Hypoglycaemia

What is Hypoglycaemia?
Causes and Treatment of Hypoglycaemia
Warning Symptoms of Hypoglycaemia
Loss of Warnings or Hypoglycaemia Unawareness
Is Hypoglycaemia Dangerous?
Hypoglycaemia and Alcohol
Living With The Daily Risk of Hypos
Hypoglycaemia and Family Carers
Useful Research – Hypoglycaemia

 

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Useful Research – Hypoglycaemia

How to ameliorate the problem of hypoglycaemia in intensive as well as non-intensive treatment of type 1 diabetes

Intensive therapy in Type 1 diabetes has been shown to increase the frequency of severe hypoglycaemia. This study asks the questions – is it possible to maintain long-term HbA1c levels of less than 7.0% without increasing the frequency of severe hypoglycaemia and secondly is it possible to do this without increasing the frequency of mild, recurrent hypoglycaemia? The author maintains that the answer is ‘yes’ and the key factors are use of a physiological model of insulin replacement and the education of patients so that they are able to make the appropriate decisions about insulin dose based on blood monitoring and eating patterns. He goes on to point out that whenever the HbA1c is less than 6.0 [where the upper normal limit is 5.5%] and the patient does not report autonomic warning symptoms [classic early warning symptoms] when their blood glucose is less than 3.0mmol/l, then hypoglycaemia unawareness should be suspected. Patients with hypo unawareness should be treated with short-term meticulous avoidance of hypos which reverses the abnormalities of responses of symptoms, hormonal counter-regulation and brain cognitive function and therefore decreases the risk of severe hypoglycaemia. This does not result in a loss of long-term near normal blood glucose levels.
Diabetes Care 1999Mar; 22 Suppl 2: B43-52

Frequency and morbidity of severe hypoglycaemia in insulin-treated diabetic patients
This study surveyed 600 randomly selected patients from a large diabetic clinic in a teaching hospital to estimate the frequency and morbidity of insulin-induced hypoglycaemia.

  • Morbidity (hypoglycaemia-related injuries, convulsions, and road traffic accidents) was ascertained in 302 patients. 175 (29.2%) of the 600 patients reported a total of 964 episodes of severe hypoglycaemia in the preceding year.
  • The frequency of severe hypoglycaemia, which was documented in 544 Type 1 (ketosis prone) diabetic patients, was double that observed in a subgroup of 56 Type 2 diabetic patients who were being treated with insulin.
  • 20 patients (6.6%) reported a total of 37 convulsions associated with hypoglycaemia, 5 of which had occurred in the preceding year.
  • 5 patients reported road traffic accidents in the preceding year which had been caused by hypoglycaemia.

The authors concluded that the only reliable predictors of severe hypoglycaemia were a history of previous severe hypoglycaemia, a history of hypoglycaemia-related injury or convulsion and the duration of insulin therapy.
Diabet Med 1993 Apr;10(3):238-45 MacLeod KM; Hepburn DA; Frier BM

Physical and psychological well-being in adults with type 1 diabetes
This study looked at the physical and psychological wellbeing of 397 people with Type 1 diabetes using a series of questionnaires. Diabetes complications and HbA1cs were also measured. The results showed that older people, those with complications, women, the less physically active and those on lower incomes were more likely to experience a poorer quality of life. People that reported at least one hypoglycaemic episode per month also had a poorer quality of life. The authors point out that it is of particular interest that hypoglycaemia is associated with a poorer quality of life, especially given the importance of reducing blood glucose levels to avoid complications. They also point out that with the emphasis on reducing blood glucose levels, the impact that hypoglycaemia may have on quality of life may be overlooked.
Diabetes Res Clin Prac 1999 Apr; 44[1]:9-19

The relationship between hypoglycaemia and crime
This research shows the types of crimes that have been associated with hypoglycaemia.

Person

  • Disorderly conduct
  • Resisting arrest
  • Assault
  • Murder

Property

  • Wilful destruction
  • Shoplifting
  • Petty larceny
  • Embezzlement
  • Driving violations

Behaviour

  • Exhibitionism
  • Blasphemy
  • Slander
  • Sexual perversion
  • Sadism

[David Kerr and Joan Everett, Journal of Nursing Vol 1: N0 4 1997]

The impact of severe hypoglycamia on spouses of patients with diabetes
23 wives and 38 husbands of IDDM patients took part in this study to compare spouses with and without a history of recent severe hypoglycaemia. Results showed no difference in spouses of patients with and without a history of severe hypoglycaemia for depression, anxiety and general marital conflict, but spouses with a recent history of severe hypoglycaemia showed significantly more fear of it, marital conflict about diabetes management and sleep disturbances. There were no differences between husbands and wives except that husbands showed more sleep disturbance. The authors point out that severe hypoglycaemia may be associated with other forms of distress which are not easily measured.
Diabetes Care 1997; Vol 20:No10

Changes in attention with hypo and hyperglycaemia in children with Type 1 diabetes
Researchers in Austria compared the results of a computerised attention test in 38 children with IDDM in relation to various spontaneously occurring blood glucose levels. The attention varied significantly with blood glucose levels, those used being <3.3mmols/l, 3.3-8.3mmols/land >8.3mmols/l. The highest number of errors and the longest response time was observed during the test run for hyperglycaemia.

The results showed that the attention in children with diabetes was significantly reduced compared to the norms for the test used, especially during mild hypoglycaemia. Age, sex, age at diagnosis, metabolic control and the results of the intelligence test had no influence on the results. The authors concluded that in children with diabetes a significant reduction in attention was found at mild hypoglycaemia but also at low normal blood glucose levels. This shows that attention deficits may occur in children with diabetes before they are aware of any hypo symptoms.
Eur J Paed 1998 Oct; 157[10]: 802-5

Nocturnal hypoglycaemia and young people
Doctors at from the John Radcliffe hospital in Oxford visited the homes of 29 children with diabetes aged between 5 and 13 to measure their overnight blood sugars. They also looked at 15 children without diabetes as a control group. They then carried out tests to see if low blood glucose levels during the night had any effects on the children’s cognitive abilities and mood the next day.

The results showed that 20 of the 29 children had a hypo during the two-night study period. There were no effects on cognitive function the next day but the children had a decrease in wellbeing and low mood. The doctors concluded that children with Type1 diabetes should have a bedtime snack and if parents are suspicious that there are further hypos during the night, then a midnight blood test may be advisable.
Archives of Diseases in Childhood 1999; 81:138-42

The effect of hypogycaemic seizures on cognitive function in children with diabetes: a 7-year prospective study
This study was carried out in Canada and 16 children with IDDM were evaluated at diagnosis and after 1, 3 and 7 years. They showed significant declines in verbal but not visuo-spatial abilities particularly if they had any seizures from hypoglycaemia. At the 7-year assessment those with hypoglycaemic seizures showed deficits on perceptual, motor, and attention tasks.
Hospital for Sick Children and The University of Toronto, Canada

Neurocognitive functioning in children diagnosed with diabetes before the age of 10 years
This study was carried out in California with 55 children who were diagnosed with diabetes before the age of 10 years and had an average age of 7.9 years. They were given a series of tests to evaluate memory/attention, visual –perception, broad cognitive function, academic achievement and fine motor speed/co-ordination. 15 siblings non-diabetic siblings acted as controls. 27 of the children were less than 5 years old when diagnosed. The average duration of diabetes was 2.6 years. 18 children had a history of severe hypoglycaemia, 8 of them had hypos with seizures.

The results showed that there was no association between neurocognitive test scores and severe hypoglycaemia but that the children with a history of seizures had lower scores on tests assessing memory skills including short term memory and memory for words. They also found lower HbA1cs and an increase in the number of blood tests were associated with higher scores in some areas of academic achievement and memory. The authors conclude that specific aspects of neurocognitive functioning may be adversely affected by having hypos with seizures but not by severe hypos without seizure. They also suggest that stable blood glucose levels may influence some aspects of academic achievement. They recommend that there should be investigation into ways of avoiding the risks of seizures with hypoglycaemia.
J Diabetes Complications 1999 Jan-Feb; 13[1]:31-8

Conventional versus intensive diabetes therapy in children with type 1 diabetes
This study was carried out because severe hypoglycaemia may impair medial temporal-mediated cognitive skills, such as the ability to recall past events [delayed declarative memory]. The aim of this study was to find out whether this delayed declarative memory is present in children with diabetes who have an increased risk of severe hypoglycaemia – those on intensive therapy, defined as those using 3-4 injections a day. 34 children at the time of diagnosis were randomised to either intensive or conventional therapy so that an accurate assessment of the number of severe hypoglycaemic episodes could be made. The importance of avoidance of hypoglycaemia was emphasised in both groups. A control group of non-diabetic children was also set up to carry out the various memory tests as well. The results showed that:

  • The intensively treated group had a threefold higher rate of severe hypoglycaemia than the conventionally treated group.
  • They performed less accurately on the spatial declarative memory task [recalling of past events] than the conventionally treated group or the controls.
  • They performed more slowly, but not less accurately, on the pattern recognition task than the conventionally treated group or the controls.
  • In both groups of children with diabetes there was significant impairment on a motor speed task compared to the non-diabetic children.

The results indicate that there is selective memory impairment associated with intensive therapy and this is consistent with the effects of severe hypoglycaemia and medial temporal [this is an area of the brain] damage or dysfunction. The authors suggest that if larger prospective studies show that severe hypoglycaemia does cause memory impairment then extreme caution should be taken before imposing strict glucose levels on children with diabetes because of the associated risk of hypoglycaemia with intensive therapy. However the editorial in the same journal by Christopher Ryan suggests that we should build on the existing studies which would be more cost effective before going as far as setting up a large prospective study. He suggests that in the meantime there needs to be prevention of hypoglycaemia in children with diabetes to “avoid the very small risk that the treatment of diabetes could affect memory and other cognitive processes in the child.”
Diabetes Care, Vol 22, No 8, Aug1999

Content

HbA1c Converter

This is just to remind you that the HbA1c measurements have changed. Well, they were supposed to change everywhere but predictably this doesn't appear to be the case. Some people and some articles are still using the old measurements so it is important that we are aware of both.

Here is a table showing the current DCCT measurements, the proposed new IFCC measurements, and the average blood glucose measurements you can expect to be associated with each particular level of HbA1c

HbA1c (DCCT) Current measurement (%)

HbA1c (IFCC) Measurement from June 2011 (mmol/mol)

Average blood glucose level for this HbA1c, mmol/L

6

42

7.0 (range 5.5-8.5)

7

53

8.6 (range 6.8-10.3)

8

64

10.2 (range 8.1-12.1)

9

75

11.8 (range 9.4-13.9)

10

86

13.4 (range 10.7-15.7)

11

97

14.9 (range 12.0-17.5)

12

108

16.5 (range 13.3-19.3)

13

119

18.6 (range 14.6-21.1)