It can be difficult to define severe hypoglycaemia, especially for a paediatric population. This is because in adult studies an episode of hypoglycaemia is often defined as severe if the patient requires assistance to be treated (156).
In paediatric groups, the likelihood that a child will need assistance in treating an episode of hypoglycaemia, is high, because often a parent will take responsibility for this. Some studies (25, 27, 40) use a stricter definition citing the presence of a coma/seizure to define an episode of severe hypoglycaemia. Nevertheless, as the measure for frequency of hypoglycaemia (47) defines an episode of SH as an episode requiring assistance for treatment, this is the definition that will be used for the present study.
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Experience of severe hypoglycaemia for the whole sample showed that 48% of the entire CYP cohort had experienced more than 5 episodes of severe hypoglycaemia in their lives.
Figure 5: Self-reported and parent proxy reported episodes of severe
hypoglycaemia in CYP since diagnosis, by age group
The data in the Figure 5, above, show that the majority of CYP, overall, have experienced at least one episode of severe hypoglycaemia, since diagnosis. Episodes of severe hypoglycaemia seem to be similar between under 11 year olds and adolescents. However, a higher percentage of adolescents reported experiencing 3-5 episodes of severe hypoglycaemia, whereas more of the younger group reported more than five epiodes of severe hypoglycaemia in their lives. This indicates that, in general, both under 11 year olds and adolescents experience a high number of episodes of severe hypoglycaemia.
Grouping the higher frequency categories together (i.e. ‘3 to 5’ and ‘more than 5’ episodes) we can see that adolescents actually experience a greater number of episodes of severe hypoglycaemia than the under 11 group. This could be due to impaired awareness of hypoglycaemia (as mentioned earlier, this will be discussed later in the chapter). Having impaired awareness of hypoglycaemia means that a person might not experience or recognise the warning signs of hypoglycaemia until the episode becomes more serious and
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requires assistance from another person. Having said that, the estimated number of episodes of severe hypoglycaemia is also high for the under 11 group. This could be explained by the fact that parents tend to have to assist their children in treating an episode of hypoglycaemia, so in this instance may report these episodes as severe hypoglycaemia. Another explanantion is that younger children themselves might not recognise the symptoms associated with hypoglycaemia or might be unable to verbalise this to their parents, or their parents might not be able to recognise the signs of hypoglycaemia in their child (157), thus resulting in a more severe episode of hypoglycaemia.
Either way, hypoglycaemia and severe hypoglycaemia both seem a real problem for children and young people in this sample. Further analysis of self-reported frequency of hypoglycaemia and episodes of severe hypoglycaemia is reported below.
4.3 Group comparisons of self-reported frequency of
hypoglycaemia
and
self-reported
episodes
of
severe
hypoglycaemia.
Self-reports of the frequency of hypoglycaemia and episodes of severe hypoglycaemia were explored further by age group and also insulin regimen group. The tables below show all CYP responses to the multiple choice options presented in the frequency of hypoglycaemia measure (47) (which can be found in Appendix 1).
Responses in the table below are shown for adolescents and 8-10 year olds. Parents completed a proxy report for under 8 year olds, results of which can be found in the parent frequency tables (Table 11-16).
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Table 7: Self-reported frequency of hypoglycaemia (%) by age group
CYP N=193 8-10 ^ N=43 11-18 N=150 Frequency of hypoglycaemia Never 9 (5) 1 (2) 8 (5)Less than once/year 5 (3) 0 (0) 5 (3)
1-3 times/year 18 (9) 3 (7) 15 (16)
4-12 times/year 37 (19) 6 (14) 31 (21)
More than once/month 67 (35) 15 (35) 52 (35)
More than once/week 57(29) 18 (42) 39 (26)
The table shows the CYP responses to the frequency measure. The number in brackets indicates the percentage of CYP who responded in each category.
^ Children aged under 8 did not complete the self-report Frequency of Hypoglycaemia measure (however parents completed a proxy report for under 8 year olds, results of which can be seen in the parent frequency table, Table 11).
A chi-square test was carried out on the categorical frequency data in order to identify whether there were any significant differences in reported frequency of hypoglycaemia. There was no significant difference in reports of the frequency of hypoglycaemia and between age groups (p=0.288) or across gender (p=0.298). The categories were dichotomised into ‘less than once a week’ vs ‘more than once a week, to allow comparison of episodes of hypoglycaemia that were less disruptive vs extremely disruptive. Chi-square analysis here showed a significant difference between age groups, x2(1) = 4.58, p=0.032, with more of the younger age group experiencing hypoglycaemia
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more frequently than adolescents (42% vs 26%). This difference in reports of hypoglycaemia could be attributed to the fact that younger children are more likely to be newly diagnosed or have had T1DM for a shorter period than their adolescent counterparts and therefore may not have quite managed to get their blood sugars under control.
Table 8: Self-reported episodes of severe hypoglycaemia (%) by age
group
CYP N=193 8-10 ^ N=43 11-18 N=150Episodes of severe hypoglycaemia (in CYP’s life)
None 62 (32) 16 (37) 46 (31)
1 or 2 65 (34) 16 (37) 48 (32)
3-5 26 (13) 1 (2) 25 (17)
More than 5 times 40 (21) 10 (24) 30 (20)
This table shows the CYP responses to the frequency measure. The number in brackets indicates the percentage of CYP who responded in each category.
^ Children aged under 8 did not complete the self-report Frequency of Hypoglycaemia measure (however parents completed a proxy report for under 8 year olds, results of which can be seen in the parent frequency table, Table 11).
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Chi-square analysis also showed no significant difference in reports of the number of episodes of severe hypoglycaemia between age groups (p=0.120) or across gender (p=0.509).
Table 9: Self-reported frequency of hypoglycaemia (%) by insulin
regimen
Conventional insulin regimen N=37 Intensive insulin regimen N=156 Frequency of hypoglycaemia * Never 6 (16) 3 (2)Less than once/year 1 (3) 4 (3)
1-3 times/year 8 (22) 10 (6)
4-12 times/year 7 (19) 30 (19)
More than once/month 6 (16) 61 (39)
More than once/week 9 (24) 48 (31)
The table shows the CYP responses to the frequency measure. The number in brackets indicates the percentage of CYP who responded in each category.
*p<0.05 (overall significant difference between conventional and intensive insulin regimens).
Chi-square analysis revealed significant differences between the insulin regimen groups where, not surprisingly, overall, CYP on intensive insulin regimens reported a higher frequency of hypoglycaemia than CYP on the conventional insulin regimen (x2 (5) = 25.46,
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of hypoglycaemia (more than once per month) compared to those on conventional insulin therapy (70% vs. 40%; p= <0.001). These results were not unexpected. By trying to maintain optimum blood glucose levels, those CYP who managed their diabetes with intensive insulin regimes were potentially more likely to experience blood glucose levels that fell below the recommended 4-7mmol/L and were therefore more likely to experience hypoglycaemia.
This finding suggests that when CYP intensively manage their T1DM then the frequency of hypoglycaemia is likely to be high. It is important to note the relevance of this finding in the management of T1DM today, because recommended diabetes regimens have changed since this study was carried out (26) and intensive regimens are more common-place than they were previously. More often than not CYP diagnosed with T1DM will be started on an intensive regimen straight away.
Table 10: Self-reported episodes of severe hypoglycaemia (%) by
insulin regimen
Conventional insulin regimen N=37 Intensive insulin regimen N=156Episodes of severe hypoglycaemia (in CYP’s life)
**
None 20 (54) 42 (27)
1 or 2 9 (24) 55 (35)
3-5 3 (8) 23 (15)
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This table shows the CYP responses to the frequency measure. The number in brackets indicates the percentage of CYP who responded in each category.
**p<0.01 (overall significant difference between conventional and intensive insulin regimens).
Further chi-square analysis revealed significant differences between the insulin regimen groups where, again, not surprisingly, overall, CYP on intensive insulin regimens reported a higher number of episodes of severe hypoglycaemia than CYP on the conventional insulin regimen x2(3) =10.17, p=0.017. Overall, those on intensive insulin regimens were also
more likely to experience more episodes (more than 5) of severe hypoglycaemia than those on conventional regimens (23% vs. 14%, p=0.017). Again these results were expected. It seems that CYP who managed their diabetes with intensive insulin regimes were more likely to experience blood glucose levels that fell well below the recommended 4-7mmol/L and were therefore more likely to experience severe hypoglycaemia. The implications of this have already been discussed in relation to the relationship between insulin regimen and frequency of hypoglycaemia. However, it should be noted that in a review of data of Danish children with T1DM from 1998-2009, intensive insulin regimens (multiple daily injections and pump therapy) significantly reduced the risk of severe hypoglycaemia in these patients (39).