Nocturnal hypoglycaemia in patients receiving conventional treatment with insulin

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

CONTEXT

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Investigation of Daily Glucose Profile of Inpatients in Non-endocrinology Departments in Chinese Population

Background: Inpatient hyperglycemia is associated with poor prognosis and increased hospitalization expenses. China has a large population of inpatients with hyperglycemia, but their glucose monitoring states (including preprandial, postprandial and bedtime glucose) are unknown, especially in non-endocrinology departments.

Methods: In this cross-sectional study, 5,790 patients with hyperglycemia from 31 non-endocrinology departments were enrolled, and a total of 1,22,032 point-of-care blood glucose (POC-BG) records were collected. The “patient-day” unit of measure was used as a metric for the inpatient glucose. A total of 2,763 patients from endocrinology wards were included for the comparison of the improvement of glycemic management during hospitalization in non-endocrinology wards.

Results: A total of 61.16% of patient-days had <4 POC-BG tests. Postprandial POC-BG was tested significantly less frequently than preprandial POC-BG (10.60% vs. 58.85% of all records, P < 0.001). The patient-day-weighted mean BG was higher in non-ICU wards than in the ICU (9.72 ± 3.37 vs. 9.00 ± 3.19 mmol/L, P < 0.001). The rate of hyperglycemia (BG >10 mmol/L) was 37.60% in all non-endocrinology wards (ICU vs. non-ICU: 33.19% vs. 39.17%, P < 0.001). In non-ICU wards, the rate of hyperglycemia (BG >10 mmol/L) was significantly higher in surgical wards than in medical wards (40.30% vs. 36.90%, P < 0.001). ICU had a significantly higher rate of achieving the blood glucose target than the non-ICU wards (32.50% vs. 26.38%, P < 0.001). In the non-ICU departments, medical wards had higher rate of achieving the blood glucose target than surgical wards (39.70% vs. 19.08%, P < 0.001). With increasing days of hospitalization, there was no improvement in glycemic control in non-endocrinology wards. The ICU had a significantly higher rate of hypoglycemia than non-ICU wards (4.62% vs. 3.73%, P < 0.05). In non-ICU wards, medical wards had a significantly higher rate of hypoglycemia than surgical wards (5.71% vs. 2.75%, P < 0.05).

Conclusions: Both the frequency of BG monitoring and the daily glucose profile of inpatients in Chinese non-endocrinology departments were less than ideal and need to be urgently improved.

The Effect of LM25 and LM50 on Hypoglycemia in Chinese T2DM Patients: Post Hoc Analysis of a Randomized Crossover Trial

INTRODUCTION

To investigate the safety of insulin lispro Mix 25 and 50 (LM25 and LM50) in hypoglycemia in patients with type 2 diabetes mellitus (T2DM).

METHODS

This was a post hoc analysis of a phase IV, randomized, crossover clinical trial in Chinese patients with T2DM switching from premixed human insulin 70/30 (PHI70/30) to LM25 or LM50. Eighty-one subjects received a two-stage crossover protocol of either LM25 or LM50 twice daily for 16 weeks. Habitual diet was taken, and self-monitoring of blood glucose (SMBG) was performed throughout the study period. High-carbohydrate diet (HCD), high-fat diet (HFD) and habitual diet patterns were taken, and 72 h continuous glucose monitoring (CGM) was performed at the last 3 days of each treatment stage.

RESULTS

The frequencies of nocturnal hypoglycemia in LM50 were lower than those in LM25 under a Chinese habitual diet pattern. The related factors of hypoglycemia in patients with T2DM treated with a LM25 or LM50 regimen were the weight-based daily mean insulin dose and the type of combined oral hypoglycemic agents. Under both HCD and habitual diet patterns, the optimal cut point values of bedtime glucose predicting nocturnal hypoglycemia in LM50 were lower than those in LM25.

CONCLUSIONS

The risk of nocturnal hypoglycemia in the LM50 regimen was lower than that in the LM25 regimen under the HCD pattern, and the safety range of bedtime glucose for the LM50 regimen was wider than that of the LM25 regimen in Chinese T2DM patients. Premixed insulin analogs combined with acarbose were more helpful to reduce the incidence of hypoglycemia.

TRIAL REGISTRATION

http://www.chictr.org.cn #ChiCTR-TTRCC-12002516.

The effect of insulin degludec on risk of symptomatic nocturnal hypoglycaemia in adults with type 1 diabetes and high risk of nocturnal severe hypoglycaemia (the HypoDeg trial): study rationale and design

BACKGROUND

Hypoglycaemia, especially nocturnal, remains the main limiting factor of achieving good glycaemic control in type 1 diabetes. The effect of first generation long-acting insulin analogues in reducing nocturnal hypoglycaemia is well documented in patient with type 1 diabetes. The effect of the newer long-acting insulin degludec on risk of nocturnal hypoglycaemia remains undocumented in patients with type 1 diabetes and recurrent severe nocturnal hypoglycaemia. The HypoDeg trial is designed to investigate whether insulin degludec in comparison with insulin glargine U100 is superior in limiting the occurrence of nocturnal hypoglycaemia in patients with recurrent nocturnal severe hypoglycaemia. This paper reports the study design of the HypoDeg trial.

METHODS/DESIGN

A Danish investigator-initiated, prospective, randomised, open, blinded endpoint (PROBE), multicentre, two-year cross-over study investigating the effect of insulin degludec versus insulin glargine U100 on frequency of nocturnal hypoglycaemia in patients with type 1 diabetes and one or more episodes of nocturnal severe hypoglycaemia during the preceding two years as the major inclusion criteria. Patients are randomised (1:1) to basal therapy with insulin degludec or insulin glargine. Insulin aspart is used as bolus therapy in both treatment arms.

DISCUSSION

In contrast to most other insulin studies the HypoDeg trial includes only patients at high risk of hypoglycaemia. The HypoDeg trial will compare treatment with insulin degludec to insulin glargine U100 in terms of risk of nocturnal hypoglycaemic episodes in patients with type 1 diabetes with the greatest potential to benefit from near-physiological insulin replacement therapy. www.clinicaltrials.gov : NCT02192450.

Analysis of Risk Factors for Hypoglycemic Coma in 194 Patients with Type 2 Diabetes

Background

The present study was conducted to analyze possible risk factors in patients with type 2 diabetes who are in hypoglycemic coma.

Material/Methods

A total of 194 patients with type 2 diabetic hypoglycemic coma who were admitted to our hospital between January 2010 and January 2016 were included. The patients were all in coma on admission, and their blood glucose levels were lower than 2.8 mmol/L. None of the patients had type I diabetes, specific types of diabetes, or gestational diabetes. Multiple linear regression analysis was used to determine possible factors associated with hypoglycemic coma.

Results

Among the patients, 82 were male and 112 were female (mean age, 66.88±10.62 years). In addition, 72 patients lived in urban areas and 122 lived in rural areas. Occurrence of hypoglycemic coma was correlated with difference between urban and rural residence, glycosylated hemoglobin (HbA1c) level, combined hypertension, and combined neural complications. Self-purchased drugs resulted in significantly lower blood glucose level at the onset of hypoglycemic coma than insulin, secretagogue, or non-secretagogue drugs. Blood glucose level at onset was correlated with season. Patients living in rural areas or with combined macrovascular or microvascular complications had prolonged hospital stay and poor prognosis.

Conclusions

Our results demonstrate that rural residence, higher HbA1c level, combined hypertension, and combined neural complications increase the incidence of hypoglycemic coma. Use of self-purchased drugs and colder seasons may result in lower blood glucose levels in patients with hypoglycemic coma.

Rebound hyperglycaemia in diabetic cats

OBJECTIVES

Rebound hyperglycaemia (also termed Somogyi effect) is defined as hyperglycaemia caused by the release of counter-regulatory hormones in response to insulin-induced hypoglycaemia, and is widely believed to be common in diabetic cats. However, studies in human diabetic patients over the past quarter century have rejected the common occurrence of this phenomenon. Therefore, we evaluated the occurrence and prevalence of rebound hyperglycaemia in diabetic cats.

METHODS

In a retrospective study, 10,767 blood glucose curves of 55 cats treated with glargine using an intensive blood glucose regulation protocol with a median of five blood glucose measurements per day were evaluated for evidence of rebound hyperglycaemic events, defined in two different ways (with and without an insulin resistance component).

RESULTS

While biochemical hypoglycaemia occurred frequently, blood glucose curves consistent with rebound hyperglycaemia with insulin resistance was confined to four single events in four different cats. In 14/55 cats (25%), a median of 1.5% (range 0.32-7.7%) of blood glucose curves were consistent with rebound hyperglycaemia without an insulin resistance component; this represented 0.42% of blood glucose curves in both affected and unaffected cats.

CONCLUSIONS AND RELEVANCE

We conclude that despite the frequent occurrence of biochemical hypoglycaemia, rebound hyperglycaemia is rare in cats treated with glargine on a protocol aimed at tight glycaemic control. For glargine-treated cats, insulin dose should not be reduced when there is hyperglycaemia in the absence of biochemical or clinical evidence of hypoglycaemia.

A rarely seen multilevel thoracic vertebral fracture after a nocturnal hypoglycemic convulsion attack

A 49-year-old male presented with acute midthoracic severe back pain following a witnessed nocturnal convulsion attack. There was no history of trauma and the patient had a 23-year history of Type I diabetes mellitus. MRI scans of the thoracic spine revealed compression fractures at T5, T6, T7, and T8 vertebrae. The patient was treated conservatively. At 17 months after the initial diagnosis, the complaints of back pain had been resolved and the patient was able to easily undertake daily living activities. Hypoglycaemia is a common problem in diabetic patients treated with insulin. Convulsions may occur as a consequence of insulin-induced hypoglycemia. Nontraumatic compression fractures of the thoracic spine following seizures are a rare injury. Contractions of strong paraspinal muscles can lead to compression fracture of the midthoracic spine. Unrecognized hypoglycaemia should be considered to be a possible cause of convulsions in insulin-dependent diabetic patients. The aim of this report is to point out a case of rarely seen multilevel consecutive vertebrae fractures in a diabetic patient after a nocturnal hypoglycaemic convulsion attack.

Causative anti-diabetic drugs and the underlying clinical factors for hypoglycemia in patients with diabetes

Recent clinical trials indicated that the intensive glycemic control do not reduce cardiovascular disease mortality among diabetic patients, challenging a significance of the strict glycemic control in diabetes management. Furthermore, retrospective analysis of the Action to Control Cardiovascular Risk in Diabetes study demonstrated a significant association between hypoglycemia and mortality. Here, we systematically reviewed the drug-induced hypoglycemia, and also the underlying clinical factors for hypoglycemia in patients with diabetes. The sulfonylurea use is significantly associated with severe hypoglycemia in patients with type 2 diabetes. The use of biguanide (approximately 45%-76%) and thiazolidinediones (approximately 15%-34%) are also highly associated with the development of severe hypoglycemia. In patients treated with insulin, the intensified insulin therapy is more frequently associated with severe hypoglycemia than the conventional insulin therapy and continuous subcutaneous insulin infusion. Among the underlying clinical factors for development of severe hypoglycemia, low socioeconomic status, aging, longer duration of diabetes, high HbA1c and low body mass index, comorbidities are precipitating factors for severe hypoglycemia. Poor cognitive and mental functions are also associated with severe hypoglycemia.

Nocturnal continuous glucose monitoring: accuracy and reliability of hypoglycemia detection in patients with type 1 diabetes at high risk of severe hypoglycemia

BACKGROUND

A reliable method to detect biochemical nocturnal hypoglycemia is highly needed, especially in patients with recurrent severe hypoglycemia. We evaluated reliability of nocturnal continuous glucose monitoring (CGM) in patients with type 1 diabetes at high risk of severe hypoglycemia.

PATIENTS AND METHODS

Seventy-two type 1 diabetes patients with recurrent severe hypoglycemia (two or more events within the last year) participated for 4 nights in blinded CGM recordings (Guardian(®) REAL-Time CGMS and Sof-Sensor(®); Medtronic MiniMed, Northridge, CA). Blood was drawn hourly from 23:00 to 07:00 h for plasma glucose (PG) measurements (gold standard).

RESULTS

Valid data were obtained in 217 nights. The sensitivity of CGM was 65% (95% confidence interval, 53-77%) below 4 mmol/L, 40% (24-56%) below 3 mmol/L, and 17% (0-47%) below 2.2 mmol/L. PG and CGM readings correlated in the total measurement range (Spearman's ρ=0.82; P<0.001). In the normo- and hyperglycemic ranges CGM underestimated PG by 1.1 mmol/L (0.9-1.2 mmol/L) (P<0.001); in contrast, in the hypoglycemic range (PG<4 mmol/L) CGM overestimated PG levels by 1.0 mmol/L (P<0.001). The mean absolute relative differences in the hypo- (≤3.9 mmol/L), normo- (4-9.9 mmol/L), and hyperglycemic (≥10 mmol/L) ranges were 45% (37-53%), 23% (22-25%), and 20% (19-21%), respectively. Continuous glucose error grid analysis indicated a clinical accuracy of 56%, 99%, and 93% in the hypo-, normo-, and hyperglycemic ranges, respectively.

CONCLUSIONS

The accuracy in the hypoglycemic range of nocturnal CGM data using Sof-Sensor is suboptimal in type 1 diabetes patients at high risk of severe hypoglycemia. To ensure clinical useful sensitivity in detection of nocturnal hypoglycemic episodes, an alarm threshold should not be lower than 4 mmol/L.

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.

Approach to managing hypoglycemia in elderly patients with diabetes

Hypoglycemia is a common clinical problem in elderly patients with diabetes. Aging modifies the counterregulatory and symptomatic responses to hypoglycemia. Hypoglycemia in the elderly is not only due to tight blood sugar control, but also due to a multitude of other factors. Hypoglycemia often occurs with insulin, sulfonylureas, or meglitinide therapy. However, other causes may also contribute to hypoglycemia, such as decreased cognition, renal impairment, or polypharmacy. The presenting features of hypoglycemia may be atypical and misinterpreted, resulting in delayed treatment. Morbidity is greater in elderly patients, and the risk of progression to severe hypoglycemia is high because of their altered symptom profile, diminished symptom intensity, and altered glycemic thresholds. Hypoglycemia seems to be the main limiting factor in their glycemic control. In this article we discuss strategies to prevent hypoglycemic episodes.

Once-daily initiation with biphasic insulin aspart 30 versus insulin glargine in patients with type 2 diabetes inadequately controlled with oral drugs: an open-label, multinational RCT

OBJECTIVES

To assess the efficacy and safety of biphasic insulin aspart 70/30 (BIAsp 30) and insulin glargine, administered once daily in subjects with type 2 diabetes inadequately controlled with oral anti-diabetic drugs.

RESEARCH DESIGN AND METHODS

In this 26-week, open-labeled, randomized, parallel-group, multinational, treat-to-target trial, 480 insulin-naïve subjects were randomized to receive either BIAsp 30 before dinner or insulin glargine at bedtime, both in combination with metformin and glimepiride.

TRIAL REGISTRATION

NCT00469092, ClinicalTrials.gov.

RESULTS

A total of 433 subjects completed the trial. Estimated mean reduction in HbA(1c) from baseline to end of treatment was -1.41% with BIAsp 30 and -1.25% with insulin glargine (BIAsp 30 - insulin glargine = -0.16%, 95% CI [-0.30; -0.02], p = 0.029). At the end of treatment, mean HbA(1c) was 7.1% and 7.3% for BIAsp 30 and insulin glargine, respectively. Significantly lower plasma glucose levels were observed with BIAsp 30 post-dinner (BIAsp 30 - insulin glargine = -0.52 mmol/L, 95% CI [-1.02; -0.03], p = 0.04) and at bedtime (BIAsp 30 - insulin glargine = -0.78 mmol/L, 95% CI [-1.25; -0.31], p < 0.01). The relative risk (RR) of experiencing a nocturnal hypoglycemic episode (00:00-06.00 a.m.) was significantly higher with BIAsp 30 than with insulin glargine (1.1 versus 0.5 episodes/year, RR = 2.41, 95% CI [1.34; 4.34], p = 0.003), but overall hypoglycemia rates were low. There were three major hypoglycemic episodes in each group.

CONCLUSIONS

With respect to HbA(1c), BIAsp 30 fulfilled the statistical criteria for non-inferiority and superiority to insulin glargine and, according to pre-defined criteria, the improvements in HbA(1c) are considered clinically equivalent. Subjects had an increased risk of minor nocturnal hypoglycemia with BIAsp 30. There were no differences in treatment satisfaction between the two groups.

Incidence of nocturnal hypoglycaemia in insulin-dependent diabetic patients on intensive therapy

The frequency of nocturnal hypoglycaemia, i.e. blood glucose concentration (BG) less than 3.0 mmol/l, was evaluated in consecutively selected insulin-dependent patients on multiple insulin injections (MII), n = 23, or continuous subcutaneous insulin infusions (CSII), n = 25. Blood was sampled hourly from 23.00 to 07.00. Seven patients (30%) on MII had at least one BG less than 3.0 mmol/l during the night. Eleven patients (44%) on CSII had hypoglycaemia (NS). The total number of BGs less than 3.0 mmol/l was higher on CSII, 42 of 225, versus 16 of 207 on MII (p less than 0.025). The duration of hypoglycaemia was 2 hours (range 1-6) on MII and 4 hours (range 1-7) on CSII with a maximal prevalence at 4 hours and between 5 and 7 hours, respectively (p = less than 0.05). The frequency of nocturnal hypoglycaemia is high in patients on intensified insulin regimens. Nocturnal hypoglycaemia occurs later in the night and is of longer duration on CSII than on MII. HbA1c, BG before bedtime and in the morning might be useful in the evaluation of nocturnal hypoglycaemia.

Hypoglycemia during sleep impairs consolidation of declarative memory in type 1 diabetic and healthy humans

OBJECTIVE

Early nocturnal sleep enhances the consolidation of declarative memories acquired during prior wakefulness. Patients with type 1 diabetes frequently experience hypoglycemic episodes during sleep. We investigated whether short-lasting hypoglycemia during early nocturnal sleep affects the sleep-associated consolidation of declarative memories.

RESEARCH DESIGN AND METHODS

Sixteen type 1 diabetic patients and 16 healthy subjects matched for age and BMI were tested. On one condition, a linear fall of plasma glucose to 2.2 mmol/l was induced within 60 min by infusing insulin during early sleep. On the control condition, euglycemia (>3.86 mmol/l) was maintained throughout the night. In the morning, subjects recalled word pairs learned in the preceding evening. To assess mood and attention, a symptom questionnaire, an adjective check list, and the Stroop test were applied. Also, auditory event-related brain potentials were recorded.

RESULTS

After euglycemia, subjects recalled 1.5 +/- 0.5 more word pairs than after hypoglycemia (P < 0.01), remembering 2.0 +/- 0.6 more word pairs than at immediate recall before sleep (P = 0.002). Across the hypoglycemic night, no such gain occurred (+0.5 +/- 0.6 words; P = 0.41). Hypoglycemia during sleep also impaired mood (P < 0.05) but did not affect attention. Effects compared well between type 1 diabetic patients and healthy control subjects.

CONCLUSIONS

Our findings indicate specific sensitivity of declarative memory consolidation during sleep to rather short episodes of mild hypoglycemia. This effect may disable memory processing in type 1 diabetic patients prone to nocturnal hypoglycemic episodes and underlines the importance of considering sleep as a critical period in the treatment of these patients.

Nocturnal hypoglycaemias in type 1 diabetic patients: what can we learn with continuous glucose monitoring?

AIM

In type 1 diabetic patients (T1DM), nocturnal hypoglycaemias (NH) are a serious complication of T1DM treatment; self-monitoring of blood glucose (SMBG) is recommended to detect them. However, the majority of NH remains undetected on an occasional SMBG done during the night. An alternative strategy is the Continuous glucose monitoring (CGMS), which retrospectively shows the glycaemic profile. The aims of this retrospective study were to evaluate the true incidence of NH in T1DM, the best SMBG time to predict NH, the relationship between morning hyperglycaemia and NH (Somogyi phenomenon) and the utility of CGMS to reduce NH.

METHODS

Eighty-eight T1DM who underwent a CGMS exam were included. Indications for CGMS evaluation, hypoglycaemias and correlation with morning hyperglycaemias were recorded. The efficiency of CGMS to reduce the suspected NH was evaluated after 6-9 months.

RESULTS

The prevalence of NH was 67% (32% of them unsuspected). A measured hypoglycaemia at bedtime (22-24 h) had a sensitivity of 37% to detect NH (OR=2.37, P=0.001), while a single measure < or =4 mmol/l at 3-hour had a sensitivity of 43% (OR=4.60, P<0.001). NH were not associated with morning hyperglycaemias but with morning hypoglycaemias (OR=3.95, P<0.001). After 6-9 months, suspicions of NH decreased from 60 to 14% (P<0.001).

CONCLUSION

NH were highly prevalent and often undetected. SMBG at bedtime, which detected hypoglycaemia had sensitivity almost equal to that of 3-hour and should be preferred because it is easier to perform. Somogyi phenomenon was not observed. CGMS is useful to reduce the risk of NH in 75% of patients.

Awakening and counterregulatory response to hypoglycemia during early and late sleep

OBJECTIVE

Nocturnal hypoglycemia represents an important problem for diabetic patients, which has been primarily attributed to an attenuated hormonal counterregulation during sleep. So far, hypoglycemia counterregulation has been exclusively examined during early nocturnal sleep, although early sleep differs markedly in sleep stage architecture from late sleep. Here, we investigated whether awakening and counterregulatory responses differ between early and late sleep.

RESEARCH DESIGN AND METHODS

Sixteen healthy subjects were tested on three occasions. On two nights, a linear fall in plasma glucose to a nadir of 2.2 mmol/l within 60 min was induced by insulin infusion. On one night, this was done immediately after sleep onset and on the other night after approximately 3.5 h of sleep. In a further control night, no hypoglycemia was induced.

RESULTS

During early sleep, 10 subjects awoke in response to hypoglycemia, whereas no subject awoke during the corresponding interval of the control night (P < 0.004). During late sleep, all subjects awoke upon hypoglycemia, and four subjects awoke spontaneously during the corresponding control interval (P < 0.001). The pattern indicates that the frequency of awakenings caused by hypoglycemia is similar for early and late sleep. Increases in epinephrine, norepinephrine, ACTH, cortisol, and growth hormone were distinctly weaker during late than early hypoglycemia (all P < 0.05).

CONCLUSIONS

Diminished hormonal counterregulation during late sleep could be one factor contributing to the clinically observed accumulation of hypoglycemic episodes in the later part of the night in patients with diabetes.

Defective awakening response to nocturnal hypoglycemia in patients with type 1 diabetes mellitus

BACKGROUND

Nocturnal hypoglycemia frequently occurs in patients with type 1 diabetes mellitus (T1DM). It can be fatal and is believed to promote the development of the hypoglycemia-unawareness syndrome. Whether hypoglycemia normally provokes awakening from sleep in individuals who do not have diabetes, and whether this awakening response is impaired in T1DM patients, is unknown.

METHODS AND FINDINGS

We tested two groups of 16 T1DM patients and 16 healthy control participants, respectively, with comparable distributions of gender, age, and body mass index. In one night, a linear fall in plasma glucose to nadir levels of 2.2 mmol/l was induced by infusing insulin over a 1-h period starting as soon as polysomnographic recordings indicated that stage 2 sleep had been reached. In another night (control), euglycemia was maintained. Only one of the 16 T1DM patients, as compared to ten healthy control participants, awakened upon hypoglycemia (p = 0.001). In the control nights, none of the study participants in either of the two groups awakened during the corresponding time. Awakening during hypoglycemia was associated with increased hormonal counterregulation. In all the study participants (from both groups) who woke up, and in five of the study participants who did not awaken (three T1DM patients and two healthy control participants), plasma epinephrine concentration increased with hypoglycemia by at least 100% (p < 0.001). A temporal pattern was revealed such that increases in epinephrine in all participants who awakened started always before polysomnographic signs of wakefulness (mean +/- standard error of the mean: 7.5 +/- 1.6 min).

CONCLUSIONS

A fall in plasma glucose to 2.2 mmol/l provokes an awakening response in most healthy control participants, but this response is impaired in T1DM patients. The counterregulatory increase in plasma epinephrine that we observed to precede awakening suggests that awakening forms part of a central nervous system response launched in parallel with hormonal counterregulation. Failure to awaken increases the risk for T1DM patients to suffer prolonged and potentially fatal hypoglycemia.

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.

Efficacy of continuous real-time blood glucose monitoring during and after prolonged high-intensity cycling exercise: spinning with a continuous glucose monitoring system

BACKGROUND

Hypoglycemia is the most common and serious side effect of insulin therapy in type 1 diabetes (T1DM), frequently occurring both during and after vigorous exercise. Late-onset hypoglycemia (LOH) is of great concern, occurring 1-36 h after exercise, often going unnoticed during sleep. Repeated exposure to LOH causes autonomic glucose counterregulatory failure and sometimes coma and death. Continuous glucose monitoring systems have recently emerged as a potentially important tool in diabetes management, allowing individuals to track glucose levels continuously and learn how various behaviors influence glucose control.

METHODS

In this pilot study, we determined the efficacy of using a real-time continuous glucose monitoring system (Guardian RT, Minimed, Northridge, CA) to detect blood glucose excursions associated with exercise and LOH (i.e., blood glucose concentration <4 mM) after exercise in individuals with T1DM. Five subjects with T1DM were monitored before, during, and after a 60 min vigorous spin class using Guardian RT (48 h in total).

RESULTS

Following the exercise, three of the five subjects had LOH, while the other two experienced decreases in blood glucose concentrations to 4 mM. The Guardian RT monitor was effective in notifying all of the subjects of such glycemic excursions over the 48 h surveillance period. A strong correlation (r = 0.89, P < 0.001) was found between conventional self-monitoring of blood glucose and Guardian RT data pairs.

CONCLUSION

These limited data suggest that nocturnal LOH occurs commonly following vigorous exercise and that a Guardian RT is a useful and important diagnostic tool. Further study into clinical strategies for preventing hypoglycemia associated with this common form of mixed aerobic and anaerobic exercise is urgently needed through insulin modification and carbohydrate supplementation.

Differences between nighttime and daytime hypoglycemia counterregulation in healthy humans

Disturbances in hormonal counterregulation may be the main reason why many type 1 diabetic patients are asymptomatic during nighttime hypoglycemia. While it is known that sleep attenuates counterregulatory responses to hypoglycemia, the influence of the time of day on hormonal counterregulation regulation remains obscure. We induced hypoglycemia at 2 different time intervals, ie, in the morning and in the early night, in healthy subjects staying awake throughout the experiments. As compared with the morning hypoglycemia, epinephrine response during early nighttime hypoglycemia was markedly enhanced (P < .001). Baseline corticotropin (ACTH) and cortisol levels were higher in the morning than during nighttime (P < .001 for both). However, the increase of both hormones was stronger at nighttime (P = .045 and P < .001, respectively), so that at the end of the hypoglycemic clamp, levels at nighttime were comparable to morning levels. In the morning, the increase in glucagon levels was more pronounced than during nighttime (P = .019), but given that baseline glucagon levels were distinctly higher at nighttime than in the morning (P = .003), at the end of the clamps, levels of this hormone remained still higher at nighttime than in the morning (P = .017). The increase in growth hormone during hypoglycemia did not differ between morning and nighttime (P = .728). Data shows that several components of hormonal counterregulation against hypoglycemia are influenced by the time of day. Especially, the markedly enhanced epinephrine response to early nighttime hypoglycemia could be clinically important, because this neuroendocrine response is known to play a crucial role in mediating the awareness of and metabolic defensive mechanism against hypoglycemia.

Nocturnal hypoglycemia: clinical manifestations and therapeutic strategies toward prevention

OBJECTIVE

To review the features of nocturnal hypoglycemia and various preventive strategies.

METHODS

We discuss the physiologic changes, the potential precipitating factors, the immediate and long-term effects, and the currently available options for treatment of nocturnal hypoglycemia in patients with diabetes.

RESULTS

Nocturnal hypoglycemia is common in patients with type 1 diabetes and is usually asymptomatic. Nocturnal hyperinsulinemia frequently occurs with insulin therapy, and although blood glucose levels are often low during sleep, they are seldom measured routinely. Almost 50% of all episodes of severe hypoglycemia occur at night during sleep. Such episodes can cause convulsions and coma and have been implicated as a precipitating factor in cardiac arrhythmias resulting in sudden death--the "dead-in-bed syndrome." Nocturnal hypoglycemia seems to have no immediate detrimental effect on cognitive function; however, on the following day, mood and well-being may be adversely affected. Recurrent exposure to nocturnal hypoglycemia may impair cognitive function; other substantial long-term morbidity includes the development of acquired hypoglycemia syndromes, such as impaired awareness of hypoglycemia, through the putative effect of unsuspected recurrent episodes of nocturnal hypoglycemia.

CONCLUSION

In efforts to decrease the risk of nocturnal hypoglycemic episodes, various strategies can be used to minimize the nocturnal hyperinsulinemia that is associated with many insulin replacement regimens. Regular blood glucose monitoring (particularly at bedtime), the ingestion of appropriate bedtime snacks, and the utilization of short- and long-acting insulin analogues may all help to prevent or minimize the frequency of nocturnal hypoglycemia.

Hypoglycemia in children with type 1 diabetes: current issues and controversies

Hypoglycemia is a common complication of insulin therapy, particularly in the young. For children and adolescents with diabetes, the risk of hypoglycemia may not only prevent optimal glycemic control but can also add significantly to the psychosocial burden of the disease. Recently, surveys employing prospective monitoring techniques have allowed more precise information to be gained about rates of hypoglycemia, its clinical associations, and the impact of new therapies and technologies. A number of reports have estimated rates of hypoglycemic comas and convulsions to be approximately 20 events per 100 patient years in children on current conventional therapy. There is evidence that the introduction of new analog short- and longer-acting insulins and the more widespread use of continuous subcutaneous infusion therapies may allow improvements in glycemic control to occur without the usual increased rate of severe hypoglycemic episodes. The use of glucose sensor technology has brought into focus the widespread occurrence of asymptomatic hypoglycemia. Asymptomatic hypoglycemia has long been recognized, particularly at night, when the combination of excessive insulin action and suppressed counter-regulatory hormone responses put children at special risk of hypoglycemia. Hypoglycemia unawareness is common in the young and is associated with an increased risk of severe hypoglycemia. Whether episodes of severe hypoglycemia have long-term consequences is controversial. Early studies suggesting that the developing brain is sensitive to permanent neurological damage as a result of hypoglycemia have not been confirmed in more recent reports. Many studies have not found convincing evidence of neurological sequelae of the hypoglycemic events that are an inevitable complication of insulin therapy. The question, however, remains under active investigation. Continued prospective monitoring of hypoglycemia rates and consequences has become an essential component of diabetes management.

Insulin lispro: a potential role in preventing nocturnal hypoglycaemia in young children with diabetes mellitus

AIMS

The long duration of action of soluble insulin given in the evening could contribute to the high prevalence of nocturnal hypoglycaemia seen in young children with Type 1 diabetes mellitus (T1DM). We examined whether replacing soluble insulin with insulin lispro reduced this risk in children on a three times daily insulin regimen.

METHODS

Open crossover study comparing insulin lispro vs. soluble insulin in 23 (16 boys) prepubertal children (age 7-11 years) with T1DM on three injections/day; long-acting isophane insulin remained identical. At the end of each 4-month treatment arm, an overnight 15-min venous sampled blood glucose profile was performed.

RESULTS

Despite similar blood glucose levels pre-evening meal (lispro vs. soluble: mean +/- se 6.5 +/- 1.0 vs. 7.1 +/- 1.1 mmol/l, P = 0.5), post-meal (18.00-22.00 h) blood glucose levels were lower on insulin lispro (area under curve 138 +/- 12 vs. 170 +/- 13 mmol min-1 l-1, P = 0.03). In contrast, in the early night (22.00-04.00 h) the prevalence of low blood glucose levels (< 3.5 mmol/l) was lower on lispro (8% of blood glucose levels) than on soluble insulin (13%, P = 0.01). In the early morning (04.00-07.00 h) mean blood glucose and prevalence of low levels were no different between the two treatment groups, and fasting (07.00 h) blood glucose levels were similar (6.1 +/- 0.8 vs. 6.3 +/- 0.9 mmol/l, P = 0.8). At the end of each treatment arm there were no differences in HbA1c (lispro vs. soluble 8.6% vs. 8.4%, P = 0.3), or in insulin doses (mean, range 0.97, 0.68-1.26 vs. 0.96, 0.53-1.22 U/kg per day, P = 0.2).

CONCLUSIONS

The shorter duration of action of insulin lispro given before the evening meal may reduce the prevalence of early nocturnal hypoglycaemia without compromising HbA1c in young children with T1DM.

Insulin analogues and other developments in insulin therapy for diabetes

Diabetes mellitus is a common chronic disorder, which is increasing in prevalence on a global scale. Insulin replacement therapy is required for all people with Type 1 diabetes and for many with Type 2 diabetes, to correct the metabolic abnormalities of these disorders. However, the pharmacokinetics and glucodynamics of available insulins have numerous limitations. Problems include delayed absorption from subcutaneous absorption sites (soluble [regular] insulin), and wide variability of absorption characteristics (insulin isophane suspension [NPH] and insulin lente) that is influenced by the adequacy of resuspension, and by a variable and insufficient duration of action, which usually requires intermediate-acting insulins to be administered twice-daily. All insulin preparations are associated with the common side effect of hypoglycaemia, and encourage weight gain.

Interactions between hypoglycemia and sleep architecture in children with type 1 diabetes mellitus

OBJECTIVES

To assess the interactions between nocturnal hypoglycemia and sleep in children with type 1 diabetes mellitus (DM).

STUDY DESIGN

Children with DM (n = 15) and 15 matched control children underwent full night polysomnographic recordings. Blood glucose levels were measured in the diabetic children by means of the MiniMed Continuous Glucose Monitoring System. Six of the diabetic children were also studied by peripheral arterial tonometry (an indirect indicator of sympathetic responses).

RESULTS

Five children with DM (33%) had profound nocturnal hypoglycemia, which was associated with increased sleep efficiency, increased slow wave sleep, and increased Delta power in spectral analysis of the electroencephalogram. Hypoglycemic episodes were not associated with sympathetic activation. Rapid decline in glucose levels (>25 mg/dL/hour) but not the absolute degree of hypoglycemia were associated with awakenings from sleep.

CONCLUSIONS

We conclude that sleep may inhibit sympathetic and arousal response to hypoglycemia. Rapid changes in glucose levels, independent of absolute glucose levels, may result in awakening from sleep. Continuous measurement of glucose levels during sleep may add important features in the treatment of children with DM.

Impact of bedtime snack composition on prevention of nocturnal hypoglycemia in adults with type 1 diabetes undergoing intensive insulin management using lispro insulin before meals: a randomized, placebo-controlled, crossover trial

OBJECTIVE

To determine the impact of four bedtime (HS) snack compositions on nocturnal glycemic control, including frequency of hypoglycemia (<4 mmol/l) and morning hyperglycemia (>10 mmol/l), in adults with type 1 diabetes using lispro insulin before meals and NPH insulin at bedtime.

RESEARCH DESIGN AND METHODS

Substitutions of 15 g carbohydrate (one starch exchange) for an equivalent amount of uncooked cornstarch or pure protein were compared to a standard snack (control: two starch + one protein exchange) and to no snack (placebo) in 15 adults using a randomized, cross-over design. All snacks were equivalent in kcal, fat, and total available glucose. An intravenous facilitated hourly blood glucose sampling during the night (11:00 P.M. to 7:00 A.M.).

RESULTS

The glycemic level at bedtime (<7, 7-10, and >10 mmol/l) mediated the effects observed. A total of 14 hypoglycemic episodes, in 60% of patients, and 23 morning hyperglycemic episodes occurred over 50 nights. Most hypoglycemic episodes (10 of 14, 71%) occurred with no snack compared to any snack (P < 0.001) and at HS levels of <7 mmol/l (P = 0.05). The standard and protein snacks resulted in no nocturnal hypoglycemia at all HS glucose levels (P < 0.001). Only HS glucose >10 mmol/l was protective against hypoglycemia, even in the absence of a snack (P = 0.05); 46% of morning hyperglycemic episodes were associated (r = 0.37, P = 0.07) with this HS glucose level.

CONCLUSIONS

The need for and composition of an HS snack depends on the HS glucose such that no snack is necessary at levels >10 mmol/l. At levels between 7 and 10 mmol/l, any snack is advised, and at <7 mmol/l, a standard or protein snack is recommended.

Nocturnal hypoglycemia detected with the Continuous Glucose Monitoring System in pediatric patients with type 1 diabetes

OBJECTIVE

To use the Continuous Glucose Monitoring System (CGMS, MiniMed, Sylmar, Calif) to determine if bedtime blood glucose levels were associated with the occurrence of nocturnal hypoglycemia.

STUDY DESIGN

Patients (n = 47, 18 boys, mean age 11.8 +/- 4.6 years) with type 1 diabetes used CGMS for 167 nights. Data were analyzed for glucose </=40 or </=50 mg/dL, comparing bedtime blood glucose levels of </=100 or >100 mg/dL and </=150 or >150 mg/dL.

RESULTS

A glucose value of </=40 mg/dL occurred on 27% of nights and </=50 mg/dL on 35% of nights. There was a 2-fold increase (45% vs 22%, P =.015) in the incidence of hypoglycemia with a bedtime glucose </=100 mg/dL and a 1.7-fold increase (46% vs 26%, P =.01) with a value of </=150 mg/dL; most episodes occurred between 9 PM and 1 AM. There was no difference in hypoglycemia duration (86.4 minutes for glucose </=100 mg/dL vs 84.5 minutes for >100 mg/dL, P = NS), and no bedtime glucose value between 110 and 300 mg/dL decreased the incidence of nocturnal hypoglycemia to </=10%. The incidence of nocturnal hypoglycemia was similar for patients using insulin pump and injection therapy, and there was no correlation between hemoglobin A1c and incidence or duration of hypoglycemia.

CONCLUSIONS

Nocturnal hypoglycemia is frequent, of long duration, associated with bedtime glucose values </=100 to 150 mg/dL, and predominately in the early part of the night. CGMS is a useful tool to diagnose asymptomatic nocturnal hypoglycemia.

Therapeutic targets in the management of Type 1 diabetes

For historical reasons, diabetes has long been linked with blood and urine glucose control, partly because these were clearly linked to acute symptoms, and partly because glucose became measurable around 200 years ago. Today it is recognized that there is far more to diabetes than simply monitoring symptoms and blood glucose. Intensive management has an impact on the quality of life. Late complications have their own risk factors and markers. Monitoring and early detection of these risk factors and markers can lead to changes in treatment before tissue damage is too severe. Accordingly, professionals now find themselves monitoring a range of adverse outcomes, markers for adverse outcomes, risk factors and risk markers for microvascular and arterial disease, acute complications of therapy, and the care structures needed to deliver this. Adverse outcomes lend themselves to targets for complication control in populations, and markers of adverse outcomes (such as retinopathy and raised albumin excretion rate) in treatment cohorts. Surveillance systems will have targets for yearly recall and review of early complications. Metabolic (surrogate) outcomes can be monitored in individual patients, but monitoring is only of value in so far as it guides interventions, and this requires comparison to some intervention level or absolute target. Even for blood glucose control this is not easy, for conventional measures such as glycated haemoglobin have their own problems, and more modern approaches such as post-prandial glucose levels are controversial and less convenient to measure. In many people with type 1 diabetes targets for blood pressure, LDL cholesterol, and serum triglycerides will also be appropriate, and need to be part of any protocol of management.

Symptoms of hypoglycaemia in people with diabetes

The symptoms of hypoglycaemia are fundamental to the early detection and treatment of this side-effect of insulin and oral hypoglycaemic therapy in people with diabetes. The physiology of normal responses to hypoglycaemia is described and the importance of symptoms of hypoglycaemia is discussed in relation to the treatment of diabetes. The symptoms of hypoglycaemia are described in detail. The classification of symptoms is considered and the usefulness of autonomic and neuroglycopenic symptoms for detecting hypoglycaemia is discussed. The many external and internal factors involved in the perception of symptoms are reviewed, and symptoms of hypoglycaemia experienced by people with Type 2 diabetes are addressed. Age-specific differences in the symptoms of hypoglycaemia have been identified, and are important for clinical and research practice, particularly with respect to the development of acquired hypoglycaemia syndromes in people with Type 1 diabetes that can result in impaired awareness of hypoglycaemia. In addition, the routine assessment of hypoglycaemia symptoms in the diabetic clinic is emphasized as an important part of the regular review of people with diabetes who are treated with insulin.

Influence of a beta-glucan-enriched bedtime snack on nocturnal blood glucose levels in diabetic children

BACKGROUND

The high prevalence of low nocturnal blood glucose levels is a major problem in the treatment of children with diabetes.

METHODS

The effect of a beta-glucan-enriched bedtime snack on nocturnal blood glucose levels was examined in comparison with an equicaloric conventional snack in 38 children with diabetes during a 12-night study period.

RESULTS

A significant influence of the type of bedtime snack on the blood glucose course until 2 AM could be observed (P < 0.05). However, there was no difference in the prevalence of nocturnal hypoglycemic blood glucose levels, which was 27% at 2 AM.

CONCLUSION

Silent nocturnal hypoglycemia is common in children with diabetes. The introduction of a fiber-enriched bedtime snack may flatten the blood glucose curve before midnight but cannot prevent low 2 AM blood glucose. Other therapeutic strategies that reduce the risk of asymptomatic and symptomatic nocturnal hypoglycemia would be beneficial to many children with diabetes.

Factors associated with nocturnal hypoglycaemia among patients with type 2 diabetes new to insulin therapy: experience with insulin lispro

AIM

To identify factors associated with nocturnal hypoglycaemia in patients with type 2 diabetes who were new (< 2 months therapy) to insulin therapy.

METHODS

A randomised, multicentre, 12-month parallel open-label study compared the clinical safety and efficacy of insulin lispro with regular human insulin. A cohort of North American patients completed a health-related quality of life (HRQOL) questionnaire which included questions related to the Health Beliefs Model (HBM). Measurements of hypoglycaemia rate and short-and long-term glucose control assessed clinical safety and efficacy. Three hundred and sixty-five type 2 diabetic patients were enrolled in the study, and 195 North American patients completed the HRQOL questionnaire.

RESULTS

After adjustment for demographic and psychological factors, the study population demonstrated lower nocturnal hypoglycaemia risk with insulin lispro. Higher nocturnal hypoglycaemia risk was associated with reduced body mass index (b.m.i.), lower age, and basal ultralente insulin therapy. The associated hypoglycaemia risk was lower with increased alcohol consumption. Patients who completed the HRQOL survey demonstrated higher risk for nocturnal hypoglycaemia if they: (1) had more troublesome hyperglycaemia symptoms in the week before starting insulin; (2) were more confident in their ability to control their diabetes; or (3) thought that diabetes control did not offer a clear health benefit. Nocturnal hypoglycaemia risk was inversely associated with fear of hypoglycaemia.

CONCLUSIONS

Type 2 diabetic patients new to insulin therapy demonstrated lower risk of nocturnal hypoglycaemia with insulin lispro. Practitioners should consider patient characteristics and psychological factors that may predispose type 2 diabetes patients to nocturnal hypoglycaemia when initiating insulin therapy.

Cognitive function and mood after profound nocturnal hypoglycaemia in prepubertal children with conventional insulin treatment for diabetes

OBJECTIVES

To examine the frequency of nocturnal hypoglycaemia, and the effects on cognitive function and mood, in children with insulin dependent diabetes mellitus (IDDM).

DESIGN

Two overnight glucose profiles, in the home environment, and assessments of cognitive function and mood the following day. Twenty nine prepubertal patients with IDDM (median age, 9.4 years; range, 5.3-12.9) and 15 healthy controls (single overnight profile), median age 9.5 (range, 5.6-12.1) years were studied.

RESULTS

Asymptomatic hypoglycaemia (glucose < 3.5 mmol/l) was observed in 13 of 29 patients studied on night 1: four of these and seven others were hypoglycaemic on night 2. The median glucose nadir was 1.9 (range, 1.1-3.3) mmol/l and the median duration of hypoglycaemia was 270 (range, 30-630) minutes. Hypoglycaemia was related to insulin dose, but not glycosylated haemoglobin (HbA1c) values, and was partially predicted by a midnight glucose of < 7.2 mmol/l. Cognitive performance was not altered after hypoglycaemia but a lowering of mood was observed.

CONCLUSIONS

Young children on conventional insulin regimens are at high risk for profound, asymptomatic nocturnal hypoglycaemia, which is difficult to predict. There was no short term effect on cognitive function but mood change was detected.

Intensive treatment of type 1 diabetes

There have been amazing advances for the treatment of type 1 diabetes. As clinicians proceed into the twenty-first century, it is appropriate to reflect both about accomplishments and about the prospects of improved therapeutic options. Regarding the former, perhaps no advance can be compared to the discovery of insulin. Since then, the improvements in therapy have appeared to be too slow for physicians, patients, and their families. In actuality, over the past 20 years, the pace for the development of new tools for the treatment of this once fatal disease has been remarkable. The treatment of type 1 diabetes has evolved with advances in the treatment of microvascular, neuropathic, and macrovascular complications. The future is even more promising, with the possibility of even preventing the disease before the development of hyperglycemia. The challenge for the present is teaching all individuals involved with the management of patients with type 1 diabetes to manage the condition as effectively as possible.

Preliminary experience of the DIAS computer model in providing insulin dose advice to patients with insulin dependent diabetes

The Diabetes Advisory System (DIAS) is a model of human glucose metabolism which predicts hourly blood glucose concentrations and provides advice on insulin dose. Its ability to provide appropriate advice was assessed in 20 well-controlled IDDM patients (mean (SD) age 38 (11), duration 17 (9) years; HbA1 8.8 (0.9)%, reference range 5.4-7.6%). Patients recorded blood glucose measurements, insulin dose and food intake for 4 days. These data were used to generate insulin dose advice by both DIAS and a diabetes specialist nurse. Patients were then allocated to follow either DIAS or nurse advice for a further 4 days. There was no significant difference in mean recorded blood glucose values or frequency of reported hypoglycaemia between the DIAS and nurse groups either before or after insulin dose adjustment. The DIAS model, however, generated significantly lower insulin dose advice than the nurse (median (range)% change in insulin dose: DIAS group -13.3% (-25.0 to +11.6) versus nurse group 0% (-8.7 to +2.5), P < 0.05). We conclude that, in the patients studied, DIAS provided insulin dose advice which maintained good short term control of diabetes, despite significant reductions in dose in some cases.

High incidence of hypoglycemic episodes with neurologic manifestations in children with insulin dependent diabetes mellitus

Hypoglycemia is a serious frequent complication of insulin therapy in type 1 diabetes.

PATIENTS AND METHODS

We surveyed 139 IDDM patients.

RESULTS

Forty-four patients (32%) reported at least one severe hypoglycemic episode. All patients with severe hypoglycemia experienced neurological manifestations. Symptoms included confusion and abnormal behavior, convulsions, coma, transient hemiparesis and one case of permanent hemiparesis. Most episodes occurred at night or during morning hours. 44% of episodes were related to delayed meal or snack, 11% to excess insulin administration and 13% to extra physical activity. HbA1c was significantly lower in patients with severe hypoglycemia compared with diabetic controls (7.33 +/- 1.09% and 9.45 +/- 4.32%, respectively).

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

OBJECTIVES

To evaluate the prevalence and risk factors of nocturnal hypoglycemia (NH) in children and adolescents with insulin-dependent diabetes mellitus.

STUDY DESIGN

A total of 150 patients, 87% of whom were receiving conventional therapy, were admitted to the hospital for one night. Blood glucose (BG) levels were measured hourly from 10 PM to 8 AM.

RESULTS

The prevalence of NH was 47%; NH was asymptomatic in 49% of the cases. Risk factors were as follows: at least two episodes of severe hypoglycemia from onset of insulin-dependent diabetes mellitus (p = 0.0004), insulin dosage > 0.85 IU/kg per day (p = 0.02), more than 5% of BG measurements < or = 3.3 mmol/L during the last month of monitoring (p = 0.04). The risk decreased significantly with age (p = 0.0001). Both high predictive values and significant relative risk were found for BG thresholds < or = 5.2 mmol/L at dinner time (p < 0.0001) and < or = 6.7 mmol/L at 7 AM (p < 0.0001). When BG values at 10 PM were used, prediction of NH was weak.

CONCLUSIONS

Nocturnal hypoglycemia occurred frequently in children and adolescents with insulin-dependent diabetes mellitus. Our study found risk factors that will help pediatricians to identify those children with a high risk of NH. Especially in these patients, counseling based on the BG values before dinner and early in the morning is indicated to reduce the prevalence of NH.

Use of the DIAS model to predict unrecognised hypoglycaemia in patients with insulin-dependent diabetes

The Diabetes Advisory System (DIAS) is a model of human glucose metabolism implemented in a causal probabilistic network. It handles data on insulin dose, carbohydrate intake and blood glucose concentration to predict hourly blood glucose concentrations and thus provide an indication of blood glucose values between home blood tests. DIAS was used to predict blood glucose profiles in eight patients with well-controlled insulin-dependent diabetes, who are at increased risk of hypoglycaemia (abnormally low blood glucose levels). DIAS predicted nocturnal hypoglycaemia in six patients and daytime hypoglycaemia in one patient. The occurrence of nocturnal hypoglycaemia was not recognised by the patient or suspected by their doctor but was subsequently confirmed by blood testing in five patients. It is known that unrecognised nocturnal hypoglycaemia is common in patients with well-controlled diabetes. The ability of DIAS to identify such periods of hypoglycaemia with reasonable accuracy illustrates how the advanced technology it employs may provide reliable decision support to clinicians.

Analysing the hypoglycaemic counter-regulation: a clinically relevant phenomenon?

This paper describes an analysis of the temporal relation between episodes of low blood glucose (hypoglycaemia) and counter-regulations, i.e., episodes of elevated blood glucose (hyperglycaemia), in patients with insulin dependent diabetes. The relation was assessed by statistical methods based on a metabolic computer model of the human glucose metabolism. The study material was standard collected clinical data on meals, insulin injections, and measured blood glucose from hospitalised patients. We have found that a typical hypoglycaemic counter-regulation begins 6-8 h after the hypoglycaemia, that it lasts 16-18 h, giving a total duration of 24 h, and that it elevates the blood glucose by 4-10 mmol/l. The phenomenon was demonstrated in the data from more than half of the patients with hypoglycaemic episodes.

Severe hypoglycemia in insulin-dependent diabetic children treated by multiple injection insulin regimen

The occurrence and risk factors of severe hypoglycemic attacks were analyzed during a 4-year study in a group of children and adolescents who received human insulin and followed a multiple daily injection regimen (three or four injections per day); 29 patients experienced severe hypoglycemia at least once in 4 years. Of these, 13 suffered recurrent episodes: 8 had two episodes, 4 had four episodes, and 1 patient had seven episodes. For comparative purposes, the nonhypoglycemic population (217 diabetic children) was used as a control group. The hypoglycemic children received insulin doses which were significantly higher than for nonhypoglycemic patients (1.05 +/- 0.6 U/kg daily vs 0.87 +/- 0.7; P < 0.05). Moreover, the hypoglycemic group had a significantly higher mean number of previous episodes of severe hypoglycemia than the nonhypoglycemic group (0.98 +/- 1.2 vs 0.26 +/- 0.7; P < 0.001). There was no significant difference in age, sex, duration of disease, and metabolic control between hypoglycemic and nonhypoglycemic children. There was no association between severe hypoglycemia and the presence of retinopathy, persistent microalbuminuria, or autonomic neuropathy. Severe hypoglycemia is a recurrent problem, not related to the quality of metabolic control nor to the presence of long-term microvascular complications, and diabetic children with a personal history of severe hypoglycemia are at risk for future episodes.

Impact of injection sites for soluble insulin on glycaemic control in type 1 (insulin-dependent) diabetic patients treated with a multiple insulin injection regimen

The absorption rate of rapid acting (soluble) insulin is slow from the subcutaneous tissue of the thigh compared to intramuscular injection into the thigh and s.c. injection into the abdominal wall. The aim of the study was to evaluate the impact of soluble insulin injected either intramuscularly into the thigh (IMT), s.c. into the abdominal wall (SCA) or s.c. into the thigh (SCT) on glycaemic control in Type 1 (insulin-dependent) diabetic outpatients treated with the basal bolus insulin delivery regimen. Fifty-five, C-peptide negative Type 1 diabetic outpatients were included in a randomised 3-month intervention study. The insulin doses were adjusted frequently by blinded observers based on the patients' self-monitored blood glucose values and reported hypoglycaemic episodes. The serum fructosamine value was within normal limits in three patients in the IMT group, in six patients in the SCA group and in none of the patients in the SCT group following the intervention period (p < 0.01). However, the difference in mean serum fructosamine values did not reach statistical significance (IMT: 1.24 mmol/l (95% confidence interval; 1.17 to 1.31), SCA: 1.25 mmol/l (1.18 to 1.32), SCT: 1.34 mmol/l (1.26 to 1.41), (p = 0.09). Blood glucose excursions were larger in the SCT group than in the SCA and IMT group from post-lunch to pre-dinner measurements and from pre- to post-dinner measurements. A higher number of measured low nocturnal blood glucose values (less than 4 mmol/l) was observed in the SCT group (34 of 85) than in the IMT (14 of 64) and SCA (21 of 81) group (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Glucose profiles in children two years after the onset of type 1 diabetes

The relationship of 24-h glucose profiles to age, haemoglobin A1c (HbA1c), and C-peptide concentration was analysed in consecutive, unselected children who had developed Type 1 diabetes 2 years earlier. Seventy-seven children in four age groups (age 2-4 years, n = 9; 5-8 years, n = 14; 9-12 years, n = 26; and 13-17 years, n = 28) were studied. Each child was hospitalized for 2 days for the investigations. Mean blood glucose concentration was 9.7 +/- 4.1 (SD) mmol l-1 in children aged 2-4 years; 10.7 +/- 4.0 mmol l-1 in those aged 5-8 years; 11.3 +/- 3.4 mmol l-1 in those aged 9-12 years; and 9.8 +/- 3.3 mmol l-1 in those aged 13-17 years. Results were > 7.0 mmol l-1 in 69% (range 56-76%) and > 10 mmol l-1 in 49% (39-57%) of the measurements. Values decreased by 30% (21-43%) between 10 pm and 3 am. The nadir of the mean profiles of the groups was always at 3 am. Glucose concentration was mmol l-1 in 25% (14-50%), < 2.5 mmol l-1 in 9.6% (0-21%), and < 2.0 mmol l-1 in 2.7% (0-4.2%) of the children at 3 am; hypoglycaemia was most common in those aged 5-8 years. Of the four profile characteristics used, mean blood glucose predicted HbA1c (R2 = 24.7%, p < 0.00005, multiple linear regression analysis), and slightly more in combination with age (R2 = 32.0%, p < 0.00005).(ABSTRACT TRUNCATED AT 250 WORDS)

Adverse effects of exogenous insulin. Clinical features, management and prevention

Insulin has been in therapeutic use for around 70 years, and the range of adverse effects associated with its use is very limited. Insulin allergy and other local cutaneous reactions, which were common with the early insulins, are now rarely seen with highly purified and biosynthetic preparations. By far the most important complication of exogenous insulin is hypoglycaemia, which affects almost all insulin-treated patients and is largely a manifestation of nonphysiological insulin regimens and routes of administration. The problem of hypoglycaemia unawareness is now being increasingly recognised, with onset of severe neuroglycopenia and coma which is not preceded by the characteristic warning symptoms associated with autonomic activation. This can occur with excessively tight glycaemic control, and this situation is usually reversible. More commonly, however, hypoglycaemia unawareness is a chronic problem which is predominantly a feature of long duration of diabetes. Although individual episodes of hypoglycaemic coma can usually be effectively treated with parenteral dextrose or glucagon, management of patients with chronic hypoglycaemia unawareness is a difficult clinical challenge, with limited therapeutic options. In the past few years, there has been concern that the use of human insulin preparations may predispose to hypoglycaemia unawareness. The evidence for and against this is discussed, although at present it is difficult to draw any absolutely firm conclusions.

Cognitive function in type 1 (insulin-dependent) diabetic patients after nocturnal hypoglycaemia

Eight Type 1 (insulin-dependent) diabetic patients with no diabetic complications were studied on two consecutive and one subsequent overnight occasions. The aim was to evaluate the influence of nocturnal hypoglycaemia on neuropsychological and reaction time tests the following morning. Hypoglycaemia was induced by i.v. insulin infusion, blood glucose nadir was 1.5 +/- 0.3 mmol/l. Duration of hypoglycaemia (blood glucose less than 3 mmol/l) was 101 +/- 38 min. Whole night sleep statistics for all patients showed no statistical differences between the normoglycaemic and hypoglycaemic nights, however, there was a tendency of prolongation of the second sleep cycle in the nights with hypoglycaemia. Each patient was used as his own control and periods with blood glucose concentration less than 3 mmol/l were compared to exactly the same periods in nights with blood glucose level over 5 mmol/l. During hypoglycaemia the amount of deep sleep was reduced and replaced by superficial sleep and arousals of short duration. Further, the reduction in deep sleep was replaced later at night. Neuropsychological test scores and reaction time measurements in the morning showed no differences between the normoglycaemic and hypoglycaemic nights.

IN CONCLUSION

despite sleep disturbances, nocturnal hypoglycaemia did not impair cognitive function the following morning in Type 1 (insulin-dependent) diabetic patients.

Impaired glucose disposal following mild hypoglycemia in nondiabetic and type I diabetic humans

Insulin-mediated glucose disposal was studied immediately prior to and following moderate hypoglycemia in nondiabetic subjects and subjects with insulin-dependent (type I) diabetes mellitus (IDDM), the latter having varying epinephrine secretory capacities. Plasma insulin concentration was fixed throughout the study at approximately 300 to 400 pmol/L to avoid effects of waning insulin action and plasma glucose was clamped at either 5 mmol/L (euglycemic control) or at 3.1 mmol/L (hypoglycemic) periods of 120 minutes. Baseline (clamp 1) and postexperiment (clamp 2) periods were assessed for net glucose disposal (as a function of the exogenous glucose infusion rate) and glucose kinetics using 3H-glucose. In normal subjects, glucose disposal increased progressively by 132% during control studies but only by 57% with intervening hypoglycemia (P less than .005). Similarly, 33% during hypoglycemia, P less than .025). These changes were mediated by reduction of whole-body glucose uptake (rate of glucose disappearance [Rd], [3H]-3-glucose) and metabolic clearance rates with comparable suppression of hepatic glucose production in both groups. The increase in plasma free-fatty acids (FFA) following hypoglycemia was modest but greater in subjects with IDDM (P less than .01), whereas IDDM had reduced concentrations of epinephrine (P less than .01) and glucagon (P less than .005) during hypoglycemia. In subjects with IDDM but not in normal subjects, the change in posthypoglycemia glucose disposal was inversely correlated with the increase in plasma norepinephrine (R2 = .54, P less than .004) and epinephrine (R2 = .32, P less than .04). Glucose disposal did not correlate with other counterregulatory hormones, plasma FFA, or antecedent glycemic control.(ABSTRACT TRUNCATED AT 250 WORDS)