My A1c came back a few weeks ago in my target range. As soon as I saw the number, I said to my endo: ‘It’s because of this,’ and I gently patted my arm where my Dexcom was sitting firmly, doing its thing.

I was right. Wearing CGM fulltime has allowed me to better understand what is going on with my glucose levels and how they responds to a variety of different factors.

Puppy on my lap and CGM on my arm.

But it’s only part of the picture and the more I’ve thought about it, the more I’ve come to realise it. I’ve been using CGM almost fulltime for four years now, yet this A1c was ‘more’ in-range than any other in that time.

It can’t just be the device.

No, it’s when I add the low(er) carb way I’ve been eating to the equation that the improvement starts to make sense.

The most obvious thing I noticed when I started eating lower carb was that my CGM trace stayed far straighter for far more of the time.

Before I started eating this way, I’d see a lot of spikes. Sure, I’d come back into range after an hour or two, but there was a good while there that I was above range while I waited for the insulin to do its thing with the carbs I’d just ingested. Insulin isn’t perfect; its action can be unpredictable.

Eating lower carb means the spikes just don’t happen as they used to. Of course there are other contributing factors that do cause my glucose levels to head out of range, but by eliminating – or rather minimising – the one that is most responsible has resulted in a significant change.

So, what is that change? It’s all about time in range (TIR).

And that is how I now measure my glucose management. It’s not about A1c – I don’t like averages because they conceal a lot of what is going on. The A1c average might be a pretty number, but what is going on outside that number to get there?  But when I look at how much of the day is spent in range, there is less place to hide. It is starkly clear the days that I am within my upper and lower limits.

And there is a flow on effect from more time in range. When I think about how I feel on the days that I am far more in range than out, I feel better – more energised, more focused, more able to just get things done.

CGM data easily provides me with this data (and flash glucose monitoring would as well) so I can see at a glance just how much of each day is actually spent in my target range. This means that I don’t really care about what my A1c is. It may creep up a little bit, but if overall I am spending more time in range, then I’m happy.

This is just another reason that A1c measurements are flawed. It was first recommended as a way to measure diabetes management back in 1976 and a lot has happened in diabetes since then. I’m certainly not suggesting that we throw it out the window. But I am saying that with new (and some not-so-new) tools to provide even more information – more meaningful information – I certainly am not using it as the only way I to track and measure how I am going.

TIR. I’m calling it the new A1c! (And adding yet another acronym to my diabetes lexicon…)

Want more? This great piece about ‘going beyond A1C’ from diaTribe is a must read.

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