Is Time in Range More Important than A1C?
What is time in range? How about time in tight range? My doctor wants to know my A1C all the time. Doesn’t that matter?
Yes, we know there is a lot of new talk about time in range and then time in tight range. If you follow our Instagram (make this a link to the Instagram) we just posted about it too. If you feel a little confused you’re in the right place!
As your friendly neighborhood dietitians and diabetes educator, we want to help you understand what these phrases mean and what they have to do with each other.
Time in Range (TiR) is generally defined as when your blood glucose levels remain between 70-180 milligrams per deciliter. That means if we were to draw a tenth of a liter of your blood, you would have between 70-180 milligrams of glucose in it. This can actually correlate to a range of A1C levels, but for the most part averages out to be about 7. A good goal for time in range is >70%. This means that on any given day your blood glucose levels were between 70-180 for an average of 16 hours out of the day. This is more easily monitored with a Continuous Glucose Monitor (CGM). If you’re unsure about those stay tuned, we have a blog post coming on them! (Insert photo of appropriate blood glucose in range)
The down side to this range is that there are studies showing that even if you are in this range 70% of the time, you still have an increased risk for cardiovascular disease. Also, with type 2 diabetes, there is a correlation between a higher A1C and dementia. Higher A1C has also been linked to kidney and liver diseases.
Time in Tight Range is a blood glucose level between 70-140 mg/dL. Yes, we know that the 40 mg difference can seem a bit daunting. Especially if your blood glucose levels aren’t exactly…. well controlled. But it makes a big difference! This correlates to a range of A1C levels as well, but averages out to a 6. (Insert photo here)
The difference between these two ranges results in a 50-76% reduction in rates of microvascular events according to the American Diabetic Association. What are those? Things like retinopathy, kidney disease and neuropathy. The tighter range has also been linked to a longer and higher quality life.
So is time in range better than A1C? The answer, ultimately, is yes. A1C is limited in that it is an average of your blood glucose over 3 months. Meaning that someone with an A1C of 7 could have a graph over 3 months that looks like the Rocky Mountains, and another person with that same A1C level could have a graph that is a pretty straight line. Those highs and lows cause enormous stress on the body and its systems. That stress causes the damage that leads to those microvascular events.
Do you have a rocky relationship with your blood glucose? Are you unsure how to keep your blood glucose between 70-140? Reach out to us today for an appointment. We are here to help!