Association between severe hypoglycemia, adverse macrovascular events, and inflammation in the Edinburgh Type 2 Diabetes Study

Associations of fasting plasma glucose with all-cause mortality and cardiovascular events in older Chinese diabetes patients: A population-based cohort study

AIMS/INTRODUCTION

Our aim was to investigate the optimal fasting glucose (FPG) range in Chinese older adults with type 2 diabetes, and to clarify whether the optimal range varies according to the control of risk factors.

MATERIALS AND METHODS

The baseline survey for the cohort study began in 2018, with follow up ending in 2022. Our study enrolled 59,030 older diabetes patients with no history of cardiovascular disease (CVD). Participants were divided into nine groups based on their baseline glycemic status. The association between FPG and the risk of adverse outcomes was mainly estimated by multivariate Cox proportional risk models and restricted spline analysis.

RESULTS

During the 4-year follow-up period, a total of 5,637 deaths and 4,904 CVD events occurred. The associations of FPG with mortality and CVD events showed J-shaped curves. Among all-cause deaths, the hazard ratios for FPG ≤4.50 and >11.50 mmol/L were 1.50 (95% confidence interval [CI] 1.31-1.71) and 1.84 (95% CI 1.67-2.02). Among CVD, the hazard ratios for FPG ≤4.50 and >11.50 mmol/L were 1.31 (95% CI 1.13-1.53) and 1.71 (95% CI 1.54-1.89), respectively. The optimal FPG ranges of all-cause mortality and CVD were 5.50-7.50 and 4.50-7.50 mmol/L, respectively. For participants with at least two risk factors, the optimal FPG levels were higher than those with fewer risk factors.

CONCLUSIONS

In older Chinese diabetes patients, the FPG ranges related to the minimum death and CVD event rates were 5.50-7.50 and 4.50-7.50 mmol/L, respectively. Patients with more cardiovascular risk factors had higher optimal blood glucose ranges than those with fewer risk factors.

Washed microbiota transplantation reduces glycemic variability in unstable diabetes

BACKGROUND

Dysbiosis of gut microbiota is causally linked to impaired host glucose metabolism. We aimed to study effects of the new method of fecal microbiota transplantation, washed microbiota transplantation (WMT), on reducing glycemic variability (GV) in unstable diabetes.

METHODS

Fourteen eligible patients received three allogenic WMTs and were followed up at 1 week, 1 month, and 3 months. Primary outcomes were daily insulin dose, glucose excursions during meal tests, and GV indices calculated from continuous monitoring or self-monitoring glucose values. Secondary outcomes were multiomics data, including 16S rRNA gene sequencing, metagenomics, and metabolomics to explore underlying mechanisms.

RESULTS

Daily insulin dose and glucose excursions markedly dropped, whereas GV indices significantly improved up to 1 month. WMT increased gut microbial alpha diversity, beta diversity, and network complexity. Taxonomic changes featured lower abundance of genera Bacteroides and Escherichia-Shigella, and higher abundance of genus Prevotella. Metagenomics functional annotations revealed enrichment of distinct microbial metabolic pathways, including methane biosynthesis, citrate cycle, amino acid degradation, and butyrate production. Derived metabolites correlated significantly with improved GV indices. WMT did not change circulating inflammatory cytokines, enteroendocrine hormones, or C-peptide.

CONCLUSIONS

WMT showed strong ameliorating effect on GV, raising the possibility of targeting gut microbiota as an effective regimen to reduce GV in diabetes.

Effect of hypoglycemia on baroreflex sensitivity in individuals with type 2 diabetes: implications for autonomic control of cardiovascular function in diabetes

PURPOSE

Hypoglycemia is associated with increased mortality, though the mechanisms underlying this association are not established. Hypoglycemia impairs the counterregulatory hormonal and autonomic responses to subsequent hypoglycemia. It is unknown whether hypoglycemia elicits a generalized impairment in autonomic control of cardiovascular function in individuals with type 2 diabetes. We tested the hypothesis that in individuals with type 2 diabetes, hypoglycemia impairs a key measure of cardiovascular autonomic homeostasis, baroreflex sensitivity.

METHODS

Sixteen individuals with well-controlled type 2 diabetes and without known cardiovascular disease were exposed to two 90-min episodes of experimental hypoglycemia (2.8 mmol/L, 50 mg/dL) on the same day. All individuals experienced a hypoglycemic-hyperinsulinemic clamp in the morning (AM clamp) and again in the afternoon (PM clamp). Baroreflex sensitivity was assessed using the modified Oxford method before the initiation of each hypoglycemic-hyperinsulinemic clamp, during the last 30 min of hypoglycemia, and the following morning. A mixed effects model adjusting for sex, age, BMI, and insulin level, demonstrated a significant effect of hypoglycemia on baroreflex sensitivity. The study is registered at ClinicalTrials.gov (NCT03422471).

RESULTS

Baroreflex sensitivity during PM hypoglycemia was reduced compared to baseline, during AM hypoglycemia, and the next day. Insulin levels positively correlated with baroreflex sensitivity at baseline and during AM hypoglycemia.

CONCLUSION

Exposure to hypoglycemia impairs a key measure of autonomic control of cardiovascular function and, thus, may increase the risk of cardiac arrhythmias and blood pressure lability in individuals with type 2 diabetes. This effect is attenuated in part by increased insulin levels.

Effectiveness of the SUGAR intervention on hypoglycaemia in elderly patients with type 2 diabetes: A pragmatic randomised controlled trial

BACKGROUND

A pharmacist-led, individualised, educational intervention (SUGAR) was formulated to prevent hypoglycaemia among elderly patients with type 2 diabetes mellitus (T2DM) in Jordan.

OBJECTIVE(S)

To evaluate the effectiveness of the SUGAR intervention added to usual care compared with usual care only in preventing hypoglycaemic attacks in elderly patients with T2DM in Jordan.

METHODS

A single-centre, pragmatic, open-label, randomised controlled trial with embedded process evaluation was conducted at the outpatient clinics of a hospital in Jordan. Elderly patients (≥65 years) with T2DM and on sulfonylurea, insulin, or at least three anti-diabetic medications were recruited and parallelly randomised to the SUGAR intervention with usual care or the control (usual care) groups. The primary outcome was the rate of total hypoglycaemic attacks per patient after 3 months from randomisation. Secondary outcomes included rate of hypoglycaemia subtypes, the incidence of any and subtypes of hypoglycaemia, hypoglycaemia-free survival probability, and incidence of fasting hyperglycaemia necessitating therapy modification. Outcomes were measured through glucose meters and diaries, assessed at 3 months, and analysed by intention to treat.

RESULTS

A total of 212 participants (mean age 68.98 years, 58.96% men) were randomly allocated (106 in each group), with 190 (89.62%) participants completing the study. The mean of total hypoglycaemic attacks was less in the intervention group compared with the control group (3.91 [SD 7.65] vs. 6.87 [SD 11.99]; p < 0.0001) at three months. The intervention significantly reduced the rate of hypoglycaemia subtypes; the odds to experience any, severe, and symptomatic hypoglycaemia; and increased hypoglycaemia-free survival probability compared with the control group at three months. Incidence of fasting hyperglycaemia necessitating therapy modification was similar between groups.

CONCLUSIONS

The SUGAR intervention can prevent hypoglycaemia without increasing the risk of fasting hyperglycaemia warranting therapy adjustment in elderly Jordanians with T2DM.

In-hospital glycemic variability and all-cause mortality among patients hospitalized for acute heart failure

BACKGROUND

High glycemic variability (GV) is a poor prognostic marker in cardiovascular diseases. We aimed to investigate the association of GV with all-cause mortality in patients with acute heart failure (HF).

METHODS

The Korean Acute Heart Failure registry enrolled patients hospitalized for acute HF from 2011 to 2014. Blood glucose levels were measured at the time of admission, during hospitalization, and at discharge. We included those who had 3 or more blood glucose measurements in this study. Patients were divided into two groups based on the coefficient of variation (CoV) as an indicator of GV. Among survivors of the index hospitalization, we investigated all-cause mortality at 1 year after discharge.

RESULTS

The study analyzed 2,617 patients (median age, 72 years; median left-ventricular ejection fraction, 36%; 53% male). During the median follow-up period of 11 months, 583 patients died. Kaplan-Meier curve analysis revealed that high GV (CoV > 21%) was associated with lower cumulative survival (log-rank P < 0.001). Multivariate Cox proportional analysis showed that high GV was associated with an increased risk of 1-year (HR 1.56, 95% CI 1.26-1.92) mortality. High GV significantly increased the risk of 1-year mortality in non-diabetic patients (HR 1.93, 95% CI 1.47-2.54) but not in diabetic patients (HR 1.19, 95% CI 0.86-1.65, P for interaction = 0.021).

CONCLUSIONS

High in-hospital GV before discharge was associated with all-cause mortality within 1 year, especially in non-diabetic patients with acute HF.

Severe hypoglycemia and risk of hospitalization for heart failure in adults with diabetes treated with oral medications with or without insulin: A population-based study

AIMS

We aimed to determine if severe hypoglycemia (SH) independently increases the risk of hospitalization for heart failure (hHF) in type 2 diabetes, regardless of the prevalent or incident cardiovascular disease (CVD).

METHODS

This was a nationwide population-based propensity score-matched study using Korean National Health Insurance Service data (2002-2018). The hazards of hHF were compared in individuals who experienced SH (n = 8,965) and 1:3 matched controls, among adults with diabetes using oral anti-diabetes medications (OADs) with or without insulin and without previous hHF at baseline.

RESULTS

During 236,417 person-years, 1,189 cases of hHF occurred. The hazard of hHF was higher in individuals with SH compared to matched controls (adjusted hazard ratio [aHR] 1.503, 95 % confidence interval [CI] 1.324-1.707). The increase in aHR remained significant when excluding participants with prevalent or incident major adverse cardiovascular events (MACE; aHR 1.352, 95 % CI 1.228-1.622) and any CVD (aHR 1.342, 95 % CI 1.025-1.756). Two or more SH events were associated with further increase in hHF risk.

CONCLUSION

SH was associated with increased risks of hHF among adults with diabetes using OAD with or without insulin. The increased risk was attenuated but remained significant in those without prevalent or incident MACE or CVDs.

Relationship between the early initiation of insulin treatment and diabetic complications in patients newly diagnosed with type 2 diabetes mellitus in Korea: A nationwide cohort study

AIMS/INTRODUCTION

To evaluate the relationship between early insulin initiation within a year after type 2 diabetes mellitus diagnosis and the risk of diabetic complications.

MATERIALS AND METHODS

We carried out a cohort study using the Korean National Health Insurance Service database. The study participants were newly diagnosed with type 2 diabetes mellitus between 2009 and 2013. After applying propensity score matching (1:1) to the cohort of patients who received two or more oral antidiabetic drugs (OADs) or insulin as the first prescription within 1 year after type 2 diabetes mellitus diagnosis, we computed hazard ratios (HRs) and 95% confidence intervals (CIs) using a Cox proportional hazards regression to compare the risk of diabetes-related microvascular and macrovascular complications and all-cause mortality in insulin versus OAD initiators.

RESULTS

Within the cohort, 52,188 and 1,804 patients received OAD and insulin, respectively. After matching, each group contained 534 patients. Compared with the OAD group, the risk of overall microvascular complications was significantly higher for insulin (HR 1.48, 95% CI 1.28-1.71). No increased risks of overall macrovascular complications (HR 0.90, 95% CI 0.62-1.30) and all-cause mortality were observed (HR 1.06, 95% CI 0.67-1.68).

CONCLUSIONS

In the present study, early insulin treatment was not associated with the risk of macrovascular complications and all-cause mortality compared with OAD treatment; however, the risk of microvascular complications was higher in the insulin group.

Description of a Cohort of Type 1 Diabetes Patients: Analysis of Comorbidities, Prevalence of Complications and Risk of Hypoglycemia

BACKGROUND

Despite major medical advances, Type 1 Diabetes (T1D) patients still have greater morbimortality than the general population. Our aim was to describe our cohort of T1D patients and identify potential risk factors susceptible to prevention strategies.

METHODS

Cross-sectional, observational study, including T1D patients treated at our center, from 1 March 2017 to 31 March 2020.

INCLUSION CRITERIA

T1D, age > 14 years and signed informed consent.

EXCLUSION CRITERIA

diabetes other than T1D, age < 14 years and/or refusal to participate.

RESULTS

Study population n = 2181 (49.8% females, median age at enrollment 41 years, median HbA1c 7.7%; 38.24% had at least one comorbidity). Roughly 7.45% had severe hypoglycemia (SH) within the prior year. Macro/microvascular complications were present in 42.09% (5.83% and 41.14%, respectively). The most frequent microvascular complication was diabetic retinopathy (38.02%), and coronary disease (3.21%) was the most frequent macrovascular complication. The risk of complications was higher in males than in females, mainly macrovascular. Patients with SH had a higher risk of complications (OR 1.42; 1.43 in males versus 1.42 in females).

CONCLUSIONS

Our T1D population is similar to other T1D populations. We should minimize the risk of SH, and male patients should perhaps be treated more aggressively regarding cardiovascular risk factors.

Severe Hypoglycemia and Incident Heart Failure Among Adults With Type 2 Diabetes

CONTEXT

The association of severe hypoglycemia on the incidence of heart failure (HF) is unclear.

OBJECTIVE

We evaluated the association of severe hypoglycemia with incident HF among individuals with type 2 diabetes.

METHODS

We included participants with type 2 diabetes from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study. Severe hypoglycemia episodes were assessed during the initial 24 months following randomization and defined using 2 methods: (1) symptomatic, severe hypoglycemic event requiring medical assistance (first definition); or (2) requiring any assistance (second definition). Participants without HF at baseline and during the first 24 months of the study were prospectively followed for incident HF hospitalization. Multivariable Cox regression was used to generate adjusted hazard ratios (HR) for the association of severe hypoglycemia and incident HF.

RESULTS

Among 9208 participants (mean age 63 years, 38% female, 62% White), 365 had ≥ 1 episode of severe hypoglycemic. Over a median follow-up duration of 3 years, there were 249 incident HF events. After multivariable adjustment for relevant confounders, participants with severe hypoglycemia requiring medical assistance had a 68% higher relative risk of incident HF (HR 1.68; 95% CI, 1.06-2.66), as compared with individuals who never experienced any episode of hypoglycemia. Severe hypoglycemia requiring any assistance was also associated with a 49% higher relative risk of HF (HR 1.49; 95% CI, 1.01-2.21).

CONCLUSION

In a large cohort of adults with type 2 diabetes, severe hypoglycemia was independently associated with greater risk of incident HF.

Hypoglycemia induces vascular endothelial dysfunction in subjects with normal glucose tolerance

This prospective study determined the effects of hypoglycemic stimulation on vascular endothelial function in non-diabetic patients using reactive hyperemia peripheral arterial tonometry (RH-PAT). The study included non-diabetic patients who were hospitalized for an insulin tolerance test (ITT) for the diagnosis of hypoadrenocorticism or hypopituitarism. Vascular endothelial function was assessed using the reactive hyperemia index (RHI) measured by the RH-PAT. We also measured the levels of anterior pituitary hormone, adrenaline, noradrenaline, and dopamine at the time of hypoglycemia. The primary endpoint was a change in the RHI at 120 min after insulin administration. The study included 27 patients. ITT was associated with significant increases in systolic blood pressure, pulse rate, and the blood levels of adrenocorticotropic hormone, cortisol, growth hormone, adrenaline, noradrenaline, and dopamine. RHI significantly decreased after ITT from 2.24 ± 0.51 to 1.71 ± 0.42. A significant inverse correlation was observed between the change in RHI and change in adrenaline (r = − 0.670, p = 0.012). We concluded that hypoglycemic stimulation altered vascular endothelial function, as measured by RH-PAT, even in patients free of glucose intolerance. The observed deterioration in vascular endothelial function correlated with increases in catecholamine levels during hypoglycemia.

Trial registration: UMIN000033244.

A higher non-severe hypoglycaemia rate is associated with an increased risk of subsequent severe hypoglycaemia and major adverse cardiovascular events in individuals with type 2 diabetes in the LEADER study

AIMS/HYPOTHESIS

Hypoglycaemia is a common side effect of insulin and some other antihyperglycaemic agents used to treat diabetes. Severe hypoglycaemia has been associated with adverse cardiovascular events in trials of intensive glycaemic control in type 2 diabetes. The relationship between non-severe hypoglycaemic episodes (NSHEs) and severe hypoglycaemia in type 2 diabetes has been documented. However, an association between more frequent NSHEs and cardiovascular events has not been verified. This post hoc analysis of the LEADER (Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results) trial aimed to confirm whether there is an association between NSHEs and severe hypoglycaemic episodes in individuals with type 2 diabetes. In addition, the possible association between NSHEs and major adverse cardiac events (MACE), cardiovascular death and all-cause mortality was investigated.

METHODS

LEADER was a double-blind, multicentre, placebo-controlled trial that found that liraglutide significantly reduced the risk of MACE compared with the placebo. In this post hoc analysis, we explored, in all LEADER participants, whether the annual rate of NSHEs (defined as self-measured plasma glucose <3.1 mmol/l [56 mg/dl]) was associated with time to first severe hypoglycaemic episode (defined as an episode requiring the assistance of another person), time to first MACE, time to cardiovascular death and time to all-cause mortality. Participants with <2 NSHEs per year were used as reference for HR estimates. Cox regression with a time-varying covariate was used.

RESULTS

We demonstrate that there is an association between NSHEs (2-11 NSHEs per year and ≥12 NSHEs per year) and severe hypoglycaemic episodes (unadjusted HRs 1.98 [95% CI 1.43, 2.75] and 5.01 [95% CI 2.84, 8.84], respectively), which was consistent when baseline characteristics were accounted for. Additionally, while no association was found between participants with 2-11 NSHEs per year and adverse cardiovascular outcomes, higher rates of NSHEs (≥12 episodes per year) were associated with higher risk of MACE (HR 1.50 [95% CI 1.01, 2.23]), cardiovascular death (HR 2.08 [95% CI 1.17, 3.70]) and overall death (HR 1.80 [95% CI 1.11, 2.92]).

CONCLUSIONS/INTERPRETATION

The analysis of data from the LEADER trial demonstrated that higher rates of NSHEs were associated with both a higher risk of severe hypoglycaemia and adverse cardiovascular outcomes in individuals with type 2 diabetes. Therefore, irrespective of the cause of this association, it is important that individuals with high rates of hypoglycaemia are identified so that the potentially increased risk of cardiovascular events can be managed and steps can be taken to reduce NSHEs.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT01179048).

MiRNA and associated inflammatory changes from baseline to hypoglycemia in type 2 diabetes

OBJECTIVE

Hypoglycemia in type 2 diabetes (T2D) increases morbidity and mortality but the underlying physiological response is still not fully understood, though physiological changes are still apparent 24 hours after the event. Small noncoding microRNA (miRNA) have multiple downstream biological effects that may respond rapidly to stress. We hypothesized that hypoglycemia would induce rapid miRNA changes; therefore, this pilot exploratory study was undertaken.

METHODS

A pilot prospective, parallel study in T2D (n=23) and controls (n=23). Insulin-induced hypoglycemia (2mmol/l: 36mg/dl) was induced and blood sampling performed at baseline and hypoglycemia. Initial profiling of miRNA was undertaken on pooled samples identified 96 miRNA that were differentially regulated, followed by validation on a custom designed 112 miRNA panel.

RESULTS

Nine miRNAs differed from baseline to hypoglycemia in control subjects; eight were upregulated: miR-1303, miR-let-7e-5p, miR-1267, miR-30a-5p, miR-571, miR-661, miR-770-5p, miR-892b and one was downregulated: miR-652-3p. None of the miRNAs differed from baseline in T2D subjects.

CONCLUSION

A rapid miRNA response reflecting protective pathways was seen in control subjects that appeared to be lost in T2D, suggesting that mitigating responses to hypoglycemia with blunting of the counter-regulatory response in T2D occurs even in patients with short duration of disease.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT03102801?term=NCT03102801&draw=2&rank=1, identifier NCT03102801.

Hypoglycemia-induced changes in complement pathways in type 2 diabetes

Background and aims

An association between hypoglycaemia and adverse cardiovascular events has been suggested from longitudinal and retrospective cohort studies. The complement pathway proteins in hypoglycemia are not well studied. Here, we hypothesized that these circulating proteins would be elevated in response to hypoglycemia in type 2 diabetes (T2D) through the inflammatory response.

Methods

A prospective, parallel study in T2D (n = 23) and controls (n = 23). Subjects underwent insulin-induced hypoglycemia with blood sampling at baseline, hypoglycemia and post-hypoglycemia; SOMAscan proteomic analysis of complement pathway-related proteins, cytokines and inflammatory proteins was undertaken.

Results

At baseline: Complement C2 (p < 0.05) and Factor B (p < 0.05) were elevated in T2D. At hypoglycemia: Complement C2 (p < 0.05) and Factor B (p < 0.01) remained elevated, whilst Factor I became elevated (p < 0.05) in T2D; Complement C4b became elevated in controls (p < 0.05). In the post-hypoglycemia follow up period, Complement C2, Factor B and Factor I remained elevated in T2D; in addition, Factor D, Factor H and mannose-binding protein C showed elevations in T2D, whilst properdin, complement C3b, Factor H-related protein 5, complement C1q and decay-accelerating factor (DAF) showed elevations in controls. Granger causality analysis showed that inflammatory proteins appeared to drive complement protein changes in T2D; conversely, in controls, complement proteins drove inflammatory protein changes.

Conclusions

Baseline elevations in C2 and Factor B indicate upregulation of the complement pathway in T2D. Changes in complement pathway-related protein levels in response to hypoglycemia suggest both intrinsic and alternative pathway activation at 2-h that appears driven by the underlying inflammation in T2D and could contribute to a cardiovascular event.ClinicalTrials.gov NCT03102801. Date of registration April 6, 2017, retrospectively registered. https://clinicaltrials.gov/ct2/show/NCT03102801?term=NCT03102801&draw=2&rank=1.

Felix dies natalis, insulin… ceterum autem censeo "beta is better"

One hundred years after its discovery, insulin remains the life-saving therapy for many patients with diabetes. It has been a 100-years-old success story thanks to the fact that insulin therapy has continuously integrated the knowledge developed over a century. In 1982, insulin becomes the first therapeutic protein to be produced using recombinant DNA technology. The first "mini" insulin pump and the first insulin pen become available in 1983 and 1985, respectively. In 1996, the first generation of insulin analogues were produced. In 1999, the first continuous glucose-monitoring device for reading interstitial glucose was approved by the FDA. In 2010s, the ultra-long action insulins were introduced. An equally exciting story developed in parallel. In 1966. Kelly et al. performed the first clinical pancreas transplant at the University of Minnesota, and now it is a well-established clinical option. First successful islet transplantations in humans were obtained in the late 1980s and 1990s. Their ability to consistently re-establish the endogenous insulin secretion was obtained in 2000s. More recently, the possibility to generate large numbers of functional human β cells from pluripotent stem cells was demonstrated, and the first clinical trial using stem cell-derived insulin producing cell was started in 2014. This year, the discovery of this life-saving hormone turns 100 years. This provides a unique opportunity not only to celebrate this extraordinary success story, but also to reflect on the limits of insulin therapy and renew the commitment of the scientific community to an insulin free world for our patients.

New Fast Acting Glucagon for Recovery from Hypoglycemia, a Life-Threatening Situation: Nasal Powder and Injected Stable Solutions

The goal of diabetes care is to achieve and maintain good glycemic control over time, so as to prevent or delay the development of micro- and macrovascular complications in type 1 (T1D) and type 2 diabetes (T2D). However, numerous barriers hinder the achievement of this goal, first of all the frequent episodes of hypoglycemia typical in patients treated with insulin as T1D patients, or sulphonylureas as T2D patients. The prevention strategy and treatment of hypoglycemia are important for the well-being of patients with diabetes. Hypoglycemia is strongly associated with an increased risk of cardiovascular disease in diabetic patients, due probably to the release of inflammatory markers and prothrombotic effects triggered by hypoglycemia. Treatment of hypoglycemia is traditionally based on administration of carbohydrates or of glucagon via intramuscular (IM) or subcutaneous injection (SC). The injection of traditional glucagon is cumbersome, such that glucagon is an under-utilized drug. In 1983, it was shown for the first time that intranasal (IN) glucagon increases blood glucose levels in healthy volunteers, and in 1989-1992 that IN glucagon is similar to IM glucagon in resolving hypoglycemia in normal volunteers and in patients with diabetes, both adults and children. IN glucagon was developed in 2010 and continued in 2015; in 2019 IN glucagon obtained approval in the US, Canada, and Europe for severe hypoglycemia in children and adults. In the 2010s, two ready-to-use injectable formulations, a stable non-aqueous glucagon solution and the glucagon analog dasiglucagon, were developed, showing an efficacy similar to traditional glucagon, and approved in the US in 2020 and in 2021, respectively, for severe hypoglycemia in adults and in children. Fast-acting glucagon (nasal administration and injected solutions) appears to represent a major breakthrough in the treatment of severe hypoglycemia in insulin-treated patients with diabetes, both adults and children. It is anticipated that the availability of fast-acting glucagon will expand the use of glucagon, improve overall metabolic control, and prevent hypoglycemia-related complications, in particular cardiovascular complications and cognitive impairment.

Impact of insulin therapy on the mortality of acute heart failure patients with diabetes mellitus

BACKGROUND

Patients with diabetes mellitus (DM) have a higher prevalence of heart failure (HF) than those without it. Approximately 40 % of HF patients have DM and they tend to have poorer outcomes than those without DM. This study evaluated the impact of insulin therapy on mortality among acute HF patients.

METHODS

A total of 1740 patients from the Korean Acute Heart Failure registry with DM were included in this study. The risk of all-cause mortality according to insulin therapy was assessed using the Cox proportional hazard models with inverse probability of treatment weighting to balance the clinical characteristics (pretreatment covariates) between the groups.

RESULTS

DM patients had been treated with either oral hypoglycemic agents (OHAs) alone (n = 620), insulin alone (n = 682), or insulin combined with OHAs (n = 438). The insulin alone group was associated with an increased mortality risk compared with the OHA alone group (HR = 1.41, 95 % CI 1.21-1.66]). Insulin therapy combined with OHAs also showed an increased mortality risk (HR = 1.29, 95 % CI 1.14-1.46) compared with the OHA alone group. Insulin therapy was consistently associated with increased mortality risk, regardless of the left ventricular ejection fraction (LVEF) or HF etiology. A significant increase in mortality was observed in patients with good glycemic control (HbA1c < 7.0 %) receiving insulin, whereas there was no significant association in patients with poor glycemic control (HbA1c ≥ 7.0%).

CONCLUSIONS

Insulin therapy was found to be associated with increased mortality compared to OHAs. The insulin therapy was harmful especially in patients with low HbA1c levels which may suggest the necessity of specific management strategies and blood sugar targets when using insulin in patients with HF.

History of Severe Hypoglycemia in Type 2 Diabetes Mellitus Unmasked Significant Atherosclerotic Coronary Artery Disease: A Comparative Case Control Study

Objectives

A history of severe hypoglycemia (SH) is associated with cardiovascular (CV) events among patients with type 2 diabetes mellitus (T2DM). In this study, we compared the severity of atherosclerotic coronary artery disease (ACAD) in T2DM patients with and without a history of SH.

Methodology

We conducted a comparative case-control study involving 28 T2DM patients with a history of SH within the last 5 years with no documented ACAD, and matched them with 28 T2DM patients with no history of SH. All subjects underwent coronary artery calcium scoring (CACS) with or without coronary computed tomographic angiography (CCTA) to evaluate the severity of ACAD.

Results

A history of SH in T2DM was associated with a higher prevalence of significant ACAD (79% versus 46%, p=0.026). A high CACS (≥100) was seen in a greater number of patients with a history of SH compared to those without (75% versus 43%, p=0.029). Similarly, there was a higher prevalence of obstructive CAD in those with a history of SH compared to those without (72% versus 39%, p=0.036). Median C-reactive protein level was also higher among patients with a history of SH (0.41 mg/dL versus 0.16 mg/dL, p=0.029).

Conclusion

In patients with T2DM, a history of SH is significantly associated with ACAD compared to those without SH. A history of SH warrants screening for ACAD.

Randomised controlled trial of pharmacist-led patient counselling in controlling hypoglycaemic attacks in older adults with type 2 diabetes mellitus (ROSE-ADAM): A study protocol of the SUGAR intervention

INTRODUCTION

Hypoglycaemia is one of the most serious adverse effects of diabetes treatment. Older adults are at the highest risk to develop hypoglycaemia. Several studies have established the important positive role of educational interventions on achieving glycaemic control and other clinical outcomes, however, there is still a lack in studies that evaluate the impact of such type of interventions on hypoglycaemia risk in elderly patients with type 2 diabetes. The purpose of this research is to evaluate the effectiveness of pharmacist-led patient counselling on reducing hypoglycaemic attacks in older adults with type 2 diabetes mellitus.

METHODS

and analysis: This study is an open-label, parallel controlled randomised trial, which will be conducted in the outpatient clinics at the largest referral hospital in the north of Jordan. Participants who are elderly (age ≥ 65 years), diagnosed with type 2 diabetes mellitus, and taking insulin, sulfonylurea, or any three anti-diabetic medications will be randomly assigned to intervention (SUGAR Handshake) and control (usual care) groups. The SUGAR Handshake participants will have an interactive, individualised, medications-focused counselling session reinforced with a pictogram and a phone call at week six of enrolment. The primary outcome measure is the frequency of total hypoglycaemic events within 12 weeks of follow up. Secondary outcomes include the frequency of asymptomatic, symptomatic, and severe hypoglycaemic events, hypoglycaemia incidence, and time to the first hypoglycaemic attack. We will also conduct a nested qualitative study for process evaluation.

ETHICS AND DISSEMINATION

The Human Research Ethics Committee of the University of Lincoln and the Institutional Review Board of King Abdullah University Hospital approved this protocol. The findings of this study will be presented in international conferences and published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

The study protocol has been registered with ClinicalTrials.gov, NCT04081766.

Severe hypoglycemia as a preventable risk factor for cardiovascular disease in patients with type 2 diabetes mellitus

Glucose-lowering medication and lifestyle modification are essential for optimal glycemic control in patients with type 2 diabetes mellitus (T2DM). However, glucose-lowering agents, particularly insulin and insulin secretagogues, may cause hypoglycemia, which has multiple negative effects on the cardiovascular (CV) system and may cause death. Previous studies using institutional data from the Korean Nationwide Health Insurance database have consistently found a causal relationship between severe hypoglycemia and CV outcomes and mortality. Screening for high-risk patients, appropriate management, and intensive individualized education are the most effective measures and essential for the prevention of harmful hypoglycemic events. Based on identified risk factors that predict severe hypoglycemia, we developed an 1-year risk prediction model for severe hypoglycemia that can be used in clinical settings. In this review, we describe the current understanding of severe hypoglycemia and the clinical implications in patients with T2DM. Furthermore, we highlight the importance of intensive individualized education for high-risk patients and the risk prediction model to reduce severe hypoglycemia.

Glucose variability and diabetes complications: Risk factor or biomarker? Can we disentangle the "Gordian Knot"?

« Variability in glucose homoeostasis » is a better description than « glycaemic variability » as it encompasses two categories of dysglycaemic disorders: i) the short-term daily glucose fluctuations and ii) long-term weekly, monthly or quarterly changes in either HbA1c, fasting or postprandial plasma glucose. Presently, the relationship between the "variability in glucose homoeostasis" and diabetes complications has never been fully clarified because studies are either observational or limited to retrospective analysis of trials not primarily designed to address this issue. Despite the absence of definitive evidence from randomized controlled trials (RCTs), it is most likely that acute and long-term glucose homoeostasis "cycling", akin to weight and blood pressure "cycling" in obese and hypertensive individuals, are additional risk factors for diabetes complications in the presence of sustained ambient hyperglycaemia. As hypoglycaemic events are strongly associated with short- and long-term glucose variability, two relevant messages can be formulated. Firstly, due consideration should be given to avoid within-day glucose fluctuations in excess of 36% (coefficient of variation) at least for minimizing the inconvenience and dangers associated with hypoglycaemia. Secondly, it seems appropriate to consider that variability in glucose homoeostasis is not only associated with cardiovascular events but is also a causative risk factor via hypoglycaemic episodes as intermediary step. Untangling the" Gordian Knot", to provide confirmation about the impact of variability in glucose homoeostasis and diabetes complications remains a daunting prospect.

To Assess Liraglutide's Therapeutic Effect in Patients with Type 2 Diabetes Mellitus Using Flash Glucose Monitoring System

PURPOSE

Liraglutide, a type of glucagon-like peptide-1 receptor agonist, has significant anti-hyperglycaemic activity without increasing the incidence of hypoglycaemia. In addition, it can improve β-cell function and insulin resistance. The flash glucose monitoring system (FGMS) is a novel method to document consecutive and detailed interstitial glucose levels, further reflecting blood glucose levels. This study aimed to investigate the therapeutic effect of liraglutide on blood glucose management (glucose variability, hyperglycaemia, and the incidence of hypoglycaemia), β-cell function, and insulin resistance in patients with diabetes.

PATIENTS AND METHODS

Thirty-three patients with type 2 diabetes mellitus were recruited in this study. On the basis of metformin monotherapy, these patients received liraglutide add-on treatment for 3 months. The FGMS was used to document glucose levels before and after add-on treatment. Parameters of glucose variability, blood glucose levels at specific time periods, and the incidence of hypoglycaemia were assessed according to FGMS data and compared before and after liraglutide add-on treatment. Further, β-cell function and insulin resistance were assessed and compared before and after liraglutide add-on treatment.

RESULTS

According to FGMS monitoring data, liraglutide add-on treatment significantly improved general, within-day, and day-to-day glucose variability and the glucose-target-rate. Further, the specifically analysed blood glucose levels at different time periods showed that blood glucose levels significantly decreased at nocturnal, fasting, and postprandial periods after add-on treatment. The incidence of hypoglycaemia was comparable during the whole day, daytime, and night-time according to the prespecified cutoffs (3.9 mmol/L and 3.0 mmol/L) before and after add-on treatment. Analysis of other assessed parameters revealed significant differences in glycosylated hemoglobin A1c and fasting blood glucose levels as well as parameters of β-cell function and insulin resistance before and after add-on treatment.

CONCLUSION

In type 2 diabetes mellitus, liraglutide treatment can effectively decrease glucose variability and ameliorate hyperglycaemia without increasing the incidence of hypoglycaemia. In addition, liraglutide can significantly improve the β-cell function and insulin resistance.

Meta-Analysis: Association Between Hypoglycemia and Serious Adverse Events in Older Patients Treated With Glucose-Lowering Agents

AIMS

We conducted a meta-analysis of serious adverse events (dementia, macro- and micro-vascular events, falls and fractures, and death) associated with hypoglycemia in older patients treated with glucose lowering drugs.

MATERIALS AND METHODS

Meta-analysis of studies reporting on hypoglycemia and adverse events. The search included studies from two previously published systematic reviews, and an updated search of MEDLINE and EMBASE from April 2014 to November 2019. We assessed study validity based on ascertainment of hypoglycemia, adverse events and adjustment for confounders, and conducted a random effects meta-analyses, assessing heterogeneity using the I² statistic.

RESULTS

We included 44 studies involving 2,507,434 participants. Most of the studies used adjusted analysis for confounders and hypoglycaemic events were typically identified based on healthcare databases (severe events). Hypoglycemia was associated with increased likelihood of death in a meta-analysis of eighteen studies, pooled OR 2.02 (95% Confidence Interval 1.75-2.32). Studies assessing mortality signal a time-response relationship with a higher risk of adverse events occurring within the first 90 days after hypoglycemia. Our meta-analysis of nine studies demonstrated that hypoglycaemic episodes were associated with dementia - pooled OR 1.50 (95% CI 1.29-1.74). Our meta-analysis of nineteen studies demonstrated associations between hypoglycaemia and macrovascular complications, pooled OR 1.81 (95% CI 1.70-1.94), and microvascular complications (two studies) pooled OR 1.77 (95% CI 1.49-2.10). There is also an association between hypoglycemia and cardiovascular death (six studies) - pooled OR 2.11 (95% CI 1.55 to 2.87). Similarly, our meta-analysis of six studies demonstrated an association between hypoglycemia and falls and fractures, pooled OR 1.78 (95% CI 1.44-2.21) and 1.68 (95% CI 1.37-2.07) respectively.

CONCLUSION

This meta-analysis confirms previously reported concerns of serious harm following hypoglycemia, especially in the immediate time period after a hypoglycaemic event. Avoidance of hypoglycaemic episodes should be a priority in this vulnerable population.

Hypoglycemia increases endothelial-dependent vasodilation through suppressing phosphorylation at Threonine 495/497 site of endothelial nitric oxide synthase

OBJECTIVE

Phosphorylation plays an essential role in the regulation of endothelial nitric oxide synthase (eNOS) activity. However, the phosphorylation of eNOS under hypoglycemia and whether hypoglycemia changes eNOS activity is unknown. This paper aims to clarify the regulation of eNOS phosphorylation and its activity change under hypoglycemia.

METHODS

Bovine aortic endothelial cells (BAECs) and Sprague-Dawley rats were treated with hypoglycemia, and the phosphorylation of eNOS was subjected to western blot. Blood nitric oxide (NO) concentration was determined by NO kit and endothelial-dependent vasodilation was detected by multi-wire myograph.

RESULTS

In both BAECs and rats' thoracic aorta, hypoglycemia induced eNOS phosphorylation decrease specifically on Threonine (Thr) 497. Inhibition of ubiquitination of protein kinase C α subunit (PKCα) reverses the decrease of eNOS phosphorylation in hypoglycemia. Ubiquitinated PKCα can be reversed by AMPK knockdown. In rats, insulin induced hypoglycemia increased the concentration of NO in arterial blood, and progressively enhanced the endothelium-dependent vasodilation of the thoracic and mesenteric aorta.

CONCLUSIONS

In vitro, the activation of AMPK may lead to the expression of PKCα by regulating ubiquitination, resulting in a decrease in the level of P-eNOS Thr497 phosphorylation under hypoglycemia. In vivo, insulin-induced hypoglycemia produces a beneficial cardiovascular effect on rats.

Impact of Ramadan Diurnal Intermittent Fasting on Hypoglycemic Events in Patients With Type 2 Diabetes: A Systematic Review of Randomized Controlled Trials and Observational Studies

Ramadan is the 9th month of the lunar calendar during which Muslims abstain from food and drink between dawn and sunset for 30 consecutive days. Ramadan fasting is observed by all healthy Muslim adults, as well many Muslims with type 2 diabetes (T2DM). Hypoglycemic events (HE) are a serious complication associated with diabetes management and are associated with increased cardiovascular disease risk. Conflicting results have been reported concerning the incidence of HE among people with T2DM observing Ramadan fasting. This review summarizes available scientific evidence on the occurrence of HE and the effects of different moderators on the incidence of HE among patients with T2DM during Ramadan. We conducted a systematic review of available observational studies and randomized controlled trials (RCTs) for patients with T2DM who fasted during Ramadan, with HE as the primary outcome. Ten databases were searched for relevant studies from inception until October 31, 2020. In total, 68 studies (35 RCTs and 33 observational studies) met the inclusion criteria. Non-sulfonylureas hypoglycemic medications showed superior effects in lowering the incidence of HE over sulfonylureas hypoglycemic medications. Variable moderators were associated with experiencing HE during Ramadan in both observational studies and RCTs, including sex, geographical location, body anthropometric indicators, season, dietary behaviors, fasting duration, time since diagnosis, and pre-fasting education. This comprehensive systematic review covered the largest number of observational and clinical studies investigating the impact of Ramadan on HE among patients with T2DM. The study highlights the significance of different moderators that influence the effect of Ramadan fasting on HE, including dietary behaviors, fasting time duration, sex, season, country, pre-fasting education, age, and time since diagnosis. The study also highlighted the impact of different hypoglycemic medications on HE and noted the superiority of non-sulfonylureas over sulfonylureas hypoglycemic medications in lowering the risk for hypoglycemia in people with T2DM during Ramadan fasting.

Limited impact of impaired awareness of hypoglycaemia and severe hypoglycaemia on the inflammatory profile of people with type 1 diabetes

AIM

To investigate whether a history of severe hypoglycaemia (SH) or the associated presence of impaired awareness of hypoglycaemia (IAH) is characterized by a pro-inflammatory profile in people with type 1 diabetes.

RESEARCH DESIGN AND METHODS

We measured circulating inflammatory markers and pro- and anti-inflammatory cytokine production after ex vivo stimulation of peripheral blood mononuclear cells (PBMCs) in a well-characterized cohort of individuals with type 1 diabetes (n = 239) and in people without diabetes (n = 56). Data were corrected for confounders by using multivariate linear regression models.

RESULTS

People with type 1 diabetes had higher circulating concentrations of high-sensitivity C-reactive protein (hs-CRP; 0.91 [0.36-2.25] vs. 0.52 [0.20-0.98] pg/mL, P < 0.001 and interleukin-18-binding protein (IL-18BP; 1746 [1304-2112] vs. 1381 [1191-1807] pg/mL; P = 0.001) than those without diabetes. In multivariate analysis, only higher hs-CRP concentrations persisted. Neither circulating immune cells nor ex vivo cytokine levels produced by PBMCs in response to an extensive panel of stimuli differed in groups defined by awareness state or a history of SH, apart from elevated IL-18BP in people with, versus those without, history of SH (1524 [1227-1903] vs. 1913 [1459-2408] pg/mL; P < 0.001).

CONCLUSIONS

IAH or history of SH in people with type 1 diabetes was not associated with altered inflammatory profiles, arguing against chronically elevated inflammatory activity mediating the increased cardiovascular risk associated with hypoglycaemia. The finding of higher circulating concentrations of IL-18BP in individuals with a history of SH requires further investigation.

Risk of severe hypoglycaemia and its impact in type 2 diabetes in DEVOTE

AIMS

To undertake a post-hoc analysis, utilizing a hypoglycaemia risk score based on DEVOTE trial data, to investigate if a high risk of severe hypoglycaemia was associated with an increased risk of cardiovascular events, and whether reduced rates of severe hypoglycaemia in patients identified as having the highest risk affected the risk of cardiovascular outcomes.

MATERIALS AND METHODS

The DEVOTE population was divided into quartiles according to patients' individual hypoglycaemia risk scores. For each quartile, the observed incidence and rate of severe hypoglycaemia, major adverse cardiovascular event (MACE) and all-cause mortality were determined to investigate whether those with the highest risk of hypoglycaemia were also at the greatest risk of MACE and all-cause mortality. In addition, treatment differences within each risk quartile [insulin degludec (degludec) vs. insulin glargine 100 units/mL (glargine U100)] in terms of severe hypoglycaemia, MACE and all-cause mortality were investigated.

RESULTS

Patients with the highest risk scores had the highest rates of severe hypoglycaemia, MACE and all-cause mortality. Treatment ratios between degludec and glargine U100 in the highest risk quartile were 95% confidence interval (CI) 0.56 (0.39; 0.80) (severe hypoglycaemia), 95% CI 0.76 (0.58; 0.99) (MACE) and 95% CI 0.77 (0.55; 1.07) (all-cause mortality).

CONCLUSIONS

The risk score demonstrated that a high risk of severe hypoglycaemia was associated with a high incidence of MACE and all-cause mortality and that, in this high-risk group, those treated with degludec had a lower incidence of MACE. These observations support the hypothesis that hypoglycaemia is a risk factor for cardiovascular events.

Development of a hypoglycaemia risk score to identify high-risk individuals with advanced type 2 diabetes in DEVOTE

AIMS

The ability to differentiate patient populations with type 2 diabetes at high risk of severe hypoglycaemia could impact clinical decision making. The aim of this study was to develop a risk score, using patient characteristics, that could differentiate between populations with higher and lower 2-year risk of severe hypoglycaemia among individuals at increased risk of cardiovascular disease.

MATERIALS AND METHODS

Two models were developed for the risk score based on data from the DEVOTE cardiovascular outcomes trials. The first, a data-driven machine-learning model, used stepwise regression with bidirectional elimination to identify risk factors for severe hypoglycaemia. The second, a risk score based on known clinical risk factors accessible in clinical practice identified from the data-driven model, included: insulin treatment regimen; diabetes duration; sex; age; and glycated haemoglobin, all at baseline. Both the data-driven model and simple risk score were evaluated for discrimination, calibration and generalizability using data from DEVOTE, and were validated against the external LEADER cardiovascular outcomes trial dataset.

RESULTS

Both the data-driven model and the simple risk score discriminated between patients at higher and lower hypoglycaemia risk, and performed similarly well based on the time-dependent area under the curve index (0.63 and 0.66, respectively) over a 2-year time horizon.

CONCLUSIONS

Both the data-driven model and the simple hypoglycaemia risk score were able to discriminate between patients at higher and lower risk of severe hypoglycaemia, the latter doing so using easily accessible clinical data. The implementation of such a tool (http://www.hyporiskscore.com/) may facilitate improved recognition of, and education about, severe hypoglycaemia risk, potentially improving patient care.

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.

Clinical Management of Stable Coronary Artery Disease in Patients With Type 2 Diabetes Mellitus: A Scientific Statement From the American Heart Association

Although cardiologists have long treated patients with coronary artery disease (CAD) and concomitant type 2 diabetes mellitus (T2DM), T2DM has traditionally been considered just a comorbidity that affected the development and progression of the disease. Over the past decade, a number of factors have shifted that have forced the cardiology community to reconsider the role of T2DM in CAD. First, in addition to being associated with increased cardiovascular risk, T2DM has the potential to affect a number of treatment choices for CAD. In this document, we discuss the role that T2DM has in the selection of testing for CAD, in medical management (both secondary prevention strategies and treatment of stable angina), and in the selection of revascularization strategy. Second, although glycemic control has been recommended as a part of comprehensive risk factor management in patients with CAD, there is mounting evidence that the mechanism by which glucose is managed can have a substantial impact on cardiovascular outcomes. In this document, we discuss the role of glycemic management (both in intensity of control and choice of medications) in cardiovascular outcomes. It is becoming clear that the cardiologist needs both to consider T2DM in cardiovascular treatment decisions and potentially to help guide the selection of glucose-lowering medications. Our statement provides a comprehensive summary of effective, patient-centered management of CAD in patients with T2DM, with emphasis on the emerging evidence. Given the increasing prevalence of T2DM and the accumulating evidence of the need to consider T2DM in treatment decisions, this knowledge will become ever more important to optimize our patients' cardiovascular outcomes.

How tightly controlled do fluctuations in blood glucose levels need to be to reduce the risk of developing complications in people with Type 1 diabetes?

In 2011, the James Lind Alliance published a 'top 10' list of priorities for Type 1 diabetes research based on a structured consultation process. Whether reducing fluctuations in blood glucose can prevent long-term microvascular and macrovascular complications was one of these. In this narrative review, 8 years on, we have assessed the updated evidence for the assertion that increased glucose variability plays an independent and clinically important role in the complications of Type 1 diabetes, over and above mean blood glucose and the effects of hypoglycaemia: the 'glucose variability hypothesis'. Although studies in cultured cells and ex vivo vessels have been suggestive, most studies in Type 1 diabetes have been small and/or cross-sectional, and based on 'finger-prick' glucose measurements that capture glucose variability only in waking hours and are affected by missing data. A recent analysis of the Diabetes Control and Complications Trial that formally imputed missing data found no independent effect of short-term glucose variability on long-term complications. Few other high-quality longitudinal studies have directly addressed the glucose variability hypothesis in Type 1 diabetes. We conclude that there is little substantial evidence to date to support this hypothesis in Type 1 diabetes, although increasing use of continuous glucose monitoring provides an opportunity to test it more definitively. In the meantime, we recommend that control of glycaemia in Type 1 diabetes should continue to focus on the sustained achievement of target HbA_1c and avoidance of hypoglycaemia.

Effect of induced hypoglycemia on inflammation and oxidative stress in type 2 diabetes and control subjects

Intensive diabetes control has been associated with increased mortality in type 2 diabetes (T2DM); this has been suggested to be due to increased hypoglycemia. We measured hypoglycemia-induced changes in endothelial parameters, oxidative stress markers and inflammation at baseline and after a 24-hour period in type 2 diabetic (T2DM) subjects versus age-matched controls. Case-control study: 10 T2DM and 8 control subjects. Blood glucose was reduced from 5 (90 mg/dl) to hypoglycemic levels of 2.8 mmol/L (50 mg/dl) for 1 hour by incremental hyperinsulinemic clamps using baseline and 24 hour samples. Measures of endothelial parameters, oxidative stress and inflammation at baseline and at 24-hours post hypoglycemia were performed: proteomic (Somalogic) analysis for inflammatory markers complemented by C-reactive protein (hsCRP) measurement, and proteomic markers and urinary isoprostanes for oxidative measures, together with endothelial function. Between baseline and 24 -hours after hypoglycemia, 15 of 140 inflammatory proteins differed in T2DM whilst only 1 of 140 differed in controls; all returned to baseline at 24-hours. However, elevated hsCRP levels were seen at 24-hours in T2DM (2.4 mg/L (1.2-5.4) vs. 3.9 mg/L (1.8-6.1), Baseline vs 24-hours, P < 0.05). In patients with T2DM, between baseline and 24-hour after hypoglycemia, only one of 15 oxidative stress proteins differed and this was not seen in controls. An increase (P = 0.016) from baseline (73.4 ng/mL) to 24 hours after hypoglycemia (91.7 ng/mL) was seen for urinary isoprostanes. Hypoglycemia resulted in inflammatory and oxidative stress markers being elevated in T2DM subjects but not controls 24-hours after the event.

Hypoglycaemia

In health hypoglycaemia is rare and occurs only in circumstances like extreme sports. Hypoglycaemia in type 1 Diabetes (T1D) and advanced type 2 Diabetes (T2D) are the result of interplay between absolute or relative insulin access and defective glucose counterregulation. The basic mechanism is, failure of decreasing insulin and failure of the compensatory increasing counterregulatory hormones at the background of falling blood glucose. Any person with Diabetes on anti-diabetic medication who behaves oddly in any way whatsoever is hypoglycaemic until proven otherwise. Hypoglycaemia can be a terrifying experience for a patient with Diabetes. By definition, hypoglycaemic symptoms are subjective and vary from person to person and even episode to episode in same person. Fear of iatrogenic hypoglycaemia is a major barrier in achieving optimum glycaemic control and quality of life which limits the reduction of diabetic complications. Diabetes patients with comorbidities especially with chronic renal failure, hepatic dysfunction, major limb amputation, terminal illness, cognitive dysfunction etc. are more vulnerable to hypoglycaemia. In most cases, prompt glucose intake reverts hypoglycaemia. Exogenous insulin in T1D and insulin treated advanced T2D have no control by pancreatic regulation. Moreover, failure of increase of glucagon and attenuated secretion in epinephrine causes the defective glucose counterregulation. In this comprehensive review, I will try to touch all related topics for better understanding of hypoglycaemia.

Use of flash glucose-sensing technology in patients with type 2 diabetes treated with liraglutide combined with CSII: a pilot study

Glycemic variability (GV) may be linked to the development of diabetic complications by inducing inflammation, oxidative stress, and endothelial dysfunction. Flash glucose monitoring (FGM) provides a novel method of continuously monitoring interstitial glucose levels for up to 14 days. This study randomly assigned poorly controlled type 2 diabetes mellitus patients treated with metformin and multiple daily injections of insulin (n=60) to either continuous subcutaneous insulin infusion (CSII) treatment or CSII in combination with liraglutide (CSII+Lira) treatment for 14 days during hospitalization. GV was assessed using a FGM system; weight and cardiometabolic biomarkers were also evaluated. The coefficient of variation was significantly reduced in the CSII+Lira group (P<0.001), while no significant change was observed in the CSII group. The changes differed significantly between the two groups in mean amplitude of glycemic excursions (P=0.004), standard deviation (P=0.006), and the percentage of time in the target range (4–10 mmol/L, P=0.005 and >10 mmol/L, P=0.028). The changes in mean of daily differences, interquartile range, and percentage of time in hypoglycemia (<3.3 mmol/L) and hyperglycemia (>13.9 mmol/L) identified by FGM showed no difference. Treatment with liraglutide increased serum adiponectin [33.5 (3.5, 47.7) pg/mL, P=0.003] and heme oxygenase-1 levels [0.4 (–0.0, 1.8) ng/mL, P=0.001] and reduced serum leptin levels [–2.8 (3.9) pg/mL, P<0.001]. Adding the glucagon-like peptide-1 analog liraglutide improved GV, weight, and some cardiometabolic risk markers. The FGM system is, therefore, shown to be a novel and useful method for glucose monitoring.

Severe hypoglycemia and the risk of cardiovascular disease and mortality in type 2 diabetes: a nationwide population-based cohort study

BACKGROUND

We investigated the association regarding severe hypoglycemia episodes with cardiovascular disease risk and all-cause mortality in patients with type 2 diabetes.

METHODS

Baseline and follow-up data (n = 1,568,097) from patients with type 2 diabetes were retrieved from the National Health Insurance System database (covering the entire Korean population). Type 2 diabetes, severe hypoglycemia, and major comorbidities were identified using International Classification of Diseases 10 codes and medication information. Individuals who were classified as type 2 diabetes in the year of 2009 were screened, and we counted severe hypoglycemia episodes from 2007 to 2009. The primary outcome was newly developed myocardial infarction (MI), stroke, heart failure, or all-cause mortality. Participants were followed from the baseline index date to the date of death or until December 31, 2015.

RESULTS

In total, 19,660 (1.2%) patients developed at least one severe hypoglycemia event during the period from 2007 to 2009. Mean follow-up was 5.7 years. After adjustment for confounding factors, the hazard ratio (HR) of MI significantly and sequentially increased: 0 vs. 1 episode, HR 1.56, 95% CI 1.46-1.64; 0 vs. 2 episodes, HR 1.86, 95% CI 1.61-2.15; 0 vs. 3 or more episodes, HR 1.86, 95% CI 1.48-2.35, P for trend < 0.001. Similar findings were noted regarding the relationship of severe hypoglycemia episodes with stroke, heart failure, and all-cause mortality. Risks for all outcomes were highest within 1 year from the index date and showed decreasing trends with follow-up. Sensitivity analyses of the data from the subgroup population and 797,544 subjects who received a national health examination did not change the significance of the main findings.

CONCLUSION

Among adult Korean patients with type 2 diabetes, a severe hypoglycemia episode is associated with increased risk for cardiovascular outcomes and all-cause mortality. Significant results from dose-response, temporal, and sensitivity analyses may suggest the possibility of direct causality between severe hypoglycemia and cardiovascular outcomes and mortality.

Hypoglycaemia, cardiovascular disease, and mortality in diabetes: epidemiology, pathogenesis, and management

Hypoglycaemia has long been recognised as a dangerous side-effect of treatment of diabetes with insulin or insulin secretagogues. With its potential to disrupt cerebral function, hypoglycaemia can have a major effect on peoples' lives. Study findings have suggested that hypoglycaemia is associated with an increased risk of cardiovascular events and mortality. Different mechanisms by which hypoglycaemia might provoke cardiovascular events have been identified in experimental studies, and in clinical studies cardiac arrhythmias have been reported to be induced by hypoglycaemia, with one report describing sudden death during a severe episode. Emerging evidence suggests that the association between hypoglycaemia and cardiovascular events and mortality is likely to be multifactorial. The association is probably partly caused by confounding, with hypoglycaemia occurring more frequently in people with comorbidities who are also more likely to die than those without. However, people with type 1 or type 2 diabetes also seem at risk of hypoglycaemia-induced cardiovascular effects. This risk should be recognised by clinicians when agreeing glycaemic goals with patients and choosing appropriate glucose-lowering therapies.

The effect of lithium chloride on the attenuation of cognitive impairment in experimental hypoglycemic rats

BACKGROUND

Hypoglycemia is the most common complication in the treatment of diabetes mellitus. Accumulating evidence indicated that severe hypoglycemia could induce cognitive impairment. However, the molecular mechanism of regulating this progress is largely unknown.

METHODS

We established a model of insulin-induced recurrent hypoglycemia in adult male Wistar rats (n = 40). Lithium chloride was injected after hypoglycemia once a day for consecutive 30 days. The loss of cognition function was evaluated by water maze test in these hypoglycemic rats. Glial cells activation and Wnt and inflammatory cytokines IL-1β, IL-6, IL-4, IL-10, TGFβ and TNFα expression were further examined to determine the mechanism of cognitive function impairment.

RESULTS

Hypoglycemia could induce impairment of cognitive function in rats and administration of lithium chloride could partly attenuate cognitive impairment compared to the control (p < 0.05). Lithium chloride could significantly up-regulate Wnt signaling and reduce hypoglycemia-induced neuronal death, glial cells activation and inflammatory response in the hippocampus of rats compared to the control (p < 0.05). The efficacy of lithium chloride could be reversed by injecting canonical Wnt signaling antagonist the dickkopf homolog 1.

CONCLUSION

Lithium chloride attenuated hypoglycemia-induced cognitive function impairment in rats; and it was associated with Wnt signaling up-regulation and reduction of inflammatory response. Our results suggested that activating Wnt signaling pathways and inhibiting inflammatory response were the therapeutic potential to prevent hypoglycemia-induced neurological damage.

Effects of Severe Hypoglycemia on Cardiovascular Outcomes and Death in the Veterans Affairs Diabetes Trial

OBJECTIVE

To determine the risk factors for severe hypoglycemia and the association between severe hypoglycemia and serious cardiovascular adverse events and cardiovascular and all-cause mortality in the Veterans Affairs Diabetes Trial (VADT).

RESEARCH DESIGN AND METHODS

This post hoc analysis of data from the VADT included 1,791 military veterans (age 60.5 ± 9.0 years) with suboptimally controlled type 2 diabetes (HbA1c 9.4 ± 2.0%) of 11.5 ± 7.5 years disease duration with or without known cardiovascular disease and additional cardiovascular risk factors. Participants were randomized to intensive (HbA1c <7.0%) versus standard (HbA1c <8.5%) glucose control.

RESULTS

The rate of severe hypoglycemia in the intensive treatment group was 10.3 per 100 patient-years compared with 3.7 per 100 patient-years in the standard treatment group (P < 0.001). In multivariable analysis, insulin use at baseline (P = 0.02), proteinuria (P = 0.009), and autonomic neuropathy (P = 0.01) were independent risk factors for severe hypoglycemia, and higher BMI was protective (P = 0.017). Severe hypoglycemia within the past 3 months was associated with an increased risk of serious cardiovascular events (P = 0.032), cardiovascular mortality (P = 0.012), and total mortality (P = 0.024). However, there was a relatively greater increased risk for total mortality in the standard group compared with the intensive group (P = 0.019). The association between severe hypoglycemia and cardiovascular events increased significantly as overall cardiovascular risk increased (P = 0.012).

CONCLUSIONS

Severe hypoglycemic episodes within the previous 3 months were associated with increased risk for major cardiovascular events and cardiovascular and all-cause mortality regardless of glycemic treatment group assignment. Standard therapy further increased the risk for all-cause mortality after severe hypoglycemia.

Lower mean blood glucose during short-term intensive insulin therapy is associated with long-term glycemic remission in patients with newly diagnosed type 2 diabetes: Evidence-based recommendations for standardization

AIMS/INTRODUCTION

Optimal glycemic targets during short-term intensive insulin therapy in patients with newly diagnosed type 2 diabetes are not standardized. The present study was carried out to determine the optimal glycemic targets during therapy by analyzing the impacts of glucose levels on therapeutic outcomes.

MATERIALS AND METHODS

A total of 95 individuals with newly diagnosed type 2 diabetes were enrolled. Short-term intensive insulin therapy was carried out using an insulin pump to achieve and maintain glycemic targets (fasting blood glucose ≤6.0 mmol/L, 2-h postprandial blood glucose ≤7.8 mmol/L) for 14 days, with daily eight-point capillary blood glucose profiles recorded. Patients were followed up for 1 year after discharge.

RESULTS

In most participants, the mean blood glucose and glycemic excursion parameters during the therapy were controlled within the normal range. Mean blood glucose was independently associated with amelioration of acute insulin response (r = -0.25, P = 0.015) and 1-year remission (odds ratio 0.12, 95% confidence interval 0.034-0.426), but negatively associated with more level 1 hypoglycemia (r = -0.34, P = 0.001), although major hypoglycemia was rare. Among mean blood glucose tertiles, patients in the middle (68.7%) and lower (75.0%) tertiles had a higher 1-year remission rate compared with the upper tertile (32.3%, both P < 0.001), whereas only the middle tertile did not have increased hypoglycemia compared with the upper tertile (8.1 ± 5.4 vs 7.2 ± 3.9 events/person, P = 0.48).

CONCLUSIONS

Stricter glycemic control during short-term intensive insulin therapy produced more remission despite self-manageable hypoglycemia. Based on glycemic parameters in the middle mean tertile, we propose new glycemic targets that are approximately 0.4 mmol/L lower than current the targets, as long-term benefit outweighs short-term risks.

Levels of serum uric acid at admission for hypoglycaemia predict 1-year mortality

AIMS

Hypoglycaemia represents a critical burden with clinical and social consequences in the management of diabetes. Serum uric acid (SUA) has been associated with cardiovascular diseases (CVD), but no conclusive findings are available nowadays in patients suffering from hypoglycaemia. We investigated whether SUA levels at the time of hypoglycaemia could predict all-cause mortality after 1-year follow-up.

METHODS

In total, 219 patients admitted to the Emergency Department (ED) of Ospedale Policlinico S. Martino of Genoa (Italy) have been enrolled between January 2011 and December 2014. The primary endpoint of the study consisted in determining whether SUA levels at the time of ED admission could predict the occurrence of death after 1 year.

RESULTS

The majority of patients were diabetic, especially type 2. CVD and chronic kidney disease were prevalent comorbidities. By a cut-off value obtained by the receiver operating characteristic curve analysis, a Kaplan-Meier analysis demonstrated that patients with SUA levels > 5.43 mg/dL were more prone to death after 1 year compared to those with lower SUA levels. The risk of death increased with high SUA levels both in the univariate and the multivariate models including estimated glomerular filtration rate, C-reactive protein, type of diabetes, and age-adjusted Charlson comorbidity index.

CONCLUSIONS

SUA could be useful as a predictor of 1-year mortality in hypoglycaemic patients, irrespective of severe comorbidities notably increasing the risk of death in these frail patients.

Decreased iron stores are associated with cardiovascular disease in patients with type 2 diabetes both cross-sectionally and longitudinally

BACKGROUND AND AIMS

The possible contribution of iron to cardiovascular complications of type 2 diabetes (T2D) has been scarcely investigated. We aimed to study whether serum ferritin is linked to prevalent/incident cardiovascular disease (CVD) in T2D.

METHODS

The prevalence of coronary heart disease (CHD), cerebrovascular disease (CEVD) and CVD was evaluated in the SIDIAP study (n = 38,617) and prevalence and 7-year incidence were analysed in the Edinburgh Type 2 Diabetes Study (ET2DS) (n = 821). Logistic and Cox regressions were used to describe associations between serum ferritin and CVD adjusting for confounding variables.

RESULTS

Increase of 1 SD unit in log-ferritin was associated with lower CVD prevalence in fully-adjusted models (ET2DS odds ratio (OR) 95% confidence interval (CI): 0.81 (0.68-0.96), p = 0.018; SIDIAP study: 0.91 (0.88-0.94), p < 0.001). In ET2DS, ferritin in the highest (vs. the lowest) quintile was associated with lower incidence of CVD (fully adjusted HR 95% CI: 0.46 (0.26-0.83), p = 0.010). This association persisted after removing subjects with CVD at baseline (n = 536) (HR 95% CI: 0.34 (0.14-0.81), p = 0.016).

CONCLUSIONS

Low iron status was associated with CVD risk in T2D. This pattern was consistent in populations at different cardiovascular risk. Low iron status seems to be harmful for cardiovascular health in T2D and it may be a target for intervention.

The Association of Severe Hypoglycemia With Incident Cardiovascular Events and Mortality in Adults With Type 2 Diabetes

OBJECTIVE

There is suggestive evidence linking hypoglycemia with cardiovascular disease, but few data have been collected in a community-based setting. Information is lacking on individual cardiovascular outcomes and cause-specific mortality.

RESEARCH DESIGN AND METHODS

We conducted a prospective cohort analysis of 1,209 participants with diagnosed diabetes from the Atherosclerosis Risk in Communities (ARIC) study (analytic baseline, 1996-1998). Severe hypoglycemic episodes were identified using first position ICD-9 codes from hospitalizations, emergency department visits, and ambulance calls through 2013. Cardiovascular events and deaths were captured through 2013. We used adjusted Cox regression models with hypoglycemia as a time-varying exposure.

RESULTS

There were 195 participants with at least one severe hypoglycemic episode during a median fellow-up of 15.3 years. After severe hypoglycemia, the 3-year cumulative incidence of coronary heart disease was 10.8% and of mortality was 28.3%. After adjustment, severe hypoglycemia was associated with coronary heart disease (hazard ratio [HR] 2.02, 95% CI 1.27-3.20), all-cause mortality (HR 1.73, 95% CI 1.38-2.17), cardiovascular mortality (HR 1.64, 95% CI 1.15-2.34), and cancer mortality (HR 2.49, 95% CI 1.46-4.24). Hypoglycemia was not associated with stroke, heart failure, atrial fibrillation, or noncardiovascular and noncancer death. Results were robust within subgroups defined by age, sex, race, diabetes duration, and baseline cardiovascular risk.

CONCLUSIONS

Severe hypoglycemia is clearly indicative of declining health and is a potent marker of high absolute risk of cardiovascular events and mortality.

The Infamous, Famous Sulfonylureas and Cardiovascular Safety: Much Ado About Nothing?

PURPOSE OF REVIEW

Sulfonylureas (SUs) are one of the most commonly used glucose-lowering agents worldwide. While their efficacy is undisputed, their cardiovascular safety has been debated since the 1970's.

RECENT FINDINGS

With no dedicated cardiovascular studies to definitively answer this question, observational studies and meta-analyses abound and have reported divergent results, fueling the controversy. Studies that compared SUs to metformin or newer agents, like GLP-1 agonists and SGLT2 inhibitors, suggest a difference in cardiovascular events, yet this is likely the result of beneficial effects of the latter. Studies comparing SUs to other agents have been reassuring. SUs remain a common choice of treatment for patients with type 2 diabetes due to their exceptional value. They are effective at lowering glucose and thus contributing to the prevention of microvascular complications. Weight gain and hypoglycemia are their main side effects, although less severe when compared to insulin treatment. Their cardiovascular safety will remain a controversial topic due to lack of conclusive data, but there is no definitive evidence of harm with the second-generation agents.

Comparison of non-traditional biomarkers, and combinations of biomarkers, for vascular risk prediction in people with type 2 diabetes: The Edinburgh Type 2 Diabetes Study

BACKGROUND AND AIMS

We aimed at comparing the impact of multiple non-traditional biomarkers (ankle brachial pressure index (ABI), N-terminal pro-brain natriuretic peptide (NT-proBNP), high sensitivity cardiac troponin (hs-cTnT), gamma-glutamyl transpeptidase (GGT) and four markers of systemic inflammation), both individually and in combination, on cardiovascular risk prediction, over and above traditional risk factors incorporated in the QRISK2 score, in older people with type 2 diabetes.

METHODS

We conducted a prospective study of 1066 men and women aged 60-75 years with type 2 diabetes mellitus, living in Lothian, Scotland.

RESULTS

After 8 years, 205 cardiovascular events occurred. Higher levels of hs-cTNT and NT-proBNP and lower ABI at baseline were associated with increased risk of CV events, independently of traditional risk factors (basic model). The C statistic of 0.722 (95% CI 0.681, 0.763) for the basic model increased on addition of individual biomarkers, most markedly for hs-cTnT (0.732; 0.690, 0.774)). Models including different combinations of biomarkers had even greater C statistics, with the highest for ABI, hs-cTnT and GGT combined (0.740; 0.699, 0.781).

CONCLUSIONS

Individually, hs-cTnT appeared to be the most promising biomarker in terms of improving vascular risk prediction in people with type 2 diabetes, over and above traditional risk factors incorporated in the QRISK2 score. Combining several non-traditional biomarkers added further predictive value, and this approach merits further investigation when developing cost effective risk prediction tools for use in clinical practice.

Association between mild and severe hypoglycemia in people with type 2 diabetes initiating insulin

AIMS

Primary objective: Identify risk factors associated with severe hypoglycemia (SH) and investigate the association between mild hypoglycemia and SH in people with type 2 diabetes starting insulin. Secondary objectives: Investigate the association of demographics and clinical factors with SH incidence.

METHODS

Integrated trial database data were obtained for 3 randomized controlled trials that included insulin-naïve people with type 2 diabetes initiating basal (insulin glargine) versus biphasic (insulin lispro mixture) insulin. Standard definitions were used for SH; mild hypoglycemia was defined as all non-SH. Cox regression identified risk factors associated with SH and the correlation between SH and mild hypoglycemia.

RESULTS

Data were pooled (N=2931). During 24-48weeks' treatment, 2127 (72.6%) participants experienced ≥1 mild hypoglycemic event but no SH (mean mild hypoglycemia rate=2.33/month). 56 participants (1.9%) experienced ≥1 SH event plus mild hypoglycemia (mean mild hypoglycemia rate=3.95/month); 748 participants (25.5%) had no hypoglycemia. Among factors tested, only mild hypoglycemia rate/month was associated with SH. SH risk was higher (HR=4.24; 95%CI=2.57-6.99;p<0.0001) for participants experiencing multiple mild hypoglycemic events/month compared with those experiencing ≤1 mild hypoglycemic event/month.

CONCLUSIONS

Mild hypoglycemia may predict the first SH event, which is important because SH is a strong and consistent risk factor for morbidity/mortality.

Transfer factor for carbon monoxide in patients with COPD and diabetes: results from the German COSYCONET cohort

Background

An impairment of CO diffusing capacity has been shown in diabetic patients without lung disease. We analyzed how diffusing capacity in patients with COPD is affected by the concurrent diagnosis of diabetes.

Methods

Data from the initial visit of the German COPD cohort COSYCONET were used for analysis. 2575 patients with complete lung function data were included, among them 358 defined as diabetics with a reported physician diagnosis of diabetes and/or specific medication. Pairwise comparisons between groups and multivariate regression models were used to identify variables predicting the CO transfer factor (TLCO%pred) and the transfer coefficient (KCO%pred).

Results

COPD patients with diabetes differed from those without diabetes regarding lung function, anthropometric, clinical and laboratory parameters. Moreover, gender was an important covariate. After correction for lung function, gender and body mass index (BMI), TLCO%pred did not significantly differ between patients with and without diabetes. The results for the transfer coefficient KCO were similar, demonstrating an important role of the confounding factors RV%pred, TLC%pred, ITGV%pred, FEV₁%pred, FEV₁/FVC, age, packyears, creatinine and BMI. There was not even a tendency towards lower values in diabetes.

Conclusion

The analysis of data from a COPD cohort showed no significant differences of CO transport parameters between COPD patients with and without diabetes, if BMI, gender and the reduction in lung volumes were taken into account. This result is in contrast to observations in lung-healthy subjects with diabetes and raises the question which factors, among them potential anti-inflammatory effects of anti-diabetes medication are responsible for this finding.

Understanding the impact of hypoglycemia on the cardiovascular system

INTRODUCTION

Hypoglycemia occurs commonly in insulin requiring individuals with either Type 1 or Type 2 Diabetes.

AREAS COVERED

This article will review recent information on the pro-inflammatory and pro-atherothrombotic effects of hypoglycemia. Additionally, effects of hypoglycemia on arrhythmogenic potential and arterial endothelial dysfunction will be discussed. Effects of hypoglycemia on cardiovascular morbidity and mortality from large clinical studies in Type 1 and Type 2 DM will also be reviewed.

EXPERT COMMENTARY

The relative and absolute risk of severe hypoglycemia leading to death and serious adverse events in both cardiovascular and other organ systems has been highlighted following the publication of recent large clinical trials focused on glucose control and outcomes. It would be helpful if future studies could develop broader end points to include minor and moderate hypoglycemia as well as more robust methods for capturing hypoglycemia contemporaneously with adverse events. In addition, perhaps consideration of including hypoglycemia as a primary outcome, may help identify the possible cause and effect of hypoglycemia on cardiovascular morbidity and mortality.

Dynamin-related protein 1 mediates low glucose-induced endothelial dysfunction in human arterioles

Intensive glycemic regulation has resulted in an increased incidence of hypoglycemia. Hypoglycemic burden correlates with adverse cardiovascular complications and contributes acutely and chronically to endothelial dysfunction. Prior data indicate that mitochondrial dysfunction contributes to hypoglycemia-induced endothelial dysfunction, but the mechanisms behind this linkage remain unknown. We attempt to determine whether clinically relevant low-glucose (LG) exposures acutely induce endothelial dysfunction through activation of the mitochondrial fission process. Characterization of mitochondrial morphology was carried out in cultured endothelial cells by using confocal microscopy. Isolated human arterioles were used to explore the effect LG-induced mitochondrial fission has on the formation of detrimental reactive oxygen species (ROS), bioavailability of nitric oxide (NO), and endothelial-dependent vascular relaxation. Fluorescence microscopy was employed to visualize changes in mitochondrial ROS and NO levels and videomicroscopy applied to measure vasodilation response. Pharmacological disruption of the profission protein Drp1 with Mdivi-1 during LG exposure reduced mitochondrial fragmentation among vascular endothelial cells (LG: 0.469; LG+Mdivi-1: 0.276; P = 0.003), prevented formation of vascular ROS (LG: 2.036; LG+Mdivi-1: 1.774; P = 0.005), increased the presence of NO (LG: 1.352; LG+Mdivi-1: 1.502; P = 0.048), and improved vascular dilation response to acetylcholine (LG: 31.6%; LG+Mdivi-1; 78.5% at maximum dose; P < 0.001). Additionally, decreased expression of Drp1 via siRNA knockdown during LG conditions also improved vascular relaxation. Exposure to LG imparts endothelial dysfunction coupled with altered mitochondrial phenotypes among isolated human arterioles. Disruption of Drp1 and subsequent mitochondrial fragmentation events prevents impaired vascular dilation, restores mitochondrial phenotype, and implicates mitochondrial fission as a primary mediator of LG-induced endothelial dysfunction.NEW & NOTEWORTHY Acute low-glucose exposure induces mitochondrial fragmentation in endothelial cells via Drp1 and is associated with impaired endothelial function in human arterioles. Targeting of Drp1 prevents fragmentation, improves vasofunction, and may provide a therapeutic target for improving cardiovascular complications among diabetics.Listen to this article's corresponding podcast @ http://ajpheart.podbean.com/e/mitochondrial-dynamics-impact-endothelial-function/.