Sex- and gender-differences in chronic long-term complications of type 1 and type 2 diabetes mellitus in Italy

AIMS

This review summarizes the contribution of Italian diabetologists devoted to a better understanding of the complex relationship linking sex/gender and long-term complications of type 1 (T1DM) and type 2 diabetes (T2DM) over the last fifteen years.

DATA SYNTHESIS

Microvascular and macrovascular complications of diabetes show sex- and gender-related differences, involving pathophysiological mechanisms, epidemiological features and clinical presentation, due to the interaction between biological and psychosocial factors. These differences greatly impact on the progression of diabetes and its long-term complications, especially in the cardiovascular, renal and liver districts.

CONCLUSION

A better knowledge of such sex- and gender-related characteristics is required for a more precise patient phenotypization, and for the choice of a personalized antihyperglycemic treatment. Despite such mounting evidence, current diabetes clinical guidelines do not as yet adequately consider sex/gender differences.

Effects of Metformin in Heart Failure: From Pathophysiological Rationale to Clinical Evidence

Type 2 diabetes mellitus (T2DM) is a worldwide major health burden and heart failure (HF) is the most common cardiovascular (CV) complication in affected patients. Therefore, identifying the best pharmacological approach for glycemic control, which is also useful to prevent and ameliorate the prognosis of HF, represents a crucial issue. Currently, the choice is between the new drugs sodium/glucose co-transporter 2 inhibitors that have consistently shown in large CV outcome trials (CVOTs) to reduce the risk of HF-related outcomes in T2DM, and metformin, an old medicament that might end up relegated to the background while exerting interesting protective effects on multiple organs among which include heart failure. When compared with other antihyperglycemic medications, metformin has been demonstrated to be safe and to lower morbidity and mortality for HF, even if these results are difficult to interpret as they emerged mainly from observational studies. Meta-analyses of randomized controlled clinical trials have not produced positive results on the risk or clinical course of HF and sadly, large CV outcome trials are lacking. The point of force of metformin with respect to new diabetic drugs is the amount of data from experimental investigations that, for more than twenty years, still continues to provide mechanistic explanations of the several favorable actions in heart failure such as, the improvement of the myocardial energy metabolic status by modulation of glucose and lipid metabolism, the attenuation of oxidative stress and inflammation, and the inhibition of myocardial cell apoptosis, leading to reduced cardiac remodeling and preserved left ventricular function. In the hope that specific large-scale trials will be carried out to definitively establish the metformin benefit in terms of HF failure outcomes, we reviewed the literature in this field, summarizing the available evidence from experimental and clinical studies reporting on effects in heart metabolism, function, and structure, and the prominent pathophysiological mechanisms involved.

Depressed Cardiac Mechanical Energetic Efficiency: A Contributor to Cardiovascular Risk in Common Metabolic Diseases-From Mechanisms to Clinical Applications

Cardiac mechanical energetic efficiency is the ratio of external work (EW) to the total energy consumption. EW performed by the left ventricle (LV) during a single beat is represented by LV stroke work and may be calculated from the pressure-volume loop area (PVLA), while energy consumption corresponds to myocardial oxygen consumption (MVO₂) expressed on a per-beat basis. Classical early human studies estimated total mechanical LV efficiency at 20-30%, whereas the remaining energy is dissipated as heat. Total mechanical efficiency is a joint effect of the efficiency of energy transfer at three sequential stages. The first step, from MVO₂ to adenosine triphosphate (ATP), reflects the yield of oxidative phosphorylation (i.e., phosphate-to-oxygen ratio). The second step, from ATP split to pressure-volume area, represents the proportion of the energy liberated during ATP hydrolysis which is converted to total mechanical energy. Total mechanical energy generated per beat-represented by pressure-volume area-consists of EW (corresponding to PVLA) and potential energy, which is needed to develop tension during isovolumic contraction. The efficiency of the third step of energy transfer, i.e., from pressure-volume area to EW, decreases with depressed LV contractility, increased afterload, more concentric LV geometry with diastolic dysfunction and lower LV preload reserve. As practical assessment of LV efficiency poses methodological problems, De Simone et al. proposed a simple surrogate measure of myocardial efficiency, i.e., mechano-energetic efficiency index (MEEi) calculated from LV stroke volume, heart rate and LV mass. In two independent cohorts, including a large group of hypertensive subjects and a population-based cohort (both free of prevalent cardiovascular disease and with preserved ejection fraction), low MEEi independently predicted composite adverse cardiovascular events and incident heart failure. It was hypothesized that the prognostic ability of low MEEi can result from its association with both metabolic and hemodynamic alterations, i.e., metabolic syndrome components, the degree of insulin resistance, concentric LV geometry, LV diastolic and discrete systolic dysfunction. On the one part, an increased reliance of cardiomyocytes on the oxidation of free fatty acids, typical for insulin-resistant states, is associated with both a lower yield of ATP per oxygen molecule and lesser availability of ATP for contraction, which might decrease energetic efficiency of the first and second step of energy transfer from MVO₂ to EW. On the other part, concentric LV remodeling and LV dysfunction despite preserved ejection fraction can impair the efficiency of the third energy transfer step. In conclusion, the association of low MEEi with adverse cardiovascular outcome might be related to a multi-step impairment of energy transfer from MVO₂ to EW in various clinical settings, including metabolic syndrome, diabetes, hypertension and heart failure. Irrespective of theoretical considerations, MEEi appears an attractive simple tool which couldt improve risk stratification in hypertensive and diabetic patients for primary prevention purposes. Further clinical studies are warranted to estimate the predictive ability of MEEi and its post-treatment changes, especially in patients on novel antidiabetic drugs and subjects with common metabolic diseases and concomitant chronic coronary syndromes, in whom the potential relevance of MEE can be potentiated by myocardial ischemia.

Effects of linagliptin on left ventricular DYsfunction in patients with type 2 DiAbetes and concentric left ventricular geometry: results of the DYDA 2 trial

AIMS

To evaluate the effect of linagliptin on left ventricular systolic function beyond glycaemic control in type 2 diabetes mellitus.

METHODS AND RESULTS

A multicentre, randomised, double-blind, placebo controlled, parallel-group study, was performed (the DYDA 2 trial). Individuals with type 2 diabetes mellitus and asymptomatic impaired left ventricular systolic function were randomly allocated in a 1:1 ratio to receive for 48 weeks either linagliptin 5 mg daily or placebo, in addition to their diabetes therapy. Eligibility criteria were age 40 years and older, haemoglobin A1c 8.0% or less (≤64 mmol/mol), no history of cardiac disease, concentric left ventricular geometry (relative wall thickness ≥0.42), impaired left ventricular systolic function defined as midwall fractional shortening 15% or less at baseline echocardiography. The primary end point was the modification of midwall fractional shortening over time. The main secondary objectives were changes in diastolic and/or in longitudinal left ventricular systolic function as measured by tissue Doppler echocardiography. One hundred and eighty-eight patients were enrolled, predominantly men with typical insulin-resistance comorbidities. At baseline, mean midwall fractional shortening was 13.3%±2.5. At final evaluation, 88 linagliptin patients and 86 placebo patients were compared: midwall fractional shortening increased from 13.29 to 13.82 (+4.1%) in the linagliptin group, from 13.58 to 13.84 in the placebo group (+1.8%, analysis of covariance P = 0.86), corresponding to a 2.3-fold higher increase in linagliptin than the placebo group, although non-statistically significant. Also, changes in diastolic and longitudinal left ventricular systolic function did not differ between the groups. Serious adverse events or linagliptin/placebo permanent discontinuation occurred in very few cases and in the same percentage between the groups.

CONCLUSIONS

In the DYDA 2 patients the addition of linagliptin to stable diabetes therapy was safe and provided a modest non-significant increase in left ventricular systolic function measured as midwall fractional shortening.

TRIAL REGISTRATION NUMBER

ClinicalTrial.gov (ID NCT02851745).

Issues for the management of people with diabetes and COVID-19 in ICU

In the pandemic “Corona Virus Disease 2019” (COVID-19) people with diabetes have a high risk to require ICU admission. The management of diabetes in Intensive Care Unit is always challenging, however, when diabetes is present in COVID-19 the situation seems even more complicated. An optimal glycemic control, avoiding acute hyperglycemia, hypoglycemia and glycemic variability may significantly improve the outcome. In this case, intravenous insulin infusion with continuous glucose monitoring should be the choice. No evidence suggests stopping angiotensin-converting-enzyme inhibitors, angiotensin-renin-blockers or statins, even it has been suggested that they may increase the expression of Angiotensin-Converting-Enzyme-2 (ACE2) receptor, which is used by “Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to penetrate into the cells. A real issue is the usefulness of several biomarkers, which have been suggested to be measured during the COVID-19. N-Terminal-pro-Brain Natriuretic-Peptide, D-dimer and hs-Troponin are often increased in diabetes. Their meaning in the case of diabetes and COVID-19 should be therefore very carefully evaluated. Even though we understand that in such a critical situation some of these requests are not so easy to implement, we believe that the best possible action to prevent a worse outcome is essential in any medical act.

Endothelial Dysfunction: A Contributor to Adverse Cardiovascular Remodeling and Heart Failure Development in Type 2 Diabetes beyond Accelerated Atherogenesis

Endothelial dysfunction, associated with depressed nitric oxide (NO) bioavailability, is awell-recognized contributor to both accelerated atherogenesis and microvascular complications intype 2 diabetes (DM). However, growing evidence points to the comorbidities-driven endothelialdysfunction within coronary microvessels as a key player responsible for left ventricular (LV)diastolic dysfunction, restrictive LV remodeling and heart failure with preserved ejection fraction(HFpEF), the most common form of heart failure in DM. In this review we have described: (1)multiple cellular pathways which may link depressed NO bioavailability to LV diastolicdysfunction and hypertrophy; (2) hemodynamic consequences and prognostic effects of restrictiveLV remodeling and combined diastolic and mild systolic LV dysfunction on cardiovascularoutcomes in DM and HFpEF, with a focus on the clinical relevance of endothelial dysfunction; (3)novel therapeutic strategies to improve endothelial function in DM. In summary, beyondassociations with accelerated atherogenesis and microvascular complications, endothelialdysfunction supplements the multiple interwoven pathways affecting cardiomyocytes, endothelialcells and the extracellular matrix with consequent LV dysfunction in DM patients. The associationamongst impaired endothelial function, reduced coronary flow reserve, combined LV diastolic anddiscrete systolic dysfunction, and low LV stroke volume and preload reserve-all of which areadverse outcome predictors-is a dangerous constellation of inter-related abnormalities, underlyingthe development of heart failure. Nevertheless, the relevance of endothelial effects of novel drugsin terms of their ability to attenuate cardiovascular remodeling and delay heart failure onset in DMpatients remains to be investigated.

Issues of Cardiovascular Risk Management in People With Diabetes in the COVID-19 Era

People with diabetes compared with people without exhibit worse prognosis if affected by coronavirus disease 2019 (COVID-19) induced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), particularly when compromising metabolic control and concomitant cardiovascular disorders are present. This Perspective seeks to explore newly occurring cardio-renal-pulmonary organ damage induced or aggravated by the disease process of COVID-19 and its implications for the cardiovascular risk management of people with diabetes, especially taking into account potential interactions with mechanisms of cellular intrusion of SARS-CoV-2. Severe infection with SARS-CoV-2 can precipitate myocardial infarction, myocarditis, heart failure, and arrhythmias as well as an acute respiratory distress syndrome and renal failure. They may evolve along with multiorgan failure directly due to SARS-CoV-2-infected endothelial cells and resulting endotheliitis. This complex pathology may bear challenges for the use of most diabetes medications in terms of emerging contraindications that need close monitoring of all people with diabetes diagnosed with SARS-CoV-2 infection. Whenever possible, continuous glucose monitoring should be implemented to ensure stable metabolic compensation. Patients in the intensive care unit requiring therapy for glycemic control should be handled solely by intravenous insulin using exact dosing with a perfusion device. Although not only ACE inhibitors and angiotensin 2 receptor blockers but also SGLT2 inhibitors, GLP-1 receptor agonists, pioglitazone, and probably insulin seem to increase the number of ACE2 receptors on the cells utilized by SARS-CoV-2 for penetration, no evidence presently exists that shows this might be harmful in terms of acquiring or worsening COVID-19. In conclusion, COVID-19 and related cardio-renal-pulmonary damage can profoundly affect cardiovascular risk management of people with diabetes.

Neutrophil: lymphocyte ratio is positively associated with subclinical diabetic cardiomyopathy

BACKGROUND

Subclinical diabetic cardiomyopathy (DCM) occurs frequently in asymptomatic subjects with Type 2 diabetes mellitus (T2DM). The direct association between the immune system and DCM with effective biomarkers has been demonstrated in previous studies.

METHODS

Five hundred seven subjects with T2DM were recruited from April 2018 to October 2019 and divided into T2DM with cardiac dysfunction (DCM) group and T2DM without cardiac dysfunction (non-DCM) group. The relationship between the quartiles of Neutrophil: lymphocyte ratio (NLR) and subclinical DCM was evaluated by using adjusted logistic regression models.(covariates: age, sex, BMI, duration of diabetes, and hyperlipidemia).

RESULTS

Blood NLR was significantly upregulated in DCM group compared to non-DCM group (P = 0.05). Then the adjusted odds ratio (95% CI) of the highest NLR quartile was 14.32 (2.92-70.31) compared with the lowest quartile of NLR after multiple adjusted (P < 0.001). However, there was no significant relation between neutrophil and lymphocyte counts and the occurrence of DCM in T2DM patients.

CONCLUSIONS

This study demonstrated that NLR was associated with the occurrence of subclinical DCM, suggesting that NLR may be a biomarker for predicting DCM with effectiveness and accuracy.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR1900027080) . Registered 30 October 2019. Retrospectively registered: www.medresman.org.

Effects of Dipeptidyl Peptidase-4 Inhibitor Linagliptin on Left Ventricular Dysfunction in Patients with Type 2 Diabetes and Concentric Left Ventricular Geometry (the DYDA 2™ Trial). Rationale, Design, and Baseline Characteristics of the Study Population

PURPOSE

A multicentre, randomized, double-blind, placebo-controlled, parallel-group study aimed to define the potential positive effect of dipeptidyl peptidase-4 inhibition on left ventricular systolic function (LVSF) beyond glycemic control in type 2 diabetes mellitus (T2DM) (DYDA 2™ trial).

METHODS

Individuals with fairly controlled T2DM and asymptomatic impaired LVSF were randomized in a 1:1 ratio to receive for 48 weeks either linagliptin 5 mg daily or placebo, in addition to their stable diabetes therapy. Eligibility criteria were age ≥ 40 years, history of T2DM with a duration of at least 6 months, HbA1c ≤ 8.0% (≤ 64 mmol/mol), no history or clinical signs/symptoms of cardiac disease, evidence at baseline echocardiography of concentric LV geometry (relative wall thickness ≥ 0.42), and impaired LVSF defined as midwall fractional shortening (MFS) ≤ 15%. The primary end-point was the modification from baseline to 48 weeks of MFS. As an exploratory analysis, significant changes in LV global longitudinal strain and global circumferential strain, measured by speckle tracking echocardiography, were also considered. Secondary objectives were changes in diastolic and/or in systolic longitudinal function as measured by tissue Doppler.

RESULTS

A total of 188 patients were enrolled. They were predominantly males, mildly obese, with typical insulin-resistance co-morbidities such as hypertension and dyslipidemia. Mean relative wall thickness was 0.51 ± 0.09 and mean MFS 13.3% ± 2.5.

CONCLUSIONS

DYDA 2 is the first randomized, double-blind, placebo-controlled trial to explore the effect of a dipeptidyl peptidase-4 inhibitor on LVSF in T2DM patients in primary prevention regardless of glycemic control. The main characteristics of the enrolled population are reported.

TRIAL REGISTRATION

ClinicalTrial.gov Identifier: NCT02851745.

An in-depth analysis of glycosylated haemoglobin level, body mass index and left ventricular diastolic dysfunction in patients with type 2 diabetes

BACKGROUND

Glycosylated hemoglobin (HbA1c) has a detrimental impact on the myocardium with left ventricular (LV) diastolic dysfunction. Obesity is a risk factor of type 2 diabetes. To understand the relationships between HbA1c, body mass index (BMI) and LV diastolic dysfunction, we performed this interaction analysis in patients with type 2 diabetes.

METHODS

Total 925 type 2 diabetes patients were selected from the patients who were diagnosed and treated at the First Affiliated Hospital of Shenzhen University. Patients' BMI levels were defined as normal (BMI < 24 kg/m²) and overweight /obese (BMI ≥ 24 kg/m²). Patients' HbA1c levels were grouped as HbA1c ≥ 9%、7% ≤ HbA1c < 9% and HbA1c < 7%. Logistic regression, stratified, interaction analysis, multivariate Cox regression and curve fitting analysis were performed to investigate the correlations and interactions between HbA1c and BMI with LV diastolic dysfunction.

RESULTS

The BMI levels were significantly associated with LV diastolic dysfunction in the patients with type 2 diabetes [adjusted model: 1.12 (1.05, 1.20), P = 0.001]. While HbA1c levels had association with LV diastolic dysfunction only in normal BMI group patients [adjusted model: 1.14 (1.01, 1.30), P = 0.0394] and curve correlation was observed. There was a significant interaction between BMI and HbA1c to affect LV diastolic dysfunction (P = 0.0335). Cox regression model analysis showed that the risk of LV diastolic dysfunction was a U type correlation with HbA1c levels in the normal weight group and the turning point was HbA1c at 10%. HbA1c level was not found to have a significant association with LV diastolic dysfunction in overweight/obese group.

CONCLUSIONS

In patients with type 2 diabetes, correlation between LV diastolic dysfunction and HbA1c was interactively affected by BMI. Glycemic control is beneficial to the heart function in normal body weight patients. For overweight/obese patients, the risk of LV diastolic dysfunction was not determined by the HbA1c level, indicating it may be affected by other confounding factors.

Presystolic Wave is Associated with Subclinical Left Ventricular Dysfunction Assessed by Myocardial Performance Index in Type 2 Diabetes Mellitus

BACKGROUND

Myocardial performance index (MPI), demonstrates both systolic and diastolic functions of the left ventricle. Presystolic wave (PSW) is frequently detected on Doppler examination of the left ventricular outflow tract and possible mechanism of PSW is impaired LV compliance and left ventricular stiffness.

OBJECTIVE

To investigate the relationship between PSW and MPI in type 2 diabetic patients.

METHOD

A total of 129 type 2 diabetic patients were included in this study. Patients were divided into two groups according to the presence of PSW on Doppler echocardiography. There were 90 patients (38 male, mean age 57.77 ± 10.91 years) in the PSW-positive group and 39 patients (13 male; mean age: 55.31 ± 11.29 years) in the PSW-negative group. The p values of < 0.05 were considered statistically significant.

RESULTS

MPI was higher in PSW- positive group (0.63 ± 0.17vs 0.52 ± 0.13, p < 0.001). In addition, subclinical left ventricle dysfunction (LVD) was higher in the PSW- positive group (p = 0.029). Univariate analysis showed that the presence of PSW associated with abnormal MPI (p = 0.031). Pearson correlation analysis showed that PSW velocity correlated with MPI (r: 0.286, p = 0.006).

CONCLUSION

Presence of the PSW on Doppler examination was associated with subclinical LV dysfunction in patients with DM type 2. This easy-to-perform echocardiographic parameter may be related to subclinical LVD among patients with type 2 DM.

Depressed systemic arterial compliance and impaired left ventricular midwall performance in aortic stenosis with concomitant type 2 diabetes: a retrospective cross-sectional study

Background

Degenerative aortic stenosis (AS), a disease of the elderly, frequently coexists with concomitant diseases, including type 2 diabetes (T2DM) which amplifies the cardiovascular (CV) risk. T2DM affects left ventricular (LV) structure and function via hemodynamic and metabolic factors. In concentric LV geometry, typical for AS, indices of LV midwall mechanics are better estimates of LV function than ejection fraction (EF). Effects of T2DM coexisting with AS on circumferential LV midwall systolic function and large artery properties have not been reported so far. Our aim was to compare characteristics of AS patients with and without T2DM, with a focus on LV midwall systolic function and arterial compliance.

Methods

Medical records of 130 electively hospitalized patients with moderate or severe isolated degenerative AS were retrospectively analyzed. Exclusion criteria included clinical instability, atrial fibrillation, coronary artery disease and relevant non-cardiac diseases. From in-hospital echocardiography and blood pressure, we calculated LV midwall fractional shortening (mwFS), circumferential end-systolic LV wall stress (cESS) and valvulo-arterial impedance (Zva), estimates of LV afterload, as well as systemic arterial compliance.

Results

Patients with (n = 50) and without T2DM (n = 80) did not differ in age, AS severity, LV mass and LV diastolic diameter. T2DM patients exhibited elevated cESS (247 ± 105 vs. 209 ± 84 hPa, p = 0.025) and Zva (5.8 ± 2.2 vs. 5.1 ± 1.8 mmHg per mL/m², p = 0.04), and lower stroke volume index (33 ± 10 vs. 38 ± 12 mL/m², p = 0.01) and systemic arterial compliance (0.53 ± 0.16 vs. 0.62 ± 0.22 mL/m² per mmHg, p = 0.01). mwFS (11.9 ± 3.9 vs. 14.1 ± 3.7%, p = 0.001), but not EF (51 ± 14 vs. 54 ± 13%, p = n.s.), was reduced in T2DM. mwFS and cESS were inversely interrelated in patients both with (r = − 0.59, p < 0.001) and without T2DM (r = − 0.53, p < 0.001) By multiple regression, higher cESS (p < 0.001) and T2DM (p = 0.02) were independent predictors of depressed mwFS.

Conclusions

In AS, coexistent T2DM appears associated with reduced systemic arterial compliance and LV dysfunction at the midwall level, corresponding to slightly depressed myocardial contractility.

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0894-1) contains supplementary material, which is available to authorized users.

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

INTRODUCTION

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

Metformin reduces all-cause mortality and diseases of ageing independent of its effect on diabetes control: A systematic review and meta-analysis

This systematic review investigated whether the insulin sensitiser metformin has a geroprotective effect in humans. Pubmed and Embase were searched along with databases of unpublished studies. Eligible research investigated the effect of metformin on all-cause mortality or diseases of ageing relative to non-diabetic populations or diabetics receiving other therapies with adjustment for disease control achieved. Overall, 260 full-texts were reviewed and 53 met the inclusion criteria. Diabetics taking metformin had significantly lower all-cause mortality than non-diabetics (hazard ratio (HR)=0.93, 95%CI 0.88-0.99), as did diabetics taking metformin compared to diabetics receiving non-metformin therapies (HR=0.72, 95%CI 0.65-0.80), insulin (HR=0.68, 95%CI 0.63-0.75) or sulphonylurea (HR=0.80, 95%CI 0.66-0.97). Metformin users also had reduced cancer compared to non-diabetics (rate ratio=0.94, 95%CI 0.92-0.97) and cardiovascular disease (CVD) compared to diabetics receiving non-metformin therapies (HR=0.76, 95%CI 0.66-0.87) or insulin (HR=0.78, 95%CI 0.73-0.83). Differences in baseline characteristics were observed which had the potential to bias findings, although statistical adjustments were made. The apparent reductions in all-cause mortality and diseases of ageing associated with metformin use suggest that metformin could be extending life and healthspans by acting as a geroprotective agent.

Metformin effects on the heart and the cardiovascular system: A review of experimental and clinical data

BACKGROUND

Metformin, the eldest and most widely used glucose lowering drug, is likely to be effective also on cardiac and vascular disease prevention. Nonetheless, uncertainty still exists with regard to its effects on the cardiovascular system as a whole and specifically on the myocardium, both at the organ and cellular levels.

METHODS

We reviewed the available data on the cardiac and vascular effects of metformin, encompassing both in vitro, either tissue or isolated organ, and in vivo studies in experimental animals and humans, as well as the evidence generated by major clinical trials.

RESULTS

At the cellular level metformin's produces both AMP-activated kinase (AMPK) dependent and independent effects. At the systemic level, possibly also through other pathways, this drug improves endothelial function, protects from oxidative stress and inflammation, and from the negative effects of angiotensin II. On the myocardium it attenuates ischemia-reperfusion injury and prevents adverse remodeling induced by humoral and hemodynamic factors. The effects on myocardial cell metabolism and contractile function being not evident at rest or in more advanced stages of cardiac dysfunction, could be relevant during transient ischemia, during an acute increase in workload and in the early stages of diabetic/hypertensive cardiomyopathy as confirmed by few small clinical trials and some observational studies. The overall evidence emerging from both clinical trials and real world registry is in favor of a protective effect of metformin with respect to both coronary events and progression to heart failure.

CONCLUSIONS

Given this potential, its efficacy and its safety (and also its low cost) metformin remains the central pillar of the therapy of diabetes.

Renal function estimation and Cockroft-Gault formulas for predicting cardiovascular mortality in population-based, cardiovascular risk, heart failure and post-myocardial infarction cohorts: The Heart 'OMics' in AGEing (HOMAGE) and the high-risk myocardial infarction database initiatives

BACKGROUND

Renal impairment is a major risk factor for mortality in various populations. Three formulas are frequently used to assess both glomerular filtration rate (eGFR) or creatinine clearance (CrCl) and mortality prediction: body surface area adjusted-Cockcroft-Gault (CG-BSA), Modification of Diet in Renal Disease Study (MDRD4), and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. The CKD-EPI is the most accurate eGFR estimator as compared to a "gold-standard"; however, which of the latter is the best formula to assess prognosis remains to be clarified. This study aimed to compare the prognostic value of these formulas in predicting the risk of cardiovascular mortality (CVM) in population-based, cardiovascular risk, heart failure (HF) and post-myocardial infarction (MI) cohorts.

METHODS

Two previously published cohorts of pooled patient data derived from the partners involved in the HOMAGE-consortium and from four clinical trials - CAPRICORN, EPHESUS, OPTIMAAL and VALIANT - the high risk MI initiative, were used. A total of 54,111 patients were included in the present analysis: 2644 from population-based cohorts; 20,895 from cardiovascular risk cohorts; 1801 from heart failure cohorts; and 28,771 from post-myocardial infarction cohorts. Participants were patients enrolled in the respective cohorts and trials. The primary outcome was CVM.

RESULTS

All formulas were strongly and independently associated with CVM. Lower eGFR/CrCl was associated with increasing CVM rates for values below 60 mL/min/m². Categorical renal function stages diverged in a more pronounced manner with the CG-BSA formula in all populations (higher χ² values), with lower stages showing stronger associations. The discriminative improvement driven by the CG-BSA formula was superior to that of MDRD4 and CKD-EPI, but remained low overall (increase in C-index ranging from 0.5 to 2 %) while not statistically significant in population-based cohorts. The integrated discrimination improvement and net reclassification improvement were higher (P < 0.05) for the CG-BSA formula compared to MDRD4 and CKD-EPI in CV risk, HF and post-MI cohorts, but not in population-based cohorts. The CKD-EPI formula was superior overall to MDRD4.

CONCLUSIONS

The CG-BSA formula was slightly more accurate in predicting CVM in CV risk, HF, and post-MI cohorts (but not in population-based cohorts). However, the CG-BSA discriminative improvement was globally low compared to MDRD4 and especially CKD-EPI, the latter offering the best compromise between renal function estimation and CVM prediction.

Lower free testosterone level is correlated with left ventricular diastolic dysfunction in asymptomatic middle-aged men with type 2 diabetes mellitus

AIMS

Low testosterone (T) level is associated with cardiovascular risk factors. However, the relationship between T level and heart function in asymptomatic men with type 2 diabetes mellitus (T2DM) is unknown.

METHODS

A total of 325 men were recruited who had no history, symptoms, or signs of heart disease.

RESULTS

T2DM had significantly lower free T (FT) levels than those with normal glucose metabolism (NGM) (428 ± 38 pmol/l vs. 444 ± 38 pmol/l, p = 0.0002), and had an increased risk of LVDD (66.1% vs. 31.8%). There was a significant difference in FT level between subjects with and without LVDD among those with T2DM (421 ± 37 pmol/l vs. 442 ± 40 pmol/l, p = 0.0007), but not among those with NGM (439 ± 37 pmol/l vs. 447 ± 39 pmol/l, p = 0.247) or in the group overall (426 ± 38 pmol/l vs. 445 ± 38 pmol/l, p = 0.156). Lower FT level was significantly associated with LVDD [univariate odds ratio (OR) = 0.63, p = 0.032; multivariate OR = 0.71, p = 0.039]. Receiver operating characteristic curve analysis of the usefulness of FT level for predicting LVDD showed an area under the curve (AUC) of 0.85 for T2DM (p < 0.001) and 0.66 for NGM (p < 0.05). FT level had a high predictive value for LVDD in T2DM (83% for FT < 414 pmol/l), but a low predictive value in NGM (61% for FT < 423 pmol/l). Comparison of the AUCs showed that FT level was more strongly correlated with LVDD in T2DM than in NGM.

CONCLUSIONS

Lower FT level is correlated with LVDD in asymptomatic middle-aged men with T2DM.

Heart 'omics' in AGEing (HOMAGE): design, research objectives and characteristics of the common database

Heart failure is common in older people and its prevalence is increasing. The Heart ‘omics’ in AGEing (HOMAGE) project aims to provide a biomarker approach that will improve the early diagnosis of heart failure. A large clinical database, based on (1) prospective population studies or (2) cross-sectional, prospective studies or randomized controlled trials (RCTs) of patients at risk for or with overt cardiovascular disease will be constructed to determine most promising ‘omics’-based biomarkers to identify the risk of developing heart failure and/or comorbidities. Population studies, patient cohorts and RCTs are eligible for inclusion in the common database, if they received ethical approval to obtain and share data and have baseline information on cardiovascular risk factors. Currently, the HOMAGE database includes 43,065 subjects, from 20 studies in eight European countries, including healthy subjects from three population studies in France, Belgium and Italy (n  =  7,124), patients with heart failure (n  =  4,312) from four cohorts in the UK, Spain and Switzerland and patients at high risk for cardiovascular disease (n  =  31,629) in 13 cohorts. It is anticipated that more partners will join the consortium and enlarge the pooled data. This large merged database will be a useful resource with which to identify candidate biomarkers that play a role in the mechanism underlying the onset and progression of heart failure.

Usefulness of subclinical left ventricular midwall dysfunction to predict cardiovascular mortality in patients with type 2 diabetes mellitus

In this study, we tested the hypothesis that impaired midwall shortening predicts cardiovascular (CV) mortality in patients with type 2 diabetes mellitus (DM). In patients with DM without overt cardiac disease, systolic left ventricular (LV) function analyzed by midwall shortening may be impaired although LV ejection fraction is preserved. Impaired midwall shortening is an early independent prognosticator of adverse clinical outcome in patients with arterial hypertension. We analyzed the echocardiographic data from 360 outpatients with DM collected during the years 1990 to 2007. Patients had no history or symptoms attributable to cardiac disease. Stress-corrected midwall shortening (sc-MS) was taken as index of systolic LV function and considered impaired if <89%. The study outcome was CV mortality. At baseline, impaired sc-MS was detected in 140 patients (39%). During a mean follow-up period of 11 years, 54 patients (15%) died, 31 (8.6%) of them from CV causes. CV deaths occurred in 21 of 140 patients (15%) with impaired sc-MS and in 10 of 220 patients (4.5%) with normal sc-MS (p=0.006). Multivariate Cox regression analysis revealed that impaired sc-MS (hazard ratio 1.03, 95% confidence interval 1.01 to 1.08, p=0.039), together with lower estimated glomerular filtration rate (hazard ratio 0.96, 95% confidence interval 0.93 to 0.99, p=0.004), was independently associated with CV mortality even after adjustment for age, diabetes duration, hemoglobin A1c, left atrial diameter, and heart valve calcium. In conclusion, subclinical systolic LV dysfunction as measured by sc-MS occurs frequently in patients with DM without overt cardiac disease and independently predicts long-term CV mortality in such patients together with lower estimated glomerular filtration rate.

Biomarker and imaging responses to spironolactone in subclinical diabetic cardiomyopathy

BACKGROUND

Subclinical diabetic cardiomyopathy (DCM) is frequent in asymptomatic subjects with type 2 diabetes (T2DM). We sought the response of functional and fibrosis markers to therapy in a trial of aldosterone antagonism for treatment of DCM.

METHODS

Biochemical, anthropometric, and echocardiographic data were measured in 225 subjects with T2DM. Myocardial function was evaluated with standard echocardiography and myocardial deformation; ischaemia was excluded by exercise echocardiography. Calibrated integrated backscatter and post-contrast T1 mapping from cardiac magnetic resonance imaging were used to assess myocardial structure. Amino-terminal propeptides of pro-collagen type I (PINP) and III (PIIINP), the carboxy-terminal propeptide of pro-collagen type I (PICP) and transforming growth factor beta-1 were measured from peripheral blood or urine to assess myocardial collagen turnover.

RESULTS

Diastolic dysfunction was identified in 81 individuals, of whom 49 (25 male, age 60 ± 10 years) were randomized to spironolactone 25 mg/day or placebo therapy for 6 months. Groups were well-matched at baseline. Spironolactone therapy was associated with improvements in diastolic filling profile (Δpeak E wave velocity -4 ± 15 vs. 9 ± 10 ms, P = 0.001; ΔE/A ratio -0.1 ± 0.3 vs. 0.2 ± 0.2, P < 0.001) and cIB values (-21.2 ± 4.5 dB vs. -18.0 ± 5.2 dB, P = 0.026; ΔcIB -5.1 ± 6.8 vs. -1.3 ± 5.2, P = 0.030). ΔcIB was independently associated with spironolactone therapy (β = 0.320, P = 0.026) but not Δblood pressure. With intervention, pro-collagen biomarkers (ΔPINP P = 0.92, ΔPICP P = 0.25, ΔPIIINP P = 0.52, and ΔTGF-β1 P = 0.71) and T1 values (P = 0.54) remained similar between groups.

CONCLUSIONS

Spironolactone-induced changes in myocardial structure and diastolic properties in DCM are small, and are unassociated with changes in collagen biomarkers or T1 values.

The activity of circulating dipeptidyl peptidase-4 is associated with subclinical left ventricular dysfunction in patients with type 2 diabetes mellitus

Background

Patients with type 2 diabetes mellitus (T2DM) present subclinical left ventricular systolic and/or diastolic dysfunction (LVD). Dipeptidyl peptidase-4 (DPP4) inactivates peptides that possess cardioprotective actions. Our aim was to analyze whether the activity of circulating DPP4 is associated with echocardiographically defined LVD in asymptomatic patients with T2DM.

Methods

In this cross-sectional study, we examined 83 T2DM patients with no coronary or valve heart disease and 59 age and gender-matched non-diabetic subjects. Plasma DPP4 activity (DPP4a) was measured by enzymatic assay and serum amino-terminal pro-brain natriuretic peptide (NT-proBNP) was measured by enzyme-linked immunosorbent assay. LV function was assessed by two-dimensional echocardiographic imaging, targeted M-mode recordings and Doppler ultrasound measurements. Differences in means were assessed by t-tests and one-way ANOVA. Associations were assessed by adjusted multiple linear regression and logistic regression analyses.

Results

DPP4a was increased in T2DM patients as compared with non-diabetic subjects (5855 ± 1632 vs 5208 ± 957 pmol/min/mL, p < 0.05). Clinical characteristics and echocardiographic parameters assessing LV morphology were similar across DPP4a tertiles in T2DM patients. However, prevalence of LVD progressively increased across incremental DPP4a tertiles (13%, 39% and 71%, all p < 0.001). Multivariate regression analysis confirmed the independent associations of DPP4a with LVD in T2DM patients (p < 0.05). Similarly, multiple logistic regression analysis showed that an increase of 100 pmol/min/min plasma DPP4a was independently associated with an increased frequency of LVD with an adjusted odds ratio of 1.10 (95% CI, 1.04 to 1.15, p = 0.001).

Conclusions

An excessive activity of circulating DPP4 is independently associated with subclinical LVD in T2DM patients. Albeit descriptive, these findings suggest that DPP4 may be involved in the mechanisms of LVD in T2DM.

The increasing detection of asymptomatic left ventricular dysfunction in patients with type 2 diabetes mellitus without overt cardiac disease: data from the SHORTWAVE study

AIMS

Type 2 diabetes mellitus (DM) is associated with higher risk of heart failure. Over the last three decades several studies demonstrated the presence of asymptomatic systolic and/or diastolic left ventricular (LV) dysfunction (asymLVD) in patients with normal LV ejection fraction (LVEF). Purpose of our study was to assess the prevalence and factors associated with asymLVD in DM patients by echocardiographic indexes more sensitive than LVEF and transmitral flow detected by pulsed Doppler.

METHODS

386 DM patients without overt cardiac disease were enrolled from January to October 2011. Stress-corrected midwall shortening (sc-MS) and mitral annular peak systolic velocity (S') were considered as indexes of systolic function of circumferential and longitudinal myocardial fibers, respectively. Early diastolic velocity of transmitral flow was divided by early diastolic Tissue Doppler velocity of mitral annulus for identifying diastolic LVD.

RESULTS

asymLVD was detected in 262 patients (68%). 106 (27%) had isolated systolic asymLVD, 61 (16%) isolated diastolic asymLVD; in 95 (25%) systolic and diastolic asymLVD coexisted. Patients with asymLVD were older, had lower glomerular filtration rate, higher levels of glycated hemoglobin, C reactive protein, LV mass, relative wall thickness and prevalence of valve calcifications. Older age (HR 1.1 [1.02-1.18], p=0.01), aortic valve calcifications (HR 6.3 [1.31-30.31], p=0.02), LV concentric geometry defined as relative wall thickness ≥0.43 (HR 15.44 [2.96-80.44], p=0.001) were independent predictors of asymLVD at multivariate analysis.

CONCLUSIONS

Using suitable echocardiographic indexes, asymLVD is detectable in two/third of DM patients without overt cardiac disease and is predicted by older age, cardiac valve calcifications and LV concentric remodeling.

Left ventricular dysfunction and outcome at two-year follow-up in patients with type 2 diabetes: The DYDA study

AIMS

Left ventricular dysfunction (LVD) in type 2 diabetes mellitus (DM) (DYDA) study is a prospective investigation enrolling 960 with DM without overt cardiac disease. At baseline, a high prevalence of LVD was detected by analysing midwall shortening. We report here the incidence of clinical events in DYDA patients after 2-year follow-up and the frequency of LVD detected at baseline and 2-year evaluation.

METHODS

Systolic LVD was defined as midwall shortening ≤15%, diastolic LVD as any condition different from "normal diastolic function" identified as E/A ratio on Doppler mitral flow between 0.75 and 1.5 and deceleration time of E wave >140 ms. Major outcome was a composite of major events, including all-causes death and hospital admissions.

RESULTS

During the study period, any systolic/diastolic LVD was found in 616 of 699 patients (88.1%) in whom LVD function could be measured at baseline or at 2 years. Older age and high HbA1c predicted the occurrence of LVD. During the follow-up 15 patients died (1.6%), 3 for cardiovascular causes, 139 were hospitalized (14.5%, 43 of them for cardiovascular causes, 20 for a new cancer).

CONCLUSIONS

During a 2-year follow-up any LVD is detectable in a large majority of patients with DM without overt cardiac disease. Older age and higher HbA1c predict LVD. All-cause death or hospitalization occurred in 15% of patients, cardiovascular cause was uncommon. Independent predictors of events were older age, pathologic lipid profile, high HbA1c, claudicatio and repaglinide therapy. Echo-assessed LVD at baseline was not prognosticator of events.

Left atrial volume index as a marker of left ventricular diastolic dysfunction in asymptomatic Tanzanian diabetic patients

AIM

To determine the prevalence of left atrial (LA) enlargement and its relation to left ventricular (LV) diastolic dysfunction among asymptomatic diabetic outpatients attending Muhimbili National Hospital in Dar es Salaam, Tanzania.

METHODS

Echocardiography was performed in 122 type 2 and 58 type 1 diabetic patients. Diastolic dysfunction was defined as peak transmitral blood velocity to medial mitral annulus velocity (E/E') ratio ≥ 15. LA volume indexed to body surface area (LAVI) was considered enlarged if ≥ 29 ml/m(2).

RESULTS

Enlarged LAVI and LV diastolic dysfunction were more common in type 2 than in type 1 diabetic patients (44.3 vs 25.9% and 20.5 vs 3.5%, respectively, both p < 0.05). In multivariate linear regression analysis, larger LAVI was associated with LV diastolic dysfunction independent of significant associations with LV mass index and presence of mitral regurgitation in type 2 diabetic patients, while LV mass index, lower ejection fraction and longer duration of diabetes were the main covariates of larger LAVI in type 1 diabetic patients (all p < 0.05).

CONCLUSION

Enlarged LA is common among asymptomatic Tanzanian diabetic patients, and particularly associated with LV diastolic dysfunction in type 2, and with cardiomyopathy and lower systolic function in type 1 diabetic patients.