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A Comparative Effectiveness Analysis of Three Continuous Glucose Monitors The Navigator, G4 Platinum

Discussion in 'Continuous Glucose Sensing' started by Ellen, May 8, 2014.

  1. Ellen

    Ellen Senior Member

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    A Comparative Effectiveness Analysis of Three Continuous Glucose Monitors

    The Navigator, G4 Platinum, and Enlite



    • [SUP]1[/SUP]Department of Biomedical Engineering, Boston University, Boston, MA, USA
    • [SUP]2[/SUP]Biostatistics Center, Massachusetts General Hospital, Boston, MA, USA
    • [SUP]3[/SUP]Diabetes Research Center, Massachusetts General Hospital, Boston, MA, USA

    • Steven J. Russell, MD, PhD, Diabetes Research Center, Massachusetts General Hospital, 50 Staniford St, Ste 301, Boston, MA 02114, USA. Email:sjrussell@mgh.harvard.edu



    Abstract

    The effectiveness and safety of continuous glucose monitors (CGMs) is dependent on their accuracy and reliability. The objective of this study was to compare 3 CGMs in adult and pediatric subjects with type 1 diabetes under closed-loop blood-glucose (BG) control. Twenty-four subjects (12 adults) with type 1 diabetes each participated in one 48-hour closed-loop BG control experiment. Venous plasma glucose (PG) measurements obtained every 15 minutes (4657 values) were paired in time with corresponding CGM glucose (CGMG) measurements obtained from 3 CGMs (FreeStyle Navigator, Abbott Diabetes Care; G4 Platinum, Dexcom; Enlite, Medtronic) worn simultaneously by each subject. The Navigator and G4 Platinum (G4) had the best overall accuracy, with an aggregate mean absolute relative difference (MARD) of all paired points of 12.3 ± 12.1% and 10.8 ± 9.9%, respectively. Both had lower MARDs of all paired points than Enlite (17.9 ± 15.8%, P < .005). Very large errors (MARD > 50%) were less common with the G4 (0.5%) than with the Enlite (4.3%, P = .0001) while the number of very large errors with the Navigator (1.4%) was intermediate between the G4 and Enlite (P = .1 and P = .06, respectively). The average MARD for experiments in adolescent subjects were lower than in adult subjects for the Navigator and G4, while there was no difference for Enlite. All 3 devices had similar reliability. A comprehensive head-to-head-to-head comparison of 3 CGMs revealed marked differences in both accuracy and precision. The Navigator and G4 were found to outperform the Enlite in these areas.

     
    Last edited: May 8, 2014
  2. Mish

    Mish Approved members

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    I"m glad it's been published, but it's sort of one of those things where nearly all of us here could have said the same thing. LOL.
     
  3. Don

    Don Approved members

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    True, the DOC already knows this but it is good to see some (belated) official recognition of Dexcom/Nav over Enlite. It is amazing and kinda cool that a startup has out-done a larger, better-resourced competitor.
     
  4. hawkeyegirl

    hawkeyegirl Approved members

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    Yep. Seems to confirm the other studies out there. Although I do find it odd that they are testing the Navigator in 2014 when it hasn't been available commercially in the U.S. since...2009? 2010? Are they testing the version that was sold here, or the version that is still available overseas? I guess it doesn't really matter - I'm not sure I would buy an Abbott CGM if it also made the bed, took the dog for a walk and vacuumed.
     
  5. Mish

    Mish Approved members

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    The overseas version. At least I am pretty sure that's what Ed Damiano told me when I asked. These are pretty much studies they need for the BP work. And they're not married to any one sensor at this point, so that really is a good thing.

    Not sure I'd buy a nav either, but..maybe.
     
  6. Ellen

    Ellen Senior Member

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  7. Joa

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    Does anybody have an idea if they have used the old or the new Enlite sensor in this study?
    (the new is a enlite with some upgrade work, e.g. more filigran with no more plastic coating around the central part)

    It is out here (Europe) since begin of 2014 and it is perfoming better than the old enlite.

    Regards
    Joa
     
  8. Ali

    Ali Approved members

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    i would guess not.
    ali


     
  9. mmgirls

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    I pulled this from the full text study, not sure if this answers some questions about the Elite and Navigator.

    Data using the Enlite sensor were collected initially using the Guardian receiver. Medtronic has integrated the Enlite sensor into their Veo and 530G devices, which uses a different calibration algorithm from the Guardian or the Revel pump. We provided to Medtronic the raw Enlite sensor data and calibration PG values that were entered into the Guardian receiver. Medtronic postprocessed the data with the Veo/530G algorithm. If the calibration algorithm requested additional calibrations, we provided to Medtronic the first PG measurement after the calibration request. Therefore, calibrations were provided prospectively to the calibration algorithm just as they would have been if the Veo or 530G systems had been used. Thus, the results presented here are representative of the performance of the Enlite sensor with the Veo or 530G device, not with the Guardian or Revel. Abbott Diabetes Care declined to similarly postprocess the Navigator data with their latest calibration algorithm, which is used in the product currently available outside of the United States.
     
  10. Joa

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    Thanks for ideas! :)

    I've posted the question to Mr. Damiano and got very quickly the answer that the new Enlite, released with the 530G, was used.
    I am still a little bit unsure if new Enlite means the 2nd generation of Enlite sensors.

    Mr. Damiano also wrote, that the Navigator 1.0 was used.

    Regards
    Joa
     
  11. suej

    suej Approved members

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    Hi
    The "new Enlite" seems to have been introduced in South Africa recently and is working better and longer for my ds. I see from Joa's post it is also in Europe. What improvements have you noticed and do you know how to access information about the second generation enlite?
    Thank you
     
  12. Joa

    Joa Approved members

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    As I can say it works more accurate than the first generation Enlite. But I only are having little experience with the old enlite sensors.
    Because the new Enlite you have is second generation (my term) you just should ask the Medtronic hotline? What information are you searching for?

    Regards
    Joa
     
  13. Joa

    Joa Approved members

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    I've asked a Medtronic rep. here in Germany. She said that in the US the old version of Enlite is the actual available version. So the sensor should be the one with oval formed transparent plastic coating around the central sensing element that is going sc.

    Regards
    Joa
     
  14. suej

    suej Approved members

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    I tried to ask helpline but they were evasive. The only reason I think the "second generation" enlite has come to South Africa (not US) is that my ds was asked to trial an "enhanced" enlite and it seemed more accurate and went to 8 days which was unusual for us. We then went back to old stock and had 3 sensors give up on day 2 or 3 that almost drove us to distraction. Medtronic then replaced the whole box - (well 4 sensors) and they all had the same exp date as the "trial sensor" and we are on the 3rd and all are behaving well and going to 8-9 days. I suppose I just want reassurance that better things are in store for my son and am interested in how they have changed. To me the "trial sensor" and the old sensors look the same.
    Thank you
     
  15. Joa

    Joa Approved members

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    Perhaps you can take a close-up foto of the sensing element that goes under the skin? I had taken one of the new Enlite with my cellphone but unfortunally deleted it some time ago. If I use a sensor again I will take a foto again after using it.

    As it is said there are some adjustments done with the new enlite. So at the sensing field where the reaction between GOD and glucose is located.

    Regards
    Joa
     
  16. suej

    suej Approved members

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    I see what you mean now that I have looked at the sensors closely and compared to old. And when one googles new generation enlite it does come up and explain differences - sorry, should have done that in the first place. Anyway, am grateful for progress, really helps when CGM working well.
    Thank you
     

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