Adam Brown at diaTribe posted a great column yesterday about the time-in-range (TIR) measurement and how we might think about it.
While I’ve been using a continuous glucose monitor or CGM for eight years now, it’s only been in the latter portion of that period that I’ve come to appreciate the beauty of this metric. The medical and research community seem slow to fully embrace this measurement and fixate instead on the A1c number. There are definite exceptions to this A1c-centric focus and I think things are starting to change.
The biggest weakness of the A1c is in hiding blood glucose volatility and the extent of hypoglycemia. Unfortunately, it has led some clinicians to reflexively warn about hypoglycemia incidence based on an A1c number alone. Statements by clinicians such as, “I don’t like my diabetic patients to pursue an A1c below 6.0% since that means too much hypoglycemia,” don’t even consider that some of us can achieve lower A1c’s without increasing hypo risk.
To me, time-in-range, is the perfect diabetes statistic. A high percentage of TIR (80%-90%+) inherently means less time both high and low. When I can consistently measure 80%+ time in range, I feel better and enjoy more energy and clarity of mind.
Focusing on staying in my ideal range (I aim for 65-140 mg/dL or 3.6-7.8 mmol/L) means I have to tame blood glucose variability. Variability is the main impediment to lowering average BG and spending more time in range. Lowering variability also means fewer hypos and increased safety.
Adam is an unashamed adherent of the high-fat, low-carb way of eating, something I share with him. This graph hammers home his point.
I encourage everyone to click on the link and read his entire column. He brings experts into the conversation, including doctors like Irl Hirsch who lives with T1D. It’s well worth the read!