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Dexcom Seven Plus CGM Review

Discussion in 'Book and Product Reviews' started by NickW, May 8, 2010.

  1. NickW

    NickW · Well-Known Member

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    About 2 weeks ago I finally took the plunge and bought a Dexcom Seven Plus continuous glucose monitor (CGM), and thought I'd write a review of my initial impressions.

    Buying the device

    I bought the monitor from Advanced Therapeutics (UK) Ltd, the official UK distributors, and they've been excellent. One of the owners (John) spent a long time answering my questions before I went ahead and bought it, and they offer the unit on a trial basis - you can return the monitor after a couple of weeks if you choose, and they'll refund the cost of the device itself (they don't refund the sensors you've used for obvious reasons, and they charge for one further sensor which they use to test that the device still works). This was a major factor in my decision to even try a CGM, since I was reluctant to pay a grand for something that might not be of any benefit.

    The guys are also happy to take calls out of hours if you have any problems, and even offered to travel up to Northumberland (from Warwick) just to show me how to insert a sensor - for no charge. I didn't take them up on this offer, mainly because I'd have felt guilty making them travel so far, but it was great to know the option existed.

    The monitor itself is £975, and sensors are £60 each (usually sold in a box of four for £240, although they were happy to split a box open and only send me 2 units for the trial period).

    Sensor - Insertion, Comfort and Longevity
    As the sensors are £60 a pop, you probably want to take your time inserting them. I read and re-read the instructions first, but when it came to it, the process is pretty simple; I can explain it in detail if anyone wants, but there are a few videos on YouTube that show it clearly.

    Inserting the sensor didn't really hurt; I felt it very slightly more than an injection, but it's certainly nothing to worry about. The most off-putting part of the process (for me) is in removing the insertion device and clicking the transmittor into the sensor; it takes a bit of effort and I was worried about damaging the sensor. Nothing untoward happened though, and I'm sure it's just a case of getting used to it.

    Once inserted, the sensor is comfortable to wear - I've had no pain, discomfort or irritation.

    I've found that the adhesive starts to work free from my skin after a few days, which is a bit of a worry. The sensor is waterproof, but getting the tape wet definitely shortens its lifespan so I've started trying to keep the area as dry as possible in the shower. I'm not sure how it'll stand up to swimming or bathing; I'll be starting to swim again next week so I'll add something to the review then.

    For the first sensor I added zinc oxide tape to keep it in place, which worked OK as long as it was kept dry, but failed abysmally when wet. However, despite the tape coming loose the sensor still lasted a full 7 days.

    I've bought (but not yet tried) some OpSite Flexifix tape to try when my current sensor starts to come unstuck; I've seen this recommended on other diabetes sites, along with Tegaderm tape. I've also seen SkinTac and Mastidol recommended and may give them a try (both are additional adhesives that make the sensor tape stick better). Again, I'll update the review when and if I try any of these methods.

    One thing to bear in mind is that I exercise a lot. I typically train about 12 times per week, so the sensor's getting sweated on a lot, and of course I have a lot of showers. The adhesive might last longer if I weren't so active.

    Finally, it's too early to say how long I get from each sensor, as I'm only on to my second. The first lasted the full 7 days, after which time I tried to restart it but it gave me an error so I removed it. In retrospect, I should have left it a while longer as it turns out the sensors can sometimes take a bit longer than normal to "settle in". I'll post back later to say how long the current sensor lasts.

    The Monitor
    My initial reaction to the monitor itself was one of slight disappointment. Considering it costs nearly a grand it feels quite cheap and plasticky, and while the build quality is fine I was hoping for something a little better. The screen is pretty low-resolution and not terribly attractive, and the buttons make an audible click with every press. The buttons' action is fine, but that click can seem awfully loud at night when you're checking the monitor and trying not to wake your wife up!

    Another disappointment was in the way Dexcom had converted the monitor from US units to UK (i.e. from mg/dL to mmol/L). All they've done is to divide the US units by 18.05, and made no concessions to usability.

    The main trend graph is a prime example. On a US device, the Y-axis goes up in nice increments of 50 - so it goes 0, 50, 100, 150 etc. On the UK device, I would have expected the graph might be marked in 3-unit blocks - so it might go 0, 3, 6, 9 etc. Instead, it goes up in increments of roughly 2.77 - so it actually reads 0, 2.8, 5.6, 8.3, 11.1 etc.

    This is a minor point, but it actually makes interpreting the graph far harder than it should be.

    Alerts are a similar story - on a US unit you can choose to set the "High" alarm at 180, 200, 220 etc. In the UK I'd like to set it at 9, 10, 11 etc. - but I get to set it at 8.9, 10, 11.1, 12.2... again, a very minor point, but disappointing none the less.

    I don't like the case the monitor comes with and haven't used it, but carrying it in a pocket is no problem; it's slightly thicker than a phone, but a bit shorter and narrower so I've found it a convenient shape for carrying around.

    With all of that said, the monitor is easy to use and does the job just fine - it just looks like it could do with a makeover.

    The System In Use
    My overall experience with the system has been positive. It's already helped me see the effects of certain meals and of exercise, it's prevented a couple of hypos, and pointed out some high bloods well before I noticed them. Overall I'm happy with the system and intend to keep it.

    I imagine the system's benefits will vary widely depending on the individual, how they manage their diabetes, and their lifestyle. I like to keep my diabetes tightly controlled, so being able to check the monitor regularly is great - it's cut the number of finger-pricks I do quite a bit (from about 12 per day to maybe 6). I've found it most useful in spotting when my blood is rising, which will hopefully give me slightly improved HbA1c's in future.

    The monitor has been excellent during exercise. In the past I've had a few bad hypos while out running or cycling for long distances, so being able to easily check my blood while I exercise is a real boon. This is perhaps the main benefit I've personally seen with the system, and has given me the confidence to get back into distance running and cycling.

    I have pretty good hypo awareness, so the "Low" alarms have only been useful occasionally; I've usually felt a hypo coming on slightly before the alarm sounds (and so far the alarm has sounded every time I've gone hypo). If I had worse hypo awareness I'm sure they'd be invaluable.

    However, there have been a couple of frustrations. On the second night I had the system, I had the "Low" alarm set at 4.4 and it woke me up seven times throughout the night; I did a finger-prick each time and my BG was always between 5.1 and 5.6, which is exactly where I want it. I've since changed it so the alarm triggers at 3.9 and haven't been woken up again... but I did have a hypo one night and woke up shaking etc. before the monitor went off. So for me (from my initial experience), the monitor isn't very useful for avoiding night-time hypos; I either risk being woken up unnecessarily, or have the alarm set so low that I might be hypo before it triggers. If I weren't trying to keep my blood in the 5-6 range overnight (e.g. I was aiming for 6-7 or 7-8) it would probably be a different story.

    I've also found that the sensor can be a bit erratic for the first 24 hours after insertion. It's not terribly bad, but it occasionally gets really out of whack (e.g. shows my blood rising from 6 to 12 in the space of 30 minutes, when a finger-prick shows it's been stable at about 6.5). These are temporary problems though, and aren't that big a deal.

    Overall
    As I mentioned earlier, I intend to keep the monitor. I believe that it's useful enough to be worth the hefty price tag to me; take that as you will (for info, I earn a good salary but I'm not loaded, and paying for the sensors will mean cutting back elsewhere).

    The system is relatively easy to use and not too inconvenient, although some care is needed to prolong the sensor adhesive's life. I've already found it useful in preventing hypos and limiting periods of high BG, and it has given me added confidence when exercising. I don't find it terribly useful in preventing night-time hypos, but it's still there as a backup - and seeing what's happened overnight after the fact is useful in adjusting background doses and figuring out the impact of evening meals (food and timing).

    It has to be remembered that the system isn't perfect. You do still need to do finger-pricks regularly, and you can't rely on the exact reading the monitor gives you as it'll often be out by a unit or so (e.g. reading 5 when your BG is actually 6). Rather, you need to view it as another tool that can give you useful information on trends and the direction your blood's going; as a tool to analyse the impact of food, injections, exercise etc.; and as a "backup" device that can alert you to potential problems.

    I'd describe myself with someone with decent control, and with slight OCD tendencies and a strong desire to control my diabetes tightly, so the system works well for me. I imagine that people who have a hard time controlling their bloods would find it useful for different reasons, and likewise anyone with poor hypo awareness might find it a real help.

    I'm more than happy to answer any questions anyone has (bearing in mind I'm new to the system right now), and I hope that's helpful.

    Cheers,
    Nick.
     
  2. hanadr

    hanadr · Expert

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    It's very interesting that this thing is proving valuable to you.
    It would be totally beyond my OAP budget though.
    Hana
     
  3. telmo

    telmo · Newbie

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    Hello, I am from Portugal

    Here there are no CGM so I have to get one abroad.

    I have browsed through the Internet and found this one: Dexcon seven plus, read some reviews but still have some doubts, once you have allready some experience maybe you could answer some of my doubts, I really appreciate it.

    Here they are:

    I´ve read that the sensores last longer than 7 days, if so do you just keep them on or do you need to do anything?
    When you (the transmissor) get out of range of the receiver do you do anything to "connect" it or does it connect automatically by itself?

    Best regards

    Telmo
     
  4. steamerpoint

    steamerpoint · Newbie

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    I live in the UK and have been using the Dexcom Seven Plus for nearly 2-years now.

    Your review is similar to my experience, though there is another important cost you haven't factored in yet and that is the cost of the replacement transmitter. The small grey transmitter sits on top of the sensor and sends the data to the receiver by wifi transmitions.

    Inside the transmitter is a small battery and this battery cannot be replaced when it dies, so the whole transmitter needs to be replaced and they cost £550 !!!

    Switching off and sticking your Dexcom Seven Plus in the cupboard when not in use will not preserve the battery in the receiver as this is transmitting all the time, even when it is in the box on it's way from the USA. In fact it starts working the second they fit the battery and seal the unit.

    The transmitter battery should last between 12-months and 18-months before it needs replacing.

    While I would love to use the Dexcom all the time, cost pressures mean that I ration out my sensors.

    For this reason, I have been buying around 12-sensors a year and using one sensor a month, generally 14-days per sensor and then taking 2-weeks off before fitting another one.

    Even if funds become tight, I need to plough ahead and buy some more sensors else my transmitter will die and I haven't had much use from it. Ovbiously, when it dies, I might take 3 or 4-months break, before investing in a new transmitter & sensors!

    I managed to buy my first Dexcom Seven Plus from the USA, but struggled to keep buying the sensors as they were not available in the UK at the time. When I lost my first transmitter during a house move, I made a claim under the insurance and they sent me £550 for a new one, but I opted to spend £1000 and buy a whole new UK setup instead.

    Transmitters from the USA are cheaper, but you need to know someone in the US or visit the USA from time to time to get one, as Dexcom USA are not able to send anything direct to customers outside of the states. Furthermore, the frequency of the US transmitters differ from the frequency of the European transmitters. They are not interchangeable. If someone is looking for a cheap USA version of the Dexcom Seven Plus with charger, CD and instructions, get in touch, but you'll need to source your own transmitter from the USA.

    Regards Chris.

    Oh and just to answer Telmo's questions.
    At the end of the 7-day cycle, the receiver will say that the sensor now needs changing. You simply select "Start New Sensor" on the menu as if you have inserted a new one and the system will think it has a new sensor and start working again after the 2-hour start up period has passed. The second week can be less accurate and often goes into ??? mode for hours at a time, which means that it is struggling to understand the data from the transmitter.

    If you go out of range because you have forgotten to bring your receiver with you, it simply enters no data on the receiver graph so you have a blank period. As soon as it picks up the signal again, it starts recording the data again. You can set an alert to make the sensor beep & vibrate if it goes out of range too. :)
     
  5. bonerp

    bonerp · Well-Known Member

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    Chris,
    I am currently waiting to hear whether my pct will fund/partially fund one of these for reasons to help get tighter control than currently possible - my over arching concern is to minimise further damage caused by retinopathy..

    Bottom line, is it worth it? Does it provide the answers you were looking for when you started to investigate dexcom?

    cheers
    Paul
     
  6. g-man

    g-man · Member

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    Interesting review but the point above is slightly worrying. Somewhat infuriating given the cost of the unit to begin with, but despite never having seen one of these units, I refuse to believe that the battery cannot be replaced.

    Being the practical type and if I owned one of these units, I would find a way to replace the battery (assuming it is a typical watch style battery) rather than pay £550!!
     
  7. adrian29459

    adrian29459 Type 1 · Well-Known Member

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    Good in-depth review. I've been on a similar device recently for a month trial. It was the Medtronic Enlite Sensor, in combination with my minimed paradigm pump. I've had a very similar experience to you. I only exercise about 2/3 times a week and the odd 10k run, but I've found it very helpful to see the pattern and trends of my blood glucose live on my pump. Like yourself I did have problems with the sensor waking me sometimes, I never thought to lower the hypo reading though with mine set at 4.1mmol.

    I don't think I'll ever get a sensor to wear 24/7 but I'm considering making a purchase of some for various running events I may get involved in. If you have any questions, feel free to ask, I don't want to go into too much detail right now but I will if interested.
     
  8. bonerp

    bonerp · Well-Known Member

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    I am soon to go onto the Medtronic CGMS for a week or 2 trial and will then follow up with the pump combo before I try the Dexcom one.

    Will be interesting to see the results and which is best suited to me. I am hoping the combo will be best seeing instant results and using it with their own pump.
     
  9. gerdes312

    gerdes312 · Newbie

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    I have used the Decom 7 plus unit now for 15 months and was really happy with it until now. When I didnt have the sensor my A1C reading was around 6.9 and my last doctor visit I had a A1C of 5.8 so it does help. Recently I found that I started getting readings that were inaccurate and found out I am at the end of the units life? I thought a simple battery replacement was all I had to do until I called Dexcom and they told me that I need to purchase a new transmitter and receiver! I feel spending 1200.00 dollars every 15 months is alot to spend on top of having to purchase the supplies needed for the unit.

    I wish I would of done a little more research before investing in this product my current deductable through my insurance is 2K and I have only used 200.00 dollars so far this year. So it looks like I need to either bite the bullet and spend the 1200.00 and keep using Dexcom or find another product that lasts longer then 15 months before having to being replaced. For people that have a lower deductable then 2k I feel this is an excellent product but for someone like me I think I might try something else.
     
  10. tom79

    tom79 · Well-Known Member

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    deductable through my insurance? whats that?
     
  11. greatpotoo

    greatpotoo · Newbie

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    Dear Nick,

    would you be able to write a short update on your use of the Dexcom 7+ over the last year and 1/2. I'm considering buying one but would like to hear about your experience since you purchased the CGM.

    Thanks

    Michael
     
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