2024 marks 50 years of the invention of pulse-oximetry, first presented by Takuo Aoyahi in Osaka, Japan. In development since the 1930’s, this represented one of the most significant developments in the history of medical technology,.  This tool replaced the arterial blood gas analysis, which was an invasive and painful procedure not without complications . Today you can buy a pulse oximeter utilizing the same light emitting and detecting concepts at your local drugstore. Similarly, blood glucose is long known to have different absorption rates of various lights. Finger sticks have routinely been a painful and frequent requirement for monitoring blood sugar at home, but soon they may be a thing of the past. Now, the realization of reliable and accurate non-invasive wearables for diabetes to monitor blood glucose is likely closer than you think.

Non-Invasive Wearables Lack Accuracy

Today’s non-invasive wearables for diabetes monitoring are not quite accurate enough. One study’s authors used the International Organization for Standardization (ISO) and the Food and Drug Administration (FDA) criteria to check the accuracy of non-invasive glucose meters. The ISO stated that 95% of values should be within ± 15 mg/dL of the reference reading if the reference glucose <100 mg/dL or within ± 15% of the reference reading if the reference glucose ≥100 mg/dL. However, the study found that only 18.5% of the readings followed this criterion. The FDA stated that 95% of meter readings should be within ± 15% of reference readings, and 99% should be within ± 20%. The authors found that the glucose monitor was also far behind this, with only 77.5% of the glucose readings meeting the ± 20% (Mondal et al., (2024). Separately, another device that used the ear lobe to measure blood glucose had demonstrated clinical accuracy similar to invasive glucose monitors already on the market.

Overall, non-invasive monitoring systems are not sufficiently accurate in routine use. On February 21, 2024, the U.S. Food and Drug Administration (FDA) issued a statement that it has not approved any smartwatch or ring intended to measure blood glucose values. The repercussions of inaccurate measurements for those people with diabetes are dire. At best, they can lead to poor blood sugar management; at worst, they may lead to dangerously low glucose levels that ultimately could lead to confusion, coma, or death.

Continuous Glucose Monitors Bridge the Gap

Continuous glucose monitors (CGM) seem to bridge periodic finger sticks and non-invasive monitoring. A CGM works through a sensor placed on the skin, measuring the interstitial fluid just under it 24 hours a day.  A phone app or other recording device can then collect these transmitted readings. CGMs can also be paired with an insulin pump to adjust the basal and bolus insulin doses.  Currently, the recommended target blood glucose is 70-180 mg/dl for the general adult population. Your physician will help determine the appropriate range and the time frame you should be in, typically 17 out of 24 hours each day according to the American Diabetes Association. Your provider can then use the data to assist in prescribing the proper medication regimen. More time in the appropriate range benefits blood glucose management, which leads to improved health and fewer complications from diabetes.

Non-Invasive Wearables For the Glucose Level Curious

People with and without diabetes have recently obtained greater access to the same technology. On March 5, 2024, the FDA approved the first over-the-counter continuous glucose monitor. Though readily available, they are currently not intended for those who use insulin or have problematic hypoglycemia episodes. At nearly $100 for a month’s supply, the cost can also be prohibitive. Potential concerns include the chance for misinterpreted values, such as from normal glucose spikes following a meal. Therefore, it is recommended that you let your provider know you are using one and share the collected data from the unit with them for a healthier monitoring experience.

There are many tools in the management of diabetes, all of which aim to assist in a better glycemic index. Current CGMs, which have been around for 25 years, provide an excellent alternative to daily finger sticks. Advancing technologies are getting close to putting another tool on your wrist or even a finger, but they still require more time to develop and study. Much like the pulse oximeter before it, it is a promising development in diabetes management.

Whether you are a healthcare professional working at the physician’s office, in an outpatient clinic, in patient education, or as an administrator, it is important to be aware of the technology trend versus the FDA-approved wearables and to keep abreast of the current diabetes management.  To learn more about Diabetes and Diabetes Management, please check out our courses here.

Author: Angie Jung, RN, BSN, CRRN, CCM

References:

American Diabetes Association. Statistics About Diabetes. Nov. 2023. https://diabetes.org/about-diabetes/statistics/about-diabetes#:~:text=Overall%20numbers,of%20the%20population%2C%20had%20diabetes.&text=Diagnosed%20and%20undiagnosed%3A%20Of%20the,and%208.7%20million%20were%20undiagnosed

FDA, 3/5/24. FDA Clears First over-the-Counter CGM. https://www.fda.gov/news-events/press-announcements/fda-clears-first-over-counter-continuous-glucose-monitor

FDA, 2/21/24. FDA Safety Communication. https://www.fda.gov/medical-devices/safety-communications/do-not-use-smartwatches-or-smart-rings-measure-blood-glucose-levels-fda-safety-communication#:~:text=The%20FDA%20has%20not%20authorized,glucose%20values%20on%20its%20own

GlucoTrack. June, 2022. https://www.globenewswire.com/news-release/2022/06/22/2467130/0/en/GlucoTrack-Inc-Provides-Development-Update-on-its-Gen-2-Non-Invasive-Glucose-Monitor.html

Mondal et al., (2024), Accuracy of a Non-Invasive Home Glucose Monitor for Measurement of Blood Glucose, Indian Journal of Endocrinology and Metabolism 28(1):p 60-64, Jan–Feb 2024. https://journals.lww.com/indjem/fulltext/2024/01000/accuracy_of_a_non_invasive_home_glucose_monitor.11.aspx ).

Quaresima, Valentina. Ninety years of pulse oximetry: history, current status, and outlook. Aug. 2024. https://pmc.ncbi.nlm.nih.gov/articles/PMC11330276/