Association of hemoglobin A1c variability and the incidence of heart failure with preserved ejection fraction in patients with type 2 diabetes mellitus and arterial hypertension

Roles of cMyBP-C phosphorylation on cardiac contractile dysfunction in db/db mice

Type 2 diabetes mellitus (T2DM) is a metabolic disease and comorbidity associated with several conditions, including cardiac dysfunction leading to heart failure with preserved ejection fraction (HFpEF), in turn resulting in T2DM-induced cardiomyopathy (T2DM-CM). However, the molecular mechanisms underlying the development of T2DM-CM are poorly understood. It is hypothesized that molecular alterations in myopathic genes induced by diabetes promote the development of HFpEF, whereas cardiac myosin inhibitors can rescue the resultant T2DM-mediated cardiomyopathy. To test this hypothesis, a Leptin receptor-deficient db/db homozygous (Lepr db/db) mouse model was used to define the pathogenesis of T2DM-CM. Echocardiographic studies at 4 and 6 months revealed that Lepr db/db hearts started developing cardiac dysfunction by four months, and left ventricular hypertrophy with diastolic dysfunction was evident at 6 months. RNA-seq data analysis, followed by functional enrichment, revealed the differential regulation of genes related to cardiac dysfunction in Lepr db/db heart tissues. Strikingly, the level of cardiac myosin binding protein-C phosphorylation was significantly increased in Lepr db/db mouse hearts. Finally, using isolated skinned papillary muscles and freshly isolated cardiomyocytes, CAMZYOS ® (mavacamten, MYK-461), a prescription heart medicine used for symptomatic obstructive hypertrophic cardiomyopathy treatment, was tested for its ability to rescue T2DM-CM. Compared with controls, MYK-461 significantly reduced force generation in papillary muscle fibers and cardiomyocyte contractility in the db/db group. This line of evidence shows that 1) T2DM-CM is associated with hyperphosphorylation of cardiac myosin binding protein-C and 2) MYK-461 significantly lessened disease progression in vitro, suggesting its promise as a treatment for HFpEF.

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.

Long-term glycemic variability predicts compromised development of heart failure with improved ejection fraction: a cohort study

Background

A substantial portion of heart failure (HF) patients adherent to guideline-directed medical therapies have experienced improved ejection fraction (EF), termed HFimpEF. Glycemic variability (GV) has emerged as a critical cardiometabolic factor. However, the relation between long-term GV and the incidence of HFimpEF is still unclear.

Methods

A total of 591 hospitalized HF patients with reduced EF (HFrEF, EF≤ 40%) admitted from January 2013 to December 2020 were consecutively enrolled. Repeat echocardiograms were performed at baseline and after around 12 months. The incidence of HFimpEF, defined as (1) an absolute EF improvement ≥10% and (2) a second EF > 40% and its association with long-term fasting plasma glucose (FPG) variability were analyzed.

Results

During a mean follow-up of 12.2 ± 0.6 months, 218 (42.0%) patients developed HFimpEF. Multivariate analysis showed FPG variability was independently associated with the incidence of HFimpEF after adjustment for baseline HbA1c, mean FPG during follow-up and other traditional risk factors (odds ratio [OR] for highest vs. lowest quartile of CV of FPG: 0.487 [95% CI 0.257~0.910]). Evaluation of GV by alternative measures yielded similar results. Subgroup analysis revealed that long-term GV was associated with HFimpEF irrespective of glycemic levels and diabetic conditions.

Conclusions

This study reveals that greater FPG variability is associated with compromised development of HFimpEF. A more stable control of glycemic levels might provide favorable effects on myocardial functional recovery in HF patients even without diabetes.

Correlation Between Glycemic Variability and Diabetic Complications: A Narrative Review

Diabetes mellitus is a metabolic disorder with a complex etiology in which glycemic dynamics are disturbed and the body is unable to maintain the process of glucose homeostasis through the pancreas. Persistent symptoms of high blood glucose or low blood glucose may lead to diabetic complications, such as neuropathy, nephropathy, retinopathy, and cardiovascular diseases. Glycemic variability which can represent the presence of excessive glycemic excursions is an indicator for evaluating glucose homoeostasis. Limiting glycemic variability has gradually become an emerging therapeutic target in improve diabetes metabolism and prevent associated complications. This article reviews the progress of research on the various quantifiable parameters of glycemic variability and their relationships with vascular lesions and mechanisms.

Association of visit-to-visit HbA1c variability with cardiovascular diseases in type 2 diabetes within or outside the target range of HbA1c

Background

Although a growing attention has been recently paid to the role of HbA1c variability in the risk of diabetic complications, the impact of HbA1c variability on cardiovascular diseases (CVD) in type 2 diabetes is still debated. The aim of the study is to investigate the association of HbA1c variability with CVD in individuals within or outside the target range of HbA1c.

Methods

Using data from Action in Diabetes and Vascular disease: preterAx and diamicroN-MR Controlled Evaluation (ADVANCE), we enrolled 855 patients with type 2 diabetes in China. The primary outcomes included major macrovascular events and major microvascular events. Visit-to-visit HbA1c variability was expressed as the coefficient of variation (CV) of five measurements of HbA1c taken 3-24 months after treatment. Cox proportional hazard models were used to estimate adjusted hazard ratios (aHR).

Results

Among 855 patients in the intensive glucose treatment group, 563 and 292 patients were assigned to the group of "within the target range of HbA1c" (WTH) (updated mean HbA1c ≤ 7.0%) and "outside the target range of HbA1c" (OTH) (updated mean HbA1c > 7.0%), respectively. HbA1c variability was positively associated with the risk of major microvascular events in all patients and both the subgroups during a median follow-up period of 4.8 years. Particularly, the risk related to HbA1c variability was higher in patients in WTH group for the new or worsening nephropathy [aHR: 3.35; 95% confidence interval (CI): 1.05-10.74; P = 0.042].

Conclusions

This retrospective cohort study confirmed the positive correlation between HbA1c variability and major microvascular events, especially in subjects in WTH or OTH.

Intermediate- and long-term associations between air pollution and ambient temperature and glycated hemoglobin levels in women of child bearing age

BACKGROUND

Air pollution has been linked to obesity while higher ambient temperatures typically reduce metabolic demand in a compensatory manner. Both relationships may impact glucose metabolism, thus we examined the association between intermediate- and long-term exposure to fine particulate matter (PM2.5) and ambient temperature and glycated hemoglobin(HbA1c), a longer-term marker of glucose control.

METHODS

We assessed 3-month, 6-month, and 12-month average air pollution and ambient temperature at 1-km2 spatial resolution via satellite remote sensing models (2013-2019), and assessed HbA1c at four, six, and eight years postpartum in women enrolled in the Programming Research in Obesity, Growth, Environment and Social Stressors (PROGRESS) cohort based in Mexico City. PM2.5 and ambient temperature were matched to participants' addresses and confirmed by GPS tracker. Using linear mixed-effects models, we examined the association between 3-month, 6-month, and 12-month average PM2.5 and ambient temperature with repeated log-transformed HbA1c values. All models included a random intercept for each woman and were adjusted for calendar year, season, and individual-level confounders (age, marital status, smoking, alcohol consumption level, and education level).

RESULTS

We analyzed 1,265 HbA1c measurements of 484 women. Per 1 µg/m3 increase in 3-month and 6-month PM2.5, HbA1c levels increased by 0.28% (95% confidence interval (95 %CI): 0.14, 0.42%) and 0.28% (95 %CI: 0.04, 0.52%) respectively. No association was seen for 12-month average PM2.5. Per 1 °C increase in ambient temperature, HbA1c levels decreased by 0.63% (95 %CI: -1.06, -0.21%) and 0.61% (95 %CI: -1.08, -0.13%), while the 12-month average again is not associated with HbA1c.

CONCLUSIONS

Intermediate-term exposure to PM2.5 and ambient temperature are associated with opposing changes in HbA1c levels, in this region of high PM2.5 and moderate temperature fluctuation. These effects, measurable in mid-adult life, may portend future risk of type 2 diabetes and possible heart disease.

The Scope of HbA1c Variability and Risk of Vascular Complications Among Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis of Prospective Studies

Glycated hemoglobin (HbA1c) variability is emerging as an indicator of long-term glycemic control, which may play a significant role during vascular complications. We conducted a systematic review and meta-analysis to assess the association between the scope of HbA1c variability and vascular complications in patients with type 2 diabetes mellitus. PubMed and Embase were searched for studies that evaluated the association of HbA1c variability with vascular complications in patients with type 2 diabetes. Two reviewers independently completed data extraction. Random-effects meta-analysis was conducted with stratification according to the type of vascular complications. Nine studies were eligible for inclusion in our systematic review and meta-analysis. Six studies evaluated the impact of the standard deviation of HbA1c (HbA1c-SD) on cardiovascular events and showed an association of HbA1c-SD with cardiovascular events (HR: 1.25, 95% CI 1.18-1.32, 5 studies). Six studies evaluated renal disease associated with HbA1c-SD and showed that HbA1c-SD was correlated with an increased risk of renal disease (HR: 1.19, 95% CI 1.13-1.24). Two studies evaluated HbA1c-SD and the risk of retinopathy and showed that no significant association was found between retinopathy and HbA1c-SD (HR 1.08, 95% CI 0.92-125). For HbA1c-SD ranging from 0.6 to 0.8%, HbA1c-SD was associated with an increased risk of cardiovascular events (HR: 1.25, 95% CI 1.15-1.35) and renal disease (HR: 1.16, 95% CI 1.11-1.22). For individuals with index HbA1c variability greater than or equal to 0.6%, HbA1c variability was significantly associated with vascular complications in patients with type 2 diabetes mellitus.

Glucose variability predicts 6-month mortality in patients hospitalized with acute heart failure

In diabetes mellitus (DM), glycaemic fluctuations associate with higher oxidative stress than sustained chronic hyperglycaemia and glucose variability increases the risk of chronic diabetic complications. Our hypothesis was that higher glucose variability would associate with mortality after an acute heart failure (HF) episode. We retrospectively analysed patients with DM hospitalized with acute HF between 2009 and 2010. Patients with < 2 point-of-care glucose values/day were excluded. Glucose coefficient of variation (GCV) was defined as (glucose standard deviation/mean glucose) × 100. Patients were categorized according GCV ≤ 30.0 and > 30.0%. Follow-up: 6-months. Endpoint: all-cause mortality. A Cox-regression analysis was used to study the association of glucose variability with 6-month mortality. We studied 214 diabetic patients with acute HF, 49.1% male, mean age 76 years. Mean glycaemia during hospitalization was 187 ± 50 mg/dL, hypoglycaemia (< 70 mg/dL) was reported in 21 patients and mean GCV was 28.3 ± 7.6%. Patients with GCV > 30.0% had higher mean glycaemia, more hypoglycaemic episodes and higher HbA1c; they were also more often treated with insulin. Patients were similar concerning age, gender, comorbidities, left ventricular systolic dysfunction and ischemic heart disease. During the 6-month follow-up, 38 (17.8%) patients died. Patients with GCV > 30.0% had a HR of 6-month mortality of 2.21 (95% CI: 1.16-4.21), p = 0.02. This association with more than twofold higher short-term mortality was independent of main confounders. Elevated glycaemic variability in acute HF admissions of patients with DM predicts short-term mortality. Patients with GCV > 30.0% have an independent more than twofold higher risk of 6-month death after an acute HF hospitalization.

Association of Mean and Variability of HbA1c with Heart Failure in Patients with Type 2 Diabetes

Heart failure (HF) is a common presentation in patients with type 2 diabetes mellitus (T2DM). Previous studies revealed that the HbA1c level is significantly associated with HF. However, little is known about the association between HbA1c variability and HF. We aimed to evaluate the association of mean and variability of HbA1c with HF in patients with T2DM. Using Diabetes Share Care Program data, patients with T2DM who had mean HbA1c (HbA1c-Mean), and HbA1c variability (tertiles of HbA1c-SD and HbA1c-adjSD) within 12–24 months during 2001–2008 were included. The cutoffs of HbA1c-Mean were set at <7%, 7–7.9%, and ≥8%. Hazard ratios (HRs) for HF during 2008–2018 were estimated using Cox proportional hazard models. A total of 3824 patients were included, of whom 315 patients developed HF during the observation period of 11.72 years. The associated risk of HF increased with tertiles of HbA1c variability and cutoffs of HbA1c-Mean. In mutually adjusted models, HbA1c-Mean showed a consistent dose-response association with HF, while the association of HbA1c variability with HF disappeared. Among patients with HbA1c-Mean <7%, the associated risk of HF in patients with HbA1c variability in tertile 3 was comparable to patients with HbA1c-Mean ≥8%. In conclusion, mean HbA1c was an independent predictor of HF and not explained by HbA1c variability. In addition to absolute HbA1c level, targeting on stability of HbA1c in patients with good glycemic control was also important for the development of HF in patients with T2DM.

Mean and visit-to-visit variability of glycemia and left ventricular diastolic dysfunction: A longitudinal analysis of 3025 adults with serial echocardiography

OBJECTIVE

We aimed to determine the mean glucose thresholds to increase the risk of left ventricular diastolic dysfunction (LVDD) and whether visit-to-visit variability of fasting plasma glucose (FPG) and glycated hemoglobin (A1C) could independently increase the risk in a cohort with serial echocardiography.

METHODS

This was a 3.5-year (range, 0.5-8.3) retrospective longitudinal cohort study of 3025 adults (age, 55.15 ± 7.6 years; without diabetes, n = 2755) with LV ejection fraction > 50% by serial echocardiography between 2006 and 2016. Mean, standard of deviation (SD) and coefficient of variation (CV) of FPG and A1C obtained from three consecutive measurements preceding the first echocardiography. The definition of LVDD in this study was primarily based on early peak mitral inflow velocity and early diastolic mitral annulus motion velocity.

RESULTS

LVDD developed in 611/3025 subjects (20.2%). Cox proportional hazard models showed increased adjusted hazard ratios (HRs) for incident LVDD in the highest quartile of FPG-mean (HR 1.76, 95% confidence interval [CI]; 1.36-2.30), FPG-SD (HR 1.63, 95% CI; 1.27-2.09), FPG-CV (HR 1.47, 95% CI; 1.15-1.89), and A1C-mean (HR 1.83, 95% CI; 1.41-2.38) versus the lowest quartile, which was consistent even in subjects without diabetes. Mean glucose thresholds for the increased risk were below the lower limits for pre-diabetes.

CONCLUSIONS

In terms of mean glycemia, LVDD may be initiated in the earliest diabetic continuum, and such changes could be measurable within several years. Visit-to-visit variability of FPG, but not that of A1C, predicted accelerated development of LVDD.

Comprehensive elaboration of glycemic variability in diabetic macrovascular and microvascular complications

Diabetes mellitus is the major risk factor for the development of macrovascular and microvascular complications. It is increasingly recognized that glycemic variability (GV), referring to oscillations in blood glucose levels and representing either short-term or long-term GV, is involved in the pathogenesis of diabetic complications and has emerged as a possible independent risk factor for them. In this review, we summarize the metrics and measurement of GV in clinical practice, as well as comprehensively elaborate the role and related mechanisms of GV in diabetic macrovascular and microvascular complications, aiming to provide the mechanism-based therapeutic strategies for clinicians to manage diabetes mellitus.

A Coloured Pen Needle Education System Improves Insulin Site Rotation Habits: Results of a Randomized Study

INTRODUCTION

Needle reuse and repeated injection of insulin into the same site encourage lipohypertrophy. We explored the potential of coupling a novel pen needle strategy with community pharmacists to improve injection site rotation.

METHODS

Between October 2018 and January 2019, adult insulin users with type 1 or 2 diabetes were enrolled by 16 community pharmacists across 7 Canadian provinces and randomized to their usual pen needles (control) or coloured pen needles packaged with education materials in boxes with reminder sound chips (intervention [mCPN]). A total of 203 individuals completed all requirements of the 30-day study. The primary outcome was a composite of the number of zones injected, the use of new injection zones if the number of zones equaled that at baseline, and the change in size of the injection area from baseline. The pharmacists completed two questionnaires, which provided insights into whether study participation elevated their comfort and confidence in providing injection site rotation counselling.

RESULTS

Compared to the control group, more participants in the mCPN arm improved their site rotation practices (54.1% vs. 33.7%; P = 0.005), 15 more increased the number of injection zones used (P = 0.03), and there was less needle reuse (25% vs. 12% reduction). The pharmacists reported improved knowledge of the consequences of lipohypertrophy and the proportion who were "very comfortable" with pen needle tip selection and use rose from 31.3% pre-study to 93.8% post-study.

CONCLUSION

The coloured pen needles with their education materials are a novel means of encouraging injection site rotation. Community pharmacists represent an untapped resource for improving injection self-care practices.

Single prognostic cut-off value for admission glycemia in acute myocardial infarction has been used although high-risk stems from hyperglycemia as well as from hypoglycemia (a narrative review)

All original articles and meta-analysis use the single cut-off value to distinguish high-risk hyperglycemic from other acute myocardial infarction (AMI) patients. The mortality rate is 3.9 times higher in non-diabetic AMI patients with admission glycemia ≥6.1mmol compared to normoglycemic non-diabetic AMI patients. On the other hand, admission hypoglycemia in AMI is an important predictor of mortality. Because both admission hypo- and hyperglycemia correspond to higher in-hospital mortality, this graph is recognized as "J or U shaped curve". The review suggests two cut-off values for admission glycemia for risk assessment in AMI instead of single one because hypoglycemia as well as hyperglycemia represents a high-risk factor.

Glycemic variability: adverse clinical outcomes and how to improve it?

Glycemic variability (GV), defined as an integral component of glucose homoeostasis, is emerging as an important metric to consider when assessing glycemic control in clinical practice. Although it remains yet no consensus, accumulating evidence has suggested that GV, representing either short-term (with-day and between-day variability) or long-term GV, was associated with an increased risk of diabetic macrovascular and microvascular complications, hypoglycemia, mortality rates and other adverse clinical outcomes. In this review, we summarize the adverse clinical outcomes of GV and discuss the beneficial measures, including continuous glucose monitoring, drugs, dietary interventions and exercise training, to improve it, aiming at better addressing the challenging aspect of blood glucose management.

Visit-to-visit variability in low-density lipoprotein cholesterol is associated with adverse events in non-obstructive coronary artery disease

OBJECTIVE

A higher visit-to-visit variability in low-density lipoprotein cholesterol (LDL-C) is associated with an increased frequency of cardiovascular events. We investigated the association between the visit-to-visit LDL-C variability and all-cause mortality, myocardial infarction (MI), and coronary revascularization in a population with non-obstructive coronary artery disease (CAD).

METHODS

From this retrospective cohort of individuals who underwent coronary angiography from 2006 to 2010, a total of 2.012 consecutive patients with non-obstructive CAD, who underwent three or more LDL-C determinations during the first 2 years, were identified and followed up for 5 years. The variability in the visit-to-visit LDL-C was measured by standard deviation (SD) and coefficient of variation (CV). The risk of all-cause mortality and composite endpoints, MI, and coronary revascularization were evaluated by a multivariable Cox regression analysis.

RESULTS

During a 5-year follow-up, a total of 99 (4.92%) mortality cases and 154 (7.65%) cases of composite endpoints were observed. The percentage of subjects who experienced mortality or composite endpoints was higher in those with a higher LDL-C-SD or LDL-C-CV level. The association between the LDL-C variability and clinical endpoints was regardless of possible confounding factors.

CONCLUSION

Among the patients with non-obstructive CAD, a higher visit-to-visit LDL-C variability is associated with increasing all-cause mortality or composite endpoints during the long-term follow-up.

Impact of HbA1c variability on subclinical left ventricular remodeling and dysfunction in patients with type 2 diabetes mellitus

BACKGROUND

Glycemic instability confers a risk of poor prognosis in patients with type 2 diabetes mellitus (T2DM). This study aimed to investigate whether HbA1c variability provided additional value over mean HbA1c for predicting subclinical left ventricular remodeling and dysfunction in T2DM patients.

METHODS

A total of 466 T2DM patients with normal cardiac structure and function were recruited and prospectively followed up for a median of 4.7 y. HbA1c was measured quarterly. The intrapersonal mean and standard deviation (SD) of HbA1c measurements were calculated, and SD-HbA1c was considered as a measure of HbA1c variability. All participants underwent transthoracic echocardiography at baseline and after follow-up.

RESULTS

In multivariable regression analyses, SD-HbA1c was independently associated with annualized changes in left ventricular end diastolic diameter, interventricular septum, left ventricular posterior wall, left ventricular mass index, left ventricular ejection fraction, E/e' ratio, and E/A ratio (P < 0.001). Subgroup analysis based on mean HbA1c levels (<7.0%, 7.0-7.5%, and ≥7.5%) further confirmed that SD-HbA1c was associated with most of the above parameters regardless of mean HbA1c levels.

CONCLUSION

This study indicates that HbA1c variability adds to the mean value in predicting subclinical left ventricular remodeling and dysfunction in T2DM patients.

Risk of early mortality and cardiovascular disease in type 1 diabetes: a comparison with type 2 diabetes, a nationwide study

Background

Both type 1 and type 2 diabetes are well-established risk factors for cardiovascular disease and early mortality. However, few studies have directly compared the hazards of cardiovascular outcomes and premature death among people with type 1 diabetes to those among people with type 2 diabetes and subjects without diabetes. Furthermore, information about the hazard of cardiovascular disease and early mortality among Asians with type 1 diabetes is sparse, although the clinical and epidemiological characteristics of Asians with type 1 diabetes are unlike those of Europeans. We estimated the hazard of myocardial infarction (MI), hospitalization for heart failure (HF), atrial fibrillation (AF), and mortality during follow-up in Korean adults with type 1 diabetes compared with those without diabetes and those with type 2 diabetes.

Methods

We used Korean National Health Insurance Service datasets of preventive health check-ups from 2009 to 2016 in this retrospective longitudinal study. The hazard ratios of MI, HF, AF, and mortality during follow-up were analyzed using the Cox regression analyses according to the presence and type of diabetes in ≥ 20-year-old individuals without baseline cardiovascular disease (N = 20,423,051). The presence and type of diabetes was determined based on the presence of type 1 or type 2 diabetes at baseline.

Results

During more than 93,300,000 person-years of follow-up, there were 116,649 MIs, 135,532 AF cases, 125,997 hospitalizations for HF, and 344,516 deaths. The fully-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for incident MI, hospitalized HF, AF, and all-cause death within the mean follow-up of 4.6 years were higher in the type 1 diabetes group than the type 2 diabetes [HR (95% CI) 1.679 (1.490–1.893) for MI; 2.105 (1.901–2.330) for HF; 1.608 (1.411–1.833) for AF; 1.884 (1.762–2.013) for death] and non-diabetes groups [HR (95% CI) 2.411 (2.138–2.718) for MI; 3.024 (2.730–3.350) for HF; 1.748 (1.534–1.993) for AF; 2.874 (2.689–3.073) for death].

Conclusions

In Korea, the presence of diabetes was associated with a higher hazard of cardiovascular disease and all-cause death. Specifically, people with type 1 diabetes had a higher hazard of cardiovascular disease and all-cause mortality compared to people with type 2 diabetes.

Prognostic impact of visit-to-visit glycemic variability on the risks of major adverse cardiovascular outcomes and hypoglycemia in patients with different glycemic control and type 2 diabetes

PURPOSE

The prognostic impact of visit-to-visit glycemic variability on clinical outcomes in patients with different glycemic control and type 2 diabetes remains obscure. We investigated glucose variability and clinical outcomes for patients in the groups of Good glycemic control (GC), Insufficient glycemic control (IC), and Poor glycemic control (PC) in a prospective cohort study.

METHODS

By using data from Action in Diabetes and Vascular disease: preterAx and diamicroN-MR Controlled Evaluation (ADVANCE), 930 patients were enrolled from 61 centers in China and grouped into GC, IC, and PC according to their glycated hemoglobin A1_c (HbA1_c) and fasting plasma glucose (FPG). Visit-to-visit glycemic variability was defined using the coefficient of variation (CV) of five measurements of HbA1_c and FPG taken 3-24 months after treatment. Multivariable Cox proportional hazards models were employed to estimate adjusted hazard ratio (aHR).

RESULTS

Among 930 patients in the intensive glucose control, 82, 538, and 310 patients were assigned to GC, IC, and PC, respectively. During the median of 4.8 years of follow-up, 322 patients were observed hypoglycemia and 244 patients experienced major adverse cardiovascular events (MACE). The CV of HbA1_c and FPG was significantly lower for GC (6.0 ± 3.8, 11.2 ± 6.2) than IC (8.3 ± 5.6, 17.9 ± 10.6) and PC (9.5 ± 6.3, 19.3 ± 10.8). High glycemic variability was associated with a greater risk of MACE (aHR: 2.21; 95% confidence interval (CI): 1.61-3.03; p < 0.001) and hypoglycemia (aHR: 1.36; 95% CI: 1.04-1.79; p = 0.025) than low glycemic variability in total patients. The consistent trend was also found in subgroups of GC, IC, and PC.

CONCLUSIONS

This prospective cohort study showed that glycemic variability was significantly lower for GC than IC and PC. Furthermore, glycemic variability was associated with the risk of MACE and hypoglycemia in total patients and subgroups of different glycemic control.

Visit-to-Visit Hemoglobin A1c Variability Is Associated With Later Cancer Development in Patients With Diabetes Mellitus

PURPOSE

Recent studies have shown that patients with diabetes mellitus have a higher risk of tumorigenesis. However, the effect of glycemic variability on tumorigenesis among diabetic patients has not been well investigated. Hence, we performed a retrospective cohort study to analyze the effect of visit-to-visit hemoglobin A1c (HbA1c) variability and later onset of malignancies.

METHODS

This study included 2640 patients with diabetes mellitus 50 years or older. To analyze visit-to-visit glycemic activity, we calculated intrapersonal SD of all recorded HbA1c and used SD-HbA1c as a measure of glycemic variability. Because the number of individual visits varied, we divided SD-HbA1c by visit times in order to adjust for the potential influence of visit time difference between individuals. Patients were divided into quartiles according to their HbA1c variability, and Cox regression models were used to evaluate the association between glycemic variability and later onset of tumorigenesis.

RESULTS

Three hundred thirty patients (12.5%) developed malignancy during follow-up. The median follow-up period was 1511 days (4.1 years; interquartile range, 2487.5 days). Relative to the group with the lowest glycemic variability (first quartile), the groups with higher glycemic variability showed a dose-dependent association with tumorigenesis. The odds ratios for the second, third, and fourth quartiles were 1.20 (95% confidence interval, 0.88-1.65), 1.43 (1.02-2.00), and 2.19 (1.52-3.17), respectively. The mean HbA1c and diabetes mellitus duration periods were not significantly associated with tumorigenesis. This result was consistent when limiting the number of covariates.

CONCLUSIONS

These results demonstrated that visit-to-visit HbA1c variability is a potential risk factor for later tumorigenesis. The association may be mediated by oxidative stress or hormone variability. Routine cancer screening may be suggested for diabetic patients with unstable glycemic control.

Prognostic impact of HbA1c variability on long-term outcomes in patients with heart failure and type 2 diabetes mellitus

Background

The prognostic impact of long-term glycemic variability on clinical outcomes in patients with heart failure (HF) and type 2 diabetes mellitus (T2DM) remains unclear. We determined and compared hemoglobin A1c (HbA1c) variability and clinical outcomes for patients with HF with preserved ejection fraction (HFpEF), HF with mid-range ejection fraction (HFmrEF) and HF with reduced ejection fraction (HFrEF) in a prospective longitudinal study.

Methods

Patients with HF and T2DM, undergone 3 or more HbA1c determinations during the first 18 months, were then followed for 42 months. The primary outcome was death from any cause. Secondary outcome was composite endpoints with death and HF hospitalization. Cox proportional hazards models were used to compare outcomes for patients with HFpEF, HFmrEF and HFrEF.

Results

Of 902 patients enrolled, 32.2% had HFpEF, 14.5% HFmrEF, and 53.3% HFrEF. During 42 months of follow-up, 270 (29.9%) patients died and 545 (60.4%) patients experienced composite endpoints of death and HF readmission. The risk of all-cause death or composite endpoints was lower for HFpEF than HFrEF. Moreover, higher HbA1c variability was associated with higher all-cause mortality or composite endpoints and HbA1c variability was an independent predictor of all-cause mortality or composite endpoints, regardless of EF.

Conclusions

This prospective longitudinal study showed that the all-cause death and composite events was lower for HFpEF than HFrEF. HbA1c variability was independently and similarly predictive of death or combined endpoints in the three HF phenotypes.

Electronic supplementary material

The online version of this article (10.1186/s12933-018-0739-3) contains supplementary material, which is available to authorized users.

Do we need biomarkers for diabetics progressing to heart failure?

Cardiovascular changes produce unfavorable outcomes including arterial hypertension and diabetes, which are related to the increased risk of heart failure (HF). The latter is highly prevalent in the setting of glucose metabolism dysregulation and high hemodynamic load, and identifying predictors of the incidence of HF with preserved ejection fraction (HFpEF) requires a research and is a clinical need. Toward this end, the variability in glucose regulation represents a novel dynamic way to comprehend and study the impact of glycemia. The results of the published study highlight the independent association of glycated hemoglobin A1c variability with the development of HFpEF in hypertensive diabetic patients. Based on the above, the effect of diverse antidiabetic therapies on glycemic control variability and overall management of these patients to reduce the risk of HFpEF remain essential for the modern cardiologist.

Are the effects of drugs to prevent and to treat heart failure always concordant? The statin paradox and its implications for understanding the actions of antidiabetic medications

Most treatments for chronic heart failure are effective both in preventing its onset and reducing its progression. However, statins prevent the development of heart failure, but they do not decrease morbidity and mortality in those with established heart failure. This apparent discordance cannot be explained by an effect to prevent interval myocardial infarctions. Instead, it seems that the disease that statins were preventing in trials of patients with a metabolic disorder was different from the disease that they were treating in trials of chronic heart failure. The most common phenotype of heart failure in patients with obesity and diabetes is heart failure with a preserved ejection fraction (HFpEF). In this disorder, the anti-inflammatory effects of statins might ameliorate myocardial fibrosis and cardiac filling abnormalities, but these actions may have little relevance to patients with heart failure and a reduced ejection fraction (HFrEF), whose primary derangement is cardiomyocyte loss and stretch. These distinctions may explain why statins were ineffective in trials that focused on HFrEF, but have been reported to produce favourable effects in observational studies of HFpEF. Similarly, selective cytokine antagonists were ineffective in HFrEF, but have been associated with benefits in HFpEF. These observations may have important implications for our understanding of the effects of antihyperglycaemic medications. Glucagon-like peptide-1 receptor agonists have had neutral effects on heart failure events in people at risk for HFpEF, but have exerted deleterious actions in HFrEF. Similarly, sodium-glucose co-transporter 2 inhibitors, which exert anti-inflammatory effects and reduce heart failure events in patients who are prone to HFpEF, may not be effective in HFrEF. The distinctions between HFrEF and HFpEF may explain why the effects of drugs on heart failure events in diabetes trials may not be relevant to their use in patients with systolic dysfunction.