CHAPTER 4 RESULTS
4.4 Glycaemic control
The secondary objective of this study was to establish hypoglycaemic safety of using intermittent fasting in people with T2DM. The differences in hypoglycaemia rates, HbA1c changes and diabetes medications are presented in this section.
4.4.1
Hypoglycaemic events
Four participants in each group failed to complete blood glucose diaries for all or some of the dietary intervention period. Those who failed to complete blood glucose diaries were asked at each group session / assessment session about the number of hypoglycaemic events they had experienced. None of these participants reported that they had experienced hypoglycaemic events. No participants in either group experienced a severe hypoglycaemic event, i.e. requiring the help of another to access treatment, unconsciousness or hospital admission due to
hypoglycaemia. In clinical practice it is considered within acceptable blood glucose control if people with T2DM on insulin or OHA report up to two mild hypoglycaemic events per week (McNamara, 2013). Therefore, the total “acceptable” number of hypoglycaemic events for the IFD group was up to two hypoglycaemic events per participant per week; 2 hypoglycaemic events x 8 participants x 12 weeks = 192 events. The total “acceptable” number of hypoglycaemic events for the PCD group was 2 hypoglycaemic events x 7 participants x 12 weeks = 168 events. The IFD group had a combined number of eight reported mild hypoglycaemic events (4.2%), whilst the PCD group reported 21 mild hypoglycaemic events (12.5%). There was no significant difference in the number of hypoglycaemic events between
intervention groups.
One participant in the PCD group and two participants in the IFD group reported experiencing more than two mild hypoglycaemic events a week. One participant in the PCD group experienced three hypoglycaemic events in one week during a hospital admission. This resolved after discharge from hospital. One participant (IFD group) experienced three hypoglycaemic events in one week when reducing
90 her insulin after a period on steroid treatment. One participant (IFD group)
experienced five hypoglycaemic events in week two of the study due to the change to intermittent fasting, and contacted the research team for further modification of her insulin doses.
4.4.2
Hypoglycaemic awareness score
The hypoglycaemic awareness questionnaire (Clarke et al., 1995) gives a score out
of seven. A score ≤3/7 indicated a reduced level of hypoglycaemic awareness. A score ≥5/7 indicated an awareness of hypoglycaemia. One participant in the PCD group had a score of four out of seven at the initial assessment. Medical approval was sought for whether it was safe to continue in the study. After review it was deemed appropriate for the participant to continue. All other participants reported being aware of hypoglycaemic events, and all had a score of ≥5/7. Hypoglycaemic awareness scores remained consistent throughout the study.
4.4.3
HbA1c
Serum HbA1c is a long term (three month) measure of blood glucose control. HbA1c was measured at baseline and again at week 12. Table 16 shows the changes in HbA1c during the intervention period for both groups. One participant in the intermittent fasting group did not have their final blood tests performed, and so has been excluded from the analysis of biochemistry.
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Table 16 Change in HbA1c
PCD (n=7) IFD (n=7) Between group P
value HbA1c (mmol/mmol) Baseline Week 12 Change 61 (52-63) a 61 (49-63) a -3 (-6-1) a 73 (71-87) a 66 (62-70) a -11 (-18-7) a 0.002 b* 0.144 e 0.003 e* P value 0.108 c 0.018 d*
Where non-parametric data exists, all results for that group are presented as median (25th, 75th
centile) to assist in reading the table, however appropriate parametric or non-parametric tests were performed.
* P ≤0.05
a Median (25th, 75th centile) b Mann Whitney U Test c Dependent T Test d Wilcoxon Sign Rank e Independent T Test
Both treatment groups experienced a decrease in median HbA1c. For the PCD group the median HbA1c decreased by 3 mmol/mol (not significant). At 12-weeks the IFD group had a significantly lower HbA1c (P=0.018) compared with baseline. For the IFD group HbA1c decreased by 11 mmol/mol, almost four times that experienced by the PCD group. This difference in change of HbA1c was significant (P=0.003).
Individual participant changes in HbA1c for both groups during the intervention period are shown in Figure 13. The dotted line denotes a clinically significant
decrease of 11 mmol/mol (Anderson et al., 2003, Genuth et al., 2003, Aucott et al.,
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Empty cell indicates weights that are missing due to participants missing group sessions or equipment not being available.
Figure 12 Changes in individual participant HbA1c levels (mmol/mol) over the 12-week intervention period
Participant IF4 had missing results and was excluded from the analysis. Participant PC5’s HbA1c remained stable. All intermittent fasting group participants, who had both sets of blood tests performed experienced reductions in HbA1c. Four
participants in the IFD group achieved a clinically significant decrease in HbA1c.
Four participants in the PCD group experienced reductions in their HbA1c, but none reached a clinically significant level of reduction. The HbA1c of participants PC3 and PC7 increased slightly.
4.4.4
Insulin and OHA doses
Participants in the IFD group were advised on insulin and oral hypoglycaemic agent (OHA) reductions as part of the treatment regimen for intermittent fasting.
Participants in the PCD group were also advised of insulin and OHA changes if their blood glucose control indicated changes were required. Weekly insulin and OHA doses were calculated based on normal, fasting and non-fasting day doses. All
IF1 IF2 IF3 IF4 IF5 IF6 IF7 IF8 PC1 PC2 PC3 PC4 PC5 PC6 PC7 HbA1c change -9 -23 -7 -11 -7 -12 -18 -5 -6 2 -3 0 -7 1 -25 -20 -15 -10 -5 0 5 Change in H b A1c (m mol/mol) Participant number
93 participants in the IFD had reductions in their insulin doses and two participants had reductions in OHA doses. Two participants in the PCD had reductions in insulin doses and none had changes made to OHA doses.
Table 17 Change in insulin doses during the intervention
PCD (n=6) IFD (n=8) P-value
Total weekly insulin (units) Baseline Week 12 Change 633 (± 430) 607 (± 426) -1 (± 47) 450 (± 191) 262 (± 144) -187 (± 106) 0.388 b 0.052 b 0.002 b* P-value 0.133 a 0.002 a* * P= ≤0.05
mean ± standard deviation
a Dependent T test b Independent T test
As is reported in Table 17 there was a significant difference in changes in insulin doses between treatment groups (P=0.002), and also within group reduction in the IFD group (P=0.002). One participant in the PCD group was excluded from the analysis as they changed type of insulin during the intervention period.