Comparing Dexcom G4 Platinum and Medtronic Minimed

I’ve been wearing the new Dexcom G4 Platinum continuous glucose monitor (CGM) for almost two months now. Before that, I used the Minimed CGM with my Minimed pump for about two and a half years, so I come to the Dexcom not as a new user or a familiar user, but as an experienced user with allegiance to another manufacturer. The worst kind of user for a company, in many ways — so, while others have done a great job reviewing in detail the new Dexcom G4 Platinum, I will focus on my experience with the new device as compared to what I have come to expect based on the Medtronic Minimed system. Notably, I am only two months in, so I reserve the right to change my opinions, but, thus far:

 

The Good

 

Hands down, the best part about the new Dexcom relative to the Medtronic Minimed CGM? It hurts so much less. It’s not painless, but it’s comparable to a pump infusion site, whereas the Minimed insertion device looked like an evil harpoon, and felt like one, too. Even after more than two years with the Minimed system, every time I inserted a new sensor, I would stand there for a few minutes, mentally convincing myself that it wouldn’t be that bad, and that the pain was worth it, before finally pressing the button to send the giant need into my abdomen. And at least half of the time, it was that bad, and I ended up bloody and in tears.

The Dexcom G4 Platinum, on the other hand, has a relatively slim inserted filament. The insertion device requires a slow, gradual insert, which is sort of strange, but arguably preferable to the single-button-push approach. Further, because the insertion device and sensor are so reasonable, I am able to wear the CGM places other than my abdomen, which I was terrified to even try with the Minimed. Thus far, I have worn the Dexcom on my lower back (worked all right, but sub-optimally; it was prone to getting knocked and jostled off) and my arm (works capitally). This ability to move the sensor around opens up my abdomen, which was getting bruised and scarred to the point of not being usable.

And when I say the site on my arm works capitally — I mean it. I have been using the Dexcom sensor for almost two months; my first sensor, on my back, lasted about 9 days. My second, also my back, about 12. My third sensor is on my arm. I say is because it’s still there– I’m in week six of wearing this sensor. And it’s still just as reliable as the day it was born. Granted, I have a history of getting long lives from my sensors — my longest Minimed sensor lasted about five weeks — but that was after two years of learning how to coddle the sensors. Six weeks right out of the gate with Dexcom? Awesome.

Now, this lessened pain would be enough to make me switch from the Minimed even if the Dexcom were less reliable. That said, the Dexcom is much more reliable than the Minimed. After two years with the Minimed, I had gotten pretty used to its quirks, and could often tell when it was likely to reflect my blood glucose well, and when it was likely to be off. I am still learning these things for the Dexcom, but the default behavior of the Dexcom seems much more sensitive to changes in my blood glucose. Little dips and changes that were smoothed out by the Minimed– which always seemed closer to a twenty minute moving average of my blood glucose rather than a point-in-time value– are more likely to be caught by the Dexcom.

When I originally chose the Medtronic Minimed, one of the biggest deciding factors was that I was already wearing a pump, and didn’t want to carry around an extra receiver (which, at the time, was the fugly, egg-shaped Dexcom one). Switching over to the Dexcom G4 Platinum, I worried about the extra burden of yet another device, but two months in, it hasn’t been that bad. The receiver was designed to look Apple-y, and it’s fun to show off the color plot of my blood glucose values to all my (admittedly geeky) friends. My first thought– and several friends have echoed this– was that it looks like an old, knock-off iPod. Beyond style, though, this means that the device is small and light, and I can carry it in my pocket. (As a point of comparison, I can’t carry my iPhone comfortably in my pocket, so smaller-than-my-pocket is an important measure.)

All that said, it’s not an old iPod, and sometimes that shows. Which brings me to…

 

The Bad

 

Despite giving the initial impression of an Apple-like device, the Dexcom G4 Platinum receiver proves more like a cheap knock-off when it comes to the things that make Apple device feel really well designed. The fake scroll wheel (designed to look like the patented Apple scroll wheel, I presume) is actually made up of five buttons. These buttons are sort of hard to press correctly because they are all connected and give no tactile feedback when pressed. Sometimes I press, wait for a few seconds for the screen to come on, and then realize I apparently didn’t press hard enough or in the right place. This, obviously, is not a big deal for a medical device– but this is exactly the sort of thing that makes the Dexcom receiver feel “cheap.” Similarly, the little slot for the miniUSB charger has a slide-over cover (which is a good thought), but the cover is hard to move back and forth, meaning I end up leaving it open all the time.

Style aside, one thing I had gotten used to with the Minimed was that I could easily scroll back in time and see previous glucose reads. This was especially useful if I wanted to calculate the slope of my ascent or descent. The Dexcom, however, obscures those values– I can see the most recent read, the plot of dots, and an arrow, but not previous reads. The arrows are helpful, but I want a more fine-grained evaluation of my slope, and I can’t get that with the Dexcom.

Of course, I could try estimating from the points on the graph. But that brings me to another qualm: the graph goes from 40 mg/dL to 400 mg/dL, with no option for changing that. With that expansive range, and no grid lines, it’s difficult to tell what 1 millimeter difference along the vertical axis actually correlates with in terms of glucose values– is that dot 10 mg/dL lower or 30? I can’t tell. Given that I spend most of my time in the lower half of that graph– and, frankly, if I’m in the upper half I’m panicking and not relying on my CGM anyways– I would much prefer to have the range shown be configurable, like the alarms. Or at the very least allow me to see the actual past values– but to give me a difficult-to-interpret graph and no numbers? Ugh.

I should also mention that, despite being more consistently reliable than the Minimed CGM, the Dexcom G4 is not perfect, and is not a replacement for a blood glucose monitor. During times when the interstitial glucose that the G4 is measuring becomes uncoupled from my blood glucose– during strenuous exercise, for example, or periods of rapid blood sugar change– the Dexcom reports what it measures, which is understandably distant from my blood glucose. This, however, is a problem inherent in the way CGMs are currently built, and may require new technology that relies on alternate sources of glucose to fix.

Because it is a limitation of measuring interstitial glucose, I forgive the Dexcom for its periodic diversions from blood glucose. However, there are some things I don’t forgive Dexcom for. Cardinal sins of technology. Which brings me to…

 

The Ugly

 

One of the things I was promised about the Dexcom was that their software and analysis tools were really helpful. Worlds beyond the Minimed software. That was exciting to me — I am an engineer and analyst by trade, and so I love graphs and numbers and statistics.

Does the Dexcom software live up to these promises?

I don’t know. I don’t know because when I went to the website to sign up and log in to upload my data, I saw instead a link to download the Dexcom software. “Uh-oh,” I thought, “Download?” And then I clicked the download link and was taken to a page with a single download button. “Oh no. One button. Why is there only one button?” And sure enough, when I clicked the download button, a Setup.exe file plopped itself onto my desktop.

My Mac OS X desktop, that is. I work with computers all day long. Between work and home, I have 32 GB of RAM, 5 TB of space (500 GB solid state!), and sixteen processors. I have access to three compute clusters, and I could spin up an infinity of Amazon EC2 instances if I needed them.

But I don’t have a Windows machine. Because this is 2013, and no software should be Windows only. Even Minimed had (after some time) a multi-platform web app– it was a crappy web app with Java applets, but it was at least a web app.

It’s 2013! I can send emails from my Kindle in the middle of nowhere, Finland! I can VNC to my computer at home from my iPad on an airplane! Cars drive themselves, for crying out loud! And you’re telling me you can’t make software that works on Unix systems? It’s not like this software is doing deep, complex stuff, either– you’re plotting data points and calculating trivial statistics.

Sure, Dexcom could argue that some 90% of computers still run some version of Windows. However, I would be willing to put money on the bet that the percentage of Mac users among CGM users is much higher, since you’re selecting for a higher-income, more-comfortable-with-new-technology population. Further, if you know you only have the resources to maintain one type of software, there is no reason not to build a web application in this day and age. Data security concerns have been addressed to death, and, hey, Minimed does it.

The greatest irony, of course, is that, as I mentioned above, the Dexcom G4 is clearly designed to look like an Apple product — and yet the software doesn’t work on the very products that Dexcom is imitating! It is incomprehensible to me that after so much time, money, and effort is put into building a device, Dexcom would embarrass themselves so spectacularly with the software.

Okay. Now that I have gotten that off my chest, let’s regroup and get to

The Take Home

If you’re a diabetic: if you don’t have a CGM, get one. Today. And if you get one today, it should be the Dexcom G4 Platinum, without a doubt. In a few months, the new Minimed Enlite may be a competitor, but the Dexcom is pretty darn good today.

If you’re Dexcom: I know a lot of good web developers in San Diego County. Why are you not employing any of them?

Karmel Allison is science editor of ASweetLife.  She writes the blog Where is My Robot Pancreas?.

Follow Karmel on Twitter (@karmel_a)

Comments (24)

  1. Nathan at

    Allison,
    Great comparison review! I think you are spot on with the software criticism. I’m a Minimed user and it was and is, frustrating that the software didn’t exist and then when it did, it was kind of finicky. I can’t imagine Dexcom, being everyone’s progressive darling, isn’t doing MAC compatible technology. Yikes! Get on it! I will keep me from jumping over. I like the integration with my pump too much. I’m suffering the harpoon till Mm comes through with Enlite. I’d love to hear how you get 5 weeks on a sensor. I have only gone 14 days and was pretty chuffed about it.

  2. We are a Mac family and it frustrates me to no end that I can’t download my daughter’s pump and CGM. I actually used Bootcamp to install Windows on my old Mac this past week in anticipation of our endo appointment and all it did was confirm to me how clunky Windows is.
    I completely agree about the insertion. The Medtronic harpoon device scared my daughter to the point that I could only put on a sensor while she was sleeping…and thoroughly numbed. I can put on the DexCom while she’s awake.
    And I’m loving the range. I’m able to put it on MY nightstand overnight.

  3. First of all.. I’m a software developer, tech-geek extraordinaire and I’m soooo jealous of your computer setup! (500 GB solid state!? ::drool::).

    Anyway… I’m in agreement. Like you, I used the MM sensor for about 3 years prior to switching to the Dexcom G4.  As I was reading, I nodded in agreement throughout the entire post, except for I didn’t mind the insertion for the MM sensor that much. 

    Dexcom definitely needs to get on the bandwagon with cloud data… for all systems! I use Linux at work and (unfortunately) I have a Windows computer at home, but am hoping to buy a MacBook within the next year. I would be sad to lose the data from the Dexcom. I will say it’s easier and faster to use compared to the MM web app. Those Java applets gave me a headache. The graphs and data are nice and I feel easier to understand. 

    Overall though, I am happy with the G4 and will definitely stick with it. At most I’ve gotten 21 days… but I am using my arm now so maybe I’ll get longer! 

    I do have a question though… what do you use over the sensor (as I see in the picture above)?  

  4. zip at

    Thanks for the great comparison.  I’ve  been using a Dexcom for 2.5 years and never seriously considered the Minimed.  I’m mostly loving the new G4, except for a few little things.  The transmitter is larger than the Dexcom 7+ transmitter and it makes a difference when it’s sitting on my torso and getting bumped by my arm.  Also, the larger size seems to make things even more difficult for the tape.  I’m not getting as many days out of these new suckers.  Love the new range, but if anything, the readings seem less reliable and I don’t know why.

    Leighann – I never thought about how the increased range could allow a parent to keep it with them overnight.  How awesome!

  5. Karmel Allison
    Karmel Allison at

    @Nathan — I wish I could tell you what my trick is! I’m actually a little bit worried- I feel like my body should be rejecting the sensor sooner…. I can only assume something is dreadfully wrong with my immune system that it doesn’t…

    @Melissa T — Tegaderm, from 3M. Amazing stuff: http://www.amazon.com/3M-Tegaderm-Transparent-Dressing-1624W/dp/B000WCV4DI/ . Always makes me think of The Graduate — “One word: Plastics.” 
     

  6. Mike at

    Great review, Karmel. Very much love how you look at the irony of Apple-imitation, yet it doesn’t work on Macs. That’s a priceless observation! I’m a faithful MM user, but have also used the Dex periodically. So I’ve been REALLY TEMPTED to switch up to the G4 and even go with another someday-Dex-compatible pump. But, with the U.S. version of the Veo so close, I just can’t bring myself to it… especially since it would be the integrated device, and I wouldn’t have to wait like I would for the Dex integrations. Thanks so much for your review here!

  7. God at

    The good:
    There are a lot of parts of this that I completely agree with. Why she is going so slow on the sensor insertion beats me though.

    The bad:
    While I thought the transmitter size was NOT going to be an issue, I have found it to be a rather big one since I’ve had a couple rip off due to it catching on things. I’m also afraid of the 6 month warranty on it.

    With that said, the whole apple thing is completely ridiculous. First, she should have simply prefaced it with the fact that you are an Apple fanboy. Has apple ever done or could they do anything to wrong her? I love that anything that has a modern design is automatically trying to rip off apple. The buttons are clearly marked with arrows and the screen is rotated 90 degrees. And while I do have a similar issue with the screen lag time, I wouldn’t say that has anything to do with the “Apple” knock-off, but just modern expectations from as far back as I can remember. I also wonder if there is a reason that the one button press to get the screen going doesn’t always work. Perhaps it was designed that way so that people don’t accidently turn it on? While she uses the difficulty of usb cover as the reason why it is often left open, while it isn’t easy, I question her memory more.

    The ugly:
    With regards to Mac compatibility, everyone has to remember that they are dealing with the FDA, so that adds a layer of complexity only god knows how thick it is. Then you get into iterations of software for both Windows AND Mac and now you have an even bigger headache. Maybe this is part of the reason why they bought Sweet Spot – so they could put it all online and perhaps make it both more easily Mac and PC compatible. It all comes down to business decisions with dollars to invest. Even without Mac compatibility they are owning minimed and apparently her.

  8. zip at

    Do you place the tegaderm over the entire site?  Or do you cut out a hole for the tranmitter?  I would love to find a way to wear my sensors for longer than 10 days.

  9. Scott E at

    Thanks for the review and comparison! I’ve been using the Medtronic CGM for two years, and every so often I think about switching. But I like my single device, my predictive alerts, and my comprehensive Carelink reports. I’ve not quite mastered the inserter, but I’m getting better.

    Like Mike, I’m holding out for the Veo/Enlite – I have an unjustified suspicion that’s going to be real soon! But if the Animas Vibe or the combined t:slim/Dexcom makes an appearance, then I’ve got some thinking to do…

  10. Alecia at

    Karmel,
    I upgraded from the Dexcom 7+ to the G4 about a month ago.  In the same window i switched from a Dell to a Mac at home.  I was shocked when I learned it wasn’t Mac compatible.  Hopefully with enough people requesting it, Dex will get on board!

  11. Karmel Allison
    Karmel Allison at

    @zip — I use two of the smaller Tegaderm stickers (I recently bought larger ones, but haven’t tried them yet), and tape over the entire transmitter, one Tegaderm for each half. The key is to get tight, smooth coverage; a husband is very useful in this regard, especially for an arm site :)

  12. Wonderful writing and review Karmel.

    I met with folks from Dexcom last year and re-emphasized the issue with the vertical scale. I told them that once my blood sugar was over 300ish I didn’t really need the graph, just the value and arrows. I also suggested that the value above the graph should remain on the right, like the Dexcom 7+.  Vertical space is always at a premium and really should be kept so you can see the graph detail.

    I really, truly, hope they get a Macbook version working soon. From looking at the internals of their installed software it’s clear they used a lot of Windows functionality to implement it. There are some libraries available to emulate parts of this functionality on other platforms, I really hope they do this soon. We used to be a PC only family, and now have two iPads, a Macbook Pro, iPhones, and too many iPods to count. I know we’re not alone in this. 

  13. Wonderful writing and review Karmel.

    I met with folks from Dexcom last year and re-emphasized the issue with the vertical scale. I told them that once my blood sugar was over 300ish I didn’t really need the graph, just the value and arrows. I also suggested that the value above the graph should remain on the right, like the Dexcom 7+.  Vertical space is always at a premium and really should be kept so you can see the graph detail.

    I really, truly, hope they get a Macbook version working soon. From looking at the internals of their installed software it’s clear they used a lot of Windows functionality to implement it. There are some libraries available to emulate parts of this functionality on other platforms, I really hope they do this soon. We used to be a PC only family, and now have two iPads, a Macbook Pro, iPhones, and too many iPods to count. I know we’re not alone in this. 

  14. wesley at

    How do you wear it for longer than 7 days? It tells us to replace the sensor (if it lasts that long!).

  15. rickst29 at

    wesley- you simply press the “Stop Sensor” menu item, and then scroll back up to press the  “Start Sensor” menu item after a few seconds.
    Without removing the Sensor, or even the transmitter. You can leave the transmitter clipped in through the process. You WILL have another “warm-up” countdown, just wait it out and then enter a pair of finger pokes.
    If the Sensor has already “expired”, you can skip the “Stop Sensor”. Just go directly to “Start Sensor” and the subsequent warm-up.

  16. Catherine at

    Karmel, I completely agree with you on all points. (And six weeks?!!) I really don’t understand why Dexcom has not caught up with the 21st century and dealt with the Mac issue/created the same functionality in its display as was available with Abbott’s defunct Navigator back in 2008. Drives me CRAZY. I also am frustrated that from what I’ve seen from their upcoming Sweet Spot software (the company they acquired last year to create a web-based data app), they still are not taking user concerns into account. The version I saw at last year’s ADA was very much geared toward doctors, not patients, and the guys seemed genuinely confused when I suggested they might want to take the user’s perspective into account. I was also on a call with their CEO where Bernard (along with me and some other people) raised these same concerns. I’m really happy to hear that other people are bringing this stuff up as well — as you point out, the increased accuracy is fantastic (and much more challenging than the data display issues), and I very much hope they listen to patients about how they want that data displayed. 

  17. Brian at

    @Karmel- don’t suppose you know of anyone who has done an over the wire analysis of the software poking the g4?  I’m in a similar boat- I’m off in linux land.  My plan was to just run the stupid software in a KVM instance w/ the usb device passed through.  Annoying, but workable.

    That said, I’d *much* prefer being able to rip the data off the device directly- barring that, to be able to hack out some python to do the scraping so I don’t have to keep firing up that damn KVM instance.

    Are you aware of any similar attempts?  My google-fu isn’t turning up much unfortunately. :/ 

  18. Karmel Allison
    Karmel Allison at

    @Brian– not yet, but we’re out there, and working on it. For example: https://plus.google.com/106853106802184403897/posts/1ku1SEgoJJd

    For more, check out the discussions going on around diabetes software on the Medevice Github/email list–
    http://groups.google.com/group/medevice?hl=en
    https://github.com/medevice-users
    https://github.com/medevice-users/diabetes/wiki
    Lots of good people doing interesting things, so you should check it out and get involved– 

  19. Sylvia White at

    Great review and I have the same thoughts as you with comparing the Dexcom to Medtronic With my daughter. My biggest thing with the older Dexcom was it was big and she was already wearing a pumbrand would leave the Dexcom transmitter in her room or somewhere, so we had no data. The G4 is much better with larger range but I do like having the Medtronic integrated with the pump. And my biggest hang up was not being able to scroll back through the numbers. As far as the Mac, have you tried the Diasend site to download?  I’ve had patients download both their Animas pump and Dexcom there but I think you have to choose Europe for the country. May be worth looking at. 

  20. Jeremy at

    Project Mono.  The Dexcom software is written using .net Framework 4.5  It is pretty standard C# WinForms application.  It is very nice on windows however I am trying to get it to Port to Mono and run on MacOS/Linux.  I will let you know.  The biggest issue is the USB interface.  May just need to stick with VMWare Fusion (which is what I run) or Parallels.

  21. i have had terrible itchiness and redness from the minimed sensors. has anyone had issues with the dexcom adhesive? thanks

  22. Rizzo at

    I am using both CGM right now and I am not sure which way to go, yet… I have been using minimed since 2008 and dexcom since Wednesday April 3rd…
    One of the things I like about minimed is that the transmitter tells the receiver “I’m ready to show you data” so if you restart the sensor after the transmitter is ready, the receiver is instantly ready to calibrate. With Dexcom the receiver makes the user wait 2 hours. I think the transmitter should keep track of that state, it seems cleaner to me… receiver takes data and displays it, transmitter maintains the state of the sensor…

  23. Chris at

    I’ve pretty much had the same experience with the G4 vs Minimed. There’s no question that Dexcom is more accurate. Not only does it not support Mac though, it also doesn’t support Windows 8 so even as a Windows user every time I want to upload the device I have to go to my parent’s house which is irritating. That said, if you have the patience you could always dual boot or use bootcamp.

  24. Lisa at

    I am a Registered Dietitian and a Dexcom 7+ user for about a year now.  I am thinking about switching to the new Dexcom G4, since my old monitor has a few glitches.  I have been Type 1 now for about 13 years, but I do not use a pump.  The Dexcom 7+ has given me shocking insight into my nighttime readings that I would not have known otherwise.  I’ve read the above review and comments with interest.  I am allergic to latex-type materials and typically tape, but I have not experienced any type of allergies as indicated by Patricia.  The one thing I do notice since I am a bathtub bather (yes, I admit that!), that the adhesive gets wrinkly and then will not stick within the 7 days (I may look into that Tegaderm).   I do replace my sensor after 7 days; however.  I worry more about the sensor leaving scars if left in too long as oppose to saving money.  I am a Windows user, so the above Mac concerns don’t pertain to me; HOWEVER, what does frustrate me with the software program is the inability to retrieve input data (such as past CHO and insulin units) on the readout, as I like to enter all the features such as exercise, alcohol, stress, sick times, etc. to “justify” some of my extreme readings.  I’m curious as to why the monitor allows the data input, but it cannot be retrieved on the readout?  Thus, it would seem that a duplicated effort of a paper trail is necessary for me and for my Endo to explain highs and lows.  Again, aren’t we trying to be a paper-less society?  That is my main complaint with this device; otherwise, it has been an effective tool.

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