Dead in bed syndrome in young diabetic patients in Norway

Dead in bed - A systematic review of overnight deaths in type 1 diabetes

BACKGROUND

Type 1 diabetes is a significant, life-long condition which affects many people worldwide. One of the most feared causes of type 1 diabetes mortality, overnight mortality, often caused by the dead in bed syndrome, is largely underreported. A systematic literature search was undertaken to understand the frequency, risk factors, causes and impact that diabetes-related technologies have on overnight mortality, in this population.

METHODS

MEDLINE (Ovid), Embase (Ovid) and Cochrane were searched to June 2021, using defined inclusion and exclusion criteria. Quality appraisal was undertaken.

RESULTS

Overall, 26 records met the inclusion criteria. Large-scale cohort studies examined data up to 2013, and there were no studies published after 2018. The proportion of deaths attributable to the dead in bed syndrome was between 2 and 5% of deaths in children, adolescents, and young adults, with a slight decrease in proportion of dead in bed syndrome since 1991.

CONCLUSION

Overnight mortality is occurring for people with type 1 diabetes, reported as recently as in 2018. Living alone, alcohol and illicit substances consistently appear as risk factors, and the impact of technology on overnight mortality is not fully understood, with more recent data, from larger cohort studies being required.

Nanotechnology in Immunotherapy for Type 1 Diabetes: Promising Innovations and Future Advances

Diabetes is a chronic condition which affects the glucose metabolism in the body. In lieu of any clinical “cure,” the condition is managed through the administration of pharmacological aids, insulin supplements, diet restrictions, exercise, and the like. The conventional clinical prescriptions are limited by their life-long dependency and diminished potency, which in turn hinder the patient’s recovery. This necessitated an alteration in approach and has instigated several investigations into other strategies. As Type 1 diabetes (T1D) is known to be an autoimmune disorder, targeting the immune system in activation and/or suppression has shown promise in reducing beta cell loss and improving insulin levels in response to hyperglycemia. Another strategy currently being explored is the use of nanoparticles in the delivery of immunomodulators, insulin, or engineered vaccines to endogenous immune cells. Nanoparticle-assisted targeting of immune cells holds substantial potential for enhanced patient care within T1D clinical settings. Herein, we summarize the knowledge of etiology, clinical scenarios, and the current state of nanoparticle-based immunotherapeutic approaches for Type 1 diabetes. We also discuss the feasibility of translating this approach to clinical practice.

Characteristics of fatal insulin overdoses

This study was undertaken to review fatal cases of insulin overdose in South Australia (SA) over a 20-year period to assess rates and characteristics of insulin-related deaths among insulin-dependent diabetics and non-diabetics for all manners of death. Records from the National Coronial Information System (NCIS) and Forensic Science SA (FSSA) were searched for all cases of fatal insulin overdose in South Australia (SA) between 2000 and 2019. Collected variables included age, sex, cause of death, scene findings, manner of death, decedent medical and personal histories, biochemistry, toxicology, histopathology, and autopsy findings. Statistical analyses were performed using R (version 4.1.2). Forty cases of insulin overdose were identified in SA between 2000 and 2019. Twenty-nine cases (72.5%) were suicides, with the remaining cases classified as accidental or undetermined intent. Thirteen of the 22 insulin-dependent diabetics (59%) had a history of depression, 10 of whom had previously demonstrated suicidal ideation. The current study has shown that suicides using insulin among insulin-dependent diabetics are equally as prevalent, if not more so than fatal accidental insulin overdoses. This can largely be attributed to insulin-dependent diabetic access to a potentially lethal substance. Suicide prevention strategies should focus on insulin-dependent diabetics with a history of depression, particularly for those with access to rapid-acting insulin.

Hypoglycaemia combined with mild hypokalaemia reduces the heart rate and causes abnormal pacemaker activity in a computational model of a human sinoatrial cell

Low blood glucose, hypoglycaemia, has been implicated as a possible contributing factor to sudden cardiac death (SCD) in people with diabetes but it is challenging to investigate in clinical studies. We hypothesized the effects of hypoglycaemia on the sinoatrial node (SAN) in the heart to be a candidate mechanism and adapted a computational model of the human SAN action potential developed by Fabbri et al., to investigate the effects of hypoglycaemia on the pacemaker rate. Using Latin hypercube sampling, we combined the effects of low glucose (LG) on the human ether-a-go-go-related gene channel with reduced blood potassium, hypokalaemia, and added sympathetic and parasympathetic stimulus. We showed that hypoglycaemia on its own causes a small decrease in heart rate but there was also a marked decrease in heart rate when combined with hypokalaemia. The effect of the sympathetic stimulus was diminished, causing a smaller increase in heart rate, with LG and hypokalaemia compared to normoglycaemia. By contrast, the effect of the parasympathetic stimulus was enhanced, causing a greater decrease in heart rate. We therefore demonstrate a potential mechanistic explanation for hypoglycaemia-induced bradycardia and show that sinus arrest is a plausible mechanism for SCD in people with diabetes.

Effect of switching from conventional continuous subcutaneous insulin infusion to sensor augmented pump therapy on glycemic profile in Japanese patients with type 1 diabetes

AIMS

Evidence suggests that sensor augmented pump (SAP) therapy is superior to conventional continuous subcutaneous insulin infusion (CSII) for achieving glycemic control in patients with type 1 diabetes. However, the clinical benefit of SAP therapy in East Asians has not yet been demonstrated.

METHODS

The effect of switching from conventional CSII to SAP therapy on glycemic profile was examined in 18 Japanese patients with type 1 diabetes. The glycemic profile of the patients was determined by retrospective continuous glucose monitoring (CGM) within 1 month before the treatment switch, whereas that at 6 and 12 months after the switch was evaluated with the CGM function of the SAP device. Hemoglobin A1c levels were also measured before and after the switch to SAP therapy.

RESULTS

The duration of hypoglycemia was significantly decreased at both 6 and 12 months after the change in treatment (6.6 ± 4.5, 3.2 ± 4.1, and 3.0 ± 2.8 min/h for before and 6 and 12 months, respectively), as was the HbA1c level at 12 months (7.8 ± 1.0 and 7.4 ± 0.9%, respectively). The duration of hyperglycemia did not differ between before and after the treatment switch. The decline in HbA1c level at 12 months after the switch to SAP was negatively correlated with age.

CONCLUSION

Switching from conventional CSII to SAP therapy was associated with a decrease in both the duration of hypoglycemia and the level of HbA1c in Japanese patients with type 1 diabetes.

The Development of New Composite Metrics for the Comprehensive Analytic and Visual Assessment of Hypoglycemia Using the Hypo-Triad

BACKGROUND

Quantifying hypoglycemia has traditionally been limited to using the frequency of hypoglycemic events during a given time interval using data from blood glucose (BG) testing. However, continuous glucose monitoring (CGM) captures three parameters-a Hypo-Triad-unavailable with BG monitoring that can be used to better characterize hypoglycemia: area under the curve (AUC), time (duration of hypoglycemia), and frequency of daily episodes below a specified threshold.

METHODS

We developed two new analytic metrics to enhance the traditional Hypo-Triad of CGM-derived data to more effectively capture the intensity of hypoglycemia (IntHypo) and overall hypoglycemic environment called the "hypoglycemia risk volume" (HypoRV). We reanalyzed the CGM data from the ASPIRE In-Home study, a randomized, controlled trial of a sensor-integrated pump system with a low glucose threshold suspend feature (SIP+TS), using these new metrics and compared them to standard metrics of hypoglycemia.

RESULTS

IntHypo and HypoRV provide additional insights into the benefit of a SIP+TS system on glycemic exposure when compared to the standard reporting methods. In addition, the visual display of these parameters provides a unique and intuitive way to understand the impact of a diabetes intervention on a cohort of subjects as well as on individual patients.

CONCLUSION

The IntHypo and HypoRV are new and enhanced ways of analyzing CGM-derived data in diabetes intervention studies which could lead to new insights in diabetes management. They require validation using existing, ongoing, or planned studies to determine whether they are superior to existing metrics.

Diurnal Differences in Risk of Cardiac Arrhythmias During Spontaneous Hypoglycemia in Young People With Type 1 Diabetes

OBJECTIVE

Hypoglycemia may exert proarrhythmogenic effects on the heart via sympathoadrenal stimulation and hypokalemia. Hypoglycemia-induced cardiac dysrhythmias are linked to the "dead-in-bed syndrome," a rare but devastating condition. We examined the effect of nocturnal and daytime clinical hypoglycemia on electrocardiogram (ECG) in young people with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Thirty-seven individuals with type 1 diabetes underwent 96 h of simultaneous ambulatory ECG and blinded continuous interstitial glucose monitoring (CGM) while symptomatic hypoglycemia was recorded. Frequency of arrhythmias, heart rate variability, and cardiac repolarization were measured during hypoglycemia and compared with time-matched euglycemia during night and day.

RESULTS

A total of 2,395 h of simultaneous ECG and CGM recordings were obtained; 159 h were designated hypoglycemia and 1,355 h euglycemia. A median duration of nocturnal hypoglycemia of 60 min (interquartile range 40-135) was longer than daytime hypoglycemia of 44 min (30-70) (P = 0.020). Only 24.1% of nocturnal and 51.0% of daytime episodes were symptomatic. Bradycardia was more frequent during nocturnal hypoglycemia compared with matched euglycemia (incident rate ratio [IRR] 6.44 [95% CI 6.26, 6.63], P < 0.001). During daytime hypoglycemia, bradycardia was less frequent (IRR 0.023 [95% CI 0.002, 0.26], P = 0.002) and atrial ectopics more frequent (IRR 2.29 [95% CI 1.19, 4.39], P = 0.013). Prolonged QTc, T-peak to T-end interval duration, and decreased T-wave symmetry were detected during nocturnal and daytime hypoglycemia.

CONCLUSIONS

Asymptomatic hypoglycemia was common. We identified differences in arrhythmic risk and cardiac repolarization during nocturnal versus daytime hypoglycemia in young adults with type 1 diabetes. Our data provide further evidence that hypoglycemia is proarrhythmogenic.

"Let the Algorithm Do the Work": Reduction of Hypoglycemia Using Sensor-Augmented Pump Therapy with Predictive Insulin Suspension (SmartGuard) in Pediatric Type 1 Diabetes Patients

BACKGROUND

A sensor-augmented insulin pump (SAP) using the MiniMed^® 640G system with SmartGuard™ technology allows an automatic stop of insulin delivery based on prediction of low glucose levels. Since pediatric patients are particularly prone to hypoglycemia, this device may offer additional protection beyond conventional sensor-augmented therapy.

METHODS

This prospective, pediatric multicenter user evaluation assessed 6 weeks of SAP with SmartGuard (threshold setting for hypoglycemia: 70 mg/dL) compared to a preceding period of 2 weeks with SAP only. The primary outcome was the potential reduction in the frequency of hypoglycemic episodes and hypoglycemic intensity (area under the curve [AUC] and time <70 mg/dL).

RESULTS

The study included 24 patients with at least 3 months of insulin pump use (average age: 11.6 ± 5.1 years, 15 female, average type 1 diabetes duration: 7.5 ± 4.2 years, mean ± SD) who had on average 3.2 ± 1.0 predictive suspensions/patient/day. The mean sensor glucose minimum during suspension was 78 ± 6 mg/dL and the average suspension time was 155 ± 47 min/day. Use of SmartGuard in patients treated as per the protocol (n = 18) reduced the number of instances in which the glucose level was <70 mg/dL (1.02 ± 0.52 to 0.72 ± 0.36; P = 0.027), as well as AUC <70 mg/dL (0.76 ± 0.73 to 0.38 ± 0.24; P = 0.027) and the time/day the level fell below 70 mg/dL (73 ± 56 to 31 ± 22 min). The reduction of hypoglycemia was not associated with a significant change in mean glucose concentration (171 ± 26 to 180 ± 19 mg/dL, P = 0.111) and HbA1c (7.5% ± 0.5% to 7.6% ± 0.7%, (P = 0.329). Manual resumption of insulin delivery followed by carbohydrate intake resulted in significantly higher glucose levels 1 h after suspension compared to SmartGuard suspensions with automatic resume (190.8 ± 26.5 vs. 138.7 ± 10.3 mg/dL; P < 0.001).

CONCLUSIONS

SmartGuard technology significantly reduced the risk for hypoglycemia in pediatric type 1 diabetes patients without increasing HbA1c. Patients must be educated that when using combining predictive low-glucose insulin suspension technology, extra carbohydrate intake in response to an alarm combined with manual resumption is likely to cause rebound hyperglycemia. The best results were achieved when the user did not interfere with pump operation.

Implantable cardioverter defibrillators in diabetics: efficacy and safety in patients at risk of sudden cardiac death

Diabetes mellitus is a major risk factor for arrhythmogenesis and is associated with a two-fold increase in all-cause mortality and a four-fold increase in cardiovascular mortality including sudden cardiac death when compared with nondiabetics. Implantable cardioverter defibrillators (ICD) have been shown to effectively reduce arrhythmic death and all-cause mortality in patients with severe myocardial dysfunction. With a high competing risk of nonarrhythmic cardiac and noncardiac death, survival benefit of ICD in patients with diabetes mellitus could be reduced, but the subanalysis of diabetic patients in randomized clinical trials provides reassurance regarding a similar beneficial survival effect of ICD and cardiac resynchronization therapy in diabetics, as observed in the overall population with advanced heart disease. In this article, the authors highlight some of the clinical issues related to diabetes, summarize the data on the efficacy of ICD in diabetics when compared with nondiabetics and discuss concerns related to ICD implantation in patients with diabetes.

High risk of abnormal QT prolongation in the early morning in diabetic and non-diabetic patients with severe hypoglycemia

BACKGROUND

Several studies have suggested that the occurrence of severe hypoglycemia during sleep may be more dangerous for cardiac arrhythmia than that in the day-time.

METHODS

We performed a retrospective study between January 2006 and March 2012 to assess electrocardiograms during severe hypoglycemia in patients with or without diabetes.

RESULTS

A total of 59,602 patients who visited the emergency room by ambulance were screened, and 287 patients with severe hypoglycemia were enrolled. The median blood glucose levels in patients with (DM, n = 192) and without diabetes (non-DM, n = 95) were 30 and 45 mg/dL, respectively. During severe hypoglycemia, the incidence of abnormal QT prolongation was significantly higher in the early morning (4-10 a.m.) than at other times (DM group, 74.3% versus 54.1%, P = 0.02; non-DM group, 78.3% versus 50.0%, P = 0.01). Multivariate logistic regression analysis identified the occurrence of severe hypoglycemia in the early morning as a strong factor for abnormal QT prolongation (DM group, odds ratio [OR] 2.80, 95% confidence interval [CI] 1.15-6.80, P = 0.02; non-DM group, OR 4.53, 95% CI 1.30-15.74, P = 0.01).

CONCLUSIONS

The incidence of abnormal QT prolongation during severe hypoglycemia was significantly higher in the early morning than at all other times, independent of the cause of severe hypoglycemia.

Diabetic Dead-in-Bed Syndrome: A Possible Link to a Cardiac Ion Channelopathy

Sudden unexpected nocturnal death among patients with diabetes occurs approximately ten times more commonly than in the general population. Malignant ventricular arrhythmia due to Brugada syndrome has been postulated as a cause, since a glucose-insulin bolus can unmask the Brugada electrocardiographic signature in genetically predisposed individuals. In this report we present a 16-year-old male with insulin-dependent diabetes who died suddenly at night. His diabetes had been well controlled, without significant hypoglycaemia. At autopsy, he had a full stomach and a glucose level of 7 mmol/L in vitreous humor, excluding hypoglycaemia. Genetic analysis of autopsy DNA revealed a missense mutation, c.370A>G (p.Ile124Val), in the GPD1L gene. A parent carried the same mutation and has QT prolongation. Mutations in this gene have been linked to Brugada syndrome and sudden infant death. The patient may have died from a ventricular arrhythmia, secondary to occult Brugada syndrome, triggered by a full stomach and insulin. The data suggest that molecular autopsies are warranted to investigate other cases of the diabetic dead-in-bed syndrome.

Vital signs, QT prolongation, and newly diagnosed cardiovascular disease during severe hypoglycemia in type 1 and type 2 diabetic patients

OBJECTIVE To assess vital signs, QT intervals, and newly diagnosed cardiovascular disease during severe hypoglycemia in diabetic patients. RESEARCH DESIGN AND METHODS From January 2006 to March 2012, we conducted a retrospective cohort study to assess type 1 and type 2 diabetic patients with severe hypoglycemia at a national center in Japan. Severe hypoglycemia was defined as the presence of any hypoglycemic symptoms that could not be resolved by the patients themselves in prehospital settings. RESULTS A total of 59,602 cases that visited the emergency room by ambulance were screened, and 414 cases of severe hypoglycemia were analyzed. The median (interquartile range) blood glucose levels were not significantly different between the type 1 diabetes mellitus (T1DM) (n = 88) and type 2 diabetes mellitus (T2DM) (n = 326) groups (32 [24-42] vs. 31 [24-39] mg/dL, P = 0.59). During severe hypoglycemia, the incidences of severe hypertension (≥180/120 mmHg), hypokalemia (<3.5 mEq/L), and QT prolongation were 19.8 and 38.8% (P = 0.001), 42.4 and 36.3% (P = 0.30), and 50.0 and 59.9% (P = 0.29) in the T1DM and T2DM groups, respectively. Newly diagnosed cardiovascular disease during severe hypoglycemia and death were only observed in the T2DM group (1.5 and 1.8%, respectively). Blood glucose levels between the deceased and surviving patients in the T2DM group were significantly different (18 [14-33] vs. 31 [24-39] mg/dL, P = 0.02). CONCLUSIONS T1DM and T2DM patients with severe hypoglycemia experienced many critical problems that could lead to cardiovascular disease, fatal arrhythmia, and death.

Cardiac implications of hypoglycaemia in patients with diabetes - a systematic review

BACKGROUND

Hypoglycaemia has been associated with increased cardiovascular (CV) risk and mortality in a number of recent multicentre trials, but the mechanistic links driving this association remain ill defined. This review aims to summarize the available data on how hypoglycaemia may affect CV risk in patients with diabetes.

METHODS

This was a systematic review of available mechanistic and clinical studies on the relationship between hypoglycaemia and cardiovascular risk. Study outcomes were compiled from relevant articles, and factors contributing to hypoglycaemia-mediated CVD and its complications are discussed.

RESULTS

Six recent comprehensive clinical trials have reinforced the critical importance of understanding the link between hypoglycaemia and the CV system. In addition, 88 studies have indicated that hypoglycaemia mechanistically contributes to CV risk by increasing thrombotic tendency, causing abnormal cardiac repolarization, inducing inflammation, and contributing to the development of atherosclerosis. These hypoglycaemia-associated risk factors are conducive to events such as unstable angina, non-fatal and fatal myocardial infarction, sudden death, and stroke in patients with diabetes.

CONCLUSIONS

Emerging data suggest that there is an impact of hypoglycaemia on CV function and mechanistic link is multifactorial. Further research will be needed to ascertain the full impact of hypoglycaemia on the CV system and its complications.

Standardised mortality is increased three-fold in a population-based sample of children and adolescents with type 1 diabetes

There are no type 1 diabetes (T1DM) mortality data on Australian children and limited contemporary data on their international counterparts. Fatalities in children and adolescents (1-17 yr) with T1DM were identified from the Western Australia Children's Diabetes Database between 1987-2011. Seventeen thousand four hundred and fifty-three patient-years of diabetes data were analysed and 13 deaths were confirmed (six male). The overall standardised mortality ratio was 3.1 [95% confidence interval (CI), 1.7-5.3] and was highest in the 10-14 yr age group, at 4.6 (95% CI, 1.5-10.8). Median age at death was 16.4 yr (range 5 to 17.8 yr), and median haemoglobin A1c at death was 10.5% (range 6.7 to >14). Cause of death was attributed to diabetes in 10 (77%) cases. Two patients were found 'dead-in-bed'. All diabetes-related deaths in subjects with known T1DM occurred outside the hospital setting.

The Armanni-Ebstein Lesion and the Postmortem Diagnosis of Ketoacidosis

The diagnoses of ketoacidosis and disturbances of glucose metabolism are difficult at autopsy because of changes in glucose concentrations postmortem. The Armanni-Ebstein lesion is a histological change in the kidney that has been reported as a marker of diabetic ketoacidosis. This paper examines the specificity of the Armanni-Ebstein lesion and the diagnosis of alterations in glucose metabolism and ketoacidosis at autopsy. The Armanni-Ebstein lesion consists of subnuclear vacuolation of the proximal tubules. The vacuoles contain fat and can be demonstrated on fresh and formalin fixed tissue using standard fat stains. Recently it has been reported in other conditions associated with non-diabetic ketoacidosis. The lesion has the same appearance whatever the cause of the ketoacidosis. This review, with illustrative cases shows the Armanni-Ebstein lesion is a marker of ketoacidosis and not specific for diabetic ketoacidosis. It may be seen in cases of diabetic and alcoholic ketoacidosis and in starvation and hypothermia, in which ketoacidosis occurs. It has also been reported in isopropanol poisoning.

Hypoglycemia, diabetes, and cardiovascular disease

Cardiovascular disease (CVD) remains the leading cause of death in people with diabetes, and the risk of CVD for adults with diabetes is at least two to four times the risk in adults without diabetes. Complications of diabetes, including not only CVD but also microvascular diseases such as retinopathy and nephropathy, are a major health and financial burden. Diabetes is a disease of glucose intolerance, and so much of the research on complications has focused on the role of hyperglycemia. Clinical trials have clearly demonstrated the role of hyperglycemia in microvascular complications of diabetes, but there appears to be less evidence for as strong of a relationship between hyperglycemia and CVD in people with diabetes. Hypoglycemia has become a more pressing health concern as intensive glycemic control has become the standard of care in diabetes. Clinical trials of intensive glucose lowering in both type 1 and type 2 diabetes populations has resulted in significantly increased hypoglycemia, with no decrease in CVD during the trial period, although several studies have shown a reduction in CVD with extended follow-up. There is evidence that hypoglycemia may adversely affect cardiovascular risk in patients with diabetes, and this is one potential explanation for the lack of CVD prevention in trials of intensive glycemic control. Hypoglycemia causes a cascade of physiologic effects and may induce oxidative stress and cardiac arrhythmias, contribute to sudden cardiac death, and cause ischemic cerebral damage, presenting several potential mechanisms through which acute and chronic episodes of hypoglycemia may increase CVD risk. In this review, we examine the risk factors and prevalence of hypoglycemia in diabetes, review the evidence for an association of both acute and chronic hypoglycemia with CVD in adults with diabetes, and discuss potential mechanisms through which hypoglycemia may adversely affect cardiovascular risk.

Cardiovascular disease risk in young people with type 1 diabetes

Cardiovascular disease (CVD) is the most frequent cause of death in people with type 1 diabetes (T1D), despite modern advances in glycemic control and CVD risk factor modification. CVD risk identification is essential in this high-risk population, yet remains poorly understood. This review discusses the risk factors for CVD in young people with T1D, including hyperglycemia, traditional CVD risk factors (dyslipidemia, smoking, physical activity, hypertension), as well as novel risk factors such as insulin resistance, inflammation, and hypoglycemia. We present evidence that adverse changes in cardiovascular function, arterial compliance, and atherosclerosis are present even during adolescence in people with T1D, highlighting the need for earlier intervention. The methods for investigating cardiovascular risk are discussed and reviewed. Finally, we discuss the observational studies and clinical trials which have thus far attempted to elucidate the best targets for early intervention in order to reduce the burden of CVD in people with T1D.

Prevention of hypoglycemia by using low glucose suspend function in sensor-augmented pump therapy

BACKGROUND

Severe hypoglycemic episodes are a barrier for achieving optimal glycemic control. Sensor-augmented pump (SAP) therapy with insulin in combination with a novel mechanism of automatic insulin shutoff (low glucose suspend [LGS]) can be used to prevent and reduce hypoglycemia. In a prospective study, we investigated the effect of the LGS algorithm on the frequency of hypoglycemia in children and adolescents with type 1 diabetes under real-life conditions.

METHODS

Twenty-one patients with type 1 diabetes (10.8±3.8 years old, duration of diabetes 5.9±3.0 years, pump therapy for 3.7±1.7 years, glycated hemoglobin level 7.8±1.1%) from three pediatric centers used the Paradigm(®) Veo(™) system (Medtronic Minimed, Northridge, CA) during two subseqent time periods: SAP without LGS for 2 weeks and then SAP with LGS enabled for 6 weeks. The primary objective was to assess the frequency of hypoglycemic episodes when using the LGS feature with an insulin delivery shutoff of a maximum of 2 h at a sensor glucose level below 70 mg/dL (3.9 mmol/L).

RESULTS

In total, 1,298 LGS alerts occurred (853 shorter than 5 min). Forty-two percent of LGS activations (>5 min) lasted less than 30 min, whereas 24% had a duration of 2 h. The number of hypoglycemic excursions (average/day) was reduced during SAP+LGS (<70 mg/L, 1.27±0.75 vs. 0.95±0.49, P=0.010; ≤40 mg/dL, 0.28±0.18 vs. 0.13±0.14, P=0.005) as was the time spent in hypoglycemia (average minutes/day, 101±68 vs. 58±33, P=0.002) without significant difference in the mean glucose level (145±23 vs. 148±19 mg/dL). No episodes of severe hyperglycemia or diabetic ketoacidosis were observed following LGS activation.

CONCLUSIONS

The present investigation provides evidence that SAP with LGS reduces the frequency of hypoglycemia without compromising safety.

Dynamics of blood electrolytes in repeated hyper- and/or hypoglycaemic events in patients with type 1 diabetes

AIMS/HYPOTHESIS

Electrolyte disturbances are well-known consequences of the diabetic pathology. However, less is known about the cumulative effects of repeated changes in glycaemia, a characteristic of diabetes, on the electrolyte balance. We therefore investigated the ionic profiles of patients with type 1 diabetes during consecutive hyper- and/or hypoglycaemic events using the glucose clamp.

METHODS

In protocol 1, two successive hyperglycaemic excursions to 18 mmol/l were induced; in protocol 2, a hypoglycaemic excursion (2.5 mmol/l) was followed by a hyperglycaemic excursion (12 mmol/l) and another hypoglycaemic episode (3.0 mmol/l).

RESULTS

Blood osmolarity increased during hyperglycaemia and was unaffected by hypoglycaemia. Hyperglycaemia induced decreases in plasma Na(+) Cl(-) and Ca(2+) concentrations and increases in K(+) concentrations. These changes were faithfully reproduced during a second hyperglycaemia. Hypoglycaemia provoked rapid and rapidly reversible increases in Na(+), Cl(-) and Ca(2+). In sharp contrast, K(+) levels displayed a rapid and substantial fall from which they did not fully recover even 2 h after the re-establishment of euglycaemia. A second hypoglycaemia caused an additional fall.

CONCLUSIONS/INTERPRETATION

Repeated hyperglycaemia events do not lead to any cumulative effects on blood electrolytes. However, repeated hypoglycaemias are cumulative with respect to K(+) levels due to a very slow recovery following hypoglycaemia. These results suggest that recurring hypoglycaemic events may lead to progressively lower K(+) levels despite rapid re-establishment of euglycaemia. This warrants close monitoring of plasma K(+) levels combined with continuous glucose monitoring particularly in patients under intensive insulin therapy who are subject to repeated hypoglycaemic episodes.

TRIAL REGISTRATION

Clinicaltrial.gov NCT01060917.

Characterizing sudden death and dead-in-bed syndrome in Type 1 diabetes: analysis from two childhood-onset Type 1 diabetes registries

AIMS

Type 1 diabetes mellitus increases the risk for sudden unexplained death, generating concern that diabetes processes and/or treatments underlie these deaths. Young (< 50 years) and otherwise healthy patients who are found dead in bed have been classified as experiencing 'dead-in-bed' syndrome.

METHODS

We thus identified all unwitnessed deaths in two related registries (the Children's Hospital of Pittsburgh and Allegheny County) yielding 1319 persons with childhood-onset (age < 18 years) Type 1 diabetes diagnosed between 1965 and 1979. Cause of death was determined by a Mortality Classification Committee (MCC) of at least two physician epidemiologists, based on the death certificate and additional records surrounding the death.

RESULTS

Of the 329 participants who had died, the Mortality Classification Committee has so far reviewed and assigned a final cause of death to 255 (78%). Nineteen (8%) of these were sudden unexplained deaths (13 male) and seven met dead-in-bed criteria. The Mortality Classification Committee adjudicated cause of death in the seven dead-in-bed persons as: diabetic coma (n =4), unknown (n=2) and cardiomyopathy (n=1, found on autopsy). The three dead-in-bed individuals who participated in a clinical study had higher HbA(1c) , lower BMI and higher daily insulin dose compared with both those dying from other causes and those surviving.

CONCLUSIONS

Sudden unexplained death in Type 1 diabetes seems to be increased 10-fold and associated with male sex, while dead-in-bed individuals have a high HbA(1c) and insulin dose and low BMI. Although sample size is too small for definitive conclusions, these results suggest specific sex and metabolic factors predispose to sudden unexplained death and dead-in-bed death.

Suicidality among Norwegian youth: review of research on risk factors and interventions

BACKGROUND AND AIM

Published research on suicidality among Norwegian youth and publications describing interventions were summarized in order to access the current status of knowledge building via empirical research.

METHOD

A systematic Medline search identified 29 studies on risk factors on the entire spectrum of suicidal phenomena from self-harm without suicidal ideation to completed suicide with the mean age at/under 25 years. A specialist Norwegian journal, Suicidologi, was searched for additional matter, especially interventions.

RESULT

Most studies focussed on psychological and psychiatric risk factors of attempted suicide. Other suicidal phenomena, psychosocial and societal risk factors, and impact of interventions were hardly studied. Depression, previous suicidal behaviour, alcohol use and non-intact parental unit were consistent significant risk factors found in suicide and attempted suicide studies.

CONCLUSION

Supporting non-intact parental units and the maintenance of intact parental units along with early detection and management of suicide attempts, depression and alcohol use should be targeted as suicide prevention interventions among adolescents.

The case for hypoglycaemia as a proarrhythmic event: basic and clinical evidence

Recent clinical studies show that hypoglycaemia is associated with increased risk of death, especially in patients with coronary artery disease or acute myocardial infarction. This paper reviews data from cellular and clinical research supporting the hypothesis that acute hypoglycaemia increases the risk of malignant ventricular arrhythmias and death in patients with diabetes by generating the two classic abnormalities responsible for the proarrhythmic effect of medications, i.e. QT prolongation and Ca(2+) overload. Acute hypoglycaemia causes QT prolongation and the risk of ventricular tachycardia by directly suppressing K(+) currents activated during repolarisation, a proarrhythmic effect of many medications. Since diabetes itself, myocardial infarction, hypertrophy, autonomic neuropathy and congestive heart failure also cause QT prolongation, the arrhythmogenic effect of hypoglycaemia is likely to be greatest in patients with pre-existent cardiac disease and diabetes. Furthermore, the catecholamine surge during hypoglycaemia raises intracellular Ca(2+), thereby increasing the risk of ventricular tachycardia and fibrillation by the same mechanism as that activated by sympathomimetic inotropic agents and digoxin. Diabetes itself may sensitise myocardium to the arrhythmogenic effect of Ca(2+) overload. In humans, noradrenaline (norepinephrine) also lengthens action potential duration and causes further QT prolongation. Finally, both hypoglycaemia and the catecholamine response acutely lower serum K(+), which leads to QT prolongation and Ca(2+) loading. Thus, hypoglycaemia and the subsequent catecholamine surge provoke multiple, interactive, synergistic responses that are known to be proarrhythmic when associated with medications and other electrolyte abnormalities. Patients with diabetes and pre-existing cardiac disease may therefore have increased risk of ventricular tachycardia and fibrillation during hypoglycaemic episodes.

"Dead in bed": a tragic complication of type 1 diabetes mellitus

"Dead in bed" is a tragic description of a particular type of sudden death in type 1 diabetes mellitus (DM). Patients are typically found dead in the early morning, lying in an undisturbed bed, having been well the previous evening. The incidence of "dead in bed" syndrome is not known but studies suggest figures of between 4.7 and 27.3% of all unexplained deaths in type 1 DM. The pathogenesis is unclear but patients typically have a preceding history of recurrent severe hypoglycaemia. We describe two cases of "dead in bed" syndrome which occurred at our institution within a 12-month period.

Confirmation of hypoglycemia in the "dead-in-bed" syndrome, as captured by a retrospective continuous glucose monitoring system

OBJECTIVE

To report a case that substantiates the presence of hypoglycemia at the time of death of a young man with type 1 diabetes, who was found unresponsive in his undisturbed bed in the morning.

METHODS

We describe a 23-year-old man with a history of type 1 diabetes treated with an insulin pump, who had recurrent severe hypoglycemia. In an effort to understand these episodes better and attempt to eliminate them, a retrospective (non-real-time) continuous subcutaneous glucose monitoring system (CGMS) was attached to the patient. He was found dead in his undisturbed bed 20 hours later. The insulin pump and CGMS were both downloaded for postmortem study.

RESULTS

Postmortem download of the data in the CGMS demonstrated glucose levels below 30 mg/dL around the time of his death, with only a minimal counter-regulatory response. This finding corresponded to a postmortem vitreous humor glucose of 25 mg/dL. An autopsy showed no major anatomic abnormalities that could have contributed to his death.

CONCLUSION

To our knowledge, this is the first documentation of hypoglycemia at the time of death in a patient with the "dead-in-bed" syndrome. This report should raise the awareness of physicians to the potentially lethal effects of hypoglycemia and provide justification for efforts directed at avoiding nocturnal hypoglycemia.

Dead-in-bed syndrome - a diabetes nightmare

We report in this study the death in bed of a 14-yr-old girl with type 1 diabetes and a review of the existing literature on this topic. Diagnosed at 5 yr of age, the patient followed a relatively benign disease course. Hemoglobin A1c was 6.6-8.4%, and there were no hospital admissions apart from the one at diagnosis. Hypoglycemic episodes were not excessive or severe. At age 14 yr, the patient was found dead in bed after having been well the night before. No apparent explanation could be provided. The 'dead-in-bed' syndrome accounts for 5-6% of mortality cases in patients with type 1 diabetes, amounting to two to six cases per 10 000 patient years. Theories attempting to explain the mechanism for this syndrome include hypoglycemia or cardiac autonomic dysfunction. This case emphasizes several problems faced by clinicians: the risk for sudden death in youth with diabetes, which may compromise good glycemic control, the question of early detection of autonomic dysfunction, and the need to understand this phenomenon better and search for preventive measures.

Sudden death in type 1 diabetes: the mystery of the 'dead in bed' syndrome

Sudden cardiac death is an unpredictable and devastating event, particularly in the young. A significant proportion of sudden deaths in the young are unexplained-no cause is identified either during life or at post-mortem. This is seen in a subgroup of young patients with type 1 diabetes who have dead in bed syndrome, where these victims are in good health, retire to bed, only to be found dead the following morning in a bed which is undisturbed, suggesting no terminal struggle or seizure. The underlying cause of dead in bed syndrome remains unknown, but is likely to be due to a terminal malignant arrhythmia. A plausible hypothesis is that it may be secondary to QT interval prolongation (followed by a degenerate ventricular tachycardia), caused by a number of factors including acute hypoglycaemia, on a background of cardiac autonomic neuropathy, and possible genetic influences. It is envisaged that understanding the causes and triggers of dead in bed syndrome will allow appropriate therapeutic interventions to be initiated in high-risk patients with type 1 diabetes, with the ultimate goal to prevent sudden death.

Causes of death in young Australians with type 1 diabetes: a review of coronial postmortem examinations

OBJECTIVE

To determine the causes of death in Australians with type 1 diabetes mellitus who died aged 40 years or younger.

DESIGN AND SETTING

Retrospective review of autopsy reports at the Department of Forensic Medicine, Sydney, New South Wales, 1 January 1994-31 December 2006.

MAIN OUTCOME MEASURE

Causes of mortality in people with type 1 diabetes aged <40 years.

RESULTS

Of the 26 682 autopsy reports, 1914 were for individuals with diabetes (type 1, 400; type 2, 1514). Cardiovascular disease accounted for 51% of deaths (169/333) in people with type 1 diabetes aged >40 years, versus 13% among those aged <or= 40 years (9/67; P=0.001). Acute complications of diabetes (27%; 18/67), unnatural deaths (28%; 19/67), and sudden unexpected deaths (22%; 15/67) were the predominant causes of death in young individuals with diabetes. Sudden unexpected death was more common in those with type 1 diabetes compared with a sex-matched control population in the same age range (22% v 5%; Xi(2) P<0.001). Of the sudden unexpected deaths, 10 people were found dead in an undisturbed bed with no cause of death found at autopsy ("dead-in-bed" syndrome; mean age [SD], 30.2 [9.4] years; males : females=4 :1).

CONCLUSIONS

In deceased young people with type 1 diabetes examined by the Coroner, acute diabetic complications, unnatural causes, and sudden unexpected deaths were the predominant causes of death. The relatively high frequency of sudden unexpected deaths, such as dead-in-bed syndrome, requires further investigation.

Vascular disease and diabetes: is hypoglycaemia an aggravating factor?

Acute hypoglycaemia provokes profound physiological changes affecting the cardiovascular system and several haematological parameters, principally as a consequence of sympatho-adrenal activation and counter-regulatory hormonal secretion. Many of these responses have an important role in protecting the brain from neuroglycopenia, through altering regional blood flow and promoting metabolic changes that will restore blood glucose to normal. In healthy young adults the cardiovascular effects are transient and have no obvious detrimental consequences. However, some of the effected changes are potentially pathophysiological and in people with diabetes who have developed endothelial dysfunction, they may have an adverse impact on a vasculature that is already damaged. The acute haemodynamic and haematological changes may increase the risk of localized tissue ischaemia, and major vascular events can certainly be precipitated by acute hypoglycaemia. These include myocardial and cerebral ischaemia and occasionally infarction. Established diabetic retinopathy often deteriorates after strict glycaemic control is instituted, the latter being associated with a threefold increase in frequency of severe hypoglycaemia, and enhanced exposure to mild hypoglycaemia. The possible mechanisms underlying these hypoglycaemia-induced effects include haemorrheological changes, white cell activation, vasoconstriction, and the release of inflammatory mediators and cytokines. The concept that acute hypoglycaemia could aggravate vascular complications associated with diabetes is discussed in relation to evolving comprehension of the pathogenesis of atherosclerosis and blood vessel disease.

Cardiac repolarization during hypoglycaemia in type 1 diabetes: impact of basal renin-angiotensin system activity

AIMS

Hypoglycaemia-induced cardiac arrhythmias may be involved in the pathogenesis of the 'dead-in-bed syndrome' in patients with type 1 diabetes. Evidence suggests that the renin-angiotensin system (RAS) influences the occurrence of arrhythmias. The aim of this study was to explore if basal RAS activity affects cardiac repolarization during hypoglycaemia, thereby potentially carrying prognostic information on risk of the 'dead-in-bed syndrome'.

METHODS AND RESULTS

Nine subjects with high RAS activity and nine subjects with low RAS activity were subjected to single-blinded placebo-controlled hypoglycaemia (nadir plasma glucose 2.4 mmol/L). QTc/QTcF and QT dynamics were registered by Holter monitoring. QTc prolonged during [8 (+/-2.3) ms, P < 0.01] and after [11 (+/-3) ms, P < 0.001] hypoglycaemia. Dynamic QT parameters reacted ambiguously. Low RAS activity was associated with a slightly more pronounced QT prolongation [6 (+/-3) ms, P = 0.04]. Adrenaline tended to increase more in the low-RAS group (P = 0.08) and was correlated to QTc (r = 0.67, P < 0.01) and QTcF (r = 0.58, P < 0.05) during hypoglycaemia.

CONCLUSION

Low basal RAS activity may be associated with a slightly more pronounced QT prolongation during hypoglycaemia, when compared with high RAS activity. The impact, however, is modest and the clinical consequence is unclear.

Dyssynchronous (non-uniform) Ca2+ release in myocytes from streptozotocin-induced diabetic rats

Using biochemical/pharmacological approaches, we previously showed that type 2 ryanodine receptors (RyR2) become dysfunctional in hearts of streptozotocin-induced type 1 diabetic rats. However, the functional consequence of this observation remains incompletely understood. Here we use laser confocal microscopy to investigate whether RyR2 dysfunction during diabetes alters evoked and spontaneous Ca(2+) release from the sarcoplasmic reticulum (SR). After 7-8 weeks of diabetes, steady-state levels of RyR2 remain unchanged in hearts of male Sprague-Dawley rats, but the number of functional receptors decreased by >37%. Interestingly, residual functional RyR2 from diabetic rat hearts exhibited increased sensitivity to Ca(2+) activation (EC(50activation) decreased from 80 microM to 40 microM, peak Ca(2+) activation decreased from 425 microM to 160 microM). When field stimulated, intracellular Ca(2+) release in diabetic ventricular myocytes was dyssynchronous (non-uniform) and this was independent of L-type Ca(2+) currents. Time to peak Ca(2+) increased 3.7-fold. Diabetic myocytes also exhibited diastolic Ca(2+) release and 2-fold higher frequency of spontaneous Ca(2+) sparks, albeit at a lower amplitude. The amplitude of caffeine-releasable Ca(2+) was also lower in diabetic myocytes. RyR2 from diabetic rat hearts exhibited increased phosphorylation at Ser2809 and contained reduced levels of FKBP12.6 (calstablin2). Collectively, these data suggest that RyR2 becomes leaky during diabetes and this defect may be responsible to the reduced SR Ca(2+) load. Diastolic Ca(2+) release could also serve as a substrate for delayed after-depolarizations, contributing to the increased incidence of arrhythmias and sudden cardiac death in type 1 diabetes.

Long-term mortality in a nationwide cohort of childhood-onset type 1 diabetic patients in Norway

AIMS/HYPOTHESIS

We examined long-term total and cause-specific mortality in a nationwide, population-based Norwegian cohort of patients with childhood-onset type 1 diabetes.

MATERIALS AND METHODS

All Norwegian type 1 diabetic patients who were diagnosed between 1973 and 1982 and were under 15 years of age at diagnosis were included (n=1,906). Mortality was recorded from diabetes onset until 31 December 2002 and represented 46,147 person-years. The greatest age attained among deceased subjects was 40 years and the maximum diabetes duration was 30 years. Cause of death was ascertained by reviews of death certificates, autopsy protocols and medical records. The standardised mortality ratio (SMR) was based on national background statistics.

RESULTS

During follow-up 103 individuals died. The mortality rate was 2.2/1000 person-years. The overall SMR was 4.0 (95% CI 3.2-4.8) and was similar for males and females. For ischaemic heart disease the SMR was 20.2 (7.3-39.8) for men and 20.6 (1.8-54.1) for women. Acute metabolic complications of diabetes were the most common cause of death under 30 years of age (32%). Cardiovascular disease was responsible for the largest proportion of deaths from the age of 30 years onwards (30%). Violent death accounted for 28% of the deaths in the total cohort (35% among men and 11% among women).

CONCLUSIONS/INTERPRETATION

Childhood-onset type 1 diabetes still carries an increased mortality risk when compared with the general population, particularly for cardiovascular disease. To reduce these deaths, attention should be directed to the prevention of acute metabolic complications, the identification of psychiatric vulnerability and the early detection and treatment of cardiovascular disease and associated risk factors.

Hypoglycemia: a complication of diabetes therapy in children

The experience of hypoglycemia is probably the most feared and hated consequence of life with type 1 diabetes among pediatric patients and their parents. Although transient detrimental effects are clearly disturbing and may have severe results, there is surprisingly little evidence of long-term CNS damage, even after multiple hypoglycemic episodes, except in rare instances. Despite the latter evidence, we advocate that every treatment regimen be designed to prevent hypoglycemia without inducing unacceptable hyperglycemia and increasing the risk of micro- and macrovascular complications.

Excess mortality in Black compared with White patients with Type 1 diabetes: an examination of underlying causes

AIMS

Excess mortality in Type 1 diabetes has previously been found among Black individuals. The aim of the present study was therefore to determine underlying causes.

METHODS

A longitudinal study of 1261 [1184 White (93.9%) and 76 Black (6.0%)] individuals diagnosed with Type 1 diabetes between 1965 and 1979, at age<17 years from the Allegheny County, Pennsylvania and Children's Hospital of Pittsburgh registries. Subjects were contacted in 1999 to determine living status and, where appropriate, cause of death. Living status was determined in 1183 participants (93.8%).

RESULTS

Of the 200 deaths overall, cause of death was determined in 157 subjects (79%); 31 dying from acute and 101 from chronic complications, and 25 from non-diabetes related causes. Seven deaths were investigated but no cause determined. Black participants had a significantly higher mortality rate compared with White participants for acute complications (hazard ratio=4.9, 95% confidence interval: 2.0, 11.6), but not for any other cause. There was a temporal decline in the 20-year mortality rates in both racial groups across the three cohorts diagnosed in 1965-69, 1970-74 and 1975-79.

CONCLUSIONS

These results show that the excess mortality in Black people was attributed to acute complications which therefore should be a focus for prevention.

Prolonged cardiac repolarisation during spontaneous nocturnal hypoglycaemia in children and adolescents with type 1 diabetes

AIMS/HYPOTHESIS

It has been postulated that hypoglycaemia-related cardiac dysrhythmia and, in particular, prolonged cardiac repolarisation, may contribute to increased mortality rates in children and adolescents with type 1 diabetes.

METHODS

We examined the prevalence of prolonged QT interval on ECG during spontaneous hypoglycaemia in 44 type 1 diabetic subjects (aged 7-18 years), and explored the relationships between serial overnight measurements of QT interval corrected for heart rate (QTc) and serum glucose, potassium and epinephrine levels. Each subject underwent two overnight profiles; blood was sampled every 15 min for glucose measurements and hourly for potassium and epinephrine. Serial ECGs recorded half-hourly between 23.00 and 07.00 hours were available on 74 nights: 29 with spontaneous hypoglycaemia (defined as blood glucose <3.5 mmol/l) and 45 without hypoglycaemia.

RESULTS

Mean overnight QTc was longer in females than in males (412 vs 400 ms, p=0.02), but was not related to age, diabetes duration or HbA(1)c. Prolonged QTc (>440 ms) occurred on 20 out of 74 (27%) nights, with no significant differences between male and female subjects, and was more prevalent on nights with hypoglycaemia (13/29, 44%) than on nights without (7/45, 15%, p=0.0008). Potassium levels were lower on nights when hypoglycaemia occurred (minimum potassium 3.4 vs 3.7 mmol/l, p=0.0003) and were inversely correlated with maximum QTc (r=-0.40, p=0.03). In contrast, epinephrine levels were not higher on nights with hypoglycaemia and were not related to QTc.

CONCLUSIONS/INTERPRETATION

In young type 1 diabetic subjects, prolonged QTc occurred frequently with spontaneous overnight hypoglycaemia and may be related to insulin-induced hypokalaemia.

Influence of autonomic neuropathy on QTc interval lengthening during hypoglycemia in type 1 diabetes

Hypoglycemia produces electrocardiographic QTc lengthening, a predictor of arrhythmia risk and sudden death. This results from both sympatho-adrenal activation and a lowered serum potassium. It has been suggested that cardiac autonomic neuropathy (CAN) might indicate those who are at particular risk. We tested this hypothesis in 28 adults with type 1 diabetes and 8 nondiabetic control subjects. After standard tests of autonomic function and baroreflex sensitivity (BRS) measurement, diabetic participants were divided into three groups: 1) CAN- with normal BRS (BRS+; n = 10), 2) CAN- with impaired BRS (BRS-; n = 9), and 3) CAN+ (n = 9). QTc was then measured during controlled hypoglycemia (2.5 mmol/l) using a hyperinsulinemic clamp. Mean (+/-SE) QTc lengthened from 377 +/- 9 ms (baseline) to a maximum during hypoglycemia of 439 +/- 13 ms in BRS+ subjects and from 378 +/- 5 to 439 +/- 10 ms in control subjects. Peak QTc tended to be lower in CAN+ (baseline, 383 +/- 6; maximum, 408 +/- 10) and BRS- groups (baseline, 380 +/- 8; maximum, 421 +/- 11; F = 1.7, P = 0.18). Peak epinephrine concentrations (nmol/l) were 3.1 +/- 0.8 (BRS+), 2.6 +/- 0.5 (BRS-), 1.4 +/- 0.3 (CAN+), and 5.7 +/- 0.8 (control subjects). These data do not indicate that those with CAN are at particular risk for abnormal cardiac repolarization during hypoglycemia. Indeed, they suggest that such patients may be relatively protected, perhaps as a result of attenuated sympatho-adrenal responses.

Mechanisms of abnormal cardiac repolarization during insulin-induced hypoglycemia

Prolonged cardiac repolarization causes fatal cardiac arrhythmias. There is evidence that these contribute to sudden death associated with nocturnal hypoglycemia in young people with diabetes. We measured cardiac repolarization (QT interval [QTc] and QT dispersion [QTd]) during experimental hypoglycemia with and without beta-blockade and potassium infusion to establish possible mechanisms. Two groups of 10 nondiabetic men (study 1 and study 2) each underwent four hyperinsulinemic clamps: two euglycemic (5 mmol/l) and two hypoglycemic (5 mmol/l and 2.5 mmol/l for 60 min each). Study 1 was performed with and without potassium infusion to maintain normal concentrations and study 2 with and without beta-blockade (atenolol, 100 mg/day for 7 days). QTd was unchanged during euglycemia but increased during hypoglycemia (55 ms, P < 0.0001 vs. baseline), which was prevented by potassium (6 ms, P = 0.78). QTc increased significantly during hypoglycemia alone (67 ms, P < 0.0001) and during potassium replacement (46 ms, P = 0.02). In study 2, the increase in QTd during hypoglycemia (68 ms, P < 0.0001) was prevented by beta-blockade (3 ms, P = 0.88). The increase in QTc during hypoglycemia (55 ms, P < 0.0001) was prevented by beta-blockade (1 ms, P = 0.98). Our data indicate that hypoglycemia causes an acquired long QT syndrome. Sympathoadrenal stimulation is the main cause, through mechanisms that involve but are not limited to catecholamine-mediated hypokalemia. These abnormalities are prevented by selective beta-blockade.

Increased mortality in diabetes during the first 10 years of the disease. A population-based study (DISS) in Swedish adults 15-34 years old at diagnosis

OBJECTIVES

To study, prospectively, in young adult patients, the mortality during the first years after the diagnosis of diabetes.

DESIGN

The Diabetes Incidence Study in Sweden (DISS) aims to register all incident cases aged 15-34 years. During a 10-year period all deaths were identified by record linkage to the national Cause of Death Registry.

SUBJECTS

During the period, 4097 new cases were registered and classified as type 1 diabetes (73%), type 2 (16%), secondary (2%) and unclassified (9%). The median follow-up was 5 years (21 001 person-years).

MAIN OUTCOME MEASURES

Calculation of the standardized mortality ratio (SMR) and 95% confidence interval (CI). Evaluation of all deceased by scrutiny of clinical records, death certificates and autopsy protocols.

RESULTS

Fifty-eight patients died, corresponding to an SMR of 3.5 (CI=2.7-4.5), which increased from 1.5 at 15-19 years to 4.1 at 30-34 years. SMR was 2.7 in primary diabetes: 2.3 (1.6-3.3) in type 1 and 4.1 (2.6-6.7) in type 2. In secondary diabetes, alcohol-associated pancreatitis a common cause, SMR was 32 (CI=24-45). Evidence of alcohol or drug misuse, mental dysfunction or suicide was found in 40 of all 58 deceased cases. Less often, hypoglycaemia (n=7) or hyperglycaemia-ketoacidosis (n=11) was present at death. Unexplained 'dead in bed' was found once.

CONCLUSIONS

In the investigated population-based cohort the early mortality was about threefold increased. Hypoglycaemia and ketoacidosis per se played a relatively small role compared with a heavy impact from social and mental dysfunction, and from careless use of alcohol or drugs.

The care of students with insulin-treated diabetes mellitus living in university accommodation: scope for improvement?

Concern has been expressed about the welfare of young adults with Type 1 diabetes mellitus who leave home to attend university or college for tertiary education. This has been highlighted by the local experience in Edinburgh of two male students with Type 1 diabetes, both of whom died from metabolic complications of diabetes during their first term at universities distant from their homes. One student died following the development of cerebral oedema secondary to diabetic ketoacidosis, which was probably precipitated by prolonged coma after an episode of severe hypoglycaemia. Another student, who was found 'dead in bed', had a history of previous severe hypoglycaemia. At a Fatal Accident Inquiry in Edinburgh, held following the death of the first student, recommendations were made to improve the care and personal safety of students with diabetes living in university accommodation. Despite the report being circulated to all Scottish universities, the second student died within three years of the inquiry. Further efforts to protect the welfare of students with Type 1 diabetes who are attending centres for tertiary education away from their home environment may require the more active participation by diabetes healthcare professionals.

Hypoglycemia in children with type 1 diabetes mellitus. Risk factors, cognitive function, and management

This article examines the relationship between hypoglycemia and brain function in children with type 1 diabetes. Hypoglycemic episodes occurring in the first 5 years of life may permanently disrupt cognitive function in a subset of children with diabetes, and a single acute episode of hypoglycemia may produce a transient reduction in mental efficiency, alter the electroencephalogram, and increase regional cerebral blood flow. Because iatrogenic development of hypoglycemic unawareness and autonomic failure are the most likely mediators of moderately severe hypoglycemia, medical management efforts should be directed at the prevention of frequently recurring, mild hypoglycemia.

Is undetected autonomic dysfunction responsible for sudden death in Type 1 diabetes mellitus? The 'dead in bed' syndrome revisited

AIMS

Sudden nocturnal death in young persons with Type 1 diabetes mellitus has been recently described, and is known as the 'dead in bed' syndrome. Its aetiology is unknown, and we have therefore explored the details of all papers recording the syndrome, to formulate a hypothesis of causation.

METHODS

Literature review of 'dead in bed' reports as well as of nocturnal hypoglycaemia, and autonomic dysfunction in relation to baroreceptor-cardiac reflex sensitivity.

RESULTS

Clinical reports of 'dead in bed' cases strongly suggest that nocturnal hypoglycaemia is a likely precipitant, but that the death is sudden and probably arrhythmic. Ventricular dysrhythmias may occur in the context of early autonomic neuropathy, with relative sympathetic overactivity, in young Type 1 diabetic persons.

CONCLUSION

We conclude that the 'dead in bed' syndrome probably occurs in Type 1 diabetic persons with early autonomic neuropathy, resulting in relative sympathetic overactivity. In such persons, risks of ventricular dysrhythmias will be compounded by nocturnal hypoglycaemia, which may be associated with an increase in the electrocardiographic Q-T interval, and Q-T dispersion. This could lead to the observed sudden death in undisturbed beds. Further research in this area is urgently needed, in particular into the possible protective use of drugs that modulate the autonomic nervous system.