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Study: Pumps, Carbs and DAFNE

phoenix

Expert
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Type of diabetes
Type 1
Treatment type
Pump
The effect of carbohydrate intake on glycaemic control in patients with type 1 diabetes treated with insulin pumps
M.L James, L Green, S.A. Amiel, P Choudary


This is one of the presentations from the EASD conference. The lead researcher was an undergraduate who presented really well, I would have been scared stiff.
You an view it here
http://www.easdvirtualmeeting.org/resources/5862
'I've summarised the findings. It is just a retrospective snapshot of a group of patients at one hospital and not a randomized trial but I would say interesting results in view of some of the previous discussions on the forum. The research question is the 'million dollar question!' Obviously the findings aren't necessarily transferable to MDI
Research Question

Does carbohydrate intake (which may be high as a result of dietary freedom supported by Flexible Intensive Insulin therapy courses) affect ability to control glucose?

The hypotheses were

  • Daily carbohydrate intake and mean meal size will be positively associated with HbA1c
  • Larger carbohydrate meals will result in higher post prandial glucose
This was a study .from Kings College hospital.
The subjects all used Medtronic pumps.
The vast majority had done DAFNE
. Data from the pumps on blood glucose readings, carb intake etc used for the study. They only included subjects who used the bolus wizard 80+% of the time.
A subset of the patients recorded more details of pre/postpradial glucose, CHO content and bolus
Mean HbA1c was 7.8% but there was a very wide range from 5% to 12%
Mean carb intake was 166 . The median was 158 with an interquartile range of 109-206 (that is the middle 50% so there would be 25% below and 25% above this so a broad range of carb intakes Looking at the graphs this included a handful under 50, more evenly distributed up to around 200, and a few above 300)
Results
  • This was a slight but significant negative association between carb intake and HbA1c ie the higher the daily carb intake the lower the HbA1c
  • There was no association between day to day variability of carb intake and HbA1c
  • More meals during the day tended to result in better glycemic control .
  • On an individual meal basis , a higher carb intake in a meal has a slight but positive association with higher HbA1c
( In other words not good to have all your carbs in one meal though it could be that some of those who have only boluses for a couple of main meals aren't bolusing for snacks which could affect glycemic control)
  • For post prandial readings within 3 hours there was no effect of the amount of carbohydrate on the change in glucose levels.
  • For post prandial readings at 5-7 hours there was a weak but positive correlation between a higher carb content and glucose levels.
(my moral from that one based on my own experience is that it is better not to have a higher carb meal in the evening , It works better if you are going to have to have a larger meal , to have it at lunchtime so that the next meal is a lighter one . Any potential late rise is taken into account of with the evening meal. My doctors really did try to insist on the main meal being at midday, that's how the French do things anyhow but I do find it better . It's just after so many years of having dinner in the evening, it's hard to change )
Conclusion
Dietary freedom, as part of FIIT, remains acceptable with regards to blood glucose control
From questions:
  • Higher carbs were associated with fewer hypos
  • None used extended boluses for higher carb meals (said might be interesting to see if the use of this would mitigate the late postprandial rise.I agree)
  • They didn't take into account total energy ie calorie content (as she said interesting but of course not data that is on the pump)
  • There was no association between total daily carbohydrate content and BMI
 
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Thanks for the summary, interesting results and not all what you'd expect necessarily.
 
Very interesting reading Phoenix, thanks for posting.
 
Wow.... really not what I expected. Good food for thought :)

I continually beat myself up about my high carb intake, regardless of my healthcare professionals telling me I'm doing fine. I'm not overweight, have an average(ish) hba1c but always want to improve. Just shows what you can prove with numbers.
 
I think that one has to remember that the daily carb/HbA1c was a slight negative correlation so although that was the general trend, there were certainly those that had lower intakes and good HbA1cs and also those who higher intakes and good A1cs (and the converse)
Here is the graph its quite easy to read as individuals are clearly plotted
Kings college easd carb Hba1c.JPG

The thing that did surprise me was about more meals. I didn't really look at the graph that carefully. (I'll try and find it later) It seems to suggest that maybe grazing is better than one or two big meals. Obviously if you use a pump and use the bolus wizard so that you are less likely to stack insulin then it's more possible on a pump.
Consistent carbs used to be pushed by the ADA so did my own doctors (although that is of the three meal a day variety not more)

There are of course other big variables; exercise is one that isn't accounted for. It would have been interesting to see insulin usage. That would have been on the pump although just plotting insulin/HbA1c or insulin/carb wouldn't really show much. You need a combined measure.
 
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Well, now we just need to work out how that study is flawed and/or how the researcher was secretly paid off by the high carb food industry.
 
Well, now we just need to work out how that study is flawed and/or how the researcher was secretly paid off by the high carb food industry.
She obviously needed to supplement her grant.
Or maybe I'm part of the conspiracy, my mother used to work at that hospital and my daughter was born there, very sinister!
 
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