Quarterly Clinic Report – March 2012

So yesterday was Samuel’s quarterly clinic appointment with the Paediatric Endocrinology Consultant at Bassetlaw. This was his first appointment since we got the Dexcom CGM and I was expecting to see a rise in his HbA1c.

We have been using the Dexcom CGM to reduce the number of low’s he was getting. It allows us to see them coming and treat them before he goes too low (usually) and we thought we were doing this with some success. However, in my mind a reduction in the number of lows would bring an increase in his average Bg levels – something the Dexcom software was bearing out. His average Bg in January was 7.2 and this had risen to 7.4 in February.

With his HbA1c last quarter at 6.5%, and his mean Bg’s higher I wondered if we would have a HbA1c reading starting with a 7?

Imagine our surprise – 6.2%! Result!

Having talked it over the consultant, perhaps this shouldn’t have come as such a surpirse. We had targetted reducing low’s in the first instance and that was the trend I had been concentrating on. Whilst we are catching the low’s quicker, why wouldn’t we be catching the high’s sooner too? Makes perfect sense, but we weren’t focusing on that. Clearly, we have been though.

So why were the average Bg’s higher? According to the consultant, although there is a correlation between average Bg levels and HbA1c levels, they aren’t the same. Average Bg’s is just that – an average. You can have a Bg of 12 and be 2 later and you’ll still average 7, even though that’s poorly controlled blood glucose levels.

HbA1c is a measure of glycosylated haemoglobin ie glucose that has stuck to red blood cells! There’s a good explanation here. As the cells can live for up to 120 days, a measure of the amount of red blood cells with glucose stuck on them (as a percentage) is a better measure of a diabetics control over the last few months than just using an average Bg level.

Whilst at clinic, they also measure Sam’s weight, height and BMI. He has grown 2.5cm in three months and put on a couple of Kilo’s, so he is right in the middle of puberty, with all the complications to Bg levels that growth hormones bring.

The consultant mentioned something else I didn’t know. When Bg levels are out of range, the bodies systems can shut down the production of hormones like the growth hormone whilst trying to bring things back into balance. This underlines why good control is so important, so that Sam will grow up big and strong!!

Taking all this into account means the Dexcom has proved even more valuable than I originally thought. Being able to jump on low’s and high’s as quickly as possible, and treat them, means we are keeping a tight rein on this thing called Type 1 Diabetes.