Impact of improved glycaemic control on rates of hypoglycaemia in insulin dependent diabetes mellitus

Increased emphasis on strict glycaemic control of insulin dependent diabetes mellitus (IDDM) in young patients may be expected to cause increases in rates of significant hypoglycaemia. To evaluate whether this is the case for a large population based sample of IDDM children and adolescents rates of severe (coma, convulsion) and moderate (requiring assistance for treatment) hypoglycaemia were studied prospectively over a four year period.
A total of 709 patients were studied yielding 2027 patient years of data (mean (SD) age: 12.3 (4.4); range 0-18 years, duration IDDM: 4.9 (3.8) years). Details of hypoglycaemia were recorded at clinic visits every three months when glycated haemoglobin (HbA1_c) was also measured.
Overall the incidence of severe hypoglycaemia was 7.8 and moderate was 15.4 episodes/100 patient years. Over the four years mean (SD) clinic HbA1_c steadily fell from 10.2 (1.6)% in 1992to 8.8 (1.5)% in 1995. In parallel with this there was a dramatic increase in the rate of hypoglycaemia, especially in the fourth year of the study, when severe hypoglycaemia increased from 4.8to 15.6 episodes/100 patient years. This increase was particularly marked in younger children (<6 years) in whom severe hypoglycaemia increased from 14.9 to 42.1 episodes/100 patient years in 1995.
It is concluded that attempts to achieve improved metabolic control must be accompanied by efforts to minimise the effects of significant hypoglycaemia, particularly in the younger age group.

     

Hypoglycaemia in children with type 1 diabetes mellitus

Hypoglycaemia is a frequent acute complication of IDDM and is usually defined as a blood glucose level below 3.0 mmol/l. Hypoglycaemia stimulates several neuroendocrine responses, such as secretion of glucagon, adrenaline, growth hormone and Cortisol, which are generally increased during this phenomenon. The true prevalence of hypoglycaemia is not known. Studies of the epidemiology of severe hypoglycaemia give prevalences ranging from 2.7 to 85.7 episodes per 100 patients per year. The major risk factor for severe hypoglycaemia is hypoglycaemia unawareness, which occurs particularly in patients with type 1 diabetes of long duration and in those with a history of frequent episodes of hypoglycaemia. The first step in the management of hypoglycaemia is to check blood glucose and to treat hypoglycaemia on the basis of symptoms. Hypoglycaemia requires urgent treatment with a fast-acting carbohydrate or, if severe, with parenteral glucagon or intravenous glucose. Prevention measures should be instituted to prevent subsequent episodes, particularly in younger children with hypoglycaemic seizures or when seizures are recurrent, □ Adolescents, children, hypoglycaemia, hypoglycaemia unawareness, type 1 diabetes     

Hypoglycaemia in children with type 1 diabetes mellitus

Hypoglycaemia is a frequent acute complication of IDDM and is usually defined as a blood glucose level below 3.0 mmol/l. Hypoglycaemia stimulates several neuroendocrine responses, such as secretion of glucagon, adrenaline, growth hormone and cortisol, which are generally increased during this phenomenon. The true prevalence of hypoglycaemia is not known. Studies of the epidemiology of severe hypoglycaemia give prevalences ranging from 2.7 to 85.7 episodes per 100 patients per year. The major risk factor for severe hypoglycaemia is hypoglycaemia unawareness, which occurs particularly in patients with type 1 diabetes of long duration and in those with a history of frequent episodes of hypoglycaemia. The first step in the management of hypoglycaemia is to check blood glucose and to treat hypoglycaemia on the basis of symptoms. Hypoglycaemia requires urgent treatment with a fast-acting carbohydrate or, if severe, with parenteral glucagon or intravenous glucose. Prevention measures should be instituted to prevent subsequent episodes, particularly in younger children with hypoglycaemic seizures or when seizures are recurrent.     

How well are we doing? – Metabolic control in patients with diabetes

OBJECTIVE: To compare the present level of metabolic control in children and adolescents with insulin-dependent diabetes mellitus (IDDM) attending Brisbane paediatric diabetes clinics with published overseas data. METHODOLOGY: Blood HbA1c concentrations, population characteristics, current treatment practices and short-term complications were recorded in all patients, aged 19 years and under, attending the diabetes clinics of the two Brisbane Children's Hospitals or the private practice of one of the authors (MJT) in the first quarter of 1998. RESULTS: Two hundred and sixty-eight patients were assessed (M/F 142/126). Ages ranged from 1 to 19 years (mean 11. 2 years); duration of IDDM was 0-16 years (mean 4.4 years); and 141 (53%) were pubertal. Of those aged less than 13 years, only 4% had more than two injections daily. Insulin doses (U/kg/day) rose with increasing age. Larger doses were required in regimens involving more than two injections per day than those involving one to two injections per day. Ketoacidosis or severe hypoglycaemia in the last 3 months were reported in eight (2.7%) and 17 (6.3%) of patients, respectively. Mean HbA1c (+/- SD) was 8.6 +/- 1.4% (range 5.2-14.0%), with 33% of children having a HbA1c concentration < 8%. HbA1c concentrations were significantly related (P < 0.05) to insulin dose and to duration of diabetes, but not to severe hypoglycaemia, ketoacidosis, age, frequency of injections, or number of clinic visits per year. Mean HbA1c concentration was significantly higher (P < 0.05) in those children in puberty (8.7 +/- 1.5%) than in those not in puberty (8.5 +/- 1.2%). CONCLUSION: Only 33% of patients had a HbA1C concentration less than 8% and 6.3% had a severe hypoglycaemic episode in the 3 months. These results are similar to published overseas data.     

The impact of continuous subcutaneous insulin infusion on health-related quality of life in children and adolescents with type 1 diabetes

AIM: To study the impact of continuous subcutaneous insulin infusion (CSII) therapy on health-related quality of life in children and adolescents with type 1 diabetes. METHODS: 31 children and adolescents with poorly regulated type 1 diabetes (mean HbA1c 10.4%, SD 1.8), mean age 14.4 (1.5) y (range 9.7-17.1) and mean diabetes duration of 6.8 (3.2) y (range 1.3-14.6) were consecutively assigned to CSII therapy. Data for generic (CHQ-CF87) and diabetes-specific quality of life (DQOL) were obtained before initiating pump therapy and twice during 15 mo of treatment. HbA1c, BMI and episodes of severe hypoglycaemia and ketoacidosis were recorded over 15 mo prior to and 15 mo during pump therapy. RESULTS: Analysis showed improvements on the family activity scale (p=0.041) and change in health score (p=0.042) (CHQ-CF87). Mean HbA1c decreased from 10.4% (1.8) to 9.0% (0.9) after 3 mo, increasing to 9.6% (1.2) after 15 mo. The number of overweight and obese children increased from 4 and 2 before CSII, to 6 and 3 after 15 mo (IOTF criteria). There was a reduction in severe hypoglycaemia episodes from 43.8 to 5.2 per 100 patient years, but no change in ketoacidosis episodes. CONCLUSION: The degree of limitation experienced by families due to adolescents' general health and well-being was significantly reduced. Expected improvement in metabolic control and frequency of severe hypoglycaemia was observed.     

Seasonal variation of HbA1c in intensive treatment of children with type 1 diabetes

OBJECTIVE: The aim of this study was to measure whether there is a seasonal variation in glycosylated haemoglobin concentrations and insulin dose used in the intensive treatment of children with type 1 diabetes, and whether such variation is related to severe hypoglycaemia. PATIENTS: A geographic population of 114 intensively treated type 1 diabetic patients < 19 years of age, mean 12.7 (SD 4.3) years, with diabetes onset before 1995, were studied in a cohort 1995-96. METHODS: HbA1c, insulin doses and severe hypoglycaemia were registered at regular visits scheduled quarterly, but not standardised in time. Seasonal mean values were calculated for HbA1c and insulin dose. RESULTS: Lower HbA1c was seen in spring and summer, and higher in autumn and winter (p=0.023). Patients reporting severe hypoglycaemia had a seasonal variation in HbA1c (p=0.019) and a tendency to seasonal variation in insulin dose, while patients not reporting severe hypoglycaemia did not vary in HbA1c or insulin dose. CONCLUSIONS: Self-control and adjustment of insulin doses to seasonal change need to be improved also in intensively treated children, with regard to the risk for worsened metabolic control after the summer and increased severe hypoglycaemia in spring and early summer. The findings have important implications for design of short-term studies of metabolic control.     

Sustained metabolic control and low rates of severe hypoglycaemic episodes in preschool diabetic children treated with continuous subcutaneous insulin infusion

AIM: To evaluate the safety and efficacy of continuous subcutaneous insulin infusion (CSII) in children under 7 years of age. METHODS: One hundred and ten children, aged 0.9-7 years, who had received CSII therapy for at least 6 months, were studied for 237 patient-years by a retrospective chart review. Charts were reviewed for glycosylated hemoglobin (HbA1c), severe hypoglycaemia (SH), ketoacidosis (DKA), height, weight and insulin requirement. In 69 cases (children aged 1.6-7 years) CSII was administered after at least 3 months of insulin therapy with pens. In this group, data from the year from before CSII administration were compared with values recorded during 1 year of CSII treatment. RESULTS: Mean HbA1c decreased from 7.8 +/- 0.9 before CSII to 7.5 +/- 1.0 after 6 and 12 months of pump therapy (p = 0.04). In the whole group, the mean HbA1c after 6 months of CSII was 7.5 +/- 1.0 and remained unchanged for up to 4 years of follow-up. Some episodes of SH--4.2 per 100 patient-years, and DKA--5.7 per 100 patient-years were recorded. No increase in BMI z-score occurred. CONCLUSIONS: In the youngest children, CSII therapy lowers HbA1c values and provides sustained metabolic control without increases in hypoglycaemia or ketoacidosis episodes.     

Severe hypoglycaemia,metabolic control and diabetes management in children with type 1 diabetes in the decade after the Diabetes Control and Complications Trial – a large-scale multicentre study

Hypoglycaemia is frequently the limiting factor in achieving optimal glycaemic control. Therefore, insulin therapy, the incidence of hypoglycaemia, and glycaemic control were investigated in 6309 unselected children with type 1 diabetes in a large-scale multicentre study. Using standardised computer-based documentation, the incidence of severe hypoglycaemia, HbA1 _c levels, insulin regimen, diabetes duration, and the number of patients attending a treatment centre were investigated for the age groups 0-<5 years ( n =782), 5-<7 years ( n =1053), and 7-<9 years ( n =4474). The average HbA1 _c level was 7.6% (no significant difference between age groups). Young children had more severe hypoglycaemic events (31.2/100 patient years) as compared to older children (19.7; 21.7/100 patient years, P <0.05) independent of the treatment regimen. Our data suggest that diabetes centres treating less than 50 patients per year have a higher incidence of hypoglycaemia in 0-<5-year-old children (43.0/100 patient years) as compared to larger centres (24.1/100 patient years; P <0.0001). Significant predictors of hypoglycaemia were younger age ( P <0.0001), longer diabetes duration ( P <0.0001), higher insulin dose/kg per day ( P <0.0001), injection regimen ( P <0.0005), and centre experience ( P <0.05). Conclusion:Despite modern treatment, young children have an elevated risk for developing severe hypoglycaemia compared to older children, especially when treated at smaller diabetes centres. The therapeutic goal of carefully regulating metabolic control without developing hypoglycaemia has still not been achieved. Further advances in diabetic treatment may result from giving more attention to hypoglycaemia in young children.On behalf of the German Initiative on Quality Control in Paediatric Diabetology.     

Adverse events in intensively treated children and adolescents with type 1 diabetes

The main objective of this study was to examine the relation between adverse events and degree of metabolic control and multiple-dose treatment. A total of 139 children, aged between 1 and 18 y, prospectively registered severe hypoglycaemia with or without unconsciousness, as well as hospitalized ketoacidosis, during 1994-95. Treatment from onset was multiple-dose insulin (> 95% > or = 4 doses) combined with intense training and psychosocial support. Median HbA1c was 6.9% (ref. 3.6-5.4%). The incidence of severe hypoglycaemia with unconsciousness was 0.17 events per patient-year, having decreased from the 1970s to the 1990s, parallel to a change from 1-2 to > or = 4 doses per day. There was no correlation or association to the year mean HbA1c for severe hypoglycaemia. Severe hypoglycaemic episodes in 1995 correlated to severe hypoglycaemic episodes in 1994 (r=0.38; p<0.0001). Severe hypoglycaemia with unconsciousness increased during the spring season, and according to case records the assumed causes were mainly mistakes with insulin, food and exercise. Ketoacidosis was rare: 0.015 episodes per patient-year. We conclude that multiple-dose insulin therapy from the very onset of diabetes, combined with adequate self-control, active problem-based training and psycho-social support, may limit severe hypoglycaemia and ketoacidosis. Strategies aimed at minimizing severe hypoglycaemia without compromising metabolic control need to be evaluated.     

Frequency and correlates of severe hypoglycaemia in children and adolescents with diabetes mellitus

Frequency and correlates of severe hypoglycaemia have been retrospectively analysed in a cohort of diabetic children and adolescents with median (range) age 14.5 (3.2–25.5) years followed from the onset of the disease by the same diabetic clinic. During the years 1992–1994, 53 of the 187 patients reported 74 hypoglycaemic episodes: the average frequency of hypoglycaemia during the 3 years surveyed was 14.9 episodes/100 patients per year. Frequency of hypoglycaemia decreased significantly with age (χ² = 24.1; P < 0.0001) and was independent of duration of diabetes. Glycosylated haemoglobin and insulin dose were similar in patients with and without hypoglycaemia, matched for age and duration of diabetes. One out of two hypoglycaemic episodes occurred during sleep and no explanation was available for 50% of episodes. Conclusion In this study severe hypoglycaemia was more frequent in young children than in adolescents and was independent of metabolic control and insulin dose. Received: 25 May 1996 / Accepted: 3 February 1997     

Association between diabetes,severe hypoglycaemia,and electroencephalographic abnormalities.

Serial electroencephalographic recordings were made in 70 diabetic children and findings were related to age at electroencephalography and at diagnosis, duration of diabetes, daily insulin dose, long term metabolic control assessed by glycated haemoglobin A1 (HbA1) concentrations, and severe hypoglycaemic episodes. Abnormalities were found in 18 (26%) of diabetic children, and in only five (7%) of control subjects. There were no associations between electroencephalographic abnormalities and duration of diabetes, daily insulin dose, or HbA1 concentration. Diabetic children with electroencephalographic abnormalities were younger, had an earlier onset of diabetes and 21/34 (62%) of them had previously severe attacks of hypoglycaemia, whereas abnormalities were found in only 13/43 (30%) of diabetic children who had not had severe hypoglycaemia. All diabetic children with hypoglycaemic convulsions had permanent electroencephalographic abnormalities. The degree of metabolic control had no effect on the electroencephalographic findings during the early years of diabetes, but previous severe hypoglycaemia, young age, and early onset seem to be important risk factors for electroencephalographic abnormalities.     

Cognitive function in Type 1 diabetic children with and without episodes of severe hypoglycaemia

We assessed the effect of diabetes and of episodes of severe hypoglycaemia on cognitive function in 28 diabetic children. Fifteen diabetic children (age 12.9 (SD 2.0) years) had experienced 1–4 episodes of severe hypoglycaemia. Five of these children diseased before the age of 5 years (SH-eod subgroup), and ten diseased after this age (SH-lod subgroup). Thirteen diabetic children (age 13.1 (SD 2.0) years) had not experienced episodes of severe hypoglycaemia (non-SH group). Each diabetic child was compared with a healthy control child of the same age and gender and with a similar social background. Neuropsychological assessment was blinded. The neuropsychological tests were grouped into one of seven cognitive domains. We found no effect on cognitive performance from diabetes per se or from severe hypoglycaemia in children with late-onset diabetes. However, early-onset diabetes was associated with low scores in two cognitive domains: psychomotor efficiency and attention. The SH-eod subgroup had lower scores than the SH-lod subgroup in psychomotor efficiency ( p < 0.05) and also had lower scores than the SH-lod subgroup and the non-SH group in measures of attention ( p < 0.05). Our results may indicate a slight cognitive dysfunction in children with early-onset diabetes who have experienced episodes of severe hypoglycaemia early in childhood.     

Impact of insulin pumps on glycaemic control in a pump-naïve paediatric regional population

Aim: To examine the clinical impact of insulin‐pump therapy for children with type 1 diabetes mellitus (T1DM) in a regional paediatric service, Auckland, New Zealand. Methods: Retrospective analysis of children with T1DM from the Starship paediatric diabetes database who started on insulin‐pump therapy from 2002 to 2008 compared with the whole T1DM population and with an equal number of non‐pump patients matched by age, sex, ethnicity and duration of diabetes. Results: From 621 subjects with 6680 clinic visits, 75 children were treated with insulin‐pump therapy for more than 12 months. Transitioning to insulin‐pump treatment was associated with an improvement in HbA1c compared with baseline (?0.3%/year, P < 0.001) for up to 3 years. In contrast, despite similar deprivation scores, non‐pump controls showed a continuing trend to higher HbA1C values (+0.2%/year, P < 0.01). The risk of severe hypoglycaemia fell after pump start (from 27 (0–223) to 5 (0–0.91) events/100 patient years) with no change in non‐pump controls; the rate of diabetic ketoacidosis remained low in both groups. Conclusions: In a pump‐naïve regional paediatric population, insulin‐pump therapy for T1DM was safe and effective, and associated with sustained improvements in HbA1c and lower risk of hypoglycaemia.     

Quality of paediatric IDDM care in Germany: a multicentre analysis. German Paediatric Diabetology Group.

Quality management has been applied in recent years to improve the care of children and adolescents with insulin dependent diabetes mellitus (IDDM). In 1995 the German Paediatric Diabetology Working Group published standards on quality control, in which relevant parameters on structure, process and outcome of care were defined. A computer software programme-developed at the University of Ulm under the auspices of the German Secretary of Health-has been used for quality control with central anonymous analysis in a nationwide survey. Data from 23 paediatric centres with 2407 patients seen between January and June 1996 were evaluated. The results showed an admission rate to hospital of 23.8 per 100 patient-years with an average duration of in-patient stay of 2.74 days/year. 80% of the patients were treated with an intensive insulin therapy regimen comprising three or more injections daily. The overall metabolic control was reasonably good with a mean HbA1c value of 7.8%. The rate of severe hypoglycaemia complicated by coma and/or convulsions was six per 100 patient-years and of ketoacidosis one per 100 patient-years. Unfortunately screening for diabetic retinopathy and nephropathy was not carried out consistently. The incidence was 44% and 33% respectively.     

Nocturnal hypoglycaemia and sleep disturbances in young teenagers with insulin dependent diabetes mellitus

OBJECTIVE: To determine the effect of nocturnal hypoglycaemia on sleep architecture in adolescents with insulin dependent diabetes mellitus (IDDM). DESIGN: 20 adolescents with IDDM (mean age 12.8 years, mean glycated haemoglobin (HbA1c) 8.9%) were studied on one night. Plasma glucose was measured every 30 minutes and cortisol and growth hormone levels every 60 minutes. Sleep was recorded using standard polysomnographic montages, and sleep architecture was analysed for total sleep time, stages 1-4, rapid eye movement, fragmentation, and arousals. RESULTS: Six subjects (30%) became hypoglycaemic (five subjects < 2.5 mmol/l), with one being symptomatic. There were no differences in age, HbA1c, duration of diabetes, or insulin regimen between hypoglycaemic and non-hypoglycaemic subjects. Hypoglycaemia was not predicted by glucose measurements before bed. There was no detectable rise in plasma cortisol or growth hormone concentrations during hypoglycaemia. Sleep architecture was not disturbed by nocturnal hypoglycaemia with no differences found in sleep stages, fragmentation, or arousals. CONCLUSIONS: Nocturnal hypoglycaemia is a common and usually asymptomatic complication of treatment in adolescents with IDDM. Moderate hypoglycaemia has not been shown to affect sleep architecture adversely. These findings are consistent with, and may explain, the observation that severe hypoglycaemia, with consequent seizure activity, is more common at night than during the day. Counterregulatory hormone responses to nocturnal hypoglycaemia may be less marked than with similar degrees of diurnal hypoglycaemia.     

Fear and other disturbances of severe hypoglycaemia in children and adolescents with type 1 diabetes mellitus

OBJECTIVE: To study perceived occurrence and magnitude of fear and other disturbances of severe hypoglycaemia in children and adolescents with type 1 diabetes mellitus (DM) receiving intensive treatment with active education and psychosocial support. PATIENTS AND METHODS: Out of a geographic population of 112 patients <19 years of age and their families, with a DM duration >1 year, HbA1c mean+/-SD 6.7+/-0.9 (method 1.15% below DCCT level), 74 responded to a questionnaire. Visual analogue scales, 5-graded Likert scales and open questions were used. RESULTS: Global quality of life was high, but lower among patients with severe hypoglycaemia within the last year (p = 0.0114). Worse perceived health was correlated to higher HbA1c year mean (r = 0.32, p = 0.0227). Patients and parents regard severe hypoglycaemia more as a problem (p <0.0001) and the risk of it more disturbing than mild hypoglycaemia (p <0.0001), insulin injections (p <0.0001) or blood glucose determinations (p <0.0001). The disturbance is higher during exercise, disco/party and in travel situations. Severe hypoglycaemia with unconsciousness causes more fear than severe hypoglycaemia needing assistance but without unconsciousness (p = 0.0001) or the potential late complications of DM (p = 0.0014). Severe hypoglycaemia needing assistance but without unconsciousness causes more fear than mild hypoglycaemia (p = 0.0001) and diabetic ketoacidosis (p <0.0001) but less than the potential late complications of DM (p = 0.0034). CONCLUSIONS: Severe hypoglycaemia frequently causes fear and various disturbances in spite of active education and psychosocial support. There is a potential for increased quality of life from interventions targeted at the prevention of severe hypoglycaemia. Further research and improved strategies for the prevention of severe hypoglycaemia are needed.     

Development and progression of microalbuminuria in a clinic sample of patients with insulin dependent diabetes mellitus

The evolution of abnormal albumin excretion and its association with suggested risk factors were studied in 233 children with insulin dependent diabetes mellitus (IDDM) attending a single paediatric diabetic clinic over an eight year period. Yearly albumin:creatinine ratios (ACR; measured in mg/mmol) in early morning urine samples, glycated haemoglobin (HbA1c), and blood pressure were recorded. Thirty four (14.5%) children had a persistently raised ACR (ACR ? 2.5 mg/mmol on at least three consecutive occasions) and 21(9%) had an intermittently raised ACR (ACR ? 2.5 mg/mmol on at least two occasions). Factors associated with a persistently raised ACR compared with normal albuminuria in IDDM included longer duration of diabetes, raised median HbA1c during the first five years after diagnosis, and final age adjusted systolic and diastolic blood pressure represented as standard deviation scores. The onset of persistently raised ACR in 13 of 34 children was before puberty and in 23 of 34 children it was within the first four years of diagnosis. The cross sectional prevalence of raised ACR was 12.9% at one year, 18.3% at five years, and 33% at 10 years after diagnosis. Raised ACR occurs frequently before puberty and in the early stages of childhood diabetes.     

The incidence of hypoglycaemia in children with type 1 diabetes and treated asthma.

AIMS: To investigate whether treatment of coexisting asthma has any effect on the incidence of hypoglycaemia and on glycaemic control in children with type 1 diabetes. METHODS: An observational study of children attending the paediatric diabetes clinics of five hospitals in the North Trent Region. Information on the frequency of hypoglycaemia in the preceding three months, treatment for asthma, and the individual's latest HbA1c, was recorded when they attended for review. RESULTS: Data were collected on 226 children, of whom 27 (12%) had treated asthma. Only 11/27 children with asthma were taking their prescribed inhaled steroids. All used beta agonists at least once a week. There was a reduction of 20% in the incidence of hypoglycaemia in the diabetic children with treated asthma. Of the children with diabetes and treated asthma, 52% reported an episode of hypoglycaemia in the previous three months compared to 72% of those with only diabetes. There was no difference in the proportion of children experiencing nocturnal or severe hypoglycaemia. Although not significant, those with asthma and diabetes also had better overall control (HbA1c 8.8%) compared to those with diabetes alone (HbA1c 9.3%). CONCLUSIONS: Diabetic children with treated asthma have significantly fewer episodes of hypoglycaemia and better glycaemic control compared to children with diabetes alone. This observation needs further investigation but raises an interesting question. Do the drugs used to treat asthma, in particular beta agonists, have the therapeutic potential to reduce hypoglycaemia and facilitate an improvement in glycaemic control?     

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.     

The incidence of hypoglycaemia in children with type 1 diabetes and treated asthma

Methods: An observational study of children attending the paediatric diabetes clinics of five hospitals in the North Trent Region. Information on the frequency of hypoglycaemia in the preceding three months, treatment for asthma, and the individual''s latest HbA1c, was recorded when they attended for review. Results: Data were collected on 226 children, of whom 27 (12%) had treated asthma. Only 11/27 children with asthma were taking their prescribed inhaled steroids. All used ß agonists at least once a week. There was a reduction of 20% in the incidence of hypoglycaemia in the diabetic children with treated asthma. Of the children with diabetes and treated asthma, 52% reported an episode of hypoglycaemia in the previous three months compared to 72% of those with only diabetes. There was no difference in the proportion of children experiencing nocturnal or severe hypoglycaemia. Although not significant, those with asthma and diabetes also had better overall control (HbA1c 8.8%) compared to those with diabetes alone (HbA1c 9.3%). Conclusions: Diabetic children with treated asthma have significantly fewer episodes of hypoglycaemia and better glycaemic control compared to children with diabetes alone. This observation needs further investigation but raises an interesting question. Do the drugs used to treat asthma, in particular ß agonists, have the therapeutic potential to reduce hypoglycaemia and facilitate an improvement in glycaemic control?