Continuous glucose monitoring devices help keep glucose levels stable and HbA1c results low(er) for millions of people with type 1 diabetes. Not only are these combined glucose sensors and data transmitters expected to earn their developers a projected $23 billion by the end of this year, but market growth is also predicted to be almost 17 percent in 2024.
Thanks to the high value of CGMs, for their manufacturers and users, CGM technology is under continuous development.
Representing a major change to CGM tech is the long wear Eversense 3, developed by Senseonics and distributed via Ascensia Diabetes Care.
The idea of a sensor/transmitter combo that stays in place for longer than the average 10 to 14 days is very attractive. But can Eversense truly beat its current competition with a single feature? Read on to find out if the first long wear CGM is the right choice for you.
The First Long Wear CGM
Before we start to discuss Eversense’s pros and cons, it’s important to know that this isn’t a glucose monitoring system for children with type 1 diabetes. Users must be 18 years or older.
But if you or your loved one with diabetes are over 18, then it’s time to discover whether Eversense CGM could be the right choice.
Senseonics first developed a long wear CGM in 2018. Back then, long wear meant 3 months. Today, Eversense 3 supplies 180 days of continuous interstitial glucose monitoring data. That’s right. Only 2 sensors a year – about 22 less than today’s much-shorter-wear CGMs.
Eversense 3 received FDA approval in February 2022. It’s covered by Medicare if:
- You have type 1 diabetes.
- Are treated with insulin at least 3 times a day.
- Insulin doses require regular adjustments based on CGM results.
- You see your diabetes specialist at least once every 6 months.
Thanks to FDA approval, a growing number of insurers offer Eversense 3 coverage. However, the above-described conditions will need to be met. We’ll look at Eversense out-of-pocket costs a little later.
Eversense’s top feature is longevity. At present, it has no competition. So how does it last so long?
Two reasons. The first is in the way Eversense 3 measures glucose levels.
Dexcom, Medtronic and Abbott CGM sensors use enzymes that bind with glucose molecules. Bound glucose concentration can then be measured using integrated electrochemical cells. These CGM types are calibrated during the manufacturing process. There’s no need to calibrate at home. Even so, FDA approval requires finger-stick testing when results are unusual or unexpected. Results are sent as data via an inbuilt transmitter that sends information to an app or reader via Bluetooth.
Eversense measures glucose in a very different way.
Instead of enzymes, this long wear CGM sensor measures glucose using optics. There’s a surrounding layer of gel that contains chemicals that glow when they bind to glucose molecules. The gel covers an optic sensor that measures light levels (in scientific terms, fluorescence). With the addition of an internal antenna, data is passed to a separate transmitter. As with other CGMs, data is then sent from the transmitter to an app or reader via Bluetooth.
The second reason Eversense 3 CGM lasts so long is related to where its sensor is positioned … under the skin. Unlike short-wear CGMs which come with applicator devices, Eversense’s sensor must be inserted by a medical professional.
Eversense insertion requires a small incision under local anesthetic. The incision is very small – between 0.2 and 0.3 inches (5 and 8 mm). A pocket is then created in the subcutaneous fat and a special applicator inserts the sterile Eversense sensor. You will need to keep the wound dry and clean for 5 days. If the site becomes infected, the sensor may need to be removed.
For many, the above-described procedure is a good enough reason to reject the idea of long wear CGMs. However, users say the worst part is the injection of local anesthetic. After that, they feel nothing.
Scar tissue formation is a potential risk if implants are consistently positioned in and removed from the same area. The solution is to switch sides and sites – approved sites are limited to the upper arms.
The second part of Eversense also puts potential users off – its transmitter. While the sensor is hidden under the skin, the transmitter sits on top and is quite big when compared to short-wear CGMs (1.48 inches long, 1.9 inches wide and 0.35 inches thick (37.6 x 48 x 8.8 mm)). The transmitter must be removed daily for a 10-to-15-minute charging session. You can take it off any time which is handy – just be aware that the sensor doesn’t store data which means that without the transmitter attached you won’t get glucose readings.
With the transmitter in place, glucose readings are sent to the free Eversense app on paired devices. This CGM has no dedicated reader.
According to Ascensia’s website, Eversense’s accuracy goes above and beyond in the accuracy stakes.
Using MARD measurements that indicate a discrepancy between a laboratory blood glucose test result and the result given by a CGM at the same time, Eversense 3 scores very well. It produces a MARD of just 8.5%. In short, if a lab measures blood glucose as 100 mg/dL, Eversense will, in ideal conditions, transmit a value of between 91.5 and 108.5 mg/dL most of the time.
But there’s a ‘however’ to Eversense’s claim of “exceptional accuracy”. It’s not so exceptional in the CGM world at all. Recent tests on short-wear CGMs show ever-improving results. For example, the Libre 3 boasts a 7.6% MARD value, and the Dexcom G7 a similarly exceptional 8.2%. So, while Eversense is very accurate, it’s not the most accurate across the board.
Where it surpasses other CGMs is in its accuracy in low glucose (hypo) environments. MARD% results listed in most CGM marketing blurbs is the ‘overall MARD%’ – a rough average in ideal age, weight, exercise, and glucose range environments. Accuracy tends to drop outside these generic metrics. However, Eversense 3 produces accurate results even in hypoglycemic states.
But how does the long wear CGM earn those very high (but not exceptional) accuracy scores?
For many people with type 1 diabetes, this could be the nail in Eversense’s coffin. After all, the latest short-wear CGMs have been developed to avoid calibration.
But without the enzyme activity used in short-wear CGMs, Eversense’s dependence on fluorescence requires it. A lot of it. Calibration begins after a 24-hour warm-up. During this period, you’ll have to measure glucose levels using an alternative device.
After the warm-up, the charged transmitter is attached. It then takes around 10 minutes to receive the first calibration alert. Finger-stick 1.
The next 3 calibrations (finger-sticks 2, 3 and 4) must take place within 36 hours of the first. You only start to receive data on your app after calibration number 2.
For the next 3 weeks, you must calibrate your Eversense device twice a day (finger-sticks 5 to 47).
For the remaining 5 months, once daily is sufficient (finger-sticks 48 to 85). At least in theory. Users often complain that the sensor often requests 2 tests a day during this period.
User Experience, Comfort, Usability
It’s fine reading the shiny brochures and research papers, but what do actual users think of Eversense 3?
The truth is, there aren’t so many users out there. This might be because of its unfamiliar form among doctors and its position in a market dominated by Abbott, Dexcom and Medtronic.
Browsing diabetes forums, one thing is clear. In the small population that uses Eversense CGM, there’s lots of appreciation for “on-body vibration alerts”. When glucose measurements start to take a nosedive or head for the sky, the transmitter vibrates. You don’t need to be close to your smartphone or PC. You don’t need Bluetooth. All you need is a charged and sensor-linked transmitter.
With so many complaints about irritating (and inaccurate) phone alarms with other CGM brands, it’s no wonder Eversense 3 users are full of praise for this feature.
App reviews are easier to find. Again, Eversense misses the mark. The app is easy to use but its level of integration is very, very low. If you have an iPhone, it will integrate with Apple Health. And that’s about it. No AID integration at all. In this sense, Eversense is trailing behind its short-wear competition.
Even so, active PWD shouldn’t cross this long wear CGM option from their list. The combination of sensor implant and detachable transmitter prevents many short-wear CGM frustrations where the sensor and transmitter are one, inseparable unit. Frustrations like knocks and bumps that dislodge the microneedle array, skin irritations (from sensor adhesives) or excessive sweating (that loosens adhesives). In these cases, Eversense 3 is a good CGM choice.
Is Eversense Covered by Insurance?
After FDA approval, many insurers in the US are prepared to cover Eversense 3 under specific conditions (as with any CGM type). Eversense cover in Europe is currently based on whether short-wear options are an option and if not, why not? The UK has only just started training healthcare workers to place sensors in patients with type 1 diabetes and the NHS website doesn’t include Eversense 3 on its list of available CGMs.
Eversense CGM Cost
One Eversense 180-day sensor will set you back at about $1350. Annually, that’s around $2700.
You will also need one transmitter – the average uninsured cost is $700.
Then there’s the cost of a minor surgical procedure, charged at $450 for insertion, and around $100 more for removal of an old sensor and insertion of a new one.
That’s $4400 a year (just over $365 a month).
The good news is that an Eversense 3 is a prescription-only device and usually eligible for some insurance coverage.
If you live in the US, it might be worth contacting Ascensia about their PASS program. It covers all commercially insured PWDs, including those without Eversense 3 coverage from their insurance provider.
The first year (without placement/removal cost) is just $198. From year 2, PASS members pay a maximum of $100 a month (without placement/removal costs).
Eversense in a Nutshell
|Transmitter dimensions (inches)||1.48 x 1.9 x 0.35 (37.6 x 48 x 8.8 mm)|
|Transmitter weight (ounces)||0.39 (11 grams)|
|Waterproof||Shower and bath-safe|
Transmitter: 3.2 feet water depth for up to 30 minutes
(The under skin sensor is completely waterproof)
|Accuracy (MARD%) adult||8.5|
|Warm-up time||24 hours|
|Wear time||Up to 180 days|
|Number of transmissions/minute||12|
|Transmission range (feet)||25|
Body-vibration alert possible
|Current sensor integrations||None|
|Sensor memory when out of range (days)||0|
Apple Health App
|Pairs with:||Specified Android and iOS devices|
|Data sharing?||Up to 5 people|
|Warranty||Sensor: 180 days|
Transmitter: 1 year
|Average monthly cost without CGM insurance cover||$365|
‘One sensor every six months’ sounds great, but we’re aware of the potential pitfalls of the only available CGM implant to date.
Regular calibration, device and insertion/removal costs, bulky transmitter and too little honest feedback from genuine users make it hard to arrive at a well-rounded decision.
Our advice? Wait a little longer, unless you deal with skin irritation which makes short-wear CGM use impossible, or you lead a very active lifestyle and don’t use an insulin pump.
Implanted CGM technology is still extremely young. Senseonics is already working on an enhanced under-skin sensor with an integrated battery. Implementing Bluetooth low energy instead of a transmitter, this invisible CGM is planned to work for a year at a time.
Another CGM contender, GlySens, is developing its own implantable, invisible CGM. It’s expected to operate for over 2 years without maintenance.
There’s so much to look forward to in the world of accurate, invisible, and comfortable continuous glucose monitoring systems! In our opinion, Eversense is ahead of its time, but nowhere near as good as it should be…yet.