Hba1c And Or Time In Range?

Hba1c, time in range, both or neither? These have been hot topics for discussion amongst the diabetes community in recent months. I've had diabetes for 18 years coming up and hba1c has always been the gold standard measure of how my diabetes has been behaving over a 3 month period. Simplifying how it works, I'm aware that it measures the sugar that has attached itself to our red blood cells, with the theory being that the more time sugar that has been swimming around the blood and not in the muscles or being stored, then the more time it has to attach itself to the cells.

But the thing about hba1c is, whilst a good measure, some people with diabetes worry that it can be influenced by averages. By which I mean that someone could have a high reading and a low reading and the average result shows in the middle, without necessarily reflecting the extremes. So this is where the argument of time in range comes in, because if glucose levels stay between the parameters or range that contribute to a lower hba1c, without the highs and lows, then surely this is a greater reflection. But then there's a third argument that whilst we need a tool to measure diabetes management in terms of reducing complications, it's not the be all and end all of living with the condition. As it's also important to acknowledge that diabetes sometimes has a mind of its own sometimes and so the emphasis on a number, when there are variables outside of our control can be challenging to come to terms with.

Unfortunately, time in range is information that you can currently only really get from CGM data. So I can see it when I'm wearing my pump CGM sensor and this was something I personally strived towards in order to reduce my hba1c level. Of course, everyone's diabetes is different, but amongst a number of changes this was how I got my hba1c to the lowest level it's ever been since diagnosis. I changed insulins and the new insulin enabled me to stay in range without dropping as frequently, which the previous insulin could do sometimes and I'm going to talk about what this means for sport in a future blog. With this concept of time in range in mind, I also tightened my higher alert range at which the pump would alarm, dropping it from 16mmol/l to 11mmol/l. I believe that the difference this made was that I didn't see half as many stubborn highs. As the pump would alarm at 16mmol/l before and I'd already started to develop resistance so that when it came to the correction insulin dose, it took longer for glucose levels to come down, hence greater time outside of range. But now the pump alarms at 11mmol/l, the stubbornness isn't there, enabling greater time in range.

So in conclusion, I think a combination of both hba1c achieved in combination with an aim towards time in range is the way forward. With the reminder that we are more than just a number at the heart of diabetes management.