The Importance of “Time in Range” for Diabetes Management

This content was sponsored by Abbott, the makers of FreeStyle Libre 2—a Founding Partner of Beyond Type 2.

Shifting focus

You might be familiar with A1c as a measurement of blood glucose levels, but one data point every three months can only tell you so much about your overall diabetes health. With the wealth of data available through continuous glucose monitoring (CGM) technology, many care providers are embracing time in range (TIR) as an important measure in helping patients manage their diabetes. 

Time-in-range (TIR) is a measurement that tells you what percentage of the day your blood sugars are in your goal range.

While using a CGM, you’ll work with your healthcare team to set “low” and “high” alarms that determine the appropriate goal range for your blood sugar levels. TIR tells you how often you’re actually within that goal range.

Your A1c provides a retrospective view of your average blood glucose levels over the past ~three months, but time in range measures the amount of time you spend in a specific target blood glucose range. For example, a target blood glucose range your doctor may set could be between 3.9-10.0 mmol/L70-180 mg/dL.

This target range may differ for you depending on the personal diabetes management goals determined by you and your doctor. Experts have provided some guidance and benchmarks to aim for when using time in range as a metric. It’s recommended that people with type 1 or type 2 diabetes aim to spend 70 percent or more time within their target blood glucose range, less than 4 percent below 3.9 mmol/L70 mg/dL (hypoglycemia), and less than 1 percent below 3.0 mmol/L54 mg/dL¹ (severe hypoglycemia).

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 percent, but next month it could be 60 percent. Time in range is a useful way to track your progress and to provide insights into what affects your blood glucose values. 

To know your time in range, you’ll need to monitor your blood glucose with a CGM system and download or view your blood glucose data in a report that offers this option. One option is the FreeStyle Libre 14 day system. With just a quick scan of the sensor that’s worn on the back of the upper arm with a reader or smartphone*, the FreeStyle Libre 14 day system shows you what percentage of time your sensor readings are above, below and within your target range. 

Positive impact

Evidence suggests that focusing on improving time in range has a positive impact on A1c.² Every 10 percent increase in time in range equaled an 0.8 percent (or 8.7 mmol/mol) A1c reduction.² With the FreeStyle Libre 14 day system, users who frequently tested their blood glucose spend 44 percent more time in range and 31 percent less time in hypoglycemia.³ 

The FreeStyle Libre 14 day system can provide the information you need to make a more informed decision about your diabetes management. Not only can it show you your current blood glucose reading with a scan of the sensor, but also a trend arrow shows the direction your blood glucose is heading, and the eight-hour blood glucose history shows high and low blood glucose readings. All of this and the daily pattern can help you tweak your treatment plan, food choices, exercise regimen and help you spend more time in your target range. 

Ways to take action

Ultimately, time in range targets are recommended to be personalized according to your healthcare provider. If you’re already using a CGM and are looking to improve your time in target range, here are some helpful tips: 

• Use your CGM’s log or track event feature. Use the log feature of the FreeStyle Libre 14 day system when you scan your sensor to track other variables like insulin doses and food. For instance, the FreeStyle Libre 14 day reader includes an option for you to track your medication (i.e. insulin units), food (carbohydrate amounts), and exercise. The FreeStyle LibreLink app* allows you to enter detailed notes. Using this method is helpful because it can help you pinpoint what could be causing highs and lows. 
• Assess your eating patterns. Take notice of what aspects of your eating patterns might be affecting your blood 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 blood 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 blood 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 blood 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 health care team. Discuss with your health care provider if you should adjust your target ranges and/or make any adjustments to your medication. 

* The FreeStyle LibreLink app is compatible with NFC-enabled smartphones running Android OS 5.0 or higher and iPhone 7 or later running iOS 11 or later. Use of the FreeStyle LibreLink app requires registration with LibreView, a service provided by Abbott and Newyu, Inc. The FreeStyle LibreLink app and FreeStyle Libre 14 Day reader have similar but not identical features. Fingersticks are required for treatment decisions when you see Check Blood Glucose symbol, when symptoms do not match system readings, when you suspect readings may be inaccurate, or when you experience symptoms that may be due to high or low blood glucose. When using FreeStyle LibreLink app, access to a blood glucose monitoring system is required as the app does not provide one. 

References: 1. Battelino, T. et al. Clinical Targets for Continuous Glucose Monitoring Data Interpretation: Recommendations From the International Consensus on Time in Range. Diabetes Care, 2019 Aug; 42(8): 1593- 1603. 2. Vigersky RA, McMahon C. The relationship of hemoglobin A1C to time in range in patients with diabetes. Diabetes Technol Ther 2019;21: 81–85. 3.. Ajjan R. Insights from real world use of flash continuous glucose monitoring. Symposium conducted at: American Diabetes Association 78th Scientific Sessions; June 2018; Orlando, FL.

Indications and Important Safety Information 

The FreeStyle Libre 14 day Flash Glucose Monitoring System is a continuous glucose monitoring (CGM) device indicated for the management of diabetes in persons age 18 and older. It is designed to replace blood glucose testing for diabetes treatment decisions. The System detects trends and tracks patterns aiding in the detection of episodes of hyperglycemia and hypoglycemia, facilitating both acute and long-term therapy adjustments. Interpretation of the System readings should be based on the glucose trends and several sequential readings over time. The System is intended for single patient use and requires a prescription. 

CONTRAINDICATIONS: Remove the sensor before MRI, CT scan, X-ray, or diathermy treatment. 

WARNINGS/LIMITATIONS: Do not ignore symptoms that may be due to low or high blood glucose, hypoglycemic unawareness, or dehydration. Check sensor glucose readings with a blood glucose meter when Check Blood Glucose symbol appears, when symptoms do not match system readings, or when readings are suspected to be inaccurate. The FreeStyle Libre 14 day system does not have alarms unless the sensor is scanned, and the system contains small parts that may be dangerous if swallowed. The FreeStyle Libre 14 day system is not approved for pregnant women, persons on dialysis, or critically-ill population. Sensor placement is not approved for sites other than the back of the arm and standard precautions for transmission of blood borne pathogens should be taken. The built-in blood glucose meter is not for use on dehydrated, hypotensive, in shock, hyperglycemic- hyperosmolar state, with or without ketosis, neonates, critically-ill patients, or for diagnosis or screening of diabetes. When using FreeStyle LibreLink app, access to a blood glucose monitoring system is required as the app does not provide one. Review all product information before use or contact Abbott Toll Free (855-632-8658) or visit http://www.freestylelibre.us for detailed indications for use and safety information. 

For full indications for use and safety information, see more here