Nocturnal hypoglycemia in children and adolescents with insulin-dependent diabetes mellitus: prevalence and risk factors

The Advanced Diabetes Technologies for Reduction of the Frequency of Hypoglycemia and Minimizing the Occurrence of Severe Hypoglycemia in Children and Adolescents with Type 1 Diabetes

Hypoglycemia is an often-observed acute complication in the management of children and adolescents with type 1 diabetes. It causes inappropriate glycemic outcomes and may impair the quality of life in the patients. Severe hypoglycemia with cognitive impairment, such as a convulsion and coma, is a lethal condition and is associated with later-onset cognitive impairment and brain-structural abnormalities, especially in young children. Therefore, reducing the frequency of hypoglycemia and minimizing the occurrence of severe hypoglycemia are critical issues in the management of children and adolescents with type 1 diabetes. Advanced diabetes technologies, including continuous glucose monitoring and sensor-augmented insulin pumps with low-glucose suspension systems, can reduce the frequency of hypoglycemia and the occurrence of severe hypoglycemia without aggravating glycemic control. The hybrid closed-loop system, an automated insulin delivery system, must be the most promising means to achieve appropriate glycemic control with preventing severe hypoglycemia. The use of these advanced diabetes technologies could improve glycemic outcomes and the quality of life in children and adolescents with type 1 diabetes.

Significance of "Time below Range" as a Glycemic Marker Derived from Continuous Glucose Monitoring in Japanese Children and Adolescents with Type 1 Diabetes

INTRODUCTION

We evaluated the frequencies of various glycemic markers derived from continuous glucose monitoring in Japanese children and adolescents with type 1 diabetes and assessed the significance of hypoglycemia duration.

METHODS

We enrolled 85 children and adolescents (36 boys and 49 girls) with type 1 diabetes who used FreeStyle® Libre in the present study. Frequencies of blood glucose levels as time within target range (TIR; 70-180 mg/dL), time below target range (TBR; <70 mg/dL), time below extreme hypoglycemia range (TBER; <54 mg/dL), and time above range (TAR; >180 mg/dL) were assessed during a 3-month study period. Furthermore, we evaluated the intraday frequencies of TBR and TBER.

RESULTS

The mean frequencies of TIR, TBR, and TAR were 52.7 ± 11.3%, 10.8 ± 5.4%, and 36.5 ± 10.8%, respectively, whereas the mean frequency of TBER was 1.1 ± 0.9% (0-3.0%); there was no clinical episode of severe hypoglycemia. The mean frequency of TBR was significantly greater in 0-6 h (16.9 ± 5.2%) than in 6-12 h (7.8 ± 2.9%) and 18-24 h (6.8 ± 4.8%; p < 0.01) time zones, respectively.

DISCUSSION/CONCLUSION

We found similar TIR and comparatively higher TBR frequencies, particularly during sleep, than those that were previously reported. Possible reasons for the higher frequency of TBR include differences in the quality of insulin treatment and diabetes care between the present study and the European studies. The utilization of advanced technologies, such as a predictive low-glucose suspend-function pump or closed-loop therapy, can reduce the frequency of TBR, with a consequent increase in TIR frequency and comprehensive improvement in glycemic control.

'Smart' insulin-delivery technologies and intrinsic glucose-responsive insulin analogues

Insulin replacement therapy for diabetes mellitus seeks to minimise excursions in blood glucose concentration above or below the therapeutic range (hyper- or hypoglycaemia). To mitigate acute and chronic risks of such excursions, glucose-responsive insulin-delivery technologies have long been sought for clinical application in type 1 and long-standing type 2 diabetes mellitus. Such 'smart' systems or insulin analogues seek to provide hormonal activity proportional to blood glucose levels without external monitoring. This review highlights three broad strategies to co-optimise mean glycaemic control and time in range: (1) coupling of continuous glucose monitoring (CGM) to delivery devices (algorithm-based 'closed-loop' systems); (2) glucose-responsive polymer encapsulation of insulin; and (3) mechanism-based hormone modifications. Innovations span control algorithms for CGM-based insulin-delivery systems, glucose-responsive polymer matrices, bio-inspired design based on insulin's conformational switch mechanism upon insulin receptor engagement, and glucose-responsive modifications of new insulin analogues. In each case, innovations in insulin chemistry and formulation may enhance clinical outcomes. Prospects are discussed for intrinsic glucose-responsive insulin analogues containing a reversible switch (regulating bioavailability or conformation) that can be activated by glucose at high concentrations.

Severe Hypoglycemia: Is It Still a Threat for Children and Adolescents With Type 1 Diabetes?

Severe hypoglycemia is defined as a condition with serious cognitive dysfunction, such as a convulsion and coma, requiring external help from other persons. This condition is still lethal and is reported to be the cause of death in 4-10% in children and adolescents with type 1 diabetes. The incidence of severe hypoglycemia in the pediatric population was previously reported as high as more than 50-100 patient-years; however, there was a decline in the frequency of severe hypoglycemia during the past decades, and relationship with glycemic control became weaker than previously reported. A lot of studies have shown the neurological sequelae with severe hypoglycemia as cognitive dysfunction and abnormalities in brain structure. This serious condition also provides negative psychosocial outcomes and undesirable compensatory behaviors. Various possible factors, such as younger age, recurrent hypoglycemia, nocturnal hypoglycemia, and impaired awareness of hypoglycemia, are possible risk factors for developing severe hypoglycemia. A low HbA_1c level is not a predictable value for severe hypoglycemia. Prevention of severe hypoglycemia remains one of the most critical issues in the management of pediatric patients with type 1 diabetes. Advanced technologies, such as continuous glucose monitoring (CGM), intermittently scanned CGM, and sensor-augmented pump therapy with low-glucose suspend system, potentially minimize the occurrence of severe hypoglycemia without worsening overall glycemic control. Hybrid closed-loop system must be the most promising tool for achieving optimal glycemic control with preventing the occurrence of severe hypoglycemia in pediatric patients with type 1 diabetes.

Biologically Inspired and Chemically Derived Methods for Glucose-Responsive Insulin Therapy

The controlled delivery of therapeutics in a manner responsive to physiological indicators has promise in realizing new therapeutic approaches to combat disease. This approach is especially relevant in the context of diabetes. Natural fluctuations in blood glucose seen in the healthy state, complete with peaks and troughs, are poorly regulated as a result of detrimental production or ineffective signaling of the insulin hormone. While several manifestations of diabetes are treated with regularly administered exogenous insulin, the present standard of care results in suboptimal glycemic management that poorly recreates natural hormone control, leading to long-term instability and a significantly increased risk for secondary health complications. New synthetic technologies that make insulin available only when needed, and at the exact dose required, have been explored under the broad vision of realizing a "fully synthetic pancreas." Yet, many challenges remain to realizing a technology that is appropriately responsive, safe, and well integrated into a manageable routine. Herein, many of the approaches explored thus far to sense physiological blood glucose and elicit response through the release of therapeutic insulin are summarized. The approaches point to a new, autonomous approach to managing diabetes with biomimetic therapy.

Fasting hypoglycemia is associated with disease progression in presymptomatic early stage type 1 diabetes

OBJECTIVE

In children with presymptomatic type 1 diabetes, intermittent hyperglycemia and rising hemoglobin A1c levels are a known signal of progression toward insulin-dependency. Episodes of hypoglycemia, however, have also been reported in one published case. We investigated the prevalence of hypoglycemia and its association with disease progression in children with presymptomatic type 1 diabetes.

METHODS

We compared the frequency of hypoglycemic fasting blood glucose levels (<60 mg/dL) in 48 autoantibody negative and 167 multiple β-cell autoantibody positive children aged 2 to 5 years. We classified the autoantibody positive children into three categories based on their glucose levels in fasting state (hypoglycemic [<60 mg/dL], normoglycemic [60-99 mg/dL] or hyperglycemic [≥100 mg/dL]). We then compared the glucose levels under challenge during oral glucose tolerance tests (OGTTs) between the three categories.

RESULTS

In the autoantibody positive children, 5.1% of the fasting samples were hypoglycemic, while in the autoantibody negative children no hypoglycemia was observed. Hypoglycemia occurred more often in autoantibody positive children who had already entered stage 2 or stage 3 of type 1 diabetes than in stage 1 patients (P = 0.02). Children who had hypoglycemic compared to normoglycemic fasting blood glucose values had higher 120-minute blood glucose values under OGTT challenge, and a higher rate of pathological OGTTs (P = 0.04).

CONCLUSIONS

Fasting hypoglycemia seems to be an indicator of disease progression in presymptomatic type 1 diabetes and may therefore represent a novel marker for the identification of children who should be monitored more closely for progression toward insulin-dependent type 1 diabetes.

Adrenaline and cortisol levels are lower during nighttime than daytime hypoglycaemia in children with type 1 diabetes

AIM

We investigated children's counter regulatory hormone profiles during a hyperinsulinaemic hypoglycaemic clamp procedure at day and night.

METHODS

In 2013, we assessed the counter regulatory response to hypoglycaemia in eight outpatients with type 1 diabetes, recruited from the Herlev Hospital, Denmark, at a mean age of 9.6 ± 2.3 years. Hyperinsulinaemic 80 mU/m² /min clamps were performed with a stepwise reduction in plasma glucose from euglycaemia (7-9 mmol/L) to hypoglycaemia (<3.5 mmol/L) and the glucose nadir (≤2.2 mmol/L) during the day and night. Adrenaline, cortisol, glucagon and growth hormone levels were assessed.

RESULTS

Adrenaline and growth hormone levels were higher during the day versus the night (p = 0.04 and p = 0.01, respectively). However, at the glucose nadir, the level of adrenaline was lower during the night than the day (0.6 ± 0.2 versus 1.9 ± 0.5 nmol/L, p = 0.016) and cortisol was lower during the day than the night (42 ± 15 versus 319 ± 81 nmol/L, p = 0.016). No differences were demonstrated for glucagon and growth hormone levels based on the same criteria.

CONCLUSION

The adrenaline response was blunted during nocturnal iatrogenic hypoglycaemia in our study cohort, and no increase in cortisol levels was demonstrated.

The risks of nocturnal hypoglycaemia in insulin-treated diabetes

Over half of all episodes of severe hypoglycaemia (requiring external help) occur during sleep, but nocturnal hypoglycaemia is often asymptomatic and unrecognised. The precise incidence of nocturnal hypoglycaemia is difficult to determine with no agreed definition, but continuous glucose monitoring has shown that it occurs frequently in people taking insulin. Attenuation of the counter-regulatory responses to hypoglycaemia during sleep may explain why some episodes are undetected and more prolonged, and modifies cardiovascular responses. The morbidity and mortality associated with nocturnal hypoglycaemia is probably much greater than realised, causing seizures, coma and cardiovascular events and affecting quality of life, mood and work performance the following day. It may induce impaired awareness of hypoglycaemia. Cardiac arrhythmias that occur during nocturnal hypoglycaemia include bradycardia and ectopics that may provoke dangerous arrhythmias. Treatment strategies are discussed that may help to minimise the frequency of nocturnal hypoglycaemia.

Dietary intake and risk of non-severe hypoglycemia in adolescents with type 1 diabetes

AIMS

To determine the association between dietary intake and risk of non-severe hypoglycemia in adolescents with type 1 diabetes.

METHODS

Type 1 adolescents from a randomized trial wore a blinded continuous glucose monitoring (CGM) system at baseline for one week in free-living conditions. Dietary intake was calculated as the average from two 24-h dietary recalls. Non-severe hypoglycemia was defined as having blood glucose <70mg/dL for ≥10min but not requiring external assistance, categorized as daytime and nocturnal (11PM-7AM). Data were analyzed using logistic regression models.

RESULTS

Among 98 participants with 14,277h of CGM data, 70 had daytime hypoglycemia, 66 had nocturnal hypoglycemia, 55 had both, and 17 had neither. Soluble fiber and protein intake were positively associated with both daytime and nocturnal hypoglycemia. Glycemic index, monounsaturated fat, and polyunsaturated fat were negatively associated with daytime hypoglycemia only. Adjusting for total daily insulin dose per kilogram eliminated all associations.

CONCLUSIONS

Dietary intake was differentially associated with daytime and nocturnal hypoglycemia. Over 80% of type 1 adolescents had hypoglycemia in a week, which may be attributed to the mismatch between optimal insulin dose needed for each meal and actually delivered insulin dose without considering quality of carbohydrate and nutrients beyond carbohydrate.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01286350.

Development of glucose-responsive 'smart' insulin systems

PURPOSE OF REVIEW

The complexity of modern insulin-based therapy for type I and type II diabetes mellitus and the risks associated with excursions in blood-glucose concentration (hyperglycemia and hypoglycemia) have motivated the development of 'smart insulin' technologies (glucose-responsive insulin, GRI). Such analogs or delivery systems are entities that provide insulin activity proportional to the glycemic state of the patient without external monitoring by the patient or healthcare provider. The present review describes the relevant historical background to modern GRI technologies and highlights three distinct approaches: coupling of continuous glucose monitoring (CGM) to deliver devices (algorithm-based 'closed-loop' systems), glucose-responsive polymer encapsulation of insulin, and molecular modification of insulin itself.

RECENT FINDINGS

Recent advances in GRI research utilizing each of the three approaches are illustrated; these include newly developed algorithms for CGM-based insulin delivery systems, glucose-sensitive modifications of existing clinical analogs, newly developed hypoxia-sensitive polymer matrices, and polymer-encapsulated, stem-cell-derived pancreatic β cells.

SUMMARY

Although GRI technologies have yet to be perfected, the recent advances across several scientific disciplines that are described in this review have provided a path towards their clinical implementation.

Prediction of nocturnal hypoglycemia by an aggregation of previously known prediction approaches: proof of concept for clinical application

BACKGROUND AND OBJECTIVE

Nocturnal hypoglycemia (NH) is common in patients with insulin-treated diabetes. Despite the risk associated with NH, there are only a few methods aiming at the prediction of such events based on intermittent blood glucose monitoring data and none has been validated for clinical use. Here we propose a method of combining several predictors into a new one that will perform at the level of the best involved one, or even outperform all individual candidates.

METHODS

The idea of the method is to use a recently developed strategy for aggregating ranking algorithms. The method has been calibrated and tested on data extracted from clinical trials, performed in the European FP7-funded project DIAdvisor. Then we have tested the proposed approach on other datasets to show the portability of the method. This feature of the method allows its simple implementation in the form of a diabetic smartphone app.

RESULTS

On the considered datasets the proposed approach exhibits good performance in terms of sensitivity, specificity and predictive values. Moreover, the resulting predictor automatically performs at the level of the best involved method or even outperforms it.

CONCLUSION

We propose a strategy for a combination of NH predictors that leads to a method exhibiting a reliable performance and the potential for everyday use by any patient who performs self-monitoring of blood glucose.

Development of the Likelihood of Low Glucose (LLG) algorithm for evaluating risk of hypoglycemia: a new approach for using continuous glucose data to guide therapeutic decision making

The objective was to develop an analysis methodology for generating diabetes therapy decision guidance using continuous glucose (CG) data. The novel Likelihood of Low Glucose (LLG) methodology, which exploits the relationship between glucose median, glucose variability, and hypoglycemia risk, is mathematically based and can be implemented in computer software. Using JDRF Continuous Glucose Monitoring Clinical Trial data, CG values for all participants were divided into 4-week periods starting at the first available sensor reading. The safety and sensitivity performance regarding hypoglycemia guidance "stoplights" were compared between the LLG method and one based on 10th percentile (P10) values. Examining 13 932 hypoglycemia guidance outputs, the safety performance of the LLG method ranged from 0.5% to 5.4% incorrect "green" indicators, compared with 0.9% to 6.0% for P10 value of 110 mg/dL. Guidance with lower P10 values yielded higher rates of incorrect indicators, such as 11.7% to 38% at 80 mg/dL. When evaluated only for periods of higher glucose (median above 155 mg/dL), the safety performance of the LLG method was superior to the P10 method. Sensitivity performance of correct "red" indicators of the LLG method had an in sample rate of 88.3% and an out of sample rate of 59.6%, comparable with the P10 method up to about 80 mg/dL. To aid in therapeutic decision making, we developed an algorithm-supported report that graphically highlights low glucose risk and increased variability. When tested with clinical data, the proposed method demonstrated equivalent or superior safety and sensitivity performance.

Fear of hypoglycaemia in patients with type 1 diabetes

Independently of causes and risk factors of hypoglycaemia, its manifestations are always unfavourable and evoke fear and other negative emotions that lead to negative consequences connected with quality of diabetes control. The fear of hypoglycaemia creates an internal conflict by diminishing patients? motivation to adhere to intensive treatment regimes. In addition to the severity of hypoglycaemia and its negative consequences, quality of life is one of the main criteria for evaluating the physical, psychological and social components of patient's life as a whole. Fear of hypoglycaemia is one of the most important factors; it either directly or indirectly affects quality of life and influences all aspects of the patient's life. Fear of hypoglycaemia is also a source of anxiety for the patient's relatives, causing damage to their familial and social relations. The negative consequences of hypoglycaemia can affect the relationship between spouses, as well as between parents and children with type 1 diabetes. The qualitative and quantitative data demonstrate that non-severe nocturnal hypoglycaemia causes more anxiety and fear in patients than daytime hypoglycaemia does. To quantify the fear of hypoglycaemia in adults with type 1 diabetes, the hypoglycaemia fear scale (HFS) was developed and still is the most commonly used instrument. To assess the fear of hypoglycaemia in children and their parents, the HFS scale was adapted to be used in the paediatric population: HFS for parents (PHFS) and HFS for children (CHFS). From a clinical point of view, these scales for measuring the level of fear of hypoglycaemia may be useful for monitoring adult patients and families who may need additional support, training or assistance in dealing with issues related to hypoglycaemia. The methods for regulating the fear of hypoglycaemia range from behavioural to pharmaceutical and surgical ones, and include a broad range of activities. Nevertheless, the problem remains quite relevant today and an integral approach for solving this problem, both by the physician and by the patient, should be used. Proper assessment of the patient's level of anxiety, impact of the fear of hypoglycaemia on his or her social life, awareness of the possible psychological consequences of this problem may positively affect both the behaviour and mood of the patient, and the opportunity to achieve better glycaemic control.

Closing the loop overnight at home setting: psychosocial impact for adolescents with type 1 diabetes and their parents

OBJECTIVE

To explore the experiences of adolescents with type 1 diabetes mellitus (T1DM) and their parents taking part in an overnight closed loop study at home, using qualitative and quantitative research methods.

RESEARCH DESIGN AND METHODS

Adolescents aged 12-18 years on insulin pump therapy were recruited to a pilot closed loop study in the home setting. Following training on the use of a study insulin pump and continuous glucose monitoring (CGM), participants were randomized to receive either real-time CGM combined with overnight closed loop or real-time CGM alone followed by the alternative treatment for an additional 21 days with a 2-3-week washout period in between study arms. Semistructured interviews were performed to explore participants' perceptions of the impact of the closed loop technology. At study entry and again at the end of each 21-day crossover arm of the trial, participants completed the Diabetes Technology Questionnaire (DTQ) and Hypoglycemia Fear Survey (HFS; also completed by parents).

RESULTS

15 adolescents and 13 parents were interviewed. Key positive themes included reassurance/peace of mind, confidence, 'time off' from diabetes demands, safety, and improved diabetes control. Key negative themes included difficulties with calibration, alarms, and size of the devices. DTQ results reflected these findings. HFS scores were mixed.

CONCLUSIONS

Closed loop insulin delivery represents cutting-edge technology in the treatment of T1DM. Results indicate that the psychological and physical benefits of the closed loop system outweighed the practical challenges reported. Further research from longitudinal studies is required to determine the long-term psychosocial benefit of the closed loop technology.

Hypoglycaemia, fear of hypoglycaemia and quality of life in children with Type 1 diabetes and their parents

AIM

To evaluate the association between fear of hypoglycaemia, episodes of hypoglycaemia and quality of life in children with Type 1 diabetes and their parents.

METHODS

This was a cross-sectional, population-based study of 325 children with Type 1 diabetes and their parents. The children were aged 2-18 years. A total of 325 parents of the patients aged 2-18 years and 196 of the patients themselves (aged 8-18 years) completed questionnaires including the PedsQL Diabetes Module, the Hypoglycaemia Fear Survey and Clarke's hypoglycaemia awareness questionnaire. Data were compared with HbA1c results and the history of severe hypoglycaemia episodes.

RESULTS

Parents with the highest levels of fear of hypoglycaemia reported that their children had a reduced quality of life (P < 0.001). Similarly children with the greatest fear also reported a reduced quality of life (P < 0.001); however a history of severe hypoglycaemia was not associated with the child's quality of life as perceived by the child or parent. Episodes of severe hypoglycaemia were associated with an increased fear of hypoglycaemia for the parents (P = 0.004) but not the children. Children in the highest fear quartile also had a higher HbA(1c) concentration compared with those in the lowest fear quartile [increase in HbA(1c) 7 mmol/mol (0.6%), P < 0.01].

CONCLUSIONS

Fear of hypoglycaemia and not episodes of hypoglycaemia per se is associated with increased psychological burden for children with Type 1 diabetes. Interventions to reduce fear of hypoglycaemia in these families may improve their quality of life.

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.

NON-INVASIVE NOCTURNAL HYPOGLYCEMIA DETECTION FOR INSULIN-DEPENDENT DIABETES MELLITUS USING GENETIC FUZZY LOGIC METHOD

Hypoglycemia, or low blood glucose, is the most common complication experienced by Type 1 diabetes mellitus (T1DM) patients. It is dangerous and can result in unconsciousness, seizures and even death. The most common physiological parameter to be effected from hypoglycemic reaction are heart rate (HR) and correct QT interval (QTc) of the electrocardiogram (ECG) signal. Based on physiological parameters, a genetic algorithm based fuzzy reasoning model is developed to recognize the presence of hypoglycemia. To optimize the parameters of the fuzzy model in the membership functions and fuzzy rules, a genetic algorithm is used. A validation strategy based adjustable fitness is introduced in order to prevent the phenomenon of overtraining (overfitting). For this study, 15 children with 569 sampling data points with Type 1 diabetes volunteered for an overnight study. The effectiveness of the proposed algorithm is found to be satisfactory by giving better sensitivity and specificity compared with other existing methods for hypoglycemia detection.

A prototype of a new noninvasive device to detect nocturnal hypoglycemia in adolescents with type 1 diabetes--a pilot study

BACKGROUND

Severe hypoglycemic events are a major consequence of tight diabetes control. Continuous glucose monitoring systems (CGMSs) were recently introduced in order to minimize the risk of hypoglycemia. However, the present CGMSs are invasive and costly and have been recently demonstrated to be intolerant for most children and adolescents. Hence there is a need for a simple, noninvasive, convenient, and inexpensive device to detect hypoglycemic events. The Gili Medical Hypoglycemia Non Invasive Monitoring System (GMHNIMS) (Gili Medical Ltd., Migdal HaEmek, Israel) has been currently developed for these purposes.

SUBJECTS AND METHODS

Ten patients 14-18 years old with type 1 diabetes for at least 1 year participated in a pilot study that was held at the Meyer Children's Hospital, Rambam Medical Center, Haifa, Israel. All patients were either treated by insulin pump or by multiple daily injections. The GMHNIMS was connected to the study subjects during three consecutive nights in an inpatient setting while they received their usual insulin regimen. The system is composed of four sensors (heart rate, perspiration, skin temperature, and tremor) that detect physiologic changes during hypoglycemia. In addition, each patient was connected to a real-time CGMS for 3 nights. When a hypoglycemic event was suspected clinically by the patient, a bedside capillary glucose was checked by a glucometer.

RESULTS

The system was found to be convenient without any disturbances to sleep quality. The sensitivity of the GMHNIMS for detection of true hypoglycemic events was 100% with specificity of 85.7%.

CONCLUSIONS

The new device showed high detection rates of nocturnal hypoglycemic events with an acceptable degree of false-positive readings. Being inexpensive and noninvasive, this device has the potential for routine use in insulin-treated patients.

Insulin therapy and hypoglycemia

Hypoglycemia is the most important and common side effect of insulin therapy. It is also the rate limiting factor in safely achieving excellent glycemic control. A three-fold increased risk of severe hypoglycemia occurs in both type 1 and type 2 diabetes with tight glucose control. This dictates a need to individualize therapy and glycemia goals to minimize this risk. Several ways to reduce hypoglycemia risk are recognized and discussed. They include frequent monitoring of blood sugars with home blood glucose tests and sometimes continuous glucose monitoring (CGM) in order to identify hypoglycemia particularly in hypoglycemia unawareness. Considerations include prompt measured hypoglycemia treatment, attempts to reduce glycemic variability, balancing basal and meal insulin therapy, a pattern therapy approach and use of a physiological mimicry with insulin analogues in a flexible manner. Methods to achieve adequate control while focusing on minimizing the risk of hypoglycemia are delineated in this article.

Hypoglycemia does not change the threshold for arousal from sleep in adolescents with type 1 diabetes

BACKGROUND

Nocturnal hypoglycemia is a significant problem for children and adolescents with type 1 diabetes. The counterregulatory hormone response to hypoglycemia is blunted in both patients with type 1 diabetes and healthy subjects during sleep. It is not known whether the threshold for arousal from sleep is also modified by hypoglycemia. To address this question we compared the acoustic arousal threshold from sleep during hypoglycemia and euglycemia in adolescents with type 1 diabetes.

METHODS

Adolescents with type 1 diabetes were studied on two occasions: under hypoglycemic and euglycemic conditions. During the hypoglycemia night, subjects underwent a hyperinsulinemic hypoglycemic clamp with nadir glucose level of 2.8 mmol/L. Hypoglycemia was initiated during stage 2 sleep and maintained during slow-wave sleep. During the euglycemia night, blood glucose was maintained at 5.5 mmol/L using the same clamp technique. The acoustic arousal threshold was determined during the first cycle of slow-wave sleep.

RESULTS

Seven subjects (mean±SE, 14.2±0.8 years old, mean glycosylated hemoglobin 8.1±0.3%, duration of diagnosis 2.5±0.5 years) completed both study nights. Arousal was only noted during acoustic testing and did not occur during hypoglycemia alone. The acoustic arousal threshold during slow-wave sleep was similar under both conditions: 79±8 dB during euglycemia and 71±6 dB (P=0.353) during hypoglycemia.

CONCLUSION

In adolescents with type 1 diabetes, hypoglycemia does not impair arousal from slow-wave sleep induced by an external auditory stimulus.

Insufficient sleep in young patients with diabetes and their families

OBJECTIVE

We examined sleep in families of individuals with type 1 diabetes and the relationship of sleep with obesity, diabetes, and insulin resistance.

METHODS

Probands with type 1 diabetes diagnosed before age 18 and first- and second-degree relatives were included (n = 323). Demographic, anthropometric and clinical variables, and self-reported sleep duration and napping were assessed.

RESULTS

On average, adults (≥20 years) slept 7.5 (SD 1.5) hr, whereas children (5-11 years) and adolescents (12-19 years) slept 9.8 (SD 1.1) and 8.5 (SD 1.9) hr, respectively (p < .01). Based on national recommendations, 40.9% of participants slept insufficiently, particularly young people (vs. adults, p < .01). In age-group stratified analysis, there were no significant associations of insufficient sleep or sleep duration with obesity, diabetes status, or insulin resistance after adjustment for age, race/ethnicity, and gender. In all, 42% of participants reported napping regularly (≥1/week), with adolescents significantly more likely to do so (vs. adults, odds ratio [OR] = 1.95, p < .01). Non-Hispanic Blacks and Hispanics also had higher odds of regular napping (vs. non-Hispanic Whites, OR = 3.74, p < .01 and OR = 2.52, p = .03, respectively). In adjusted analysis, leaner (vs. obese) adolescents, whether measured by body mass index, percentage body fat, or waist circumference, were significantly more likely to nap regularly.

CONCLUSIONS

We found that insufficient sleep was significantly more likely in children and adolescents compared with adults in families with type 1 diabetes. Lower adiposity was associated with regular napping in adolescents. The high prevalence of insufficient sleep in young patients with type 1 diabetes and their relatives detected in the current study may have significant health consequences.

Assessing fear of hypoglycemia in children with Type 1 diabetes and their parents

This article summarizes the literature on fear of hypoglycemia in pediatric Type 1 diabetes and the assessment of this fear in both children with Type 1 diabetes and their parents. The most common instrument for assessing fear of hypoglycemia in this population is the children's and parent's versions of the Hypoglycemia Fear Survey (HFS), although studies using other assessment measures are also reviewed. Studies using this survey have identified variables contributing to fear of hypoglycemia in children with Type 1 diabetes and their parents, such as history of frequent or traumatic hypoglycemia, as well as trait anxiety. In addition to this summary of the literature, new data are presented supporting the reliability of hypoglycemic fear assessment in younger children and comparing fear of hypoglycemia in children in different age groups (6-18 years old) and their parents. Also reviewed are studies investigating the relationship between fear of hypoglycemia and diabetes control, which have yielded inconsistent results. Given the potential importance of fear of hypoglycemia in pediatric diabetes, there has been limited research in this area.

Prevalence of nocturnal hypoglycemia in pediatric type 1 diabetes: a pilot study using continuous glucose monitoring

OBJECTIVES

To determine the prevalence of nocturnal hypoglycemia (NH) in pediatric type 1 diabetes, to compare the prevalence of NH detected by continuous glucose monitoring (CGM) and self-monitored blood glucose (SMBG), and to compare the prevalence of NH using different thresholds.

STUDY DESIGN

Twenty-five patients wore a continuous glucose monitor for 3 nights and also conducted SMBG. NH was defined with three thresholds: (1) <3.9 mmol/L; (2) <3.3 mmol/L; and (3) <2.9 mmol/L.

RESULTS

The prevalence of NH with CGM was 68%, 52%, and 48% with the different thresholds. Of the 35 episodes of NH detected by CGM, 25 were not symptomatic and therefore not detected by SMBG. The mean difference in blood glucose between CGM and SMBG was -0.18 mmol/L (P = .35).

CONCLUSIONS

This pilot study suggests that the prevalence of NH in pediatric patients with type 1 diabetes with conventional treatment may be as high as 68%, although this varied according to the method of detection and threshold used. Patients may benefit from CGM to detect asymptomatic NH.

Automated overnight closed-loop glucose control in young children with type 1 diabetes

BACKGROUND

We evaluated the effectiveness of automated overnight closed-loop (AOCL) insulin delivery and the influence of timing of initiation on glucose control overnight in young children with type 1 diabetes (T1D).

METHODS

Eight children with T1D (four boys, four girls) (mean ± SD: 9.4 ± 2.7 years old; body mass index, 18.3 ± 2.3 kg/m(2); duration of diabetes, 3.9 ± 2.5 years; total daily insulin dose, 0.7 ± 0.1 U/kg/day; glycosylated hemoglobin, 7.9 ± 0.9%) were studied in a clinical research facility on two separate occasions. Subjects had a meal at 18:00 (77 ± 8 g of carbohydrate [CHO]) and snack at 21:00 (21 ± 6 g of CHO), both accompanied by a prandial insulin bolus. In random order, AOCL was started at 18:00 or 21:00 h and ran until 08:00 h the next day. Subcutaneous continuous glucose monitoring data were fed automatically into the model predictive control algorithm. Calculated subcutaneous insulin infusion rates were sent wirelessly to an insulin pump. Plasma glucose was measured to assess closed-loop performance.

RESULTS

No rescue CHOs were administered. Time spent with plasma glucose in the target range from 3.9 to 8.0 mmol/L was 50.7% (29.0%, 72.2%), and it did not differ on the two occasions: median (interquartile range), 42% (18%, 64%) versus 58% (32%, 79%) (P = 0.161). Time when plasma glucose was above 8.0 mmol/L (42% [25%, 82%] vs. 29% [14%, 64%], P = 0.093), time below 3.9 mmol/L (0% [0%, 11%] vs. 8% [0%, 17%], P = 0.500), low blood glucose index (0.1 [0.0, 2.5] vs. 1.7 [0.4, 3.3], P = 0.380), plasma glucose at the start of AOCL (12.5 ± 2.7 vs. 11.6 ± 4.2 mmol/L, P = 0.562), and mean overnight plasma glucose (8.3 ± 2.1 vs. 7.5 ± 2.2 mmol/L, P = 0.246) were also similar.

CONCLUSIONS

AOCL is feasible in young children with T1D. Comparable results were obtained when closed-loop was initiated at 18:00 or 21:00 h.

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.

Sleep and the response to hypoglycaemia

Undetected nocturnal hypoglycaemia frequently occurs in patients with diabetes, having a negative influence on well-being, counterregulation against and awareness of subsequent hypoglycaemia, and even causing sudden death in some cases most likely by inducing cardiac arrhythmia. Sleep markedly weakens the neuroendocrine defence mechanism against hypoglycaemia by shifting the glycaemic threshold for counterregulatory activation to lower levels. While hypoglycaemia triggers awakening in healthy subjects, patients with type 1 diabetes frequently fail to awake in the presence of low plasma glucose levels. Little is known about the frequency of and responses to nocturnal hypoglycaemia in patients with type 2 diabetes. Unfortunately, effective strategies to prevent or even safely detect nocturnal hypoglycaemia are still lacking. Taken together, hypoglycaemia occurring during sleep presents a major, often neglected problem in the management of diabetic patients. Different aspects of this phenomenon such as responses to and consequences of nocturnal hypoglycaemia as well as strategies for its prevention are highlighted in this review.

Parental attitudes towards overnight closed-loop glucose control in children with type 1 diabetes

BACKGROUND

This study examined parental attitudes towards overnight closed-loop (CL) glucose control in children and young people with type 1 diabetes (T1D).

METHODS

Twelve families recruited by the INsulin PUmp Therapy group (INPUT), a U.K. patient/carer-led support group for people with T1D, attended a focus meeting on CL. The concept of CL was explained, and clinical results and plans regarding the Artificial Pancreas Project at Cambridge were presented. Participants completed a questionnaire to evaluate parental feelings about T1D management and attitudes towards overnight CL insulin delivery.

RESULTS

Nineteen parents (12 mothers and seven fathers) anonymously completed the questionnaire. Main concerns about diabetes were related to long-term complications (84%) and hypoglycemia (16%). Achieving good glucose control represented major challenge for carers (83%) with nighttime being the most difficult period to manage (56%), worrying most parents (71%) particularly because of fear of hypoglycemia (33%). The development of CL to manage diabetes was welcomed by all parents (100%) with 95% happy for their child to wear a continuous glucose monitor together with an insulin pump. All parents were ready to respond to additional alarms at night with 90% parents not worried about their child's overnight insulin delivery being controlled by a computer.

CONCLUSIONS

Selected parents of children with T1D who are already insulin pump users express implied trust in the technology for overnight CL insulin delivery. Nighttime blood glucose control is the biggest challenge and concern for parents, and the development of a commercially available overnight CL system may be an important goal.

Clinical evaluation of a noninvasive alarm system for nocturnal hypoglycemia

BACKGROUND

The aim of this study was to evaluate the performance of a prototype noninvasive alarm system (HypoMon) for the detection of nocturnal hypoglycemia. A prospective cohort study evaluated an alarm system that included a sensor belt, a radio frequency transmitter for chest belt signals, and a receiver. The receiver incorporated integrated "real-time" algorithms designed to recognize hypoglycemia "signatures" in the physiological parameters monitored by the sensor belt.

METHODS

Fifty-two children and young adults with type 1 diabetes mellitus (T1DM) participated in this blinded, prospective, in-clinic, overnight study. Participants had a mean age of 16 years (standard deviation 2.1, range 12-20 years) and were asked to follow their normal meal and insulin routines for the day of the study. Participants had physiological parameters monitored overnight by a single HypoMon system. Their BG levels were also monitored overnight at regular intervals via an intravenous cannula and read on two independent Yellow Springs Instruments analyzers. Hypoglycemia was not induced by any manipulations of diabetes management, rather the subjects were monitored overnight for "natural" occurrences of hypoglycemia. Performance analyses included comparing HypoMon system alarm times with allowed time windows associated with each hypoglycemic event.

RESULTS

The primary recognition algorithm in the prototype alarm system performed at a level consistent with expectations based on prior user surveys. The HypoMon system correctly recognized 8 out of the 11 naturally occurring overnight hypoglycemic events and falsely alarmed on 13 out of the remaining 41 normal nights [sensitivity 73% (8/11), specificity 68% (28/41), positive predictive value 38%,negative predictive value 90%].

CONCLUSION

The prototype HypoMon shows potential as an adjunct method for noninvasive overnight monitoring for hypoglycemia events in young people with T1DM.

Continuous glucose monitoring in youth with type 1 diabetes

Continuous glucose monitoring (CGM) is becoming increasingly popular and represents the third era of diabetes management. Currently available CGM devices have been studied in youth with type 1 diabetes and show similar accuracy across all age groups. Tolerability of these devices relates to alarm settings, sensor skin irritation, and durability of the device. Youth will be most successful on a CGM regimen if they have a personal investment in wearing the CGM device and have a stable support system for their diabetes care. Data indicate that glycemic control improves the most in youth who wear CGM devices >or=5 days per week, allowing for the ability to make more insulin dose changes. CGM has proven useful in alerting youth to hypoglycemia and may be a valuable tool with exercise. Further studies are needed to assess the utility of CGM for prevention of severe hypoglycemic events and increasing time spent in euglycemia. Fear of hypoglycemia may be ameliorated with CGM use; however, the potential for increased stress in families with continuous feedback must also be considered. In the future, CGM use in youth may couple with insulin pump technology to create a "closed-loop" system in which the CGM device will direct insulin administration without user input.

Mechanisms of the blunting of the sympatho-adrenal response: a theory

Development of therapeutic measures to reduce the risk of potentially fatal episodes of hypoglycaemia and thus to achieve the full benefits of intensive insulin therapy in diabetic patients requires a complete understanding of the multi-factorial mechanisms for repeated hypoglycaemia-induced blunting of the sympatho-adrenal response (BSAR). After critical analysis of the hypotheses, this review paper suggests a heuristic theory. This theory suggests two mechanisms for the BSAR, each involving a critical role for the central brain noradrenergic system. Furthermore, this theory also suggests that the lateral hypothalamus (LH) plays an important role in this phenomenon. Within the framework of this theory, explanations for 1) sexual dimorphism in the adrenomedullary response (AR), 2) dissociation in the blunting of the AR and the sympathetic response (SR) and 3) antecedent exercise-induced blunting of the AR are provided. In addition, habituation of orexin-A neurons is suggested to cause defective awakening. Moreover, potential therapeutics measures have been also suggested that will reduce or prevent severe episodes of hypoglycaemia.

Clinical evaluation of bionime rightest GM310 biosensors with a simplified electrode fabrication for alternative-site blood glucose tests

BACKGROUND

Most processes for fabricating biosensors applied to screen-printed carbon electrodes (SPCEs) are complex. This study presents a novel one-step process for manufacturing electrodes for injection-molding biosensors.

METHODS

During the sensor-fabrication process, barrel-plated gold electrodes were inserted into an injection-molded base. The electrode directly touched the electrical contact of a meter. We analyzed technical measurements for this biosensor, including tests of the measurement range, within-run imprecision, and between-meter imprecision. In clinical trials, experienced technicians tested 3 alternative sites (fingertip, palm, and arm). The results were simultaneously compared with plasma values obtained with the hexokinase method on the Olympus AU640 instrument. Analytical results were evaluated according to International Standards Organization 15197 (ISO 15197:2003) criteria and by Clarke error grid analysis (EGA), and CVs were calculated to evaluate within-run imprecision.

RESULTS

The glucose measurement range was 0.6- 33.3 mmol/L (y = 0.96x + 0.07 mmol/L; r(2) = 0.9977). The CVs in the within-run imprecision test were 1.7%-3.5%, and the overall CV was 2.1%, indicating good reproducibility of results. The Student t-tests of mean values from 5 meters revealed statistically insignificant differences (P > 0.05). In clinical trials, the agreement of the Rightest GM310 meter results with those of a laboratory method complied with ISO 15197:2003 criteria. In the EGA, 100% of the values were within the acceptable zones (A + B), and the proportion of values within zone A exceeded 95%.

CONCLUSIONS

The Bionime Rightest GM310 meter applied a simplified process for biosensor fabrication and displayed acceptable performance for monitoring glucose concentrations at alternative test sites.

Prior hypoglycemia enhances glucose responsiveness in some ventromedial hypothalamic glucosensing neurons

Antecedent insulin-induced hypoglycemia (IIH) reduces adrenomedullary responses (AMR) to subsequent bouts of hypoglycemia. The ventromedial hypothalamus [VMH: arcuate (ARC) + ventromedial nuclei] contains glucosensing neurons, which are thought to be mediators of these AMR. Since type 1 diabetes mellitus often begins in childhood, we used juvenile (4- to 5-wk-old) rats to demonstrate that a single bout of IIH (5 U/kg sc) reduced plasma glucose by 24% and peak epinephrine by 59% 1 day later. This dampened AMR was associated with 46% higher mRNA for VMH glucokinase, a key mediator of neuronal glucosensing. Compared with neurons from saline-injected rats, ventromedial nucleus glucose-excited neurons from insulin-injected rats demonstrated a leftward shift in their glucose responsiveness (EC50= 0.45 and 0.10 mmol/l for saline and insulin, respectively, P = 0.05) and a 31% higher maximal activation by glucose ( P = 0.05), although this maximum occurred at a higher glucose concentration (saline, 0.7 vs. insulin, 1.5 mmol/l). Although EC50values did not differ, ARC glucose-excited neurons had 19% higher maximal activation, which occurred at a lower glucose concentration in insulin- than saline-injected rats (saline, 2.5 vs. insulin, 1.5 mmol/l). In addition, ARC glucose-inhibited neurons from insulin-injected rats were maximally inhibited at a fivefold lower glucose concentration (saline, 2.5 vs. insulin, 0.5 mmol/l), although this inhibition declined at >0.5 mmol/l glucose. These data suggest that the increased VMH glucokinase after IIH may contribute to the increased responsiveness of VMH glucosensing neurons to glucose and the associated blunting of the AMR.

High volume-low intensity exercise camp and glycemic control in diabetic children

AIM

To evaluate the effects of the designed regime encompassing high volume-low intensity physical activity programme on glycemic control in diabetic children, 20 subjects (age 12.81 +/- 2.14) spent 2 weeks in a controlled environment of a summer camp.

METHODS

An exercise physiologist and a kinesiology specialist programme and conducted the three exercise sessions a day. Total daily caloric intake was controlled and the blood glucose was monitored four times a day with special concern for hypoglycaemia episodes. Short and long-term effects (HbA1c) of the summer camp were evaluated 10 days and 2 months following programme completion. The insulin dosage was not lowered at the beginning of the camp for everyone, but it was individually modified according to the blood glucose monitoring.

RESULTS

Initial HbA1c was 8.28 +/- 1.3% and decreased to 7.92 +/- 1.42% measured 10 days after the camp (P = 0.023) while the number of children with the satisfactory HbA1c level lower than 7.5% doubled. HbA1c increased again 2 months following the camp. The average blood glucose concentrations decreased in the last days of the camp when compared with the first day in three out of four daily measurements (P < 0.05). There were only two clinically manifested hypoglycaemia episodes recorded.

CONCLUSION

With a low rate of hypoglycaemia crisis and better glycemic control the proposed programme was found to be satisfactory but the downside was that the duration of the effects was too short. With no participation in organised exercise programmes and with absence of controlled nutrition, the beneficial effects of the camp disappeared within 2 months after the camp.

The Medtronic Minimed Gold continuous glucose monitoring system: an effective means to discover hypo- and hyperglycemia in children under 7 years of age

BACKGROUND

The glycemic patterns of children less than 7 years with type 1 diabetes have not been well studied using continuous glucose monitoring. Our goal was to assess the incidence of hypoglycemia as well as postprandial glycemic patterns in this age group utilizing continuous glucose monitoring.

METHODS

Nineteen children used the Medtronic MiniMed (Northridge, CA) CGMS System Gold on three to seven occasions over approximately 6 months.

RESULTS

Nineteen children (nine girls and 10 boys; mean age 4.8 +/- 1.4 years, range 1.6-6.8 years) used the CGMS 102 times, providing 434 days of data; 79% of days were optimal based on CGMS Solutions software version 3.0. Mild hypoglycemia (glucose <or=70 mg/dL) was noted during 28% of 323 nights. When compared to paired meter blood glucose values, the false-positive rate was 16% for mild and 55% for severe sensor hypoglycemia. The mean peak glucose during the 3 h following breakfast (247 +/- 64 mg/dL) was higher than following lunch (199 +/- 67 mg/dL) or dinner (194 +/- 63 mg/dL). The rate of glucose rise to peak was >or=2 mg/dL/min following 50% of breakfasts. Children with hemoglobin A1c levels >or=8% had higher postprandial glucose concentrations. There was no significant advantage of continuous subcutaneous insulin infusion therapy over multiple daily injection therapy in decreasing postprandial hyperglycemia.

CONCLUSIONS

CGMS tracings from young children with diabetes demonstrate frequent mild nocturnal hypoglycemia and significant postprandial hyperglycemia, with a rapid rise in glucose following the meal. The most rapid rate of rise and the most severe postprandial hyperglycemia occurred after breakfast.

Unrecognised hypoglycaemia in children and adolescents with type 1 diabetes using the continuous glucose monitoring system: prevalence and contributors

AIM

To determine prevalence of hypoglycaemia, and contributing factors, in children with type 1 diabetes, using the Medtronic MiniMed continuous glucose monitoring system (CGMS).

METHODS

Fifty-one children and adolescents with diabetes were studied with the CGMS. The studies were analysed for frequency and duration of hypoglycaemia (below 3.5 and 2.5 mmol/L). Contributing clinical factors were determined. Occurrence of nocturnal hypoglycaemia was related to bedtime and fasting home glucose recording.

RESULTS

Hypoglycaemia was common, with 1 (0-4.2) (median (range)) episode per patient per 24 hours, and 0.33 (0-2) episodes per patient per night. Nocturnal episodes were longer than daytime episodes [97.5 (5-720) versus 35 (5-295) minutes for episodes below 3.5 mmol/L, P < 0.001; and 75 (10-640) versus 25 (5-200) minutes for episodes below 2.5 mmol/L, P < 0.001], and less likely to be recognised by the subject (P < 0.001 for episodes below both 3.5 and 2.5 mmol/L). Nocturnal hypoglycaemia was more common with a bedtime glucose recording <6 mmol/L, but also occurred frequently in subjects with glucose recordings >10 mmol/L. No bedtime glucose value reduced the risk of nocturnal hypoglycaemia to <10%.

CONCLUSION

Hypoglycaemia, assessed using the CGMS, is common in children with type 1 diabetes and can be prolonged (although is predominantly mild). Bedtime home glucose recordings are poorly predictive of hypoglycaemia during the following night. Continuous glucose monitoring has proven very useful in management of individual patients, particularly adolescents experiencing difficulties with adherence to diabetes management.

Glucokinase is a critical regulator of ventromedial hypothalamic neuronal glucosensing

To test the hypothesis that glucokinase is a critical regulator of neuronal glucosensing, glucokinase activity was increased, using a glucokinase activator drug, or decreased, using RNA interference combined with calcium imaging in freshly dissociated ventromedial hypothalamic nucleus (VMN) neurons or primary ventromedial hypothalamus (VMH; VMN plus arcuate nucleus) cultures. To assess the validity of our approach, we first showed that glucose-induced (0.5-2.5 mmol/l) changes in intracellular Ca(2+) concentration ([Ca(2+)](i)) oscillations, using fura-2 and changes in membrane potential (using a membrane potential-sensitive dye), were highly correlated in both glucose-excited and -inhibited neurons. Also, glucose-excited neurons increased (half-maximal effective concentration [EC(50)] = 0.54 mmol/l) and glucose-inhibited neurons decreased (half-maximal inhibitory concentration [IC(50)] = 1.12 mmol/l) [Ca(2+)](i) oscillations to incremental changes in glucose from 0.3 to 5 mmol/l. In untreated primary VMH neuronal cultures, the expression of glucokinase mRNA and the number of demonstrable glucosensing neurons fell spontaneously by half over 12-96 h without loss of viable neurons. Transfection of neurons with small interfering glucokinase RNA did not affect survival but did reduce glucokinase mRNA by 90% in association with loss of all demonstrable glucose-excited neurons and a 99% reduction in glucose-inhibited neurons. A pharmacological glucokinase activator produced a dose-related increase in [Ca(2+)](i) oscillations in glucose-excited neurons (EC(50) = 0.98 mmol/l) and a decrease in glucose-inhibited neurons (IC(50) = 0.025 micromol/l) held at 0.5 mmol/l glucose. Together, these data support a critical role for glucokinase in neuronal glucosensing.

Insulin analogues in children and teens with type 1 diabetes: advantages and caveats

This article reviews the advantages to and caveats of the use of newer insulin formulations (insulin analogues) and regimens in children and teens who have type 1 diabetes, their affect on glycemic control, frequency of hypoglycemic events, daily insulin requirements, and adverse affects such as excessive weight gain, which provides a further major challenge in adolescents. We also address briefly the use of adjunctive agents in the treatment of type 1 diabetes in children and teens.

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.

Use of insulin glargine in children under age 6 with type 1 diabetes

AIM

Children under 6 yr have the highest incidence of severe hypoglycemia (SH) and the greatest likelihood of brain damage from SH. The purpose of this study is to evaluate the use of insulin glargine (Lantus in children under age 6 with type 1 diabetes (T1D).

METHODS

The electronic medical records were reviewed for patients under age 6 during the first 6 months of insulin glargine therapy and compared with age, sex, and duration of diabetes for matched control patients on neutral protamine Hagedorn (NPH) insulin. Data from 128 subjects (32 male pairs and 32 female pairs) were collected relating to the incidence of severe and non-severe hypoglycemic events, hemoglobin A1c (HbA1c) values, body mass index (BMI), and daily insulin dose. Additionally, parents were asked to complete a diabetes Quality of Life (QoL) survey.

RESULTS

In the 6 months before the study period, the glargine group had 16 SH events compared with three in the 6 months post-glargine. The comparison (NPH) group had seven and six SH events in their respective 6-month periods. Nighttime SH events in the glargine group decreased from 12 prestudy events to one during the study period. The average daily insulin dose in the glargine group was higher than that in the NPH group (0.8+/- 0.2 vs. 0.7+/- 0.2 U/kg/day; p=0.03). The HbA1c values, BMI, and QoL responses were not significantly different between the two groups.

CONCLUSIONS

SH was decreased, particularly at night (from 12 episodes to one), after the introduction of glargine in young children with T1D.

Hypoglycemia, hypoglycemia unawareness and counterregulation in children and adolescents with type 1 diabetes mellitus

Three clinical phenomena have been defined in the last decade in patients with diabetes mellitus as a dangerous iatrogenic sequel of hypoglycemia. These are hypoglycemia unawareness, defective glucose counterregulation and a lowered hypoglycemic threshold for hypoglycemic symptoms. Former mild hypoglycemia episodes cause a decrease and a delay in the protective hormonal counterregulatory response and warning symptoms in subsequent episodes, and in the absence of these, risk of severe hypoglycemia increases considerably. It has been demonstrated that when protection is provided against hypoglycemia with strict monitoring programs designed to avoid even mild hypoglycemia episodes, blunted autonomic symptoms and counterregulatory hormonal responses are rectified. Therefore, the best course of action in the treatment of pediatric diabetes mellitus is frequent blood sugar measurements, flexible multiple dose insulin regimens facilitating insulin dose adjustments as required, and a diet. In order to implement this, it is essential to organize an intensive training program with the patient and family, and to provide psychological support and close coordination with the diabetes treatment team.