failure and chronic kidney disease protection by SGLT2 inhibitors in nondiabetic conditions

Sodium-glucose cotransporter 2 inhibitors (SGLT2is), initially developed for type 2 diabetes (T2D) treatment, have demonstrated significant cardiovascular and renal benefits in heart failure (HF) and chronic kidney disease (CKD), irrespective of T2D. This review provides an analysis of the multifaceted mechanisms underlying the cardiorenal benefits of SGLT2i in HF and CKD outside of the T2D context. Eight major aspects of the protective effects of SGLT2i beyond glycemic control are explored: 1) the impact on renal hemodynamics and tubuloglomerular feedback; 2) the natriuretic effects via proximal tubule Na+/H+ exchanger NHE3 inhibition; 3) the modulation of neurohumoral pathways with evidence of attenuated sympathetic activity; 4) the impact on erythropoiesis, not only in the context of local hypoxia but also systemic inflammation and iron regulation; 5) the uricosuria and mitigation of the hyperuricemic environment in cardiorenal syndromes; 6) the multiorgan metabolic reprogramming including the potential induction of a fasting-like state, improvement in glucose and insulin tolerance, and stimulation of lipolysis and ketogenesis; 7) the vascular endothelial growth factor A (VEGF-A) upregulation and angiogenesis, and 8) the direct cardiac effects. The intricate interplay between renal, neurohumoral, metabolic, and cardiac effects underscores the complexity of SGLT2i actions and provides valuable insights into their therapeutic implications for HF and CKD. Furthermore, this review sets the stage for future research to evaluate the individual contributions of these mechanisms in diverse clinical settings.

Proximal versus distal diuretics in congestive heart failure

Volume overload represents a hallmark clinical feature linked to the development and progression of heart failure (HF). Alleviating signs and symptoms of volume overload represents a foundational HF treatment target that is achieved using loop diuretics in the acute and chronic setting. Recent work has provided evidence to support guideline-directed medical therapies, such as sodium glucose cotransporter 2 (SGLT2) inhibitors and mineralocorticoid receptor (MR) antagonists, as important adjunct diuretics that may act synergistically when used with background loop diuretics in people with chronic HF. Furthermore, there is growing interest in understanding the role of SGLT2 inhibitors, carbonic anhydrase inhibitors, thiazide diuretics, and MR antagonists in treating volume overload in patients hospitalized for acute HF, particularly in the setting of loop diuretic resistance. Thus, the current review demonstrates that: (i) SGLT2 inhibitors and MR antagonists confer long-term cardioprotection in chronic HF patients but it is unclear whether natriuresis or diuresis represents the primary mechanisms for this benefit, (ii) SGLT2 inhibitors, carbonic anhydrase inhibitors, and thiazide diuretics increase natriuresis in the acute HF setting, but implications on long-term outcomes remain unclear and warrants further investigation, and (iii) a multi-nephron segment approach, using agents that act on distinct segments of the nephron, potentiate diuresis to alleviate signs and symptoms of volume overload in acute HF.

How do SGLT2 inhibitors protect the kidney? A mediation analysis of the EMPA-REG OUTCOME trial

INTRODUCTION

Mechanisms underlying kidney benefits with sodium-glucose cotransporter-2 (SGLT2) inhibition in heart failure and/or type 2 diabetes (T2D) with established cardiovascular disease are currently unclear.

METHODS

We evaluated post hoc the factors mediating the effect of empagliflozin on a composite kidney outcome (first sustained estimated glomerular filtration rate ≥40% reduction from baseline, initiation of renal replacement therapy or death due to kidney disease) in EMPA-REG OUTCOME (Empagliflozin Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients). Variables, calculated as change from baseline or updated mean, were evaluated as time-dependent covariates and using a landmark approach (at Week 12) in Cox regression analyses. In multivariable analyses, variables with the greatest mediating effect were added using a step-up procedure.

RESULTS

In univariable time-dependent updated mean covariate analyses, the strongest mediator was hematocrit (99.5% mediation). Hemoglobin, uric acid and urine albumin-to-creatinine ratio mediated 79.4%, 33.2% and 31.0%, respectively. Multivariable analyses were not performed due to the very strong mediation effect of hematocrit. In univariable Week 12 landmark change from baseline analyses, the strongest mediators included hematocrit (40.7%), glycated hemoglobin (28.3%), systolic blood pressure (16.8%) and free fatty acids (16.5%), which yielded a combined mediation of 78.9% in multivariable analysis.

CONCLUSIONS

Changes in hematocrit and hemoglobin were the strongest mediators of empagliflozin's kidney benefits in EMPA-REG OUTCOME participants with T2D and cardiovascular disease.

Semaglutide and Cardiovascular Outcomes by Baseline HbA1c and Change in HbA1c in People With Overweight or Obesity but Without Diabetes in SELECT

OBJECTIVE

To evaluate the cardiovascular effects of semaglutide by baseline glycated hemoglobin (HbA1c) and change in HbA1c in a prespecified analysis of Semaglutide Effects on Cardiovascular Outcomes in People With Overweight or Obesity (SELECT).

RESEARCH DESIGN AND METHODS

In SELECT, people with overweight or obesity and atherosclerotic cardiovascular disease without diabetes were randomized to weekly semaglutide 2.4 mg or placebo. The primary end point of first major adverse cardiovascular event (MACE) (cardiovascular mortality, nonfatal myocardial infarction, or stroke) was reduced by 20% with semaglutide versus placebo. Analysis of outcomes included first MACE, its individual components, expanded MACE (cardiovascular mortality, nonfatal myocardial infarction, or stroke; coronary revascularization; or hospitalization for unstable angina), a heart failure composite (heart failure hospitalization or urgent medical visit or cardiovascular mortality), coronary revascularization, and all-cause mortality by baseline HbA1c subgroup and categories of HbA1c change (<-0.3, -0.3 to 0.3, and >0.3 percentage points) from baseline to 20 weeks using the intention-to-treat principle with Cox proportional hazards.

RESULTS

Among 17,604 participants (mean age 61.6 years, 72.3% male), baseline HbA1c was <5.7% for 33.5%, 5.7% to <6.0% for 34.6%, and 6.0% to <6.5% for 31.9%. Cardiovascular risk reduction with semaglutide versus placebo was not shown to be different across baseline HbA1c groups and was consistent with that of the overall study for all end points, except all-cause mortality. Cardiovascular outcomes were also consistent across subgroups of HbA1c change.

CONCLUSIONS

In people with overweight or obesity and established atherosclerotic cardiovascular disease but not diabetes, semaglutide reduced cardiovascular events irrespective of baseline HbA1c or change in HbA1c. Thus, semaglutide is expected to confer cardiovascular benefits in people with established atherosclerotic cardiovascular disease who are normoglycemic at baseline and/or in those without HbA1c improvements.

Post-trial monitoring of a randomised controlled trial of intensive glycaemic control in type 2 diabetes extended from 10 years to 24 years (UKPDS 91)

BACKGROUND

The 20-year UK Prospective Diabetes Study showed major clinical benefits for people with newly diagnosed type 2 diabetes randomly allocated to intensive glycaemic control with sulfonylurea or insulin therapy or metformin therapy, compared with conventional glycaemic control. 10-year post-trial follow-up identified enduring and emerging glycaemic and metformin legacy treatment effects. We aimed to determine whether these effects would wane by extending follow-up for another 14 years.

METHODS

5102 patients enrolled between 1977 and 1991, of whom 4209 (82·5%) participants were originally randomly allocated to receive either intensive glycaemic control (sulfonylurea or insulin, or if overweight, metformin) or conventional glycaemic control (primarily diet). At the end of the 20-year interventional trial, 3277 surviving participants entered a 10-year post-trial monitoring period, which ran until Sept 30, 2007. Eligible participants for this study were all surviving participants at the end of the 10-year post-trial monitoring period. An extended follow-up of these participants was done by linking them to their routinely collected National Health Service (NHS) data for another 14 years. Clinical outcomes were derived from records of deaths, hospital admissions, outpatient visits, and accident and emergency unit attendances. We examined seven prespecified aggregate clinical outcomes (ie, any diabetes-related endpoint, diabetes-related death, death from any cause, myocardial infarction, stroke, peripheral vascular disease, and microvascular disease) by the randomised glycaemic control strategy on an intention-to-treat basis using Kaplan-Meier time-to-event and log-rank analyses. This study is registered with the ISRCTN registry, number ISRCTN75451837.

FINDINGS

Between Oct 1, 2007, and Sept 30, 2021, 1489 (97·6%) of 1525 participants could be linked to routinely collected NHS administrative data. Their mean age at baseline was 50·2 years (SD 8·0), and 41·3% were female. The mean age of those still alive as of Sept 30, 2021, was 79·9 years (SD 8·0). Individual follow-up from baseline ranged from 0 to 42 years, median 17·5 years (IQR 12·3-26·8). Overall follow-up increased by 21%, from 66 972 to 80 724 person-years. For up to 24 years after trial end, the glycaemic and metformin legacy effects showed no sign of waning. Early intensive glycaemic control with sulfonylurea or insulin therapy, compared with conventional glycaemic control, showed overall relative risk reductions of 10% (95% CI 2-17; p=0·015) for death from any cause, 17% (6-26; p=0·002) for myocardial infarction, and 26% (14-36; p<0·0001) for microvascular disease. Corresponding absolute risk reductions were 2·7%, 3·3%, and 3·5%, respectively. Early intensive glycaemic control with metformin therapy, compared with conventional glycaemic control, showed overall relative risk reductions of 20% (95% CI 5-32; p=0·010) for death from any cause and 31% (12-46; p=0·003) for myocardial infarction. Corresponding absolute risk reductions were 4·9% and 6·2%, respectively. No significant risk reductions during or after the trial for stroke or peripheral vascular disease were observed for both intensive glycaemic control groups, and no significant risk reduction for microvascular disease was observed for metformin therapy.

INTERPRETATION

Early intensive glycaemic control with sulfonylurea or insulin, or with metformin, compared with conventional glycaemic control, appears to confer a near-lifelong reduced risk of death and myocardial infarction. Achieving near normoglycaemia immediately following diagnosis might be essential to minimise the lifetime risk of diabetes-related complications to the greatest extent possible.

FUNDING

University of Oxford Nuffield Department of Population Health Pump Priming.

Cardiovascular protection significantly depends on HbA1c improvement with GLP-1RAs but not with SGLT2 is in type 2 diabetes: A narrative review

BACKGROUND

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter 2 inhibitors (SGLT2is), while developed as antihyperglycaemic medications for the treatment of type 2 diabetes, have proven to reduce major cardiovascular adverse events (MACEs) and hospitalization for heart failure (especially for SGLT2is) in dedicated cardiovascular outcome trials. The contribution of the glucose-lowering effect in the cardiovascular protection is uncertain and may differ between the two drug classes.

METHODS

This narrative review compares the relative effects of glycated hemoglobin (HbA1c) reduction on the cardiovascular protection provided by GLP-1RAs and SGLT2is in placebo-controlled cardiovascular outcome trials by using the results of either post-hoc mediation analyses or meta-regression studies.

RESULTS

Both mediation and meta-regression analyses suggest that the lower cardiovascular risk with GLP-1RAs partially but substantially tracks with their glucose-lowering effect, especially when considering the reduction in nonfatal strokes. In contrast, similar analyses fail to demonstrate any significant contribution of the glucose-lowering effect with SGLT2is, not only on MACEs but also on heart failure issues.

CONCLUSION

The contribution of improved glucose control in cardiovascular protection is limited, but is much greater for GLP-1RAs than for SGLT2is. Of note, such mediation or meta-regression analyses are exploratory and can only be viewed as hypothesis generating.

Effect of SGLT2 inhibitors on anemia and their possible clinical implications

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have demonstrated cardiovascular and renal benefits in patients with type 2 diabetes mellitus, heart failure, or chronic kidney disease. Since the first studies with these drugs, an initial increase in hemoglobin/hematocrit levels was observed, which was attributed to an increase in hemoconcentration associated with its diuretic effect, although it was early appearent that these drugs increased erythropoietin levels and erythropoiesis, and improved iron metabolism. Mediation studies found that the increase in hemoglobin was strongly associated with the cardiorenal benefits of these drugs. In this review, we discuss the mechanisms for improving erythropoiesis and the implication of the increase in hemoglobin on the cardiorenal prognostic benefit of these drugs.

Potential Mediators for Treatment Effects of Novel Diabetes Medications on Cardiovascular and Renal Outcomes: A Meta-Regression Analysis

BACKGROUND

Prior research suggests clinical effects of glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter-2 inhibitors (SGLT2is) are mediated by changes in glycated hemoglobin, body weight, systolic blood pressure, hematocrit, and urine albumin-creatinine ratio. We aimed to confirm these findings using a meta-analytic approach.

METHODS AND RESULTS

We updated a systematic review of 9 GLP-1RA and 13 SGLT2i trials and summarized longitudinal mediator data. We obtained hazard ratios (HRs) for cardiovascular, renal, and mortality outcomes. We performed linear mixed-effects modeling of LogHRs versus changes in potential mediators and investigated differences in meta-regression associations among drug classes using interaction terms. HRs generally became more protective with greater glycated hemoglobin reduction among GLP-1RA trials, with average HR improvements of 20% to 30%, reaching statistical significance for major adverse cardiovascular events (ΔHR, 23%; P=0.02). Among SGLT2i trials, associations with HRs were not significant and differed from GLP1-RA trials for major adverse cardiovascular events (Pinteraction=0.04). HRs for major adverse cardiovascular events, myocardial infarction, and stroke became less efficacious (ΔHR, -15% to -34%), with more weight loss for SGLT2i but not for GLP-1RA trials (ΔHR, 4%-7%; Pinteraction<0.05). Among 5 SGLT2i trials with available data, HRs for stroke became less efficacious with larger increases in hematocrit (ΔHR, 123%; P=0.09). No changes in HRs by systolic blood pressure (ΔHR, -11% to 9%) and urine albumin-creatinine ratio (ΔHR, -1% to 4%) were found for any outcome.

CONCLUSIONS

We confirmed increased efficacy findings for major adverse cardiovascular events with reduction in glycated hemoglobin for GLP1-RAs. Further research is needed on the potential loss of cardiovascular benefits with increased weight loss and hematocrit for SGLT2i.

Hyperuricemia and Gout Reduction by SGLT2 Inhibitors in Diabetes and Heart Failure: JACC Review Topic of the Week

Gout is characterized by increased production of purines (through the pentose phosphate pathway), which is coupled with reduced renal or intestinal excretion of urate. Concurrent upregulation of nutrient surplus signaling (mammalian target of rapamycin and hypoxia-inducible factor-1a) and downregulation of nutrient deprivation signaling (sirtuin-1 and adenosine monophosphate-activated protein kinase) redirects glucose toward anabolic pathways (rather than adenosine triphosphate production), thus promoting heightened oxidative stress and cardiomyocyte and proximal tubular dysfunction, leading to cardiomyopathy and kidney disease. Hyperuricemia is a marker (rather than a driver) of these cellular stresses. By inducing a state of starvation mimicry in a state of nutrient surplus, sodium-glucose cotransporter-2 inhibitors decrease flux through the pentose phosphate pathway (thereby attenuating purine and urate synthesis) while promoting renal urate excretion. These convergent actions exert a meaningful effect to lower serum uric acid by ≈0.6 to 1.5 mg/dL and to reduce the risk of gout by 30% to 50% in large-scale clinical trials.

Mechanisms of enhanced renal and hepatic erythropoietin synthesis by sodium-glucose cotransporter 2 inhibitors

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of major heart failure events, an action that is statistically linked to enhanced erythropoiesis, suggesting that stimulation of erythropoietin and cardioprotection are related to a shared mechanism. Four hypotheses have been proposed to explain how these drugs increase erythropoietin production: (i) renal cortical reoxygenation with rejuvenation of erythropoietin-producing cells; (ii) counterregulatory distal sodium reabsorption leading to increased tubular workload and oxygen consumption, and thus, to localized hypoxia; (iii) increased iron mobilization as a stimulus of hypoxia-inducible factor-2α (HIF-2α)-mediated erythropoietin synthesis; and (iv) direct HIF-2α activation and enhanced erythropoietin gene transcription due to increased sirtuin-1 (SIRT1) signaling. The first two hypotheses assume that the source of increased erythropoietin is the interstitial fibroblast-like cells in the deep renal cortex. However, SGLT2 inhibitors do not alter regional tissue oxygen tension in the non-diabetic kidney, and renal erythropoietin synthesis is markedly impaired in patients with anemia due to chronic kidney disease, and yet, SGLT2 inhibitors produce an unattenuated erythrocytic response in these patients. This observation raises the possibility that the liver contributes to the production of erythropoietin during SGLT2 inhibition. Hypoxia-inducible factor-2α and erythropoietin are coexpressed not only in the kidney but also in hepatocytes; the liver is a major site of production when erythropoietin stimulation is maintained for prolonged periods. The ability of SGLT2 inhibitors to improve iron mobilization by derepressing hepcidin and ferritin would be expected to increase cytosolic ferrous iron, which might stimulate HIF-2α expression in both the kidney and liver through the action of iron regulatory protein 1. Alternatively, the established ability of SGLT2 inhibitors to enhance SIRT1 might be the mechanism of enhanced erythropoietin production with these drugs. In hepatic cell lines, SIRT1 can directly activate HIF-2α by deacetylation, and additionally, through an effect of SIRT in the liver, peroxisome proliferator-activated receptor-γ coactivator-1α binds to hepatic nuclear factor 4 to promote transcription of the erythropoietin gene and synthesis of erythropoietin. Since SIRT1 up-regulation exerts direct cytoprotective effects on the heart and stimulates erythropoietin, it is well-positioned to represent the shared mechanism that links erythropoiesis to cardioprotection during SGLT2 inhibition.

Empagliflozin effects on iron metabolism as a possible mechanism for improved clinical outcomes in non-diabetic patients with systolic heart failure

Sodium-glucose co-transporter-2 (SGLT2) inhibitors improve clinical outcomes in patients with heart failure (HF), but mechanisms of action are incompletely understood. In the EMPA-TROPISM trial, empagliflozin reversed cardiac remodeling and increased physical capacity in stable non-diabetic patients with systolic HF. Here we explore, post hoc, whether treatment effects in this cohort, comprising patients who had a high prevalence of iron deficiency, were related to iron metabolism. Myocardial iron content estimated by cardiac magnetic resonance T2* quantification increased after initiation of empagliflozin but not placebo (treatment effect: P = 0.01). T2* changes significantly correlated with changes in left ventricular volumes, mass and ejection fraction, peak oxygen consumption and 6-minute walking distance; concomitant changes in red blood cell indices were consistent with augmented hematopoiesis. Exploratory causal mediation analysis findings indicated that changes in myocardial iron content after treatment with empagliflozin may be an important mechanism to explain its beneficial clinical effects in patients with HF.ClinicalTrials.gov: NCT03485222 .

Early glomerular filtration rate decline is associated with hemoglobin rise following dapagliflozin initiation in heart failure with reduced ejection fraction

INTRODUCTION AND OBJECTIVES

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) induce short-term changes in renal function and hemoglobin. Their pathophysiology is incompletely understood. We aimed to evaluate the relationship between 1- and 3-month estimated glomerular filtration rate (eGFR) and hemoglobin changes following initiation of dapagliflozin in patients with stable heart failure with reduced ejection fraction (HFrEF).

METHODS

This is a post hoc analysis of a randomized clinical trial that evaluated the effect of dapagliflozin on 1- and 3-month peak oxygen consumption in outpatients with stable HFrEF (DAPA-VO2 trial, NCT04197635). We used linear mixed regression analysis to assess the relationship between eGFR and hemoglobin changes across treatment arms.

RESULTS

A total of 87 patients were evaluated in this substudy. The mean age was 67.0± 10.5 years, and 21 (24.1%) were women. The mean baseline eGFR and hemoglobin were 66.9±20.7mL/min/1.73m2 and 14.3±1.7g/dL, respectively. Compared with placebo, eGFR did not significantly change at either time points in the dapagliflozin group, but hemoglobin significantly increased at 1 and 3 months. At 1 month, the hemoglobin increase was related to decreases in eGFR only in the dapagliflozin arm (P <.001). At 3 months, there was no significant association in either treatment arms (P=.123). Changes in eGFR were not associated with changes in peak oxygen consumption, quality of life, or natriuretic peptides.

CONCLUSIONS

In patients with stable HFrEF, 1-month changes in eGFR induced by dapagliflozin are inversely related to changes in hemoglobin. This association was no longer significant at 3 months.

The Cardioprotective Effects of Semaglutide Exceed Those of Dietary Weight Loss in Mice With HFpEF

Obesity-related heart failure with preserved ejection fraction (HFpEF) has become a well-recognized HFpEF subphenotype. Targeting the unfavorable cardiometabolic profile may represent a rational treatment strategy. This study investigated semaglutide, a glucagon-like peptide-1 receptor agonist that induces significant weight loss in patients with obesity and/or type 2 diabetes mellitus and has been associated with improved cardiovascular outcomes. In a mouse model of HFpEF that was caused by advanced aging, female sex, obesity, and type 2 diabetes mellitus, semaglutide, compared with weight loss induced by pair feeding, improved the cardiometabolic profile, cardiac structure, and cardiac function. Mechanistically, transcriptomic, and proteomic analyses revealed that semaglutide improved left ventricular cytoskeleton function and endothelial function and restores protective immune responses in visceral adipose tissue. Strikingly, treatment with semaglutide induced a wide array of favorable cardiometabolic effects beyond the effect of weight loss by pair feeding. Glucagon-like peptide-1 receptor agonists may therefore represent an important novel therapeutic option for treatment of HFpEF, especially when obesity-related.

The effects of empagliflozin on measured glomerular filtration rate and estimated extracellular and plasma volumes in patients with type 2 diabetes

AIMS

To investigate the effects of empagliflozin on measured glomerular filtration rate (mGFR), estimated plasma volume (PV) and estimated extracellular volume (ECV) in a cohort of patients with type 2 diabetes (T2D) and high risk of cardiovascular events.

MATERIALS AND METHODS

In this prespecified substudy of the randomized, placebo-controlled SIMPLE trial, patients with T2D at high risk of cardiovascular events were allocated to either empagliflozin 25 mg or placebo once daily for 13 weeks. The prespecified outcome was between-group change in mGFR, measured by the 51 Cr-EDTA method after 13 weeks; changes in estimated PV and estimated ECV were included.

RESULTS

From April 4, 2017 to May 11, 2020, 91 participants were randomized. Of these, 45 patients from the empagliflozin group and 45 patients from the placebo group were included in the intention-to-treat analysis. Treatment with empagliflozin reduced mGFR by -7.9 mL/min (95% confidence interval [CI] -11.1 to -4.7; P < 0.001), estimated ECV by -192.5 mL (95% CI -318.0 to -66.9; P = 0.003) and estimated PV by -128.9 mL (95% CI -218.0 to 39.8; P = 0.005) at Week 13.

CONCLUSIONS

Treatment with empagliflozin for 13 weeks reduced mGFR, estimated ECV and estimated PV in patients with T2D and high risk of cardiovascular events.

Mechanisms of benefits of sodium-glucose cotransporter 2 inhibitors in heart failure with preserved ejection fraction

For decades, heart failure with preserved ejection fraction (HFpEF) proved an elusive entity to treat. Sodium-glucose cotransporter 2 (SGLT2) inhibitors have recently been shown to reduce the composite of heart failure hospitalization or cardiovascular death in patients with HFpEF in the landmark DELIVER and EMPEROR-Preserved trials. While improvements in blood sugar, blood pressure, and attenuation of kidney disease progression all may play some role, preclinical and translational research have identified additional mechanisms of these agents. The SGLT2 inhibitors have intriguingly been shown to induce a nutrient-deprivation and hypoxic-like transcriptional paradigm, with increased ketosis, erythropoietin, and autophagic flux in addition to altering iron homeostasis, which may contribute to improved cardiac energetics and function. These agents also reduce epicardial adipose tissue and alter adipokine signalling, which may play a role in the reductions in inflammation and oxidative stress observed with SGLT2 inhibition. Emerging evidence also indicates that these drugs impact cardiomyocyte ionic homeostasis although whether this is through indirect mechanisms or via direct, off-target effects on other ion channels has yet to be clearly characterized. Finally, SGLT2 inhibitors have been shown to reduce myofilament stiffness as well as extracellular matrix remodelling/fibrosis in the heart, improving diastolic function. The SGLT2 inhibitors have established themselves as robust, disease-modifying therapies and as recent trial results are incorporated into clinical guidelines, will likely become foundational in the therapy of HFpEF.

Changes in cardiac and vascular haemodynamics as potential mediators of improvements in cardiovascular and kidney outcomes with empagliflozin in type 2 diabetes

AIMS

Evaluate changes in haemodynamic markers as mediators of cardiovascular (CV) and kidney benefits with empagliflozin.

METHODS

Post-hoc analysis of EMPA-REG OUTCOME in patients with type 2 diabetes (T2D) and established CV disease receiving empagliflozin (10 and 25 mg) or placebo. Outcomes were CV death, hospitalisation for heart failure [HF], HF death, incident/worsening nephropathy, new onset macroalbuminuria, and the composite of sustained estimated glomerular filtration rate decline ≥40 % from baseline, renal replacement therapy or renal death. To be considered a mediator, changes in variable (pulse pressure, mean arterial pressure and cardiac workload) over time had to be (1) affected by active treatment, (2) associated with the outcome, and (3) adjustment for changes over time must reduce treatment effect versus an unadjusted analysis. Variables were evaluated in Cox regression analyses.

RESULTS

Pulse pressure, mean arterial pressure and cardiac workload were significantly reduced by empagliflozin vs placebo. Using change from baseline to Week 12 or sensitivity analyses (time-dependent updated mean and current change from baseline) of these CV parameters, only small impacts on empagliflozin effect on CV and kidney outcomes were shown.

CONCLUSIONS

Improvements in haemodynamic parameters did not substantially mediate empagliflozin benefits on CV and kidney outcomes in patients with T2DM and established CV disease.

A year in heart failure: updates of clinical and preclinical findings

We witnessed major advances in the management of heart failure (HF) in 2022. Results of recent clinical and preclinical investigations aid preventive strategies, diagnostic efforts, and therapeutic interventions, and collectively, they hold promises for a more effective HF care for the near future. Accordingly, currently available information extends the 2021 European Society of Cardiology guidelines and provides a solid background for the introduction of improved clinical approaches in the number of HF-related cases. Elaboration on the relationships between epidemiological data and risk factors lead to better understanding of the pathophysiology of HF with reduced ejection fraction and HF with preserved ejection fraction. The clinical consequences of valvular dysfunctions are increasingly interpreted not only in their haemodynamic consequences but also in association with their pathogenetic factors and modern corrective treatment possibilities. The influence of coronavirus disease 2019 pandemic on the clinical care of HF appeared to be less intense in 2022 than before; hence, this period allowed to refine coronavirus disease 2019 management options for HF patients. Moreover, cardio-oncology emerges as a new subdiscipline providing significant improvements in clinical outcomes for oncology patients. Furthermore, the introduction of state-of-the-art molecular biologic methods, multi-omic approaches forecast improved phenotyping and precision medicine for HF. All above aspects are addressed in this article that highlights a selection of papers published in ESC Heart Failure in 2022.

Cardiovascular Diseases: Therapeutic Potential of SGLT-2 Inhibitors

Cardiovascular diseases (CVD) are a global health concern, affecting millions of patients worldwide and being the leading cause of global morbidity and mortality, thus creating a major public health concern. Sodium/glucose cotransporter 2 (SGLT2) inhibitors have emerged as a promising class of medications for managing CVD. Initially developed as antihyperglycemic agents for treating type 2 diabetes, these drugs have demonstrated significant cardiovascular benefits beyond glycemic control. In our paper, we discuss the role of empagliflozin, dapagliflozin, canagliflozin, ertugliflozin, and the relatively recently approved bexagliflozin, the class of SGLT-2 inhibitors, as potential therapeutic targets for cardiovascular diseases. All mentioned SGLT-2 inhibitors have demonstrated significant cardiovascular benefits and renal protection in clinical trials, in patients with or without type 2 diabetes. These novel therapeutic approaches aim to develop more effective treatments that improve patient outcomes and reduce the burden of these conditions. However, the major scientific achievements of recent years and the many new discoveries and mechanisms still require careful attention and additional studies.

Long-term observation of estimated fluid volume reduction after the initiation of ipragliflozin in patients with type 2 diabetes mellitus: a sub-analysis from a randomized controlled trial (PROTECT)

BACKGROUNDS/AIM

Recent studies have shown that the addition of sodium-glucose co-transporter 2 (SGLT2) inhibitors gradually reduces the estimated fluid volume parameters in a broad range of patient populations, suggesting that this mediates the clinical benefits of SGLT2 inhibitors in preventing heart failure. Here, we sought to examine the long-term (24 months) effect of the SGLT2 inhibitor ipragliflozin on the estimated fluid volume parameters in patients with type 2 diabetes mellitus (T2DM).

METHODS

In this prespecified sub-analysis of the PROTECT (Prevention of Atherosclerosis by SGLT2 Inhibitor: Multicenter, Randomized Controlled Study) trial, which was an investigator-initiated, multicenter, prospective, randomized, open-label, clinical trial primarily designed to evaluate the effect of ipragliflozin treatment administered for 24 months on carotid atherosclerosis in patients with T2DM, we evaluated serial changes in estimated plasma volume (ePV, %) calculated using the Straus formula and estimated extracellular volume (eEV, mL) calculated by the body surface area by 24 months following the initiation of 50-mg ipragliflozin once daily and compared them with those following standard care for T2DM (non-SGLT2 inhibitor use).

RESULTS

This sub-analysis included 464 patients (ipragliflozin, n = 232; control, n = 232), a full analysis set of the PROTECT trial. In an analysis using mixed-effects models for repeated measures, relative to the control group, ipragliflozin significantly reduced ePV by - 10.29% (95% confidence interval [CI]  - 12.47% to - 8.11%; P < 0.001) at 12 months and - 10.76% (95% CI - 12.86% to - 8.67%; P < 0.001) at 24 months. Additionally, ipragliflozin significantly reduced eEV by - 190.44 mL (95% CI - 249.09 to - 131.79 mL; P < 0.001) at 12 months and - 176.90 mL (95% CI  - 233.36 to - 120.44 mL; P < 0.001) at 24 months. The effects of ipragliflozin on these parameters over 24 months were mostly consistent across various patient clinical characteristics.

CONCLUSIONS

This prespecified sub-analysis from the PROTECT trial demonstrated that ipragliflozin treatment, compared with the standard care for T2DM, reduced two types of estimated fluid volume parameters in patients with T2DM, and the effect was maintained for 24 months. Our findings suggest that SGLT2 inhibitor treatment regulates clinical parameters incorporated into the calculating formulas analyzed and consequently fluid volume status for the long-term, and this may be at least partly associated with clinical benefits from chronic use of SGLT2 inhibitors. Trial registration Japan Registry of Clinical Trials, ID jRCT1071220089.

Prevalent and Incident Anemia in PARADIGM-HF and the Effect of Sacubitril/Valsartan

BACKGROUND

Anemia is common in patients with heart failure with reduced ejection fraction and is associated with poor clinical outcomes. Renin-angiotensin system blockers lower hemoglobin and may induce anemia.

OBJECTIVES

The authors investigated whether concomitant neprilysin inhibition might ameliorate this effect of renin-angiotensin system blockers in PARADIGM-HF (Prospective comparison of ARNI with ACEI to Determine Impact on Global Mortality and morbidity in Heart Failure).

METHODS

Anemia was defined as hemoglobin <120 g/L in women and <130 g/L in men at screening. The authors investigated the effect of randomized treatment on clinical outcomes according to anemia status, change in hemoglobin from baseline, and the incidence of anemia.

RESULTS

Of 8,239 participants with a baseline hemoglobin measurement, 1,677 (20.4%) were anemic. Patients with anemia had a more severe heart failure profile, worse kidney function, greater neurohormonal derangement, and worse clinical outcomes. Sacubitril/valsartan, compared with enalapril, decreased the risk of cardiovascular death or heart failure hospitalization similarly in patients with (HR: 0.84; 95% CI: 0.71-1.00) and without anemia (HR: 0.78 [95% CI: 0.71-0.87]; P value for interaction = 0.478). Between baseline and 12 months, hemoglobin decreased by 1.5 g/L (95% CI: 1.2-1.7 g/L) with sacubitril/valsartan compared with 2.3 g/L (95% CI: 2.0-2.6 g/L) with enalapril: mean difference 0.8 g/L (95% CI: 0.5-1.2 g/L; P < 0.001). Patients assigned to sacubitril/valsartan were less likely to develop anemia at 12 months (321 of 2,806 [11.4%]) compared with patients randomized to enalapril (440 of 2,824 [15.6%]) (OR: 0.70 [95% CI: 0.60-0.81]; P < 0.001). These findings were similar in PARAGON-HF (Prospective Comparison of ARNI with ARB Global Outcomes in HF with Preserved Ejection Fraction) (sacubitril/valsartan vs valsartan). There was biomarker evidence of increased iron utilization with sacubitril/valsartan.

CONCLUSIONS

Irrespective of anemia status, sacubitril/valsartan compared with enalapril, decreased mortality and hospitalization. Hemoglobin decreased less with sacubitril/valsartan and the incidence of new anemia was lower with sacubitril/valsartan. (Prospective comparison of ARNI with ACEI to Determine Impact on Global Mortality and morbidity in Heart Failure [PARADIGM-HF] trial; NCT01035255).

Dapagliflozin and short-term changes on circulating antigen carbohydrate 125 in heart failure with reduced ejection fraction

Circulating antigen carbohydrate 125 (CA125) has emerged as a proxy of fluid overload in heart failure. This study aimed to evaluate the effect of dapagliflozin on short-term CA125 levels in patients with stable heart failure with reduced ejection fraction (HFrEF) and whether these changes mediated the effects on peak oxygen consumption (peakVO2). This study is a post-hoc sub-analysis of a randomized, double-blinded clinical trial in which 90 stable patients with HFrEF were randomly assigned to receive either dapagliflozin or placebo to evaluate change in peakVO2 (NCT04197635). We used linear mixed regression analysis to compare changes in the natural logarithm of CA125 (logCA125) and percent changes from baseline (Δ%CA125). We used the "rwrmed" package to perform mediation analyses. CA125 was available in 87 patients (96.7%). LogCA125 significantly decreased in patients on treatment with dapagliflozin [1-month: Δ - 0.18, (CI 95% = - 0.33 to - 0.22) and 3-month: Δ - 0.23, (CI 95% = - 0.38 to - 0.07); omnibus p-value = 0.012]. Δ%CA125 decreased by 18.4% and 31.4% at 1 and 3-month, respectively (omnibus p-value = 0.026). Changes in logCA125 mediated the effect on peakVO2 by 20.4% at 1 month (p < 0.001). We did not find significant changes for natural logarithm of NTproBNP (logNT-proBNP) [1-month: Δ - 0.03, (CI 95% = - 0.23 to 0.17; p = 0.794), and 3-month: Δ 0.73, (CI 95% = - 0.13 to 0.28; p-value 0.489), omnibus p-value = 0.567]. In conclusion, in patients with stable HFrEF, dapagliflozin resulted in a significant reduction in CA125. Dapagliflozin was not associated with short-term changes in natriuretic peptides. These changes mediated the effects on peakVO2.

Stabilization of kidney function and reduction in heart failure events with sodium-glucose co-transporter 2 inhibitors: A meta-analysis and meta-regression analysis

AIMS

Sodium-glucose co-transporter 2 (SGLT2) inhibitors reduce the risk of heart failure (HF) events regardless of diabetes status. However, factors associated with their efficacy in HF reduction remain unknown. This study aims to identify clinically relevant markers for the efficacy of SGLT2 inhibitors in HF risk reduction.

MATERIALS AND METHODS

We searched PubMed/MEDLINE and EMBASE for randomized placebo-controlled trials of SGLT2 inhibitors reporting a composite of HF hospitalization or cardiovascular death in participants with or without type 2 diabetes published until 28 February 2023. Random-effects meta-analysis and mixed-effects meta-regression were conducted to evaluate the association between the outcomes and clinical variables, including changes in glycated haemoglobin, body weight, systolic blood pressure, haematocrit and overall/chronic estimated glomerular filtration rate (eGFR) slope.

RESULTS

Thirteen trials with 90 413 participants were included. SGLT2 inhibitors reduced the hazard ratio of the composite of HF hospitalization or cardiovascular death (hazard ratio 0.77; 95% confidence interval, 0.74-0.81; p < .0001). In meta-regression analysis, chronic eGFR slope (eGFR change after the initial dip) was significantly associated with the composite outcome (p = .017), and each 1 ml/min/1.73 m² /year improvement in chronic eGFR slope led to a 14% reduction in the composite outcome. By contrast, changes in the other parameters showed no significant associations.

CONCLUSIONS

Improvement in chronic eGFR slope, which reflects the stabilization of kidney function, is significantly associated with the efficacy of the SGLT2 inhibitor in HF, highlighting the cardiorenal axis role in the beneficial effects on HF. The chronic eGFR slope can be a surrogate marker of the effects of SGLT2 inhibitors on HF reduction.

Joint association of hyperuricemia and chronic kidney disease with mortality in patients with chronic heart failure

Background

The joint association of hyperuricemia and chronic kidney disease (CKD) with mortality in patients with chronic heart failure (CHF) is not conclusive.

Methods

This retrospective cohort study was conducted in Chinese People's Liberation Army General Hospital, Beijing, China. We included 9,367 patients with CHF, who were hospitalized between January 2011 and June 2019. The definitions of hyperuricemia and CKD were based on laboratory test, medication use, and medical record. We categorized patients with CHF into 4 groups according to the absence (-) or presence (+) of hyperuricemia and CKD. The primary outcomes included in-hospital mortality and long-term mortality. We used multivariate logistic regression and Cox proportional hazards regression to estimate the mortality risk according to the hyperuricemia/CKD groups.

Results

We identified 275 cases of in-hospital mortality and 2,883 cases of long-term mortality in a mean follow-up of 4.81 years. After adjusting for potential confounders, we found that compared with the hyperuricemia-/CKD- group, the risks of in-hospital mortality were higher in the hyperuricemia+/CKD- group (odds ratio [OR], 95% confidence interval [CI]: 1.58 [1.01-2.46]), hyperuricemia-/CKD+ group (OR, 95% CI: 1.67 [1.10-2.55]), and hyperuricemia+/CKD+ group (OR, 95% CI: 2.12 [1.46-3.08]). Similar results were also found in long-term mortality analysis. Compared with the hyperuricemia-/CKD- group, the adjusted hazard ratios and 95% CI for long-term mortality were 1.25 (1.11-1.41) for hyperuricemia+/CKD- group, 1.37 (1.22-1.53) for hyperuricemia-/CKD+ group, and 1.59 (1.43-1.76) for hyperuricemia+/CKD+ group. The results remained robust in the sensitivity analysis.

Conclusions

Hyperuricemia and CKD, both individually and cumulatively, are associated with increased mortality risk in patients with CHF. These results highlighted the importance of the combined control of hyperuricemia and CKD in the management of heart failure.

A Role of Sodium-Glucose Co-Transporter 2 in Cardiorenal Anemia Iron Deficiency Syndrome

Heart failure, renal dysfunction, anemia, and iron deficiency affect each other and form a vicious cycle, a condition referred to as cardiorenal anemia iron deficiency syndrome. The presence of diabetes further accelerates this vicious cycle. Surprisingly, simply inhibiting sodium-glucose co-transporter 2 (SGLT2), which is expressed almost exclusively in the proximal tubular epithelial cells of the kidney, not only increases glucose excretion into the urine and effectively controls blood glucose levels in diabetes but can also correct the vicious cycle of cardiorenal anemia iron deficiency syndrome. This review describes how SGLT2 is involved in energy metabolism regulation, hemodynamics (i.e., circulating blood volume and sympathetic nervous system activity), erythropoiesis, iron bioavailability, and inflammatory set points in diabetes, heart failure, and renal dysfunction.

Efficacy of antihyperglycemic therapies on cardiovascular and heart failure outcomes: an updated meta-analysis and meta-regression analysis of 35 randomized cardiovascular outcome trials

BACKGROUND

Effects of antihyperglycemic therapies on cardiovascular and heart failure (HF) risks have varied widely across cardiovascular outcome trials (CVOTs), and underlying factors remain incompletely understood. We aimed to determine the relationships of glycated hemoglobin (HbA1c) or bodyweight changes with these outcomes in all CVOTs of antihyperglycemic therapies.

METHODS

We searched PubMed and EMBASE up to 25 January 2023 for all randomized controlled CVOTs of antihyperglycemic therapies reporting both major adverse cardiovascular events (MACE) and HF outcomes in patients with type 2 diabetes or prediabetes. We performed meta-regression analyses following random-effects meta-analyses to evaluate the effects of HbA1c or bodyweight reductions on each outcome.

RESULTS

Thirty-five trials comprising 256,524 patients were included. Overall, antihyperglycemic therapies reduced MACE by 9% [risk ratio (RR): 0.91; 95% confidence interval (CI) 0.88-0.94; P < 0.001; I2 = 36.5%]. In meta-regression, every 1% greater reduction in HbA1c was associated with a 14% reduction in the RR of MACE (95% CI 4-24; P = 0.010), whereas bodyweight change was not associated with the RR of MACE. The magnitude of the reduction in MACE risk associated with HbA1c reduction was greater in trials with a higher baseline prevalence of atherosclerotic cardiovascular disease. On the other hand, antihyperglycemic therapies showed no overall significant effect on HF (RR: 0.95; 95% CI 0.87-1.04; P = 0.28; I2 = 75.9%). In a subgroup analysis based on intervention type, sodium-glucose cotransporter-2 inhibitors (SGLT2i) conferred the greatest HF risk reduction (RR: 0.68; 95% CI 0.62-0.75; P < 0.001; I2 = 0.0%). In meta-regression, every 1 kg bodyweight reduction, but not HbA1c reduction, was found to reduce the RR of HF by 7% (95% CI 4-10; P < 0.001); however, significant residual heterogeneity (P < 0.001) was observed, and SGLT2i reduced HF more than could be explained by HbA1c or bodyweight reductions.

CONCLUSIONS

Antihyperglycemic therapies reduce MACE in an HbA1c-dependent manner. These findings indicate that HbA1c can be a useful marker of MACE risk reduction across a wide range of antihyperglycemic therapies, including drugs with pleiotropic effects. In contrast, HF is reduced not in an HbA1c-dependent but in a bodyweight-dependent manner. Notably, SGLT2i have shown class-specific benefits for HF beyond HbA1c or bodyweight reductions.

Increase in hematocrit with SGLT-2 inhibitors - Hemoconcentration from diuresis or increased erythropoiesis after amelioration of hypoxia?

BACKGROUND AND AIMS

The SGLT2-inhibitors significantly reduce heart failure hospitalization and progression to end-stage kidney disease. An increase in hemoglobin/hematocrit is seen with SGLT2i-inhibitor treatment. This increase has been attributed to hemoconcentration resulting from a diuretic effect. In this review, we present evidence suggesting that the hematocrit increase is not due to hemoconcentration, but to an increase in erythropoiesis due to amelioration of hypoxia and more efficient erythropoietin production with SGLT2-inhibitor treatment.

METHODS

We performed a detailed review of the literature in PubMed for articles describing various mechanisms linking hematocrit increase with SGLT2-inhibitor use to their cardio-renal benefits.

RESULTS

The best predictor of cardio-renal benefits with SGLT2-inhibitors is an increase in hematocrit and hemoglobin. If this hemoconcentration is a results of diuresis, this would be associated with volume contraction and a deterioration in renal function, as seen with long-term diuretic use. This is the opposite of what is seen with the use of SGLT2-inhibitors, which are associated with long-term preservation of renal function. There is now growing evidence that the increase in hematocrit can be attributed to an increase in erythropoiesis due to amelioration of renal hypoxia and more efficient erythropoietin production with SGLT2-inhibitor treatment. Increased erythropoiesis leads to an increase in RBC count which improves myocardial/renal tissue oxygenation and function.

CONCLUSION

The increase in hematocrit with SGLT2i treatment is not due to hemoconcentration, but to an increase in erythropoiesis due to amelioration of hypoxia and more efficient erythropoietin production with SGLT2i treatment.

Links between Metabolic Syndrome and Hypertension: The Relationship with the Current Antidiabetic Drugs

Hypertension poses a significant burden in the general population, being responsible for increasing cardiovascular morbidity and mortality, leading to adverse outcomes. Moreover, the association of hypertension with dyslipidaemia, obesity, and insulin resistance, also known as metabolic syndrome, further increases the overall cardiovascular risk of an individual. The complex pathophysiological overlap between the components of the metabolic syndrome may in part explain how novel antidiabetic drugs express pleiotropic effects. Taking into consideration that a significant proportion of patients do not achieve target blood pressure values or glucose levels, more efforts need to be undertaken to increase awareness among patients and physicians. Novel drugs, such as incretin-based therapies and renal glucose reuptake inhibitors, show promising results in decreasing cardiovascular events in patients with metabolic syndrome. The effects of sodium-glucose co-transporter-2 inhibitors are expressed at different levels, including renoprotection through glucosuria, natriuresis and decreased intraglomerular pressure, metabolic effects such as enhanced insulin sensitivity, cardiac protection through decreased myocardial oxidative stress and, to a lesser extent, decreased blood pressure values. These pleiotropic effects are also observed after treatment with glucagon-like peptide-1 receptor agonists, positively influencing the cardiovascular outcomes of patients with metabolic syndrome. The initial combination of the two classes may be the best choice in patients with type 2 diabetes mellitus and multiple cardiovascular risk factors because of their complementary mechanisms of action. In addition, the novel mineralocorticoid receptor antagonists show significant cardio-renal benefits, as well as anti-inflammatory and anti-fibrotic effects. Overall, the key to better control of hypertension in patients with metabolic syndrome is to consider targeting multiple pathogenic mechanisms, using a combination of the different therapeutic agents, as well as drastic lifestyle changes. This article will briefly summarize the association of hypertension with metabolic syndrome, as well as take into account the influence of antidiabetic drugs on blood pressure control.

The Emerging Role of Sodium-glucose Cotransporter 2 Inhibitors in Heart Failure

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are a relatively novel drug class that most cardiologists are becoming familiar with. By contrasting glucose reabsorption in the proximal convoluted tubule of the nephron, SGLT2 inhibition results in glycosuria with improved glycemic control. Although originally introduced as anti-diabetic medications, the cardiovascular effects of SGLT2i have progressively emerged, leading them to become one of the four pillars for the treatment of heart failure with reduced ejection fraction (HFrEF) according to the 2021 guidelines from the European Society of Cardiology. Also, two recent randomized trials have demonstrated SGLT2i as the first compounds with proven prognostic impact in heart failure with preserved ejection fraction (HFpEF), setting a milestone in the treatment for this condition. While the exact pathogenic mechanisms mediating the substantial reduction in cardiovascular death and heart failure (HF) hospitalizations are still controversial, there is growing clinical evidence on the efficacy and safety of SGLT2i in various subsets of patients with HF. As known, heart failure is a complex and heterogeneous clinical syndrome with a magnitude of phenotypes and a variety of underlying hemodynamic and physiological aspects which cannot be fully incorporated into the traditional left ventricular ejection fraction based classification adopted in clinical trials. The aim of this review is to provide an overview of the cardiovascular benefits and indications of SGLT2i across different HF patterns and to highlight current gaps in knowledge that should be addressed by future research.

Ketones: the double-edged sword of SGLT2 inhibitors?

Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a class of medications used by individuals with type 2 diabetes that reduce hyperglycaemia by targeting glucose transport in the kidney, preventing its reabsorption, thereby inducing glucosuria. Besides improving HbA_1c and reducing body weight and blood pressure, the SGLT2 inhibitors have also been demonstrated to improve cardiovascular and kidney outcomes, an effect largely independent of their effect on blood glucose levels. Indeed, the mechanisms underlying these benefits remain elusive. Treatment with SGLT2 inhibitors has been found to modestly increase systemic ketone levels. Ketone bodies are an ancillary fuel source substituting for glucose in some tissues and may also possess intrinsic anti-oxidative and anti-inflammatory effects. Some have proposed that ketones may in fact mediate the cardio-renal benefits of this drug category. However, a rare complication of SGLT2 inhibition is ketoacidosis, sometimes with normal or near-normal blood glucose concentrations, albeit occurring more frequently in patients with type 1 diabetes who are treated (predominately off-label) with one of these agents. We herein explore the notion that an underpinning of one of the more serious adverse effects of SGLT2 inhibitors may, in fact, explain, at least in part, some of their benefits-a potential 'double-edged sword' of this novel drug category.

How can sodium-glucose cotransporter 2 inhibitors stimulate erythrocytosis in patients who are iron-deficient? Implications for understanding iron homeostasis in heart failure

Many patients with heart failure have an iron-deficient state, which can limit erythropoiesis in erythroid precursors and ATP production in cardiomyocytes. Yet, treatment with sodium-glucose cotransporter 2 (SGLT2) inhibitors produces consistent increases in haemoglobin and haematocrit, even in patients who are iron-deficient before treatment, and this effect remains unattenuated throughout treatment even though SGLT2 inhibitors further aggravate biomarkers of iron deficiency. Heart failure is often accompanied by systemic inflammation, which activates hepcidin, thus impairing the duodenal absorption of iron and the release of iron from macrophages and hepatocytes, leading to a decline in circulating iron. Inflammation and oxidative stress also promote the synthesis of ferritin and suppress ferritinophagy, thus impairing the release of intracellular iron stores and leading to the depletion of bioreactive cytosolic Fe2+ . By alleviating inflammation and oxidative stress, SGLT2 inhibitors down-regulate hepcidin, upregulate transferrin receptor protein 1 and reduce ferritin; the net result is to increase the levels of cytosolic Fe2+ available to mitochondria, thus enabling the synthesis of heme (in erythroid precursors) and ATP (in cardiomyocytes). The finding that SGLT2 inhibitors can induce erythrocytosis without iron supplementation suggests that the abnormalities in iron diagnostic tests in patients with mild-to-moderate heart failure are likely to be functional, rather than absolute, that is, they are related to inflammation-mediated trapping of iron by hepcidin and ferritin, which is reversed by treatment with SGLT2 inhibitors. An increase in bioreactive cytosolic Fe2+ is also likely to augment mitochondrial production of ATP in cardiomyocytes, thus retarding the progression of heart failure. These effects on iron metabolism are consistent with (i) proteomics analyses of placebo-controlled trials, which have shown that biomarkers of iron homeostasis represent the most consistent effect of SGLT2 inhibitors; and (ii) statistical mediation analyses, which have reported striking parallelism of the effect of SGLT2 inhibitors to promote erythrocytosis and reduce heart failure events.

Critical Reanalysis of the Mechanisms Underlying the Cardiorenal Benefits of SGLT2 Inhibitors and Reaffirmation of the Nutrient Deprivation Signaling/Autophagy Hypothesis

SGLT2 (sodium-glucose cotransporter 2) inhibitors produce a distinctive pattern of benefits on the evolution and progression of cardiomyopathy and nephropathy, which is characterized by a reduction in oxidative and endoplasmic reticulum stress, restoration of mitochondrial health and enhanced mitochondrial biogenesis, a decrease in proinflammatory and profibrotic pathways, and preservation of cellular and organ integrity and viability. A substantial body of evidence indicates that this characteristic pattern of responses can be explained by the action of SGLT2 inhibitors to promote cellular housekeeping by enhancing autophagic flux, an effect that may be related to the action of these drugs to produce simultaneous upregulation of nutrient deprivation signaling and downregulation of nutrient surplus signaling, as manifested by an increase in the expression and activity of AMPK (adenosine monophosphate-activated protein kinase), SIRT1 (sirtuin 1), SIRT3 (sirtuin 3), SIRT6 (sirtuin 6), and PGC1-α (peroxisome proliferator-activated receptor γ coactivator 1-α) and decreased activation of mTOR (mammalian target of rapamycin). The distinctive pattern of cardioprotective and renoprotective effects of SGLT2 inhibitors is abolished by specific inhibition or knockdown of autophagy, AMPK, and sirtuins. In the clinical setting, the pattern of differentially increased proteins identified in proteomics analyses of blood collected in randomized trials is consistent with these findings. Clinical studies have also shown that SGLT2 inhibitors promote gluconeogenesis, ketogenesis, and erythrocytosis and reduce uricemia, the hallmarks of nutrient deprivation signaling and the principal statistical mediators of the ability of SGLT2 inhibitors to reduce the risk of heart failure and serious renal events. The action of SGLT2 inhibitors to augment autophagic flux is seen in isolated cells and tissues that do not express SGLT2 and are not exposed to changes in environmental glucose or ketones and may be related to an ability of these drugs to bind directly to sirtuins or mTOR. Changes in renal or cardiovascular physiology or metabolism cannot explain the benefits of SGLT2 inhibitors either experimentally or clinically. The direct molecular effects of SGLT2 inhibitors in isolated cells are consistent with the concept that SGLT2 acts as a nutrient surplus sensor, and thus, its inhibition causes enhanced nutrient deprivation signaling and its attendant cytoprotective effects, which can be abolished by specific inhibition or knockdown of AMPK, sirtuins, and autophagic flux.

Iron Deficiency in Heart Failure and Effect of Dapagliflozin: Findings From DAPA-HF

BACKGROUND

Iron deficiency is common in heart failure and associated with worse outcomes. We examined the prevalence and consequences of iron deficiency in the DAPA-HF trial (Dapagliflozin and Prevention of Adverse-Outcomes in Heart Failure) and the effect of dapagliflozin on markers of iron metabolism. We also analyzed the effect of dapagliflozin on outcomes, according to iron status at baseline.

METHODS

Iron deficiency was defined as a ferritin level <100 ng/mL or a transferrin saturation <20% and a ferritin level 100 to 299 ng/mL. Additional biomarkers of iron metabolism, including soluble transferrin receptor, erythropoietin, and hepcidin were measured at baseline and 12 months after randomization. The primary outcome was a composite of worsening heart failure (hospitalization or urgent visit requiring intravenous therapy) or cardiovascular death.

RESULTS

Of the 4744 patients randomized in DAPA-HF, 3009 had ferritin and transferrin saturation measurements available at baseline, and 1314 of these participants (43.7%) were iron deficient. The rate of the primary outcome was higher in patients with iron deficiency (16.6 per 100 person-years) compared with those without (10.4 per 100 person-years; P<0.0001). The effect of dapagliflozin on the primary outcome was consistent in iron-deficient compared with iron-replete patients (hazard ratio, 0.74 [95% CI, 0.58-0.92] versus 0.81 [95% CI, 0.63-1.03]; P-interaction=0.59). Similar findings were observed for cardiovascular death, heart failure hospitalization, and all-cause mortality. Transferrin saturation, ferritin, and hepcidin were reduced and total iron-binding capacity and soluble transferrin receptor increased with dapagliflozin compared with placebo.

CONCLUSIONS

Iron deficiency was common in DAPA-HF and associated with worse outcomes. Dapagliflozin appeared to increase iron use but improved outcomes, irrespective of iron status at baseline.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT03036124.

Attaining sinus rhythm mediates improved outcome with early rhythm control therapy of atrial fibrillation: the EAST - AFNET 4 trial

Aims

A strategy of systematic, early rhythm control (ERC) improves cardiovascular outcomes in patients with atrial fibrillation (AF). It is not known how this outcome-reducing effect is mediated.

Methods and results

Using the Early treatment of Atrial Fibrillation for Stroke prevention Trial (EAST—AFNET 4) data set, potential mediators of the effect of ERC were identified in the total study population at 12-month follow up and further interrogated by use of a four-way decomposition of the treatment effect in an exponential model predicting future primary outcome events. Fourteen potential mediators of ERC were identified at the 12-month visit. Of these, sinus rhythm at 12 months explained 81% of the treatment effect of ERC compared with usual care during the remainder of follow up (4.1 years). In patients not in sinus rhythm at 12 months, ERC did not reduce future cardiovascular outcomes (hazard ratio 0.94, 95% confidence interval 0.65–1.67). Inclusion of AF recurrence in the model only explained 31% of the treatment effect, and inclusion of systolic blood pressure at 12 months only 10%. There was no difference in outcomes in patients who underwent AF ablation compared with those who did not undergo AF ablation.

Conclusion

The effectiveness of early rhythm control is mediated by the presence of sinus rhythm at 12 months in the EAST-AFNET 4 trial. Clinicians implementing ERC should aim for rapid and sustained restoration of sinus rhythm in patients with recently diagnosed AF and cardiovascular comorbidities.

Effect of empagliflozin on circulating proteomics in heart failure: mechanistic insights into the EMPEROR programme

AIMS

Sodium-glucose co-transporter 2 (SGLT2) inhibitors improve cardiovascular outcomes in diverse patient populations, but their mechanism of action requires further study. The aim is to explore the effect of empagliflozin on the circulating levels of intracellular proteins in patients with heart failure, using large-scale proteomics.

METHODS AND RESULTS

Over 1250 circulating proteins were measured at baseline, Week 12, and Week 52 in 1134 patients from EMPEROR-Reduced and EMPEROR-Preserved, using the Olink® Explore 1536 platform. Statistical and bioinformatical analyses identified differentially expressed proteins (empagliflozin vs. placebo), which were then linked to demonstrated biological actions in the heart and kidneys. At Week 12, 32 of 1283 proteins fulfilled our threshold for being differentially expressed, i.e. their levels were changed by ≥10% with a false discovery rate <1% (empagliflozin vs. placebo). Among these, nine proteins demonstrated the largest treatment effect of empagliflozin: insulin-like growth factor-binding protein 1, transferrin receptor protein 1, carbonic anhydrase 2, erythropoietin, protein-glutamine gamma-glutamyltransferase 2, thymosin beta-10, U-type mitochondrial creatine kinase, insulin-like growth factor-binding protein 4, and adipocyte fatty acid-binding protein 4. The changes of the proteins from baseline to Week 52 were generally concordant with the changes from the baseline to Week 12, except empagliflozin reduced levels of kidney injury molecule-1 by ≥10% at Week 52, but not at Week 12. The most common biological action of differentially expressed proteins appeared to be the promotion of autophagic flux in the heart, kidney or endothelium, a feature of 6 proteins. Other effects of differentially expressed proteins on the heart included the reduction of oxidative stress, inhibition of inflammation and fibrosis, and the enhancement of mitochondrial health and energy, repair, and regenerative capacity. The actions of differentially expressed proteins in the kidney involved promotion of autophagy, integrity and regeneration, suppression of renal inflammation and fibrosis, and modulation of renal tubular sodium reabsorption.

CONCLUSIONS

Changes in circulating protein levels in patients with heart failure are consistent with the findings of experimental studies that have shown that the effects of SGLT2 inhibitors are likely related to actions on the heart and kidney to promote autophagic flux, nutrient deprivation signalling and transmembrane sodium transport.

Counteracting heart failure with diabetes drugs: a review into the pharmacokinetic and pharmacodynamic properties

INTRODUCTION

: Heart failure (HF) is becoming a huge public health burden. New diabetes drugs for type 2 diabetes (T2D), sodium-glucose cotransporter type 2 inhibitors (SGLT2is), reduce the rate of hospitalization for HF in placebo-controlled trials.

AREAS COVERED

: Pharmacokinetics of dapagliflozin and empagliflozin (in presence of renal impairment and hepatic dysfunction, two comorbidities frequently associated with HF) and pharmacodynamic studies in patients with HF. Main HF outcomes in T2D patients with cardiovascular risk and in patients with reduced (HFrEF) or preserved (HFpEF) ejection fraction, with or without T2D, from DAPA-HF, EMPEROR-Reduced and EMPEROR-Preserved original findings and post hoc analyses.

EXPERT OPINION

: No clinically relevant changes are expected concerning SGLT2i pharmacokinetics in patients with HF while pharmacodynamic studies reported improvements in myocardium/vascular parameters, biomarkers and functional status. All SGLT2is showed a remarkable reduction in hospitalization for HF in patients with T2D and high cardiovascular risk. Furthermore, both dapagliflozin and empagliflozin improved the prognosis of patients with HFrEF, independently of the presence of T2D. Similar results were reported with empagliflozin in patients with HFpEF, to be confirmed with dapagliflozin in an ongoing trial (DELIVER). Thus, SGLT2is offer a new opportunity for the prevention and management of HF in patients with or without T2D.

An Overview of the Cardiorenal Protective Mechanisms of SGLT2 Inhibitors

Sodium-glucose co-transporter 2 (SGLT2) inhibitors block glucose reabsorption in the renal proximal tubule, an insulin-independent mechanism that plays a critical role in glycemic regulation in diabetes. In addition to their glucose-lowering effects, SGLT2 inhibitors prevent both renal damage and the onset of chronic kidney disease and cardiovascular events, in particular heart failure with both reduced and preserved ejection fraction. These unexpected benefits prompted changes in treatment guidelines and scientific interest in the underlying mechanisms. Aside from the target effects of SGLT2 inhibition, a wide spectrum of beneficial actions is described for the kidney and the heart, even though the cardiac tissue does not express SGLT2 channels. Correction of cardiorenal risk factors, metabolic adjustments ameliorating myocardial substrate utilization, and optimization of ventricular loading conditions through effects on diuresis, natriuresis, and vascular function appear to be the main underlying mechanisms for the observed cardiorenal protection. Additional clinical advantages associated with using SGLT2 inhibitors are antifibrotic effects due to correction of inflammation and oxidative stress, modulation of mitochondrial function, and autophagy. Much research is required to understand the numerous and complex pathways involved in SGLT2 inhibition. This review summarizes the current known mechanisms of SGLT2-mediated cardiorenal protection.

Uric acid lowering for slowing CKD progression after the CKD-FIX trial: a solved question or still a dilemma?

Hyperuricemia has been associated with several cardiovascular risk factors and is a well-known predictor of kidney disease. In vitro studies as well as animal models highlighted a role for uric acid in the development and progression of haemodynamic and tissue damage at the renal level leading to glomerular and tubulointerstitial abnormalities. Urate-lowering treatment, especially by xanthine oxidase inhibitors, has been proposed in order to improve kidney outcomes. However, recent randomized controlled trials failed to demonstrate a beneficial effect of allopurinol or febuxostat on renal disease, casting doubts on the role of this therapeutical approach to improve nephroprotection. We provide a critical overview of current literature on this topic and offer a possible interpretation of results from recent intervention trials with urate-lowering treatment on renal outcomes.

Empagliflozin in the treatment of heart failure and type 2 diabetes mellitus: Evidence from several large clinical trials

Heart failure coexists with type 2 diabetes mellitus, which seriously affects the clinical treatment and prognosis. At present, the treatment for patients with established heart failure and type 2 diabetes mellitus is usually combined with two treatment strategies for heart failure and type 2 diabetes mellitus. Recently, increasing studies showed that empagliflozin, a sodium-glucose co-transporter-2 inhibitor, has a positive effect on the treatment of patients with established heart failure and type 2 diabetes mellitus. Here, we summarize the latest and current understanding of the management for patients with established heart failure and type 2 diabetes mellitus and further present contemporary treatment options, sodium-glucose co-transporter-2 inhibitor, for these particular populations.