We’ve said before that the diabetes device market in Europe is like looking into a crystal ball, foreshadowing what may be coming soon to the United States. But that isn’t always the case, as not everything that our fellow D-peeps have overseas makes its way to us.
So we were excited to hear from D-Blogger Don Weintraub, a Detroit, MI, native who now lives in Tel Aviv, Israel, and has been using the Abbott Freestyle Navigator II for the past five months. You remember the original Navigator continuous glucose monitor, right…? The CGM that Abbott discontinued in the U.S. back in 2011. It was pulled from market after an unexplained “supply interruption” that was supposedly only temporary, but turned out to be permanent and left many loyal CGM’ers out in the cold.
We asked Abbott Diabetes Care about plans to bring the next-gen Navigator to the States early this year, and were told that wasn’t in the cards. Nine months later, the company’s not saying anything more. Grrr.
Don was one of the first to get connected to the FreeStyle Navigator II (Nav2), and is gracious to share his insights with us here. He was diagnosed on Valentine’s Day 1975 at the age of 10, and after graduating from the University of Michigan with degrees in Marketing and Middle Eastern Studies, he’s been living in the Holyland since 1991. He works as a technology marketing consultant and freelance writer, and has recently joined the diabetes blogosphere at Sugarless 2.0.
Here’s a first look from Don on his experience so far:
A Guest Post by Don Weintraub
The overdue successor to Abbott’s first generation FreeStyle CGM delivers on all fronts: accurate sensor, smaller transmitter, longer range and flexible reports. Now if only they’d improve the sensor adhesive… While it may be a little unfair to those who don’t have access to one of these, and might bring on a little device envy, I thought it would be worthwhile to share some of my impressions on this CGM.
For those who only know the original Navigator, here are some of the biggest highlights you may get a kick out of: the receiver has a completely different look, with a vertical instead of horizontal design; the 10-hour start-up window has been slashed to only 1 hour (!); and the transmitter and sensor are about 40% smaller than the original, displaying results every minute.
Despite a few quirks and idiosyncrasies, the Nav2 has really improved my T1D quality of life. CGM accuracy is high and the minute-by-minute blood glucose updates are a godsend for this amateur athlete. Sensor life may be shorter than with Dexcom or Medtronic, but being able to go four days with only one fingertip test is a treat.
Abbott has always been a leader with the FreeStyle glucose measurement technology, and the Nav2 doesn’t disappoint. With built-in FreeStyle fingerstick glucometer, extended transmission range, flexible graphical reports and programmable alarms, the Nav2 has it all — even if the design leaves a little to be desired.
Let me be perfectly blunt: the Nav2 receiver display is nothing like a modern-day smartphone with an HD screen. Rather it’s more like a Blackberry of yesteryear with an 8-bit color display that you will be hard-pressed to read in anything more than moderate sunlight. For retro Blackberry fans, there’s a scroll wheel and two softkeys.
The display home screen shows the current BG reading, a trend arrow and four-hour graph. The current glucose level is prominently displayed on the home screen and is updated once every minute. Depending on whether the measurement is in or out of the customizable target range (mine is 80-180 mg/dL), the result appears as follows: 215 is above range (purple), 125 is within range (green), and 65 is below range (yellow). The home screen graph shows the last four hours of BG levels, and a more detailed history is accessible via the Reports sub-menu.
Trends Arrows show:
→ bg steady
↗ bg rising moderately (60-120 mg/dL per hour)
↑ bg rising rapidly (more than 120 mg/dL per hour)
↘ bg falling moderately (60-120 mg/dL per hour)
↓ bg falling rapidly (more than 120 mg/dL per hour)
The Nav2 sensor mount and transmitter are significantly (40%) smaller than in the original, with the sensor measuring glucose in the interstitial fluid 5mm under the skin. Abbott Diabetes Care (ADC) has gained approval for use of the sensor either in the abdomen or on the back of the upper arm. I have also worn the sensor on the back of my upper and lower waist with no performance degradation.
Sensor insertion is mostly pain-free and harmless, certainly in comparison to the Medtronic infusion set inserter, which I find like harpooning a whale! After disconnecting the Nav2 inserter, you slide the transmitter into the sensor mount until it “clicks.” Unfortunately, the ADC mechanical engineers have failed here because you don’t really hear a clear/firm click and you’re left wondering if the transmitter is indeed connected properly.
My No. 1 problem with the sensor is the adhesive performance, or lack thereof. The first few months I was shedding sensors early and often within a couple of days. I attribute this to a double-whammy: insertion only into the back of the upper arm (because of minimal fatty tissue in my stomach and a lot of core rotation in my exercise regimen), coupled with the fact that I play a lot of tennis in a hot/humid climate.
Working with the local ADC rep, we were able to resolve this using a couple of after-market products: pre-swiping the target site with a 3M ConvaCare barrier wipe, and post-insertion application of Smith & Nephew Opsite Flexifix transparent film strips. Notwithstanding, it would be much easier if Abbott found a stickier, water-resistant adhesive for their sensor mount.
I also had a problem with a couple of faulty sensor inserters that didn’t release the sensor into the skin. This is a known issue that Abbott is working to resolve and one that didn’t occur with the previous generation Nav inserters.
Sensors are three-digit coded, and come in boxes of six for one month of usage. I am truly using them for just 5 days. Here in Israel I have full, literally 100% reimbursement so I haven’t had to extend the sensor life to save cash. But what you can do is disconnect and then reconnect the transmitter and begin the sensor registration/calibration anew. I have done this only once, using the sensor for 9 days (5+4) before the adhesive failed on me.
As to cost, I asked last year and it was something like $2,000 for the device and $600 monthly for the consumables.
Calibration & Accuracy
You only fly blind for one hour with the Nav2. Glucose results are provided immediately after performing the first calibration so long as the calibration BG level is in the 60-400 mg/dL range.
Five calibrations – using the built-in FreeStyle (Lite) glucometer with code-free test strips – must be performed over the five-day sensor lifetime. With four calibrations in day one, you get four days with only one calibration. For me this was a major selling point: only one fingertip prick in four days! Also, BG levels are updated each and every minute, giving users the most up-to-date data.
Occasionally, after the second calibration in particular, the system may prompt you to perform an additional test (after 15 minutes, 1 hour or 3 hours) if your BG level is unstable, i.e. rapidly rising or falling during calibration testing. A shortcut workaround for this is to perform a manual calibration test (or two) before the requested wait time. You get a 30-minute grace period after the second calibration two hours in, meaning that you’ll still get readings for that half an hour without checking your sugar. The grace period goes up to two hours at the 10-hour calibration, and eight hours for the 24 and 72-hour calibrations.
I have found the Nav2 CGM readings to be quite accurate, typically within 10% of the FreeStyle glucometer results. I have done some random tests to compare, and can say non-scientifically that I am very happy with the system’s accuracy.
One minor complaint on the built-in FreeStyle Lite glucometer: while they included the bright test strip port light, it’s defaulted off, requiring an annoying button press to light up. There’s no coding, though, and all results are stored in the CGM.
Connectivity & Battery Life
The Nav2 receiver is fitted with a standard mini-USB port for PC connectivity, charging, and device data download using the FreeStyle CoPilot software; a dedicated A/C wall charger is also provided. The display timeout is programmable from 15-120 seconds. To extend battery life I have set mine to the minimum 15 seconds. This is more than enough for the quick BG check, and I am now getting over seven days between charges (ADC states a battery life of three days under typical use and a full charge time of six hours).
The transmitter battery life is quoted at one year, after which the transmitter must be replaced, i.e. one-year consumable. There is a Status sub-menu that shows the receiver and transmitter status as a percentage; after five months my transmitter status is 75%.
Events & Alarms
You can create a history of your daily activities using pre-defined events, including Insulin (type and units), Food (breakfast, lunch, dinner, snack), Exercise (aerobics, walking, jogging, running, swimming, biking, weights, other) and state of health (normal, cold, sore throat, infection, tired, stress, fever, flu, allergy, period, dizzy, feel low, feel high). You can add eight custom events; unfortunately you cannot define a custom event descriptor.
Programmable alarms include: Low Glucose, High Glucose, Projected Low, Projected High, Data Loss and System. Each alarm type includes a programmable tone and/or vibrate option as well as a snooze time. Different values can be programmed for Day and Night.
- Low Glucose Threshold – range is 60-119 mg/dL
- High Glucose Threshold – range is 120-300 mg/dL
- Projected Low – advance notification of 10/20/30 minutes when approaching the Low Glucose threshold
- Projected High – advance notification of 10/20/30 minutes when approaching the High Glucose threshold
- Data Loss – indicates glucose results are no longer available. Reasons for this include:
- Expired sensor (clicking the scroll wheel shows when the sensor will expire)
- Overdue calibration
- Sensor not working correctly
- Transmitter disconnected from the receiver
Unsurprisingly, I have gotten acquainted with each of these alarm types, in particular the Projected Low that has saved me from many a hypo. The Data Loss alarm caused by transmitter disconnect frequently occurs immediately after insertion of a new sensor. When first pairing the transmitter with the receiver after connecting a new sensor, I found that performing the “Connect to Sensor” function a couple of times seems to keep it connected going forward.
Other disconnects occurred when I was out of range in my duplex apartment with reinforced concrete. The stated range is 30m/100ft line-of-sight, similar to what I witnessed, and long enough to cover me on the tennis court.
All the Rest
This system uses the FreeStyle CoPilot Health Management software, and I give it a thumbs down as it’s available only for PC, not Mac. Really, it’s not a great software suite, I must say.
In terms of carry cases, the Nav2 comes with three colored skins: purple, pink and black. Although they protect the receiver from the occasional drop, they are not convenient when it comes to daily wear. I prefer to use the zippered case that Abbott provided with the original Nav: not only does it offer some protection, but it also has a belt clip for wearing on-person as opposed to in-pocket with the skin. Although not a perfectly snug fit, it does leave room for some cash and cards.
Overall, despite my minor complaints, the Nav2 doesn’t disappoint! My wife Meirav and I both love it for the accuracy and low predictions it provides. Now they just need to make it stick to the skin!
Thanks for the comprehensive recap, Don, and we can only hope that Abbott decides to bring this device to America at some point. U.S. CGM customers: what are your thoughts?