Med Tech Report

Smart watch glucose monitoring on the horizon


Watch-based monitoring of blood glucose is clearly in the works, and, in the near future, we expect it to change the way we manage diabetes.

Dr. Neil Skolnik, associate director of the family medicine residency program at Abington (Pa.) Hospital–Jefferson Health

Dr. Neil Skolnik

Earlier this year, technology news sites reported that the Apple Watch Series 7 and the Samsung Galaxy Watch 4 were going to have integrated optical sensors for checking interstitial fluid glucose levels with no blood sampling needed. By the summer, new articles indicated that the glucose sensing watches would not be released this year for either Apple or Samsung.

For now, the newest technology available for monitoring glucose is continuous glucose monitoring (CGM), which involves a tiny sensor being inserted under the skin. The sensor tests glucose every few minutes, and a transmitter wirelessly sends the information to a monitor, which may be part of an insulin pump or a separate device. Some CGMs send information directly to a smartphone or tablet, according to the National Institutes of Health.

In 1999 the Food and Drug Administration approved the first CGM, which was only approved for downloading 3 days of data at a doctor’s office. Interestingly, the first real-time CGM device for patients to use on their own was a watch, the Glucowatch Biographer. Because of irritation and other issues, that watch never caught on. In 2006 and 2008, Dexcom and then Abbott released the first real-time CGMs that allowed patients to frequently check their own blood sugars.1,2

How CGM has advanced diabetes management

The advent of CGM has advanced the field of diabetes management in many ways.

Dr. Victoria Persampiere

It has allowed patients to get real time feedback on how their behavior affects their blood sugar. The use of CGM along with the ensuing behavioral changes actually leads to a decrease in hemoglobin A1c, along with a lower risk of hypoglycemia. CGM has also resulted in patients having a better understanding of several aspects of glucose control, including glucose variability and nocturnal hypoglycemia.

Affordable, readily accessible CGM monitors that allow patients to intermittently use CGM have become available over the last 3 years.

In the United States alone, 34.2 million people have diabetes – nearly 1 in every 10 people. Many do not do self-monitoring of blood glucose and most do not use CGM. The current alternative to CGM – self monitoring of blood glucose – is cumbersome, and, since it requires regular finger sticks, is painful. Also, there is significant cost to each test strip that is used to self-monitor, and most insurance limits the number of times a day a patient can check their blood sugar. CGM used to be reserved only for patients who use multiple doses of insulin daily, and only began being approved for use for patients on basal insulin alone in June 2021.3

Most primary care doctors are just beginning to learn how to interpret CGM data.

Smart watch glucose monitoring predictions

When smart watch glucose monitoring arrives, it will suddenly change the playing field for patients with diabetes and their doctors alike.

We expect it to bring down the price of CGM and make it readily available to any patient who owns a smart watch with that function.

For doctors, the new technology will result in them suddenly being asked to advise their patients on how to use the data generated by watch-based CGM.

Dr. Skolnik is professor of family and community medicine at Sidney Kimmel Medical College, Philadelphia, and associate director of the family medicine residency program at Abington (Pa.) Hospital–Jefferson Health. They have no conflicts related to the content of this piece. Dr. Persampiere is a second-year resident in the family medicine residency program at Abington Jefferson Health. You can contact them at


1. Hirsh I. Introduction: History of Glucose Monitoring, in “Role of Continuous Glucose Monitoring in Diabetes Treatment.” American Diabetes Association. 2018.

2. Peters A. The Evidence Base for Continuous Glucose Monitoring, in “Role of Continuous Glucose Monitoring in Diabetes Treatment.” American Diabetes Association 2018.

3. “Medicare Loosening Restrictions for Continuous Glucose Monitor (CGM) Coverage,” Healthline. 2021 Jul 13.

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