Hypoglycemia-induced blood pressure elevation in patients with diabetes

Exosome-Enriched Plasma Analysis as a Tool for the Early Detection of Hypertensive Gestations

Hypertensive disorders of pregnancy are closely associated with prematurity, stillbirth, and maternal morbidity and mortality. The onset of hypertensive disorders of pregnancy (HDP) is generally noticed after the 20th week of gestation, limiting earlier intervention. The placenta is directly responsible for modulating local and systemic physiology by communicating using mechanisms such as the release of extracellular vesicles, especially exosomes. In this study, we postulated that an analysis of exosome-enriched maternal plasma could provide a more focused and applicable approach for diagnosing HDP earlier in pregnancy. Therefore, the peripheral blood plasma of 24 pregnant women (11 controls, 13 HDP) was collected between 20th and 24th gestational weeks and centrifuged for exosome enrichment. Exosome-enriched plasma samples were analyzed by Raman spectroscopy and by proton nuclear magnetic resonance metabolomics (¹H NMR). Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were used to analyze the Raman data, from the spectral region of 600–1,800 cm^–1, to determine its potential to discriminate between groups. Using principal component analysis, we were able to differentiate the two groups, with 89% of all variances found in the first three principal components. In patients with HDP, most significant differences in Raman bands intensity were found for sphingomyelin, acetyl CoA, methionine, DNA, RNA, phenylalanine, tryptophan, carotenoids, tyrosine, arginine, leucine, amide I and III, and phospholipids. The ¹H NMR analysis showed reduced levels of D-glucose, L-proline, L-tyrosine, glycine, and anserine in HDP, while levels of 2-hydroxyvalerate, polyunsaturated fatty acids, and very-low-density lipoprotein (VLDL) were increased. ¹H NMR results were able to assign an unknown sample to either the control or HDP groups at a precision of 88.3% using orthogonal partial least squares discriminant analysis and 87% using logistic regression analysis. Our results suggested that an analysis of exosome-enriched plasma could provide an initial assessment of placental function at the maternal-fetal interface and aid HDP diagnosis, prognosis, and treatment, as well as to detect novel, early biomarkers for HDP.

Characteristics of patients with hypertension in a population with type 2 diabetes mellitus. Results from the Turkish Nationwide SurvEy of Glycemic and Other Metabolic Parameters of Patients with Diabetes Mellitus (TEMD Hypertension Study)

BACKGROUND

The present survey aimed to find out the demographical and clinical characteristics of patients with hypertension in a population with type 2 diabetes mellitus (T2DM) in Turkey.

METHODS

Patients with T2DM who were followed-up in tertiary endocrine units for at least last one year were recruited. Demographic, clinical and biochemical data of the patients were collected. Hypertension was defined as taking anti-hypertensive medications or having office arterial blood pressure (ABP) ≥140/90 mmHg or home ABP ≥ 130/80 mmHg.

RESULTS

A total of 4756 (58.9% women) diabetic patients were evaluated. The percentage of patients with hypertension was 67.5% (n = 3212). Although 87.4% (n = 2808) of hypertensive patients were under treatment, blood pressure was on target in 52.7% (n = 1479) of patients. Hypertension proportions were higher in woman (p = 0.001), older, more obese, and those who had longer diabetes duration, lower education levels, higher frequency of hypoglycemic events (all p < 0.001) and higher triglyceride levels (p = 0.003). LDL cholesterol level and the percentage of smokers were lower in hypertensive group than in non-hypertensive group (both p < 0.001). The percentage of macro and microvascular complications was higher in the hypertensive group than in the normotensive one (both p < 0.001). In multivariate logistic regression analysis, being a woman (OR: 1.26, 95% CI: 1.04-1.51, p = 0.016), smoking (OR: 1.38, 95% CI: 1.05-1.80, p = 0.020), regular physical activity (OR: 1.24, 95% CI: 1.01-1.53, p = 0.039) and the presence of macrovascular complications (OR: 1.38 95% CI: 1.15-1.65, p = 0.001) were the significant predictors of good ABP regulation. The ratios of masked and white coat hypertension were 41.2% and 5.7%, respectively.

CONCLUSION

Our findings indicate that two-thirds (67.5%) of adult patients with T2DM have hypertension. Co-existence of hypertension increases the frequency of macro and microvascular diabetic complications in these patients. Despite the critical role of hypertension in morbidity and mortality, only half of the patients have favorable ABP levels. Masked hypertension seems to be another important issue in this population.

Role of carnitine in regulation of blood pressure (MAP/SBP) and gene expression of cardiac hypertrophy markers (α/β-MHC) during insulin-induced hypoglycaemia: Role of oxidative stress

Cardiovascular disease is a leading cause of death in diabetic patients. Hyperglycaemia and iatrogenic hypoglycaemia exacerbate several pathogenic mechanisms underlying hypertension and heart diseases. Carnitine is a potent endogenous antioxidant and cellular fatty acid transporter for antioxidative stress and energy production in the cardiovascular system. The current study aimed to find the role of carnitine in the regulation of hypoglycaemia-induced hypertension and cardiac hypertrophy. Male rats received insulin glargine (InG) to induce hypoglycaemia followed by D-carnitine or acetyl-L-carnitine for carnitine depletion or carnitine supplementation, respectively. The obtained results showed that carnitine deficiency provoked hypoglycaemia-induced hypertension. Mean arterial pressure was elevated from 78.16 ± 11.4 to 100 ± 5.11 mm Hg in InG treated group, and from 78.2 ± 8.5 to 123.4 ± 28.2 mm Hg in InG + D-carnitine treated group. Acetyl-L-carnitine resisted the elevation in blood pressure in all hypoglycaemic animals and kept it within the normal values (68.33 ± 6.7 mm Hg). Acetyl-L-carnitine increased myocardial carnitine content leading to the attenuation of hypoglycaemia-induced oxidative stress, which was evaluated through measurement of the oxidative stress biomarkers such as inducible nitric oxide synthase, NAD(P)H quinone dehydrogenase-1, heme oxygenase-I, and glutathione S-transferase. Moreover, acetyl-L-carnitine prevented induction of gene expression of cardiac hypertrophy markers during hypoglycaemic conditions, which was assessed via the evaluation of mRNA expression of α-myosin heavy chain and β-myosin heavy chain. These findings demonstrate that carnitine might play an essential role in prevention of hypoglycaemia-induced hypertension and cardiac hypertrophy through providing energy and antioxidants to the cardiovascular system.

Glycopenia - induced sympathoadrenal activation in diabetes mellitus and uncontrolled arterial hypertension: an observational study

BACKGROUND

Aim of this study is to investigate a possible association of hypoglycemic episodes and arterial hypertension. We hypothesize that hospitalized insulin-treated diabetes patients with hypertensive crisis have more hypoglycemic episodes than their counterparts without hypertensive crisis on admission.

METHODS

In a prospective, observational cohort study, 65 insulin-treated diabetes patients (type 1, type 2, type 3c) were included in Group 1, when a hypertensive crisis was present, as control patients in Group 2 without hypertensive crisis or hypoglycemia, in Group 3, when a symptomatic hypoglycemia was present on admission. All patients were subjected to open-label continuous glucose monitoring, 24-h blood-pressure- and Holter electrocardiogram recordings, and to laboratory tests including plasma catecholamines.

RESULTS

53 patients, thereof 19 Group-1, 19 Group-2, 15 Group-3 patients, completed this study. Group-1 patients had the highest maximum systolic blood pressure, a higher daily cumulative insulin dose at admission, a higher body-mass index, and a higher plasma norepinephrine than control patients of Group 2. Group-3 patients had more documented hypoglycemic episodes (0.8 ± 0.5 per 24 h) than Group-2 patients (0.2 ± 0.3 per 24 h), however, they were not different to the ones in Group-1 patients (0.4 ± 0.4 per 24 h). Plasma norepinephrine and mean arterial blood pressure were higher Group-1 and Group-3 patients than in control patients of Group 2. At discharge, the daily cumulative insulin dose was reduced in Group-1 (- 18.4 ± 24.9 units) and in Group-3 patients (- 18.6 ± 22.7 units), but remained unchanged in Group-2 control patients (- 2.9 ± 15.6 units).

CONCLUSIONS

An association between hypoglycemic events and uncontrolled hypertension was found in this study.

Measurement and Clinical Significance of Lipid Peroxidation as a Biomarker of Oxidative Stress: Oxidative Stress in Diabetes, Atherosclerosis, and Chronic Inflammation

Endothelial dysfunction is one of the initial steps in the pathogenesis of atherosclerosis and development of cardiovascular disease in patients with diabetes mellitus. Several risk factors are associated with endothelial dysfunction and atherosclerosis, such as hypertension, dyslipidaemia, inflammation, oxidative stress, and advanced glycation-end products. Among these risk factors, oxidative stress is the largest contributor to the formation of atherosclerotic plaques. Measurement of reactive oxygen species (ROS) is still difficult, and assays for the measurement of ROS have failed to show a consistent correlation between pathological states and oxidative stress. To solve this problem, this review summarizes the current knowledge on biomarkers of oxidative stress, especially lipid peroxidation, and discusses the roles of oxidative stress, as measured by indices of lipid peroxidation, in diabetes mellitus, atherosclerosis, and chronic inflammation.

Changes in Serum Electrolytes, ECG, and Baroreflex Sensitivity during Combined Pituitary Stimulation Test

The mechanisms by which hypoglycemia increases cardiovascular mortality remain unclear. The aim of the study is to investigate changes in serum electrolytes, norepinephrine concentrations, electrocardiography, and baroreflex sensitivity (BRS) and associations between corrected QT (QTc) intervals and the changes in serum electrolytes during combined pituitary stimulation test (CPST). We recruited the subjects who were admitted to the Gyeongsang National University Hospital to undergo CPST between September 2013 and December 2014. Participants were 12 patients suspected of having hypopituitarism. Among 12 patients, cardiac arrhythmia in two patients occurred during hypoglycemia. There were significant differences in serum levels of potassium (P < 0.001), sodium (P = 0.003), chloride (P = 0.002), and calcium (P = 0.017) at baseline, hypoglycemia, and 30 and 120 minutes after hypoglycemia. Also, there was a significant increase in heart rate (P = 0.004), corrected QT (QTc) interval (P = 0.008), QRS duration (P = 0.021), and BRS (P = 0.005) at hypoglycemia, compared to other time points during CPST. There was a positive association between QTc intervals and serum sodium levels (P < 0.001) in 10 patients who did not develop arrhythmia during CPST. This study showed that there were significant changes in serum levels of potassium, sodium, chloride, and calcium, as well as heart rate, QTc interval, QRSd, and BRS during CPST. It was revealed that QTc intervals had a significant association with concentrations of sodium.

Risk of Cardiovascular Events in Patients With Diabetes Mellitus on β-Blockers

Although the use of β-blockers may help in achieving maximum effects of intensive glycemic control because of a decrease in the adverse effects after severe hypoglycemia, they pose a potential risk for the occurrence of severe hypoglycemia. This study aimed to evaluate whether the use of β-blockers is effective in patients with diabetes mellitus and whether its use is associated with the occurrence of severe hypoglycemia. Using the ACCORD trial (Action to Control Cardiovascular Risk in Diabetes) data, we performed Cox proportional hazards analyses with a propensity score adjustment. The primary outcome was the first occurrence of a cardiovascular event during the study period, which included nonfatal myocardial infarction, unstable angina, nonfatal stroke, and cardiovascular death. The mean follow-up periods (±SD) were 4.6±1.6 years in patients on β-blockers (n=2527) and 4.7±1.6 years in those not on β-blockers (n=2527). The cardiovascular event rate was significantly higher in patients on β-blockers than in those not on β-blockers (hazard ratio, 1.46; 95% confidence interval, 1.24-1.72; P<0.001). In patients with coronary heart disease or heart failure, the cumulative event rate for cardiovascular events was also significantly higher in those on β-blockers than in those not on β-blockers (hazard ratio, 1.27; 95% confidence interval, 1.02-1.60; P=0.03). The incidence of severe hypoglycemia was significantly higher in patients on β-blockers than in those not on β-blockers (hazard ratio, 1.30; 95% confidence interval, 1.03-1.64; P=0.02). In conclusion, the use of β-blockers in patients with diabetes mellitus was associated with an increased risk for cardiovascular events.

Direct effects of glucose, insulin, GLP-1, and GIP on bulbospinal neurons in the rostral ventrolateral medulla in neonatal wistar rats

Although patients with diabetes mellitus (DM) often exhibit hypertension, the mechanisms responsible for this correlation are not well known. We hypothesized that the bulbospinal neurons in the rostral ventrolateral medulla (RVLM) are affected by the levels of glucose, insulin, or incretins (glucagon like peptide-1 [GLP-1] or glucose-dependent insulinotropic peptide [GIP]) in patients with DM. To investigate whether RVLM neurons are activated by glucose, insulin, GLP-1, or GIP, we examined changes in the membrane potentials of bulbospinal RVLM neurons using whole-cell patch-clamp technique during superfusion with various levels of glucose or these hormones in neonatal Wistar rats. A brainstem-spinal cord preparation was used for the experiments. A low level of glucose stimulated bulbospinal RVLM neurons. During insulin superfusion, almost all the RVLM neurons were depolarized, while during GLP-1 or GIP superfusion, almost all the RVLM neurons were hyperpolarized. Next, histological examinations were performed to examine transporters for glucose and receptors for insulin, GLP-1, and GIP on RVLM neurons. Low-level glucose-depolarized RVLM neurons exhibited the presence of glucose transporter 3 (GLUT3). Meanwhile, insulin-depolarized, GLP-1-hyperpolarized, and GIP-hyperpolarized RVLM neurons showed each of the respective specific receptor. These results indicate that a low level of glucose stimulates bulbospinal RVLM neurons via specific transporters on these neurons, inducing hypertension. Furthermore, an increase in insulin or a reduction in incretins may also activate the sympathetic nervous system and induce hypertension by activating RVLM neurons via their own receptors.

Intensive Glycemic Therapy in Patients With Type 2 Diabetes on β-Blockers

OBJECTIVE

Recent studies have suggested that β-blockers may decrease the adverse influence of hypoglycemia and reduce hypoglycemia-associated cardiac arrhythmias and death. We evaluated whether intensive glycemic therapy in patients with diabetes receiving treatment with β-blockers showed beneficial effects for the prevention of cardiovascular events without increased mortality compared with a standard glycemic therapy.

RESEARCH DESIGN AND METHODS

We used Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial data to assess the risks of cardiovascular events, all-cause death, and cardiovascular death in patients with diabetes receiving treatment with β-blockers (n = 3,079) and not receiving treatment with β-blockers (n = 7,145) using Cox proportional hazard models.

RESULTS

In patients receiving treatment with β-blockers, the cumulative event rates for cardiovascular events were significantly lower in the intensive therapy group compared with the standard therapy group (hazard ratio [HR] 0.81; 95% CI 0.67-0.97; P = 0.02), whereas those rates in patients not receiving treatment with β-blockers were not significantly different (HR 0.92; 95% CI 0.78-1.09; P = 0.36). Conversely, the cumulative event rates for all-cause and cardiovascular deaths in patients receiving treatment with β-blockers were not significantly different between the standard therapy and intensive therapy groups (all-cause death: HR 1.08; 95% CI 0.83-1.42; P = 0.54; cardiovascular death: HR 1.05; 95% CI 0.72-1.51; P = 0.79), whereas in patients not receiving treatment with β-blockers, the event rates were significantly higher in the intensive therapy group compared with the standard therapy group (all-cause death: HR 1.25; 95% CI 1.02-1.52; P = 0.02; cardiovascular death: HR 1.43; 95% CI 1.03-1.98; P = 0.03).

CONCLUSIONS

Intensive glycemic therapy may be effective in patients with type 2 diabetes receiving treatment with β-blockers.

Accelerated decline of renal function in type 2 diabetes following severe hypoglycemia

AIMS

This study aimed to evaluate whether the pronounced elevation in blood pressure during severe hypoglycemia is associated with subsequent renal insufficiency.

METHODS

We conducted a 3-year cohort study to assess the clinical course of renal function in type 2 diabetes patients with or without blood pressure surge during severe hypoglycemia.

RESULTS

Of 111 type 2 diabetes patients with severe hypoglycemia, 76 exhibited an extremely high systolic blood pressure before treatment, whereas 35 demonstrated no such increase (179.1 ± 27.7 mmHg vs. 131.1 ± 20.2 mmHg, P<0.001). At 12h after treatment, systolic blood pressure did not differ significantly (131.5 ± 30.7 mmHg vs. 123.5 ± 20.7 mmHg; P=0.39). The estimated glomerular filtration rate (GFR) before and at the time of severe hypoglycemia did not significantly differ between both groups. A multivariate Cox proportional hazards regression analysis revealed that blood pressure surge during severe hypoglycemia was independently associated with a composite outcome of a more than 15 mL/min/1.73 m(2) decrease in the estimated GFR and initiation of chronic dialysis (hazard ratio, 2.68; 95% confidence interval, 1.12-6.38; P=0.02).

CONCLUSIONS

Renal function after severe hypoglycemia was significantly worse in type 2 diabetes patients with blood pressure surge during severe hypoglycemia than those without blood pressure surge.

Effectiveness of Prior Use of Beta-Blockers for Preventing Adverse Influences of Severe Hypoglycemia in Patients With Diabetes: An Observational Study

The study aimed to identify predictors of severe acute hypertension (≥ 180/110 mmHg) during severe hypoglycemia and to assess the efficacy of prior use of catecholamine-blocking agents for preventing adverse influences in diabetic patients with severe hypoglycemia. We performed a retrospective study between January 2006 and March 2012 to assess diabetic patients with severe hypoglycemia at a single center in Japan. Severe hypoglycemia was defined as the presence of any hypoglycemic symptoms that required the medical assistance of another person after visiting the emergency room by ambulance. Multivariate logistic regression analysis was performed to identify possible predictors of severe hypertension due to severe hypoglycemia and to assess whether prior use of alpha- or beta-blockers is beneficial for the prevention of severe hypertension in diabetic patients with severe hypoglycemia. Multivariate adjustments were made for age, sex, preexisting hypertension, history of ischemic heart disease, blood glucose level upon arrival, estimated GFR, and prior use of alpha- or beta-blockers. A total of 59,602 patients who visited the emergency room were screened and 352 diabetic patients with severe hypoglycemia were enrolled. Incidences of severe hypertension before and at 3 and 6 hours after the initiation of antihypoglycemic treatment were 21.3%, 6.7%, and 0% in patients with type 1 diabetes (n = 61) and 38.8%, 18.2%, and 8.2% in patients with type 2 diabetes (n = 291), respectively. Aging was positively (odds ratio [OR], 1.02; 95% confidence interval [CI], 1.00-1.03; P = 0.02) and female sex was negatively (OR, 0.50; 95% CI, 0.29-0.86; P = 0.01) associated with occurrence of severe hypertension during severe hypoglycemia. In addition, prior use of beta-blockers was negatively associated with occurrence of severe hypertension during severe hypoglycemia using multivariate logistic regression analysis (OR, 0.31; 95% CI, 0.11-0.83; P = 0.02). None of the patients with prior use of beta-blockers had hypokalemia (<3.0 mEq/L). Prior use of beta-blockers may prevent adverse influences such as severe hypertension and hypokalemia during severe hypoglycemia in diabetic patients.

Influence of pulse pressure and spontaneous variations of macular thickness in patients with diabetic macular oedema

PURPOSE

To study spontaneous variations of central macular thickness (CMT) and its relation to blood pressure (BP) in patients with diabetic macular oedema (DME).

METHODS

23 diabetic patients presenting with DME with a CMT ≥ 260 μm on optical coherence tomography (OCT-3, Carl Zeiss Meditec, CA) were followed every 2 weeks for 3 months. At baseline, ambulatory 24H-BP monitoring (ABPM) was performed, as well as five CMT measurements (9 am, 12 am, 3 pm, 6 pm and 9 am the day after). During follow-up, BP and CMT were simultaneously measured at 9 am.

RESULTS

Significant spontaneous variations in CMT (at least one change in CMT greater than 11% compared to the median CMT value) were observed over 3 months in 48% of patients. Mean CMT decreased over the day and increased during the night, but not significantly (p = 0.1). During the 6 visits, the CMT at 9 am positively correlated with the pulse pressure (PP) measured at the same time (r = 0.29, p = 0.0008). In addition, the mean 24H-CMT was positively correlated with the mean 24H- PP (r = 0.48, p = 0.02).

CONCLUSION

Significant spontaneous changes in CMT of patients with DME were observed in nearly half of cases over 3 months. Retinal thickness was correlated to PP levels (patients with higher CMT had higher PP levels). This high variability of macular oedema, and the influence of BP on retinal thickness, should be taken into consideration by practitioners when evaluating the benefit of a therapy in DME.

Severe hypoglycaemia requiring emergency medical assistance by ambulance services in the East Midlands: a retrospective study

AIMS

To report the characteristics and treatment of individuals requiring emergency ambulance services for severe hypoglycaemia and estimate associated provider costs.

METHODS

Retrospective analysis of routinely collected data collected by the East Midlands Ambulance Trust, UK, of episodes of severe hypoglycaemia attended by emergency ambulance services during a four-month period. Standard clinical measures, response time, on-site treatment and transportation were recorded and ambulance services costs calculated.

RESULTS

90,435 emergency calls were recorded, 523 (0.6%) for severe hypoglycaemia, equating to an incidence of to 2.76 per 100 patient years; 74% of individuals were insulin-treated, 28% of events occurred nocturnally (00:00-07:59), and 32% were transported to hospital. Higher respiratory rate was a positive predictor (p=0.03), whereas higher post treatment blood glucose (p=0.05) and insulin treatment (p<0.01) were negative predictors of transport to hospital. Median treatment costs for individuals transported and not transported to hospital were £92 and £176 respectively.

CONCLUSIONS

Most cases of severe hypoglycaemia requiring assistance from emergency ambulance services are successfully treated at the scene. Individuals not responding to treatment or were non insulin-treated were more likely to be transported to hospital. Further studies are needed to evaluate the effect of prehospital ambulance care by treatment and diabetes type on subsequent outcomes.

Hypoglycaemia is associated with the absence of a decrease in diurnal macular thickness in patients with diabetic macular oedema

AIM

Spontaneous diurnal variations measured by optical coherence tomography (OCT) have been reported in diabetic macular oedema (DME) together with a daytime decrease in central macular thickness (CMT). For this reason, this study aimed to investigate the influence of acute glucose and blood pressure changes on daytime variations in CMT in patients with DME.

METHODS

In this prospective observational study of type 1 (n=4) and type 2 (n=18) diabetic patients with DME, OCT scans, capillary blood glucose, and systolic and diastolic blood pressure measurements were performed at 9 a.m., 12 a.m., 3 p.m., 6 p.m. and again at 9 a.m. the day after. At the same time, the study protocol included simultaneous ambulatory blood pressure and glucose monitoring over a 24-h period. Hypoglycaemic episodes, defined as glucose values<60mg/dL, were also recorded.

RESULTS

CMT decreased consistently between 9 a.m. and 6 p.m. in 10 patients (from 374±82μm to 337±72μm; P=0.01) and increased or remained steady in 12 others (from 383±136μm to 390±149μm; P=0.58), with a significant difference in CMT absolute change between the two groups (P<0.001). In the study population as a whole, the lower the mean diurnal blood glucose, the smaller the decrease in CMT during the day (P=0.027). Also, eight (67%) of the 12 patients with a flat CMT profile experienced a diurnal hypoglycaemic event whereas none of those with a CMT decrease had hypoglycaemia (P=0.002).

CONCLUSION

Hypoglycaemic events may explain the lack of diurnal CMT decrease in diabetic patients with DME. However, further studies need to be conducted to evaluate whether having no diurnal CMT decrease is associated with a poorer visual prognosis and whether it can be modified by better glucose control.

Hypoglycemia revisited in the acute care setting

Hypoglycemia is a common finding in both daily clinical practice and acute care settings. The causes of severe hypoglycemia (SH) are multi-factorial and the major etiologies are iatrogenic, infectious diseases with sepsis and tumor or autoimmune diseases. With the advent of aggressive lowering of HbA1c values to achieve optimal glycemic control, patients are at increased risk of hypoglycemic episodes. Iatrogenic hypoglycemia can cause recurrent morbidity, sometime irreversible neurologic complications and even death, and further preclude maintenance of euglycemia over a lifetime of diabetes. Recent studies have shown that hypoglycemia is associated with adverse outcomes in many acute illnesses. In addition, hypoglycemia is associated with increased mortality among elderly and non-diabetic hospitalized patients. Clinicians should have high clinical suspicion of subtle symptoms of hypoglycemia and provide prompt treatment. Clinicians should know that hypoglycemia is associated with considerable adverse outcomes in many acute critical illnesses. In order to reduce hypoglycemia-associated morbidity and mortality, timely health education programs and close monitoring should be applied to those diabetic patients presenting to the Emergency Department with SH. ED disposition strategies should be further validated and justified to achieve balance between the benefits of euglycemia and the risks of SH. We discuss relevant issues regarding hypoglycemia in emergency and critical care settings.

Acute consequences of hypoglycaemia in diabetic patients

Strict glycaemic control is a major concern in many people with diabetes, hypoglycaemia being the most limiting factor in the daily management of patients with diabetes. Acute consequences of hypoglycaemic attacks are not precisely evaluated. Acute cardiovascular (CV) complications as myocardial ischaemia or stroke seem to be rare, but possibly ignored mainly in older frail patients. Recent large trials in type 2 diabetic patients have not shown the anticipated mortality benefits of strict glycaemic control, and reported a higher frequency of severe hypoglycaemia in the intensive treatment arms with an excess of CV deaths. The authors of these trials persist to deny a direct link between CV deaths and hypoglycaemia. In young type 1 diabetics "dead in bed" syndrome represents a rare but devastating consequence probably due to arrhythmia and prolonged QTc interval. Driving mishaps represent another complication but with a controversial frequency. Neurologic syndromes are frequent during severe hypoglycaemia but usually reversible. Major brain damages are scarce, but cognitive defects or dementia should be underestimated in older and frail type 2 diabetics. Thus, iatrogenic hypoglycaemia due to insulin or sulphonylureas may cause recurrent morbidity in type 1 and type 2 diabetic subjects, and should be prevented by a reevaluation of glycaemic targets in some patients, patient education and the use of new antidiabetic drugs without hypoglycaemic risk.

Repeated episodes of hypoglycemia as a potential aggravating factor for preclinical atherosclerosis in subjects with type 1 diabetes

OBJECTIVE

To evaluate through early preclinical atherosclerosis assessment whether repeated episodes of hypoglycemia represent an aggravating factor for macrovascular disease in type 1 diabetes.

RESEARCH DESIGN AND METHODS

After sample-size calculation, a case-control study of 25 patients with type 1 diabetes and repeated severe/nonsevere hypoglycemia (H-group) compared with 20 age- and sex-matched type 1 diabetes control subjects (C-group) was designed. Assessment of preclinical atherosclerosis consisted of flow-mediated brachial dilatation (FMD) and carotid and femoral intima-media thickness (IMT) studies. To consider hypoglycemia awareness, two different questionnaires and symptomatic response to an acute induction to hypoglycemia were used. Evaluation of the glycemic profile was obtained from continuous glucose monitoring. Endothelial function/inflammation markers were measured in euglycemia/hypoglycemia. A multivariate linear regression analysis was performed to test whether repeated hypoglycemia was independently associated with atherosclerosis.

RESULTS

H-group subjects displayed hypoglycemia unawareness and presented a higher percentage of continuous glucose values and area under the curve <70 mg/dl compared with the C-group (14.2 ± 8.9 vs. 6.3 ± 7.1%, P < 0.02 and 2.4 ± 1.8 vs. 0.6 ± 1.0 mg/dl/day, P < 0.01). The percentage of maximal FMD was lower in the H-group than in the C-group (6.52 ± 2.92 vs. 8.62 ± 3.13%, P < 0.05). A significantly higher IMT was observed at both carotid and femoral sites in the H-group (carotid 0.53 ± 0.09 vs. 0.47 ± 0.08 mm, P < 0.05 and femoral 0.51 ± 0.17 vs. 0.39 ± 0.09 mm, P < 0.05). Baseline inflammation and endothelial function markers were higher in the H-group (leukocytes 7.0 ± 1.8 vs. 5.6 ± 1.4 × 10³/ml, von Willebrand factor 119 ± 29 vs. 93 ± 26%, fibrinogen 2.82 ± 0.64 vs. 2.29 ± 0.44 g/l, and soluble intercellular adhesion molecule-1 408 ± 224 vs. 296 ± 95 ng/ml; P < 0.05 for all).

CONCLUSIONS

In addition to the induction of hypoglycemia unawareness and an increased risk for severe hypoglycemia, repeated hypoglycemia could be related to and considered an aggravating factor for preclinical atherosclerosis in type 1 diabetes. The precise mechanisms explaining this association remain to be clarified.