How much do you want to know? – by Helen May

I was away from home for two weeks over Christmas: it was a combination of visiting family (mine and my partner’s) as well as a bit of a winter holiday. Half a week after locking up the house and turning down the heating, I received a message from my boiler telling me that it was losing pressure. I was hundreds of miles away and didn’t want to cut my holiday short. My immediate reaction was “I didn’t want to know”. However, I did not ignore the message: with some help from my neighbour and emergency plumber, a leak was detected and fixed. I did not have to return home a cold flooded house at the end of my break.

Fast forward a couple of months and I am trying out a Continous Glucose Monitor (CGM). Last month, I tried out the Freestyle Libre: a Flash glucose monitor. This month, I am trying out the Dexcom G4: a Continuous Glucose Monitor. I chose the Dexcom because it can be linked to my insulin pump (Animas Vibe). The integration is basic but the pump acts as a receiver saving me money and teh frustration of carrying around another piece of kit.

The major difference in the functionality of the Libre and Dexcom is the Continuous part. The Libre captured BG readings all the time but only told me when I swiped it. The Dexcom will tell me the reading when I look at my pump. In addition, it is keeping an eye on my readings so it can tell me when it is too high, too low, rising fast or falling fast. When the CGM detects a problem, it beeps and buzzes. This could happen any time day or night; whilst relaxing after dinner or halfway up a climbing wall; during work or during sleep. There never seems to be a convenient time for the beeps and the buzz but that’s because there’s never a good time to have a hypo.

Apart from the beeps, I have more confidence in the Dexcom than the Libre. Unlike the Libre, it has not fallen off and, the Dexcom relies on finger-prick calibration rather than a one-size fits all factory calibration.  In addition, using my pump as the receiver means I can see the estimated insulin on board (IOB) to take into consideration with my readings.

On the other hand, the Libre is cheaper, you “just” have to fund the sensor at £50 every two weeks. Whereas, the Dexcom consists of the sensor (at about £50 a go) which is supposed to last for 7 days bit can be extended to two week, the transmitter (at about £250 for a year) and, if you do not have an Animas Vibe pump, you also have to fund the receiver (at another £350).

The cost for both is high and I have not found any way to reduce the cost apart from not wearing it all the time. And, neither option removes the need for finger pricks: the readings from the Libre and Dexcom are about 10 minutes old. As a consequence, it is not considered as accurate: my nurse still recommends finger pricks before pumping and the DVLA does not accept anything except bruised fingers before driving.

The result of my investigation is a preference for the Dexcom with its annoying buzzing. As it was useful to be warned about a potential flood from my central heating before it happened, it is valuable to be woken from a low BG reading before suffering from a night time hypo. However, it is too expensive for me to fund any continuous or flash glucose meter all the time. Therefore, I will analyse the results after two weeks, make some adjustments and check how I am going with another sensor in a few weeks time: the CGM will be an occasional rather than every day accessory.

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