By Nutrition Expert – Trupti Gurav,Mumbai
“Time-in-Range” (TIR) is the percentage of time that a person spends with their blood glucose levels in a target range. The range will vary depending on the person, but general guidelines suggest starting with a range of 70 to 180 mg/dl. (Over time, some people decide to aim for a tighter range, such as 70 to 140 mg/dl.)
TIR goes beyond A1C in representing blood glucose levels because it captures variation – the highs, lows, and in-range values that characterize life with diabetes.(1)(2)
Time-in-range goals are different for every person and may depend on medication, type of diabetes, diet (especially carb intake), age, health, and risk of hypoglycemia. In general, people with diabetes should aim to spend as much time in-range as possible; taking care to avoid low blood sugars and too much burden. TIR is a key metric of the quality of glucose control. (3)(4)
Why is Time in range so important?
HbA1C alone does not provide enough information about an individual with diabetes’ day-to-day diabetes management, nor is it a value that individuals with diabetes try to access without a clinician-initiated blood test.
Thinking about blood glucose in terms of time-in-range offers a more nuanced, cause-and-effect understanding of diabetes than A1C. (5)(6)(12)
- The primary goal is to increase the time in target range, while reducing the time below target range. Your time in range goals can be entirely specific to you. Today your time in range might be 50%, but next month it could be 60%.
- TIR goes Beyond A1C in representing blood glucose levels because it captures variation – the highs, lows, and in-range values that characterize life with diabetes. While A1C provides a retrospective view of your average glucose levels over the past ~3 months, time in range measures the amount of time you spend in a specific target glucose range. For example, a target glucose range your doctor may set could be between 70-180 mg/dl (3.9-10 mmol/L) 1. This target range may differ for you depending on the personal diabetes management goals determined by you and your doctor.
- TIR is a more accurate measure than HbA1C for assessing glycemic control in certain people who have conditions that may confound HbA1C values, such as iron deficiency or other anemia’s, hemoglobinopathies, and pregnancy.
- People living with diabetes experience different energy levels, moods, and overall quality of life when they are “in-range” vs. “out-of-range.” Time-in-range can capture these differences in a way A1C cannot.
- Time-in-range can be measured at home on a daily basis or weekly basis (see below), it has a huge advantage over A1C.
- For instance, how do different foods affect your time-in-range? How does walking after meals affect your time-in-range? A1C cannot reveal these relationships.
- TIR by itself is strongly associated with the risk of micro vascular diabetes complications Therefore, using the more tangible TIR along with HbA1C can help decrease an individual’s risk of developing micro vascular complications.
This study was published in Diabetes Technol Therapeutics. 2019 Feb; 21 By Author Vigersky RA, they concluded that; There was an excellent correlation between HbA1C and %TIR that may permit the transition to %TIR as the preferred metric for determining the outcome of clinical studies, predicting of the risk of diabetes complications, and assessing of an individual patient’s glycemic control.(7)
Another study was published in Journal of Clinical Diabetes by Ava S. Runge, they are conducted; After assessing patient perspectives on the success of current diabetes therapies and the factors that have the greatest impact on daily life, they proved that time-in-range is a crucial outcome for people with diabetes and that current therapies are falling short on this metric.
They also proved that patients feel significant stress and worry, and they believe they are falling short in diet, exercise, and weight maintenance. In addition, they believe diet and exercise and in-range blood glucose are the biggest drivers of improved diabetes management and mindset. (8)
How to measure TIR
To determine your TIR, you should use at least 14 days’ worth of blood glucose data.
TIR is most accurately measured using a continuous (9):-
- Glucose meter (CGM) – CGM provides a constant stream of information about your blood sugar – every five minutes, which means that you have a full picture of precisely how many hours of the day you spent in your target range. This includes overnight and after meals, which are usually missed with finger sticks. If you don’t have access to your own personal real-time CGM, ask your healthcare provider about professional CGM. If you have CGM, TIR is calculated automatically in the software/app that comes with your device
- Blood glucose meter (BGM) – A BGM, the more finger sticks you take throughout the day, the better the picture you’ll get of your TIR. Make sure to get readings over at least two weeks, ideally with some finger sticks taken after meals and overnight. If you are using BGM data, TIR is the percentage of your data points that fall in your range over a period of time. You can most easily calculate TIR with an app, by entering or uploading your BGM finger stick data. Bluetooth-enabled meters come with paired apps.
How to improve time in range
If you’re already using a CGM and are looking to improve your time in target range, here are some helpful tips: (10) (11)
- Wear CGM or check blood glucose more often, using the data to understand patterns. Identify and replicate Bright Spots – when I have a day with lots of time-in-range, what happened? How can I replicate those decisions?
- Assess your eating patterns -Take notice of what aspects of your eating patterns might be affecting your glucose levels. Are you eating or drinking more or less carbohydrates? Has the timing of your eating changed? What about portion sizes? Consider consulting a dietitian to identify opportunities to make changes that may improve glucose levels.
- Review your exercise regimen_Have you increased or decreased the intensity of your workouts? Take note if you’ve made major changes. Learn the ways exercise affects your glucose by scanning before, during and after your workout.
- Identify other stressors that may be impacting your blood sugar. Stress, lack of sleep, mental health, and other medical conditions can impact your glucose levels. If you’re experiencing diabetes distress or are interested to talk to someone who can help you move past these barriers, consider finding a mental health provider or a certified diabetes educator.
- Talk to your healthcare team. Discuss with your healthcare provider if you should adjust your target ranges and/or make any adjustments to your medication.
- Build routines to minimize Landmines – when I see less time-in-range, what choices drove that? How can I avoid those decisions next time?
In short using “Time in Range” as a metric by which to evaluate diabetes management provides a more realistic picture of what is going on day-to-day, and also empowers individuals with diabetes to take control of their own diabetes.