Diabetes mellitus and risk of new-onset and recurrent heart failure: a systematic review and meta-analysis

Identification and correction for collider bias in a genome-wide association study of diabetes-related heart failure

Type 2 diabetes (T2D) is a major risk factor for heart failure (HF) and has elevated incidence among individuals with HF. Since genetics and HF can independently influence T2D, collider bias may occur when T2D (i.e., collider) is controlled for by design or analysis. Thus, we conducted a genome-wide association study (GWAS) of diabetes-related HF with correction for collider bias. We first performed a GWAS of HF to identify genetic instrumental variables (GIVs) for HF and to enable bidirectional Mendelian randomization (MR) analysis between T2D and HF. We identified 61 genomic loci, significantly associated with all-cause HF in 114,275 individuals with HF and over 1.5 million controls of European ancestry. Using a two-sample bidirectional MR approach with 59 and 82 GIVs for HF and T2D, respectively, we estimated that T2D increased HF risk (odds ratio [OR] 1.07, 95% confidence interval [CI] 1.04-1.10), while HF also increased T2D risk (OR 1.60, 95% CI 1.36-1.88). Then we performed a GWAS of diabetes-related HF corrected for collider bias due to the study design of index cases. After removing the spurious association of TCF7L2 locus due to collider bias, we identified two genome-wide significant loci close to PITX2 (chromosome 4) and CDKN2B-AS1 (chromosome 9) associated with diabetes-related HF in the Million Veteran Program and replicated the associations in the UK Biobank. Our MR findings provide strong evidence that HF increases T2D risk. As a result, collider bias leads to spurious genetic associations of diabetes-related HF, which can be effectively corrected to identify true positive loci.

Methods to predict heart failure in diabetes patients

INTRODUCTION

Type 2 diabetes mellitus (T2DM) is one of the leading causes of cardiovascular disease and powerful predictor for new-onset heart failure (HF).

AREAS COVERED

We focus on the relevant literature covering evidence of risk stratification based on imaging predictors and circulating biomarkers to optimize approaches to preventing HF in DM patients.

EXPERT OPINION

Multiple diagnostic algorithms based on echocardiographic parameters of cardiac remodeling including global longitudinal strain/strain rate are likely to be promising approach to justify individuals at higher risk of incident HF. Signature of cardiometabolic status may justify HF risk among T2DM individuals with low levels of natriuretic peptides, which preserve their significance in HF with clinical presentation. However, diagnostic and predictive values of conventional guideline-directed biomarker HF strategy may be non-optimal in patients with obesity and T2DM. Alternative biomarkers affecting cardiac fibrosis, inflammation, myopathy, and adipose tissue dysfunction are plausible tools for improving accuracy natriuretic peptides among T2DM patients at higher HF risk. In summary, risk identification and management of the patients with T2DM with established HF require conventional biomarkers monitoring, while the role of alternative biomarker approach among patients with multiple CV and metabolic risk factors appears to be plausible tool for improving clinical outcomes.

Epidemiology of heart failure in diabetes: a disease in disguise

Left ventricular diastolic dysfunction (LVDD) without symptoms, and heart failure (HF) with preserved ejection fraction (HFpEF) represent the most common phenotypes of HF in individuals with type 2 diabetes mellitus, and are more common than HF with reduced ejection fraction (HFrEF), HF with mildly reduced ejection fraction (HFmrEF) and left ventricular systolic dysfunction (LVSD) in these individuals. However, diagnostic criteria for HF have changed over the years, resulting in heterogeneity in the prevalence/incidence rates reported in different studies. We aimed to give an overview of the diagnosis and epidemiology of HF in type 2 diabetes, using both a narrative and systematic review approach; we focus narratively on diagnosing (using the 2021 European Society of Cardiology [ESC] guidelines) and screening for HF in type 2 diabetes. We performed an updated (2016-October 2022) systematic review and meta-analysis of studies reporting the prevalence and incidence of HF subtypes in adults ≥18 years with type 2 diabetes, using echocardiographic data. Embase and MEDLINE databases were searched and data were assessed using random-effects meta-analyses, with findings presented as forest plots. From the 5015 studies found, 209 were screened using the full-text article. In total, 57 studies were included, together with 29 studies that were identified in a prior meta-analysis; these studies reported on the prevalence of LVSD (n=25 studies, 24,460 individuals), LVDD (n=65 studies, 25,729 individuals), HFrEF (n=4 studies, 4090 individuals), HFmrEF (n=2 studies, 2442 individuals) and/or HFpEF (n=8 studies, 5292 individuals), and on HF incidence (n=7 studies, 17,935 individuals). Using Hoy et al's risk-of-bias tool, we found that the studies included generally had a high risk of bias. They showed a prevalence of 43% (95% CI 37%, 50%) for LVDD, 17% (95% CI 7%, 35%) for HFpEF, 6% (95% CI 3%, 10%) for LVSD, 7% (95% CI 3%, 15%) for HFrEF, and 12% (95% CI 7%, 22%) for HFmrEF. For LVDD, grade I was found to be most prevalent. Additionally, we reported a higher incidence rate of HFpEF (7% [95% CI 4%, 11%]) than HFrEF 4% [95% CI 3%, 7%]). The evidence is limited by the heterogeneity of the diagnostic criteria over the years. The systematic section of this review provides new insights on the prevalence/incidence of HF in type 2 diabetes, unveiling a large pre-clinical target group with LVDD/HFpEF in which disease progression could be halted by early recognition and treatment.Registration PROSPERO ID CRD42022368035.

A disease of her own? Unique features of heart failure in women

Heart failure (HF) is a significant and growing public health challenge for women. Compared with men, women tend to develop HF later in life and are more likely to experience HF with preserved ejection fraction. There are also significant sex differences in outcomes, with women reporting lower quality of life but overall better survival versus men. In this review, we summarize sex differences in traditional HF risk factors, such as hypertension, diabetes, obesity and coronary artery disease, as well as female-specific HF risk factors including menopause, pregnancy and adverse pregnancy outcomes, and breast cancer therapy. While our understanding of the sex-specific efficacy of HF therapy remains limited by the underrepresentation of women in major clinical trials, there is a suggestion of preferential benefit of specific agents for women. Further work is required to better understand the pathophysiology of HF in women uniquely and to increase representation of women in clinical trials.

Diabetes and risk of heart failure in people with and without cardiovascular disease: systematic review and meta-analysis

BACKGROUND

People with diabetes have an increased risk of heart failure (HF), compared to those without diabetes. However, no comprehensive systematic review and meta-analysis has explored whether these associations could differ in relation to prevalent cardiovascular disease (CVD).

AIMS

To estimate the association between diabetes and incident heart failure (HF), compared to without diabetes, in individuals with and without CVD.

METHODS

PubMed, Scopus, and Web of Science were searched for observational cohort studies from the earliest dates to 22nd March 2023. A random-effects model calculated the pooled relative risk (RR).

RESULTS

Of 11,609 articles, 31 and 6 studies reported data in people with type 2 diabetes (T2D) and type 1 diabetes (T1D) respectively. Individuals with T2D had an increased risk of HF irrespective of CVD prevalence: 1.61 (95% CI: 1.35-1.92) in those with CVD; 1.78 (1.60-1.99) without CVD; and 2.02 (1.75-2.33) with unspecified CVD prevalence. Meta-regression did not identify a significant difference comparing HF risk in T2D individuals with vs. without CVD (p = 0.232).

CONCLUSION

Peoplewith T2D, compared to those without diabetes, have similar increased risk of HF, regardless of CVD prevalence. Strategiesproven to lower HF risk in T2D individuals should be prioritized for those with and without CVD.

Correction for Collider Bias in the Genome-wide Association Study of Diabetes-Related Heart Failure due to Bidirectional Relationship between Heart Failure and Type 2 Diabetes

Aims

Type 2 diabetes (T2D) is a major risk factor for heart failure (HF) across demographic groups. On the other hand, metabolic impairment, including elevated T2D incidence is a hallmark of HF pathophysiology. We investigated the bidirectional relationship between T2D and HF, and identified genetic associations with diabetes-related HF after correction for potential collider bias.

Methods

We performed a genome-wide association study (GWAS) of HF to identify genetic instrumental variables (GIVs) for HF, and to enable bidirectional Mendelian Randomization (MR) analysis between T2D and HF. Since genetics and HF can independently influence T2D, collider bias may occur when T2D (i.e., collider) is controlled for by design or analysis. Thus, we conducted GWAS of diabetes-related HF with correction for collider bias.

Results

We first identified 61 genomic loci, including 24 novel loci, significantly associated with all-cause HF in 114,275 HF cases and over 1.5 million controls of European ancestry. Combined with the summary statistics of a T2D GWAS, we obtained 59 and 82 GIVs for HF and T2D, respectively. Using a two-sample bidirectional MR approach, we estimated that T2D increased HF risk (OR 1.07, 95% CI 1.04-1.10), while HF also increased T2D risk (OR 1.60, 95% CI 1.36-1.88). Then we performed a GWAS of diabetes-related HF corrected for collider bias due to prevalent HF affecting incidence of T2D. After removing the spurious association of TCF7L2 locus due to collider bias, we identified two genome-wide significant loci close to PITX2 (chromosome 4) and CDKN2B-AS1 (chromosome 9) associated with diabetes-related HF in the Million Veteran Program, and replicated the associations in the UK Biobank study.

Conclusion

We identified novel HF-associated loci to enable bidirectional MR study of T2D and HF. Our MR findings support T2D as a HF risk factor and provide strong evidence that HF increases T2D risk. As a result, collider bias leads to spurious genetic associations of diabetes-related HF, which can be effectively corrected to identify true positive loci. Evaluation of collider bias should be a critical component when conducting GWAS of complex disease phenotypes such as diabetes-related cardiovascular complications.

The cardio-renal-metabolic connection: a review of the evidence

Type 2 diabetes (T2D), cardiovascular disease (CVD) and chronic kidney disease (CKD), are recognized among the most disruptive public health issues of the current century. A large body of evidence from epidemiological and clinical research supports the existence of a strong interconnection between these conditions, such that the unifying term cardio-metabolic-renal (CMR) disease has been defined. This coexistence has remarkable epidemiological, pathophysiologic, and prognostic implications. The mechanisms of hyperglycemia-induced damage to the cardio-renal system are well validated, as are those that tie cardiac and renal disease together. Yet, it remains controversial how and to what extent CVD and CKD can promote metabolic dysregulation. The aim of this review is to recapitulate the epidemiology of the CMR connections; to discuss the well-established, as well as the putative and emerging mechanisms implicated in the interplay among these three entities; and to provide a pathophysiological background for an integrated therapeutic intervention aiming at interrupting this vicious crosstalks.

J-ACCESS investigation and nuclear cardiology in Japan: implications for heart failure

While coronary heart disease remains a global cause of mortality, the prevalence of heart failure (HF) is increasing in developed countries including Japan. The continuously increasing aging population and the relatively low incidence of ischemic origins are features of the HF background in Japan. Information about nuclear cardiology practice and prognosis has accumulated, thanks to the multicenter prognostic J-ACCESS investigations (Series 1‒4) over two decades in Japan. Although the rate of hard cardiac events is lower in Japan than in the USA and Europe, similar predictors have been identified as causes of major adverse cardiac events. The highest proportion (50-75%) of major events among patients indicated for nuclear cardiology examinations in the J-ACCESS registries is severe HF requiring hospitalization. Therefore, the background and the possible reasons for the higher proportion of severe HF events in Japan require clarification. Combinations of age, myocardial perfusion defects, left ventricular dysfunction, and comorbid diabetes and chronic kidney disease are major predictors of cardiovascular events including severe HF. Although the Japanese Circulation Society has updated its clinical guidelines to incorporate non-invasive imaging modalities for diagnosing chronic coronary artery disease, the importance of risk-based approaches to optimal medical therapy and coronary revascularization is emphasized herein.

Evolution of sodium-glucose co-transporter 2 inhibitors from a glucose-lowering drug to a pivotal therapeutic agent for cardio-renal-metabolic syndrome

Cardio-renal-metabolic (CRM) syndrome, which involves type 2 diabetes mellitus (T2DM), chronic kidney disease (CKD), and heart failure (HF), is a serious healthcare issue globally, with high morbidity and mortality. The disorders that comprise CRM syndrome are independent can mutually affect and accelerate the exacerbation of each other, thereby substantially increasing the risk of mortality and impairing quality of life. To manage CRM syndrome by preventing vicious interactions among individual disorders, a holistic treatment approach that can simultaneously address multiple disorders underpinning CRM syndrome is of great importance. Sodium-glucose co-transporter 2 inhibitors (SGLT2i) lower blood glucose levels by inhibiting glucose reabsorption in the renal proximal tubule and were first indicated for the treatment of T2DM. Several cardiovascular outcome trials have demonstrated that SGLT2i not only lower blood glucose but also reduce the risk of hospitalization for HF and worsening renal function in patients with T2DM. Results have also suggested that the observed cardiorenal benefits of SGLT2i may be independent of their blood glucose-lowering effects. Several randomized controlled trials subsequently assessed the efficacy and safety of SGLT2i in patients without T2DM, and revealed considerable benefits of SGLT2i treatment against HF and CKD, regardless of the presence of T2DM. Thus, SGLT2i have become an essential therapeutic option to prevent the onset, slow the progression, and improve the prognosis of CRM syndrome. This review assesses the evolution of SGLT2i from a glucose-lowering drug to a therapeutic agent for CRM syndrome by evaluating epoch-making clinical studies, including randomized control trials and real-world studies.

Cardiometabolic-based chronic disease: adiposity and dysglycemia drivers of heart failure

Heart failure (HF) is a complex clinical syndrome, associated with high rates of mortality, hospitalization, and impairment of quality of life. Obesity and type 2 diabetes are major cardiometabolic drivers, represented as distinct stages of adiposity- and dysglycemia-based chronic disease (ABCD, DBCD), respectively, and leading to cardiometabolic-based chronic disease (CMBCD). This review focuses on one aspect of the CMBCD model: how ABCD and DBCD influence genesis and progression of HF phenotypes. Specifically, the relationships of ABCD and DBCD stages with structural and functional heart disease, HF risk, and outcomes in overt HF are detailed. Also, evidence-based lifestyle, pharmacological, and procedural interventions that promote or reverse cardiac remodeling and outcomes in individuals at risk or with HF are discussed. In summary, driver-based chronic disease models for individuals at risk or with HF can expose prevention targets for more comprehensive interventions to improve clinical outcomes. Future randomized trials that investigate structured lifestyle, pharmacological, and procedural therapies specifically tailored for the CMBCD model are needed to develop personalized care plans to decrease HF susceptibility and improve outcomes.

Association of Baseline and Longitudinal Changes in Frailty Burden and Risk of Heart Failure in Type 2 Diabetes-Findings from the Look AHEAD Trial

BACKGROUND

Individuals with diabetes have a high frailty burden and increased risk of heart failure (HF). In this study, we evaluated the association of baseline and longitudinal changes in frailty with risk of HF and its subtypes: HF with preserved ejection fraction (HFpEF), and HF with reduced ejection fraction (HFrEF).

METHODS

Participants (age: 45-76 years) of the Look AHEAD trial without prevalent HF were included. The frailty index (FI) was used to assess frailty burden using a 35-variable deficit model. The association between baseline and longitudinal changes (1- and 4-year follow-up) in FI with risk of overall HF, HFpEF (ejection fraction [EF] ≥ 50%), and HFrEF (EF < 50%) independent of other risk factors and cardiorespiratory fitness was assessed using adjusted Cox models.

RESULTS

The study included 5 100 participants with type 2 diabetes mellitus, of which 257 developed HF. In adjusted analysis, higher frailty burden was significantly associated with a greater risk of overall HF. Among HF subtypes, higher baseline FI was significantly associated with risk of HFpEF (hazard ratio [HR] [95% CI] per 1-SD higher FI: 1.37 [1.15-1.63]) but not HFrEF (HR [95% CI]: 1.19 [0.96-1.46]) after adjustment for potential confounders, including traditional HF risk factors. Among participants with repeat measures of FI at 1- and 4-year follow-up, an increase in frailty burden was associated with a higher risk of HFpEF (HR [95% CI] per 1-SD increase in FI at 4 years: 1.78 [1.35-2.34]) but not HFrEF after adjustment for other confounders.

CONCLUSIONS

Among individuals with type 2 diabetes mellitus, higher baseline frailty and worsening frailty burden over time were independently associated with higher risk of HF, particularly HFpEF after adjustment for other confounders.

Correlation between Carbonic Anhydrase Isozymes and the Evolution of Myocardial Infarction in Diabetic Patients

Simple Summary

Heart disease in diabetics presents distinctive characteristics both anatomically and physiopathologically compared to non-diabetics. In people with diabetes, high blood pressure has a high incidence (approximately one-third of diabetic patients have high blood pressure) and is a risk factor for diabetic macro- and microvascular complications. The correlation of these parameters could represent early markers of the prognosis and evolution of diabetic patients with acute myocardial infarction and their routine determination could be included in the biological algorithm of acute myocardial infarction, but understanding of this aspect must be deepened in the future. The results showed that diabetic patients develop acute myocardial infarction more frequently, regardless of age. The level of the enzymes of myocardial necrosis was higher in diabetics compared to non-diabetics, and acute coronary syndrome occurs mainly in diabetics with inadequate metabolic balance. Our research may provide useful information for the medical community.

Abstract

(1) Background: Myocardial infarction was, until recently, recognized as a major coronary event, often fatal, with major implications for survivors. According to some authors, diabetes mellitus is an important atherogenic risk factor with cardiac determinations underlying the definition of the so-called “diabetic heart”. The present study aims to establish a correlation between the evolution of myocardial infarction in diabetic patients, by determining whether lactic acid levels, the activity of carbonic anhydrase isoenzymes, and the magnitude of ST-segment elevation are correlated with the subsequent evolution of myocardial infarction. (2) Methods: The study analyzed 2 groups of 30 patients each: group 1 consisted of diabetic patients with acute myocardial infarction, and group 2 consisted of non-diabetic patients with acute myocardial infarction. Patients were examined clinically and paraclinical, their heart markers, lactic acid, and the activity of carbonic anhydrase I and II isozymes were determined. All patients underwent electrocardiogram and echocardiography analyses. (3) Results: The results showed that diabetics develop acute myocardial infarction more frequently, regardless of how much time has passed since the diagnosis. The value of myocardial necrosis enzymes was higher in diabetics than in non-diabetics, and acute coronary syndrome occurs mainly in diabetics with poor metabolic balance. Lethality rates in non-diabetic patients with lactic acid values above normal are lower than in diabetics. (4) Conclusions: Lactic acid correlated with the activity of isozyme I of carbonic dioxide which could be early markers of the prognosis and evolution of diabetic patients with acute myocardial infarction.

Impact of diabetes and on-arrival hyperglycemia on short-term outcomes in acute heart failure patients

The impact of diabetes mellitus (DM) and hyperglycemia on short-term prognosis in patients with acute heart failure (AHF) remains controversial as most data comes from series of hospitalized patients. Our purpose was to analyze outcomes in a nation-wide registry of AHF patients attended in emergency department (ED). ED AHF patients were prospectively enrolled, with the index event and the vulnerable post-discharge phase outcomes recorded. The influence of presenting hyperglycemia (> 180 mg/dL) and DM treatment on prognosis were also investigated. All results were adjusted (a) for baseline characteristics. Of 9192 enrolled AHF patients, 4544 (49,4%) were diabetic, with 24% of diabetics and 25.1% of non-diabetic (p = 0.247) directly discharged from the ED also included. Diabetics had higher rates of comorbidities, but were slightly younger and had lower in-hospital and 30 day all-cause mortality than non-diabetics (a-OR = 0.827, 95% CI = 0.690-0980; and a-HR = 0.850, 95% CI = 0.814-1.071, respectively). Conversely, hyperglycemia on-arrival was associated with increased in-hospital, and 30 day all-cause mortality, in both DM (a-OR = 1.933, 95% CI = 1.378-2.712, and a-HR = 1.590, 95% CI = 1.304-1.938, respectively) and non-DM patients (a-OR = 1.498, 95% CI = 1.175-1.909, and a-HR = 1.719, 95% CI = 1.306-2.264, respectively). However, during the vulnerable phase, diabetics had worse short-term outcomes, with higher rates of ED-revisit and rehospitalization. These worse outcomes seemed to be unrelated to the severity of DM. In patients with AHF attended in ED, diabetes was associated with lower index event case fatality, but higher rates of rehospitalization and re-consultation in the vulnerable post-discharge period. Conversely, hyperglycemia at hospital arrival was strongly associated with early mortality, regardless of diabetes status.

Biomarkers for the prediction of heart failure and cardiovascular events in patients with type 2 diabetes: a position statement from the Heart Failure Association of the European Society of Cardiology

Knowledge on risk predictors of incident heart failure (HF) in patients with type 2 diabetes (T2D) is crucial given the frequent coexistence of the two conditions and the fact that T2D doubles the risk of incident HF. In addition, HF is increasingly being recognized as an important endpoint in trials in T2D. On the other hand, the diagnostic and prognostic performance of established cardiovascular biomarkers may be modified by the presence of T2D. The present position paper, derived by an expert panel workshop organized by the Heart Failure Association of the European Society of Cardiology, summarizes the current knowledge and gaps in evidence regarding the use of a series of different biomarkers, reflecting various pathogenic pathways, for the prediction of incident HF and cardiovascular events in patients with T2D and in those with established HF and T2D.

Diabetes leading to heart failure and heart failure leading to diabetes: epidemiological and clinical evidence

Type 2 diabetes mellitus (T2DM) is a risk factor that plays a major role in the onset of heart failure (HF) both directly, by impairing cardiac function, and indirectly, through associated diseases such as hypertension, coronary disease, renal dysfunction, obesity, and other metabolic disorders. In a population of HF patients, the presence of T2DM ranged from 20 to 40%, according to the population studied, risk factor characteristics, geographic area, and age, and it is associated with a worse prognosis. Finally, patients with HF, when compared with those without HF, show an increased risk for the onset of T2DM due to several mechanisms that predispose the HF patient to insulin resistance. Despite the epidemiological data confirmed the relationship between T2DM and HF, the exact prevalence of HF in T2DM comes from interventional trials rather than from observational registries aimed to prospectively evaluate the risk of HF occurrence in T2DM population. This review is focused on the vicious cycle linking HF and T2DM, from epidemiological data to prognostic implications.

Premature ventricular complex site of origin and ablation outcomes in patients with diabetes mellitus

BACKGROUND

Premature ventricular complexes (PVCs) are frequent in patients with diabetes mellitus (DM). Still, the PVCs characteristics as well as the outcomes after catheter ablation in this population remain unknown. Aim of the study was to describe principal features of PVCs ablated in a wide DM-patients cohort and report postablation clinical outcomes in the follow-up of patients with DM and left ventricular dysfunction.

METHODS

From April 2012 to April 2020 data of 544 patients (315 [58%] men, 55±16 y), consecutive patients submitted for PVC ablation, were prospectively collected. Patients with left ventricle (LV) systolic disfunction (LVEF<50%) were included in a prospective protocol and followed at 6 and 12 months, and annually thereafter. Baseline characteristic as well ablation outcomes were analyzed based on the presence of DM.

RESULTS

Sixty (11%) patients had DM. Patients with DM more frequently had a PVC's site of origin (SOO) in the LV (45 [75%] vs. 229 [48%], P<0.001). The most frequent PVC's SOO in DM patients was the LV outflow tract (OT) (35 [58%] patients: 12 aortic cusps; 12 LV summit; 11 in the myocardium immediately inferior to the valvular plane). Fifty-five (92%) patients with DM had an acute successful ablation, without differences compared with patients without DM (55 [92%] vs. 437 [90%], P=0.9). Twenty-tree (38%) DM-patients had LV dysfunction at the ablation time. In these patients, mean PVC burden decreased from 26±11% at baseline to 4±5% (P<0.001); LVEF increased from 36±8% to 42±11% (P<0.01) and NYHA class improved from 2.2±0.6 to 1.8+0.5 (P<0.01), after a mean follow-up of 37±14 months.

CONCLUSIONS

Patients with DM frequently have PVC with a LV-SOO, being the LVOT the most frequent SOO in this population. Among DM patients with LV dysfunction, ablation persistently and significantly reduce the PVC burden improving functional status. Patients with DM have lower benefit in terms of LV function recovery after ablation compared with non-diabetic patients.

Manifestation of Heart Failure and Chronic Kidney Disease are Associated with Increased Mortality Risk in Early Stages of Type 2 Diabetes Mellitus: Analysis of a Japanese Real-World Hospital Claims Database

INTRODUCTION

To assess the initial manifestation of comorbidities and their impact on mortality risk in patients with type 2 diabetes mellitus (T2DM) without a history of cardiovascular or renal complications (i.e., in the early stages of T2DM) compared with patients without T2DM.

METHODS

We performed a retrospective cohort study using a Japanese hospital claims database. The incidence rates of comorbidities (chronic kidney disease [CKD], heart failure [HF], myocardial infarction [MI], peripheral arterial disease [PAD], and stroke) and mortality risk were compared between patients with T2DM and age-/sex-matched patients without T2DM (matched 1:2).

RESULTS

Among the comorbidities assessed in this study, CKD and/or HF was the most frequent initial manifestation in the patients with T2DM (n = 426,186) with an incidence rate 2.02 times greater than that in matched patients without T2DM (n = 1,018,609). The mortality risk was also greater in patients with T2DM than in patients without T2DM with a hazard ratio of 1.73. In both patients with and without T2DM, the presence of CKD or HF was associated with greater mortality risks compared with the presence of MI, PAD, or stroke.

CONCLUSIONS

The high incidence of CKD or HF manifestation can contribute to the augmented mortality risk in patients in the early stages of T2DM compared with patients without T2DM. These findings highlight the importance of early interventions for preventing/treating CKD and HF to improve the prognosis of patients with T2DM.

Diabetes Mellitus and Heart Failure

Diabetes mellitus (DM) is a major risk factor for new-onset heart failure (HF) and vice versa. The pathogenesis of new-onset HF in DM is complex and has been largely attributed to the toxic cardiovascular effects of hyperglycemia and relevant metabolic abnormalities (diabetic cardiomyopathy) as well as the frequently coexisting morbidities such as hypertension (HTN), coronary artery disease (CAD), and diabetic nephropathy. In patients with type 1 DM (T1DM), HF develops in the setting of a dysregulated immune response, whereas in most patients with type 2 DM (T2DM), against a background of overweight/obesity. HF prevention in DM is feasible with rigorous treatment of cardiovascular risk factors and selective antidiabetic agents. Conversely, development of new-onset T2DM in HF (cardiogenic DM) is common and has been attributed to an increase in the resistance to insulin, especially in the skeletal muscle, liver, and adipose tissue as well as in diminished insulin secretory response to hyperglycemia by pancreatic β-cells. Cardiogenic DM further deteriorates cardiac dysfunction and adversely affects outcome in HF. Novel lifesaving medications employed in HF management such as sacubitril/valsartan and sodium glucose cotransporter 2 inhibitors (SGLT-2i) have a favorable metabolic profile and lower the incidence of cardiogenic diabetes. Whether mitigation of cardiogenic DM should be a treatment target in HF deserves further investigation.

Differential Pathophysiological Mechanisms in Heart Failure With a Reduced or Preserved Ejection Fraction in Diabetes

Diabetes promotes the development of both heart failure with a reduced ejection fraction and heart failure with a preserved ejection fraction through diverse mechanisms, which are likely mediated through hyperinsulinemia rather than hyperglycemia. Diabetes promotes nutrient surplus signaling (through Akt and mammalian target of rapamycin complex 1) and inhibits nutrient deprivation signaling (through sirtuin-1 and its downstream effectors); this suppresses autophagy and promotes endoplasmic reticulum and oxidative stress and mitochondrial dysfunction, thereby undermining the health of diabetic cardiomyocytes. The hyperinsulinemia of diabetes may also activate sodium-hydrogen exchangers in cardiomyocytes (leading to injury and loss) and in the proximal renal tubules (leading to sodium retention). Diabetes may cause epicardial adipose tissue expansion, and the resulting secretion of proinflammatory adipocytokines onto the adjoining myocardium can lead to coronary microcirculatory dysfunction and myocardial inflammation and fibrosis. Interestingly, sodium-glucose cotransporter 2 (SGLT2) inhibitors-the only class of antidiabetic medication that reduces serious heart failure events-may act to mitigate each of these mechanisms. SGLT2 inhibitors up-regulate sirtuin-1 and its downstream effectors and autophagic flux, thus explaining the actions of these drugs to reduce oxidative stress, normalize mitochondrial structure and function, and mute proinflammatory pathways in the stressed myocardium. Inhibition of SGLT2 may also lead to a reduction in the activity of sodium-hydrogen exchangers in the kidney (leading to diuresis) and in the heart (attenuating the development of cardiac hypertrophy and systolic dysfunction). Finally, SGLT2 inhibitors reduce the mass and mute the adverse biology of epicardial adipose tissue (and reduce the secretion of leptin), thus explaining the capacity of these drugs to mitigate myocardial inflammation, microcirculatory dysfunction, and fibrosis, and improve ventricular filling dynamics. The pathophysiological mechanisms by which SGLT2 inhibitors may benefit heart failure likely differ depending on ejection fraction, but each represents interference with distinct pathways by which hyperinsulinemia may adversely affect cardiac structure and function.

Ischemic Etiology and Prognosis in Men and Women with Acute Heart Failure

Coronary heart disease is common in heart failure (HF). Our aim was to determine the impact of ischemic etiology on prognosis among men and women with HF. This study is a prospective national multicenter registry. The primary endpoint was 12-month mortality. Patients with HF and ischemic heart disease were stratified according to sex. A total of 1830 patients were enrolled of which 756 (41.3%) were women. Ischemic etiology was more common in men (446 (41.6%)) than in women (167 (22.2%)). Among patients with ischemic HF, diabetes was more frequent in women than in men. Ischemic etiology was not associated with higher mortality risk, and this was true for women (Hazard Ratio [HR] 1.51, 95% Confidence Interval [CI] 0.98–2.32; p = 0.61) and men (HR 1.14, 95% CI 0.81–1.61; p = 0.46), p-value for interaction: 0.067. Mortality/readmission risk in ischemic HF increased in men with previous readmissions (HR 1.15, 95% CI 1.02–1.29; p = 0.022), chronic obstructive pulmonary disease (HR1.20, 95% CI 1.02–1.41; p = 0.026) and in women with diabetes (HR 2.23, 95% CI 1.05–4.47; p = 0.035). Ischemic etiology was not associated with mortality in HF patients. In ischemic HF, the variables associated with a poor prognosis were diabetes in women and previous readmissions and chronic obstructive pulmonary disease in men.

Concurrent diabetes and heart failure: interplay and novel therapeutic approaches

Diabetes mellitus increases the risk of developing heart failure, and the co-existence of both diseases worsens cardiovascular outcomes, hospitalization and the progression of heart failure. Despite current advancements on therapeutic strategies to manage hyperglycemia, the likelihood of developing diabetes-induced heart failure is still significant, especially with the accelerating global prevalence of diabetes and an ageing population. This raises the likelihood of other contributing mechanisms beyond hyperglycemia in predisposing diabetic patients to cardiovascular disease risk. There has been considerable interest in understanding the alterations in cardiac structure and function in the diabetic patients, collectively termed as "diabetic cardiomyopathy". However, the factors that contribute to the development of diabetic cardiomyopathies is not fully understood. This review summarizes the main characteristics of diabetic cardiomyopathies, and the basic mechanisms that contribute to its occurrence. This includes perturbations in insulin resistance, fuel preference, reactive oxygen species generation, inflammation, cell death pathways, neurohormonal mechanisms, advanced glycated end-products accumulation, lipotoxicity, glucotoxicity, and posttranslational modifications in the heart of the diabetic. This review also discusses the impact of antihyperglycemic therapies on the development of heart failure, as well as how current heart failure therapies influence glycemic control in diabetic patients. We also highlight the current knowledge gaps in understanding how diabetes induces heart failure.

Mechanisms and Perspectives of Sodium-Glucose Co-transporter 2 Inhibitors in Heart Failure

Heart failure (HF) is a common complication or late-stage manifestation of various heart diseases. Numerous risk factors and underlying causes may contribute to the occurrence and progression of HF. The pathophysiological mechanisms of HF are very complicated. Despite accumulating advances in treatment for HF during recent decades, it remains an intractable clinical syndrome with poor outcomes, significantly reducing the quality of life and expectancy of patients, and imposing a heavy economic burden on society and families. Although initially classified as antidiabetic agents, sodium-glucose co-transporter 2 (SGLT2) inhibitors have demonstrated reduced the prevalence of hospitalization for HF, cardiovascular death, and all-cause death in several large-scale randomized controlled clinical trials. These beneficial effects of SGLT-2 inhibitors can be attributed to multiple hemodynamic, inflammatory and metabolic mechanisms, not only reducing the serum glucose level. SGLT2 inhibitors have been used increasingly in treatment for patients with HF with reduced ejection fraction due to their surprising performance in improving the prognosis. In addition, their roles and mechanisms in patients with HF with preserved ejection fraction or acute HF have also attracted attention. In this review article, we discuss the possible mechanisms and applications of SGLT2 inhibitors in HF.

Cardiorespiratory fitness in patients with type 2 diabetes: A missing piece of the puzzle

Functional capacity represents an important predictor for cardiovascular and all-cause mortality in patients with diabetes mellitus (DM). Impaired cardiopulmonary fitness is frequently seen in DM patients, and it might partly explain morbidity and mortality in these patients. There are several potential reasons that could explain impaired functional capacity in DM patients: hyperglycemia, insulin resistance, endothelial dysfunction, inflammation, microvascular impairment, myocardial dysfunction, and skeletal muscle changes. These changes are partly reversible, and improvement of any of these components might increase functional capacity in DM patients and improve their outcome. Physical activity is related with decreased cardiovascular disease and all-cause mortality in patients with type 2 DM. Diabetic cardiomyopathy is the most important clinical entity in DM patients that involves left ventricular diastolic dysfunction and cardiac autonomic neuropathy, which potentially induce heart failure with preserved ejection fraction. Development of diabetic cardiomyopathy may slow oxygen uptake kinetics and affect the cardiorespiratory fitness in DM patients, but it can also induce development of heart failure. Improvement of functional capacity in DM patients represents an important therapeutic task, and it can be achieved mainly with exercise training and significantly less with pharmacological treatment. Exercise training reduces body weight and improves glycemic control, as well as left ventricular structure and function. The aim of this review was to summarize current knowledge about importance of functional capacity in DM patients, as well as possible mechanisms that could explain the relationship between DM and oxygen kinetics.

Diabetes mellitus and risk of new-onset and recurrent heart failure: a systematic review and meta-analysis

Despite mounting evidence of the positive relationship between diabetes mellitus (DM) and heart failure (HF), the entire context of the magnitude of risk for HF in relation to DM remains insufficiently understood. The principal reason is because new‐onset HF (HF occurring in participants without a history of HF) and recurrent HF (HF re‐occurring in patients with a history of HF) are not discriminated. This meta‐analysis aims to comprehensively and separately assess the risk of new‐onset and recurrent HF depending on the presence or absence of DM. We systematically searched cohort studies that examined the relationship between DM and new‐onset or recurrent HF using EMBASE and MEDLINE (from 1 Jan 1950 to 28 Jul 2019). The risk ratio (RR) for HF in individuals with DM compared with those without DM was pooled with a random‐effects model. Seventy‐four and 38 eligible studies presented data on RRs for new‐onset and recurrent HF, respectively. For new‐onset HF, the pooled RR [95% confidence interval (CI)] of 69 studies that examined HF as a whole [i.e. combining HF with preserved ejection fraction (HFpEF) and HF with reduced ejection fraction (HFrEF)] was 2.14 (1.96–2.34). The large between‐study heterogeneity (I² = 99.7%, P < 0.001) was significantly explained by mean age [pooled RR (95% CI) 2.60 (2.38–2.84) for mean age < 60 years vs. pooled RR (95% CI) 1.95 (1.79–2.13) for mean age ≥ 60 years] (P < 0.001). Pooled RRs (95% CI) of seven and eight studies, respectively, that separately examined HFpEF and HFrEF risk were 2.22 (2.02–2.43) for HFpEF and 2.73 (2.71–2.75) for HFrEF. The risk magnitudes between HFpEF and HFrEF were not significantly different in studies that examined both HFpEF and HFrEF risks (P = 0.86). For recurrent HF, pooled RR (95% CI) of the 38 studies was 1.39 (1.33–1.45). The large between‐study heterogeneity (I² = 80.1%, P < 0.001) was significantly explained by the proportion of men [pooled RR (95% CI) 1.53 (1.40–1.68) for < 65% men vs. 1.32 (1.25–1.39) for ≥65% men (P = 0.01)] or the large pooled RR for studies of only participants with HFpEF [pooled RR (95% CI), 1.73 (1.32–2.26) (P = 0.002)]. Results indicate that DM is a significant risk factor for both new‐onset and recurrent HF. It is suggested that the risk magnitude is large for new‐onset HF especially in young populations and for recurrent HF especially in women or individuals with HFpEF. DM is associated with future HFpEF and HFrEF to the same extent.