Higher hemoglobin A1c levels are associated with impaired left ventricular diastolic function and higher incidence of adverse cardiac events in patients with nonischemic dilated cardiomyopathy

How does HbA1c predict mortality and readmission in patients with heart failure? A protocol for systematic review and meta-analysis

BACKGROUND

Accumulating evidence suggests that HbA1c levels, a common clinical indicator of chronic glucose metabolism over the preceding 2-3 months, are independent risk factors for cardiovascular disease, including heart failure. However, conflicting evidence obscures clear cutoffs of HbA1c levels in various heart failure populations. The aim of this review is to assess the possible predictive value and optimal range of HbA1c on mortality and readmission in patients with heart failure.

METHODS

A systematic and comprehensive search will be performed using PubMed, Embase, CINAHL, Scopus, and the Cochrane Library databases before December 2022 to identify relevant studies. All-cause mortality is the prespecified primary endpoint. Cardiovascular death and heart failure readmission are secondary endpoints of interest. We will only include prospective and retrospective cohort studies and place no restrictions on the language, race, region, or publication period. The ROBINS-I tool will be used to assess the quality of each included research. If there were sufficient studies, we will conduct a meta-analysis with pooled relative risks and corresponding 95% confidence intervals to evaluate the possible predictive value of HbA1c for mortality and readmission. Otherwise, we will undertake a narrative synthesis. Heterogeneity and publication bias will be assessed. If heterogeneity was significant among included studies, a sensitivity analysis or subgroup analysis will be used to explore the source of heterogeneity, such as diverse types of heart failure or patients with diabetes and non-diabetes. Additionally, we will conduct meta-regression to examine the time-effect and treatment-effect modifiers on all-cause mortality compared between different quantile of HbA1c levels. Finally, a restricted cubic spline model may be used to explore the dose-response relationship between HbA1c and adverse outcomes.

DISCUSSION

This planned analysis is anticipated to identify the predictive value of HbA1c for mortality and readmission in patients with heart failure. Improved understanding of different HbA1c levels and their specific effect on diverse types of heart failure or patients with diabetes and non-diabetes is expected to be figured out. Importantly, a dose-response relationship or optimal range of HbA1c will be determined to instruct clinicians and patients.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration details: CRD42021276067.

Low stress hyperglycemia ratio predicts worse prognosis in diabetic acute heart failure patients

INTRODUCTION

Acute blood glucose but not glycated hemoglobin (HbA1c) predicts poor outcome in acute heart failure (HF). The stress hyperglycemia ratio (SHR) has been proposed as a prognostic predictor in various clinical settings.

OBJECTIVES

We assessed the prognostic implications of the SHR in acute HF patients with and without diabetes.

METHODS

We performed a retrospective analysis of an acute HF registry conducted between 2009 and 2010. Estimated average glucose (eAG) was calculated as (28.7×HbA1c)-46.7 and SHR as acute blood glucose divided by eAG. The primary endpoint was all-cause mortality. Follow-up was three months. Patients were grouped by SHR tertiles (≤0.88, 0.89-1.16, and >1.16). Cox regression analysis was used to test the association of SHR (cut-off 0.88) with all-cause mortality. Analysis was stratified according to the presence of diabetes. Multivariate models were built accounting for acute blood glucose and for eAG (models 1 and 2, respectively).

RESULTS

We studied 599 patients, mean age 76±12 years, of whom 62.1% had reduced ejection fraction and 50.9% had diabetes. Median acute blood glucose, eAG and SHR were 136 (107-182) mg/dl, 131 (117-151) mg/dl, and 1.02 (0.20-3.34), respectively. During follow-up 102 (17.0%) died. In patients with diabetes, those in the lowest SHR tertile had a hazard ratio (HR) of 2.24 (95% CI: 1.05-5.22) (model 1) and 2.34 (1.25-4.38) (model 2). In patients without diabetes, the HR of three-month death in the lowest SHR tertile was 0.71 (95% CI: 0.36-1.39) and 1.02 (0.58-1.81). Significant interaction was observed between diabetes and SHR.

CONCLUSIONS

In HF patients with diabetes, a SHR ≤0.88 was associated with a more than twofold higher three-month mortality risk. No such association was found in non-diabetic patients. The presence of diabetes influences the association of the SHR with mortality.

Elevation of hemoglobin A1c increases the risk of decline in left ventricular systolic function among patients with coronary artery disease

AIMS

The aim of this study was to investigate the association of HbA1c and left ventricular (LV) systolic function among patients with coronary artery disease (CAD).

METHODS

CAD patients from the Cardiorenal ImprovemeNt II (CIN-II, NCT05050877) registry were included in the study. They were separated into four groups based on HbA1c levels (Q1: HbA1c<5.7%; Q2: 5.7% ≤ HbA1c < 6.1%; Q3: 6.1% ≤ HbA1c < 6.9%; Q4: HbA1c ≥ 6.9%). The endpoint was decline in LV systolic function, defined as an absolute decrease in LV ejection fraction (LVEF) ≥10% from baseline to follow-up with 3-12 months. The association of HbA1c and LVEF was assessed by logistics regression models.

RESULTS

CAD patients (n = 3,994) (age 62.9 ± 10.6 years; 22.2% female) were included in the final analysis. A decline in LV systolic function was recorded in 429 (11%) patients during follow-up. After fully adjusting for confounders, HbA1c was significantly associated with the high risk of decline in LV systolic function (OR 1.12 [95%CI 1.05-1.20] P = 0.001). By stratifying HbA1c as four groups, there is a significantly increased risk of decline in LV systolic function when HbA1c ≥6.1% (Q2, Q3 and Q4 vs Q1, with OR 1.22 [0.88-1.68] P = 0.235; OR 1.48 [1.07-2.05] P = 0.019; OR 1.60 [1.160-2.22] P = 0.004, respectively). Meanwhile, patients with decline in LV systolic function had a higher risk of cardiovascular death.

CONCLUSIONS

Elevated HbA1c is a predictor of decline in LV systolic function in CAD patients. Clinicians should be aware of the risk of decline in LV systolic function in CAD patients with elevated HbA1c, and take measures as soon as possible.

Impact of type 2 diabetes mellitus on left ventricular deformation in non-ischemic dilated cardiomyopathy patients assessed by cardiac magnetic resonance imaging

Background

Type 2 diabetes mellitus (T2DM) increases the risk of worse long-term outcomes in patients with non-ischemic dilated cardiomyopathy (NIDCM). However, the additive effects of T2DM on left ventricular (LV) function in NIDCM remain unclear. Accordingly, we aimed to investigate the impact of comorbid T2DM on LV deformation in NIDCM individuals.

Materials and methods

Three hundred forty-two NIDCM patients without T2DM [NIDCM (T2DM−)], 93 with T2DM [NIDCM (T2DM+)] and 80 age- and sex-matched normal controls who underwent cardiac magnetic resonance scanning were included. LV geometry, function, and LV global strains, including peak strain (PS), peak systolic strain rate (PSSR) and peak diastolic strain rate (PDSR) in the radial, circumferential and longitudinal directions, were measured. NIDCM (T2DM+) patients were divided into two subgroups based on the HbA1c level (< 7.0% and ≥ 7.0%). The determinants of reduced LV myocardial strain for all NIDCM individuals and NIDCM (T2DM+) patients were assessed using multivariable linear regression analyses.

Results

Compared with normal controls, both NIDCM (T2DM −) and NIDCM (T2DM+) patients exhibited increased LV end-diastolic and end-systolic volume index and decreased LV ejection fraction. LV global strains progressively declined from the normal controls to the NIDCM (T2DM−) group to the NIDCM (T2DM+) group (all p < 0.017), except for radial PDSR and PSSR. Subgroup analysis showed that LV global radial PS and longitudinal PS, PSSR-L and PDSR-L were worse in NIDCM patients with poor glycemic control than in those with good glycemic control (p < 0.017). T2DM was an independent determinant of reduced LV global circumferential PS and longitudinal PS in patients with NIDCM (both p < 0.05). An increased HbA1c level was independently associated with a decreased global radial PS (β = − 0.285, p < 0.01) and longitudinal PS (β = 0.320, p < 0.01) in NIDCM (T2DM+) patients.

Conclusions

T2DM has an additive deleterious effect on LV systolic and diastolic function in NIDCM patients. Among NIDCM patients with T2DM, HbA1c was found to be associated with reduced LV myocardial strain.

The effects of glycemic control on morbidity and survival among diabetic patients

AIMS

The study intended to investigate the impact of controlled glycemia on morbidity and estimated 10-year survival (ES-10Y).

METHODS

A cross-sectional investigation was conducted at General Penang Hospital, Malaysia. Demographic criteria and laboratory tests of patients were investigated. Controlled glycemia (CG) was recognized as glycated hemoglobin (HbA1c) ≤7% depending on American Diabetes Association guidelines 2018. Charlson Comorbidity Index (CCI) was used to estimate the confounding influence of co-morbidities and predict ES-10Y. Data was managed by IBM-SPSS 23.0.

RESULTS

A total of 400 cases categorized to (44.25%) patients with CG, and (55.75%) cases had uncontrolled glycemia (UCG). HbA1c mean in CG and UCG group was (6.8 ± 0.9 vs 9.5 ± 1.6, P-value: 0.001). Fasting blood glucose was (7 ± 2.3 vs. 9.9 ± 4.3, P-value: 0.001) in CG and UCG group. CCI was (3.38 ± 2.38 vs. 4.42 ± 2.70, P-value: 0.001) and, ES-10Y was (62% vs 46.2%, p-value: 0.001) in CG vs. UCG respectively. Spearman test indicates a negative correlation between CG and CCI (r: 0.19, p-value: 0.001). Logistic regression confirmed HbA1c as a significant predictor of CCI (r²: 0.036, P-value: 0.001). CG has a positive correlation with survival (r: 0.16, P-value: 0.001) and logistic regression of survival (r²: 0.26, P-value: 0.001).

CONCLUSIONS

More than one-half of the investigated persons had UCG. Controlled HbA1c was associated with lower co-morbidities and higher ES-10Y.

Interrelationship between diabetes mellitus and heart failure: the role of peroxisome proliferator-activated receptors in left ventricle performance

Heart failure (HF) is a common cardiac syndrome, whose pathophysiology involves complex mechanisms, some of which remain unknown. Diabetes mellitus (DM) constitutes not only a glucose metabolic disorder accompanied by insulin resistance but also a risk factor for cardiovascular disease and HF. During the last years though emerging data set up, a bidirectional interrelationship between these two entities. In the case of DM impaired calcium homeostasis, free fatty acid metabolism, redox state, and advance glycation end products may accelerate cardiac dysfunction. On the other hand, when HF exists, hypoperfusion of the liver and pancreas, b-blocker and diuretic treatment, and autonomic nervous system dysfunction may cause impairment of glucose metabolism. These molecular pathways may be used as therapeutic targets for novel antidiabetic agents. Peroxisome proliferator-activated receptors (PPARs) not only improve insulin resistance and glucose and lipid metabolism but also manifest a diversity of actions directly or indirectly associated with systolic or diastolic performance of left ventricle and symptoms of HF. Interestingly, they may beneficially affect remodeling of the left ventricle, fibrosis, and diastolic performance but they may cause impaired water handing, sodium retention, and decompensation of HF which should be taken into consideration in the management of patients with DM. In this review article, we present the pathophysiological data linking HF with DM and we focus on the molecular mechanisms of PPARs agonists in left ventricle systolic and diastolic performance providing useful insights in the molecular mechanism of this class of metabolically active regiments.

Higher mortality rate in patients with heart failure who are taking commonly prescribed antidiabetic medications and achieve recommended levels of glycaemic control

Current guidelines for diabetes recommend that physicians attain a glycated haemoglobin (HbA1c) concentration ≤7.0%, but this target may not be applicable to those with heart failure. Fourteen studies in patients with chronic heart failure that examined the relationship between the level of HbA1c and risk of death specified whether HbA1c was influenced by treatment with antidiabetic medications. In patients with heart failure not receiving glucose-lowering drugs, the mortality rate was not higher among those with an HbA1c concentration <7.0%. By contrast, in patients who were treated with insulin, sulphonylureas and thiazolidinediones, an inverse or U-shaped relationship between HbA1c and the risk of death was generally observed, and mortality was lowest in patients with both heart failure and diabetes if the level of HbA1c was >7.0%. These studies suggest that patients with both heart failure and diabetes are at increased risk of death if they are prescribed certain glucose-lowering drugs to achieve levels of HbA1c <7.0%.

The effect of fluvastatin on cardiac fibrosis and angiotensin-converting enzyme-2 expression in glucose-controlled diabetic rat hearts

Independently of the lipid-lowering effects, statin has been reported to attenuate the development of diabetic cardiomyopathy. However, the effect of statin in glucose-controlled diabetic condition has not been demonstrated. We evaluated the effect of fluvastatin on cardiac function, fibrosis, and angiotensin-converting enzyme-2 (ACE2) expression in glucose-controlled diabetic rats. Male Wistar rats were randomly divided into four groups: control (Group C), diabetes (Group D), diabetes with insulin (Group I), and diabetes with insulin and fluvastatin (Group I+F). Diabetes was induced by a single injection of streptozotocin (65 mg/kg). After 8 weeks, the hearts were extracted following echocardiographic evaluation. Cardiac fibrosis was analyzed using Masson's trichrome stain. Collagens I and III and ACE2 expressions were evaluated by immunohistochemistry and western blot. Group D showed reduced cardiac systolic function compared to the other groups (all P < 0.05). However, diastolic function estimated by E/A ratio was significantly decreased in groups D and I (median: 0.88 and 1.45, respectively) compared to groups C and I+F (2.97 and 2.15) (all P < 0.05). Cardiac fibrosis was more severe in groups D and I than in groups C and I+F (all P < 0.05) on Masson's trichrome stain. On immunohistochemistry, ACE2 expression was significantly decreased only in group D (all P < 0.05). However, collagen I and III showed higher expressions in group D compared to groups C and I+F while no significant difference was observed compared with group I (all P < 0.05). On western blot, collagen I and ACE2 expressions in group D (median: 1.78 and 0.35, respectively) were significantly different from groups C (references: 1) and I+F (0.76 and 1.21) (all P < 0.05), but not from group I (1.19 and 0.92). Our study suggested a combination of fluvastatin and insulin would be more effective than insulin alone in diabetic hearts. However, the exact mechanism remains to be elucidated.