Dead-in-bed syndrome - a diabetes nightmare

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.

Continuous Glucose and Heart Rate Monitoring in Young People with Type 1 Diabetes: An Exploratory Study about Perspectives in Nocturnal Hypoglycemia Detection

A combination of information from blood glucose (BG) and heart rate (HR) measurements has been proposed to investigate the HR changes related to nocturnal hypoglycemia (NH) episodes in pediatric subjects with type 1 diabetes (T1D), examining whether they could improve hypoglycemia prediction. We enrolled seventeen children and adolescents with T1D, monitored on average for 194 days. BG was detected by flash glucose monitoring devices, and HR was measured by wrist-worn fitness trackers. For each subject, we compared HR values recorded in the hour before NH episodes (before-hypoglycemia) with HR values recorded during sleep intervals without hypoglycemia (no-hypoglycemia). Furthermore, we investigated the behavior after the end of NH. Nine participants (53%) experienced at least three NH. Among these nine subjects, six (67%) showed a statistically significant difference between the before-hypoglycemia HR distribution and the no-hypoglycemia HR distribution. In all these six cases, the before-hypoglycemia HR median value was higher than the no-hypoglycemia HR median value. In almost all cases, HR values after the end of hypoglycemia remained higher compared to no-hypoglycemia sleep intervals. This exploratory study support that HR modifications occur during NH in T1D subjects. The identification of specific HR patterns can be helpful to improve NH detection and prevent fatal events.

A Novel CGM Metric-Gradient and Combining Mean Sensor Glucose Enable to Improve the Prediction of Nocturnal Hypoglycemic Events in Patients with Diabetes

Nocturnal hypoglycemia is a serious complication of insulin-treated diabetes, and it is often asymptomatic. A novel CGM metric-gradient was proposed in this paper, and a method of combining mean sensor glucose (MSG) and gradient was presented for the prediction of nocturnal hypoglycemia. For this purpose, the data from continuous glucose monitoring (CGM) encompassing 1,921 patients with diabetes were analyzed, and a total of 302 nocturnal hypoglycemic events were recorded. The MSG and gradient values were calculated, respectively, and then combined as a new metric (i.e., MSG+gradient). In addition, the prediction was conducted by four algorithms, namely, logistic regression, support vector machine, random forest, and long short-term memory. The results revealed that the gradient of CGM showed a downward trend before hypoglycemic events happened. Additionally, the results indicated that the specificity and sensitivity based on the proposed method were better than the conventional metrics of low blood glucose index (LBGI), coefficient of variation (CV), mean absolute glucose (MAG), lability index (LI), etc., and the complex metrics of MSG+LBGI, MSG+CV, MSG+MAG, and MSG+LI, etc. Specifically, the specificity and sensitivity were greater than 96.07% and 96.03% at the prediction horizon of 15 minutes and greater than 87.79% and 90.07% at the prediction horizon of 30 minutes when the proposed method was adopted to predict nocturnal hypoglycemic events in the aforementioned four algorithms. Therefore, the proposed method of combining MSG and gradient may enable to improve the prediction of nocturnal hypoglycemic events. Future studies are warranted to confirm the validity of this metric.

Excess all-cause mortality before age 30 in childhood onset type 1 diabetes: data from the Brecon Group Cohort in Wales

BACKGROUND

Long-term outcomes in young people with type 1 diabetes continue to be of interest, and may help evaluate the effects of changes to the clinical care of children that have occurred in recent decades.

AIMS

To identify mortality and its causes before age 30 years in patients developing type 1 diabetes before age 15 years.

METHODS

Since 1995, paediatricians in Wales have compiled a prospective register of incident cases of type 1 diabetes occurring before age 15 years in Wales (the Brecon Cohort). Their subsequent mortality rates were compared with mortality in the general populations of Wales and England using the patient-years exposure method. Causes of death were ascertained from death certificates and from clinicians.

RESULTS

The standardised mortality ratio for young people with type 1 diabetes in Wales was 2.91 with no clear evidence of improvement or worsening of mortality risk over time. Most deaths occurred between ages 15 and 30 years although at a slightly younger age than in the general population. There were more deaths with increasing age at diagnosis of diabetes. Ketoacidosis remains the most common cause of death before age 30 years. Hypoglycaemia was difficult to ascertain with certainty but also caused some deaths. In this age group, chronic complications of diabetes were not a cause of mortality.

CONCLUSIONS

Despite the developments in clinical care in recent years, the mortality risk for people developing type 1 diabetes in childhood remains high in young adult life before the onset of chronic complications.

Causes of death in childhood-onset Type 1 diabetes: long-term follow-up

AIMS

To assess the causes of death and cause-specific standardized mortality ratios in two nationwide, population-based cohorts diagnosed with Type 1 diabetes during the periods 1973-1982 and 1989-2012, and to evaluate changes in causes of death during the follow-up period.

METHODS

People with Type 1 diabetes who were aged < 15 years at diagnosis were identified in the Norwegian Childhood Diabetes Registry and followed from diagnosis until death, emigration or September 2013 (n = 7871). We assessed causes of death by linking data to the nationwide Cause of Death Registry and through a review committee that evaluated medical records, autopsy reports and death certificates.

RESULTS

During a mean (range) follow-up of 16.8 (0-40.7) years, 241 individuals (3.1%) died, representing 132 143 person-years. The leading cause of death before the age of 30 years was acute complications (41/119, 34.5%). After the age of 30 years cardiovascular disease was predominant (41/122, 33.6%), although death attributable to acute complications was still important in this age group (22/122, 18.0%). A total of 5% of deaths were caused by 'dead-in-bed' syndrome. The standardized mortality ratio was elevated for cardiovascular disease [11.9 (95% CI 8.6-16.4)] and violent death [1.7 (95% CI 1.3-2.1)] in both sexes combined, but was elevated for suicide only in women [2.5 (95% CI 1.2-5.3)]. The risk of death from acute complications was approximately half in women compared with men [hazard ratio 0.43 (95% CI 0.25-0.76)], and did not change with more recent year of diagnosis [hazard ratio 1.02 (0.98-1.05)].

CONCLUSIONS

There was no change in mortality attributable to acute complications during the study period. To reduce premature mortality in people with childhood-onset diabetes focus should be on prevention of acute complications. Male gender implied increased risk.

QT interval, corrected for heart rate, is associated with HbA1c concentration and autonomic function in diabetes

AIMS

To examine QT intervals corrected for heart rate (QTc) in adolescents with Type 1 diabetes compared with control subjects, and to determine associations with metabolic control and autonomic function.

METHODS

Resting electrocardiogram recordings of 142 adolescents with Type 1 diabetes [mean (sd) age 15.3 (2.0) years, diabetes duration 9.0 (3.5) years, HbA1c 71 (17) mmol/mol or 8.7 (1.6)%] and 125 control subjects [mean (sd) age 15.7 (2.5) years] were used to calculate QTc duration and derive mean heart rate and heart rate variability (HRV) values. Linear and logistic regression models were used to examine the associations between QTc, metabolic control and autonomic function (HRV and pupillary function).

RESULTS

QTc duration was not significantly different between subjects with Type 1 diabetes and control subjects (mean duration 392 vs 391 ms; P = 0.65). In the Type 1 diabetes group, QTc was positively associated with HbA1c [β = 4 (95% CI 2, 6); P < 0.001] and inversely associated with severe hypoglycaemic events [β = -10 (95% CI -20,-2); P = 0.01], less insulin/kg [β = -12 (95% CI -22, -2); P = 0.024] and less HRV. In the Type 1 diabetes group, QTc in the highest quintile (≥409 ms) vs quintiles 1-4 had more pupillary abnormalities (83 vs 56%; P = 0.03), lower pupillary maximum constriction velocity (4.8 vs 5.3 mm/s; P = 0.04), higher heart rate (78 vs 72 beats per min; P = 0.02) and lower HRV (standard deviation of mean NN intervals 4.0 vs 4.3 ms, P = 0.004 and root-mean-square difference of successive NN intervals 3.7 vs 4.1 ms; P = 0.004).

CONCLUSIONS

Although there are concerns about hypoglycaemia in general in people with Type 1 diabetes, chronic hyperglycaemia, rather than intermittent hypoglycaemia, appears to be more deleterious to autonomic cardiac function, even in adolescence. Longer QTc was associated with higher HbA1c concentration, lower risk of hypoglycaemia and autonomic dysfunction. Longitudinal studies are warranted.

Hypoglycemia: The neglected complication

Hypoglycemia is an important complication of glucose-lowering therapy in patients with diabetes mellitus. Attempts made at intensive glycemic control invariably increases the risk of hypoglycemia. A six-fold increase in deaths due to diabetes has been attributed to patients experiencing severe hypoglycemia in comparison to those not experiencing severe hypoglycemia Repeated episodes of hypoglycemia can lead to impairment of the counter-regulatory system with the potential for development of hypoglycemia unawareness. The short- and long-term complications of diabetes related hypoglycemia include precipitation of acute cerebrovascular disease, myocardial infarction, neurocognitive dysfunction, retinal cell death and loss of vision in addition to health-related quality of life issues pertaining to sleep, driving, employment, recreational activities involving exercise and travel. There is an urgent need to examine the clinical spectrum and burden of hypoglycemia so that adequate control measures can be implemented against this neglected life-threatening complication. Early recognition of hypoglycemia risk factors, self-monitoring of blood glucose, selection of appropriate treatment regimens with minimal or no risk of hypoglycemia and appropriate educational programs for healthcare professionals and patients with diabetes are the major ways forward to maintain good glycemic control, minimize the risk of hypoglycemia and thereby prevent long-term 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.

Islet transplantation in type 1 diabetes: ongoing challenges, refined procedures, and long-term outcome

Remarkable progress has been made in islet transplantation over a span of 40 years. Once just an experimental curiosity in mice, this therapy has moved forward, and can now provide robust therapy for highly selected patients with type 1 diabetes (T1D), refractory to stabilization by other means. This progress could not have occurred without extensive dynamic international collaboration. Currently, 1,085 patients have undergone islet transplantation at 40 international sites since the Edmonton Protocol was reported in 2000 (752 allografts, 333 autografts), according to the Collaborative Islet Transplant Registry. The long-term results of islet transplantation in selected centers now match registry data of pancreas-alone transplantation, with 6 sites reporting five-year insulin independence rates ≥50%. Islet transplantation has been criticized for the use of multiple donor pancreas organs, but progress has also occurred in single-donor success, with 10 sites reporting increased single-donor engraftment. The next wave of innovative clinical trial interventions will address instant blood-mediated inflammatory reaction (IBMIR), apoptosis, and inflammation, and will translate into further marked improvements in single-donor success. Effective control of auto- and alloimmunity is the key to long-term islet function, and high-resolution cellular and antibody-based assays will add considerable precision to this process. Advances in immunosuppression, with new antibody-based targeting of costimulatory blockade and other T-B cellular signaling, will have further profound impact on the safety record of immunotherapy. Clinical trials will move forward shortly to test out new human stem cell derived islets, and in parallel trials will move forward, testing pig islets for compatibility in patients. Induction of immunological tolerance to self-islet antigens and to allografts is a difficult challenge, but potentially within our grasp.

Undeniable need for ultrafast-acting insulin: the pediatric perspective

Insulin therapy in youth with type 1 diabetes mellitus (T1DM) poses a special challenge because childhood is an unsteady state with increasing weight, height, and caloric needs, leading to varying insulin requirements. The current rapid-acting insulin analogs are not as fast and short-acting as needed to meet these challenges. This review describes the unique characteristics of insulin action in youth with T1DM based on previously published euglycemic clamp studies. It also explains the rationale behind the need for ultrafast-acting insulins to advance open- and closed-loop insulin therapy for the pediatric population with diabetes. Lastly, it briefly summarizes ongoing and future projects to accelerate insulin action in youth with T1DM.

Gain of function of cardiac ryanodine receptor in a rat model of type 1 diabetes

AIMS

Ventricular myocytes isolated from hearts of streptozotocin (STZ)-diabetic rats exhibit increased spontaneous Ca(2+) release. Studies attribute this defect to an enhancement in activity of type 2 ryanodine receptor (RyR2). To date, underlying reasons for RyR2 dysregulation remain undefined. This study assesses whether the responsiveness of RyR2 following stimulation by intrinsic ligands is being altered during experimental type 1 diabetes (T1D).

METHODS AND RESULTS

M-mode echocardiography established a cardiomyopathy in 8 weeks STZ-diabetic rats. Confocal microscopy confirmed an increase in the spontaneous Ca(2+) release in isolated ventricular myocytes. Western blots revealed no significant change in steady-state levels of the RyR2 protein. When purified to homogeneity and incorporated into planar lipid bilayers, RyR2 from STZ-diabetic rats (dRyR2) exhibited reduced current amplitude at ±35 mV. dRyR2 was also more responsive to intrinsic cytoplasmic activators Ca(2+), adenosine triphosphate, and cyclic adenosine diphosphate ribose and less responsive to the cytoplasmic deactivator Mg(2+). Threshold for the activation of RyR2 by trans (luminal) Ca(2+) was also reduced. These changes were independent of phosphorylation at Ser2808 and Ser2814. Two weeks of insulin treatment starting after 6 weeks of diabetes blunted the phenotype change, indicating that the gain of function is specific to the diabetes and not the result of STZ interacting directly with RyR2.

CONCLUSION

These data show, for the first time, that RyR2 is acquiring a gain-of-function phenotype independent of its phosphorylation status during T1D and provides new insights for the enhanced spontaneous Ca(2+) release in myocytes from T1D rats.

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.

Carbonylation contributes to SERCA2a activity loss and diastolic dysfunction in a rat model of type 1 diabetes

OBJECTIVE

Approximately 25% of children and adolescents with type 1 diabetes will develop diastolic dysfunction. This defect, which is characterized by an increase in time to cardiac relaxation, results in part from a reduction in the activity of the sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2a), the ATP-driven pump that translocates Ca(2+) from the cytoplasm to the lumen of the sarcoplasmic reticulum. To date, mechanisms responsible for SERCA2a activity loss remain incompletely characterized.

RESEARCH DESIGN AND METHODS

The streptozotocin (STZ)-induced murine model of type 1 diabetes, in combination with echocardiography, high-speed video detection, confocal microscopy, ATPase and Ca(2+) uptake assays, Western blots, mass spectrometry, and site-directed mutagenesis, were used to assess whether modification by reactive carbonyl species (RCS) contributes to SERCA2a activity loss.

RESULTS

After 6-7 weeks of diabetes, cardiac and myocyte relaxation times were prolonged. Total ventricular SERCA2a protein remained unchanged, but its ability to hydrolyze ATP and transport Ca(2+) was significantly reduced. Western blots and mass spectroscopic analyses revealed carbonyl adducts on select basic residues of SERCA2a. Mutating affected residues to mimic physio-chemical changes induced on them by RCS reduced SERCA2a activity. Preincubating with the RCS, methylglyoxal (MGO) likewise reduced SERCA2a activity. Mutating an impacted residue to chemically inert glutamine did not alter SERCA2a activity, but it blunted MGO's effect. Treating STZ-induced diabetic animals with the RCS scavenger, pyridoxamine, blunted SERCA2a activity loss and minimized diastolic dysfunction.

CONCLUSIONS

These data identify carbonylation as a novel mechanism that contributes to SERCA2a activity loss and diastolic dysfunction during type 1 diabetes.

Treatment of severe diabetic hypoglycemia with glucagon: an underutilized therapeutic approach

Tight glycemic control is important in reducing and delaying vascular complications in type 1 and 2 diabetes patients; however, the benefits achieved through strict metabolic control are counterbalanced by an increased risk of hypoglycemia. Glucagon is an effective therapy for treating severe hypoglycemia. Available as an emergency kit, glucagon is an essential tool for rapid response, but remains underappreciated and underused. This article reviews the role of glucagon in treating severe hypoglycemia and discusses the need for better education on glucagon for people with diabetes and their caregivers in order to alleviate fears of hypoglycemia and of administering glucagon in the event of an emergency.

Relationship between hypoglycemia and mortality in critically ill children

OBJECTIVES

To determine the prevalence of hypoglycemia in critically ill nondiabetic children and the association of hypoglycemia with mortality and worsening organ function in critically ill children.

DESIGN

Retrospective cohort study with matched-cohort analysis.

SETTING

Academic pediatric intensive care unit.

PATIENTS

A total of 899 nondiabetic patients <18 yrs old admitted to the pediatric intensive care unit for >1 day with at least one blood glucose measurement. Forty-two patients with a blood glucose level of <50 mg/dL (<2.8 mmol/L) were matched with 126 nonhypoglycemic patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Hypoglycemia, based on point-of-care blood glucose measurements, occurred in 2.2% (<40 mg/dL [<2.2 mmol/L]) to 7.5% (<60 mg/dL [<3.3 mmol/L]) of the patients. Hypoglycemia was more common in patients on mechanical ventilation and/or vasopressor support. Severity of hypoglycemia correlated with an increased mortality rate. The highest odds ratio of mortality was 4.49 (95% confidence interval [CI], 1.69-11.96; p < .01) at a blood glucose level of <40 mg/dL (<2.2 mmol/L). In the matched analysis, hypoglycemia was an independent risk factor for mortality. The unadjusted, covariate-adjusted, and propensity score-adjusted odds ratios of mortality were 3.69 (95% CI, 1.78-7.68; p < .01), 4.16 (95% CI, 1.53-11.32; p < .01), and 8.45 (95% CI, 1.75-40.86; p < .01), respectively. Hypoglycemia was associated with worsening organ function in the covariate-adjusted model (odds ratio, 2.37; 95% CI, 1.12-5.01; p = .02) but not in the unadjusted and propensity-score adjusted models.

CONCLUSIONS

Hypoglycemia is common in critically ill children. It is associated with increased mortality rates in critically ill nondiabetic children. Our data suggest that hypoglycemia is also associated with worsening organ function. Hypoglycemia may merely be a marker of severity of illness. Further investigations are needed to establish the mortality risk with hypoglycemia due to insulin compared to spontaneous hypoglycemia.

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.