Friday, October 19, 2012

Must Read Study on Meter Accuracy

This is a comparison of 43 meters, and I think they did a great job. Please check out your meter. I think the biggest surprise on this list was that the Bayer Contour USB performed pretty poorly (it was by no means the worst on the list but it is surprising because it's one of the pricier ones on the list). Bayer Contour USB was within 5% only a third of the time. It was more than 10% off  about a third of the time. It was more than 20% off in 4% of tests- which I think is a lot. I mean, if my bg is actually 200, it only would guess between 190-210 a third of the time. And it would guess outside the 160-240 range for 1 in 25 tests. That's a couple times per week if you're a 7x per day tester. The iBGStar did similarly poorly.

Two meters were within 10% on all 200 tests. Those were the Accu Chek Active  and the Freestyle Lite. Of the two, the Freestyle Lite was within 5% a larger portion of the time. That means, if your blood sugar was 200, it should tell you a number between 180 and 220 every single time. At least 4 times out of 5, these two would give you a number between 190 and 210. That's pretty good.
The Accu Chek Active is so old that the strips change color depending on your blood sugar, and it takes a 1 microliter blood sample.
The Freestyle lite takes 0.3 microliters and has the modern standard of a 5 second wait time.

The way I see it, if you want to think about what accuracy is okay, corrections are what's most important. I'm gonna correct for the number I see. I need to be pretty sure that the number I see represents a narrow enough range that if I aim for a blood sugar of 110 with my correction, I'm not likely to go lower than 70- that means the range that the bg I see might actually represent would ideally be less than 40. At a blood sugar of 200, a 10% error means a 40 point range in blood sugar possibilities. The meter I use, the Accu Chek Aviva, missed this mark 9% of the time. That's 1 in 11 tests.  If you test 7x per day, that's about 4 times per week.

Actually, that's just what their stats suggest. If you look at the graphs, you can see it even better. The accu chek aviva was actually off by more than 40 mg/dl in a few of their tests, and all the tests they did where the Aviva was off by more than 40 mg/dl, the Accu Chek read lower than the real value. This means that there isn't really as much risk of over correcting as I might worry; there's a much bigger risk of undercorrecting.
Bayer Contour, on the other hand, did read more than 40 mg/dl higher than the actual value in multiple instances in the study. The Freestyle Lite had a tendency to read low and didn't once read more than 15 mg/dl higher than the actual value. At very high values it tended to really under read numbers. That's something I'd be comfortable correcting off of. At blood sugars like 300, the iBGStar read more than 60 mg/dl high. Not cool.

There's also a chart in this study about the percentage bias different meters tend to have.

Like I said, a must read. Please click on that link!

Tuesday, October 09, 2012

G4 Platinum

The big news in the US diabetes online stuff is that the FDA approved the Dexcom G4 Platinum. It's shipping now, and I can order one as soon as my warranty on this one is up (in two days). I'll be waiting until I use up my sensors for the 7+ though, 'cause they won't work with the new system, and hoping my 7+ receiver works that long.

I just downloaded and watched the entire G4 Platinum tutorial (ugh) and here's what I learned that I didn't get from just looking at the press release and website:
- It is still only approved for belly sites, still has a problem with acetominophen, sensors still have the same storage recommendations, still can only be calibrated in the 40-400 mg/dl range (I am in the 30s often enough to be annoyed by this), still need to be calibrated every 12 hours, have a 2 hour warm up, and want two readings at that point, and still continue to provide readings if you miss a 12 hour calibration point. It also still has a 55 mg/dl low alarm you can't turn off, and still vibrates before beeping no matter how you set the alarms.
The transmitter is now expected to die after 6 months. Minimed has a transmitter it warranties for only 6 months and the 7+ transmitter is warrantied for a year; for me that was one of the selling points of Dexcom. But the tutorial says the transmitter will last roughly 6 months and that the receiver will give you a warning that your transmitter battery is dying, after which the transmitter is expected to last only one more week.
The range is now advertised to be 20 feet rather than 5 feet. Which is great, but apparently that 20 feet thing is only when you're out of water. Which means it might not help me in the swimming pool. It is still true that the sensor and transmitter (when attached to a sensor) are waterproof but the receiver is not even splash resistant.
Although the website says (in the for professionals section) that you can calibrate no matter how fast blood sugar is changing, in the tutorial it says not to calibrate when blood sugar is changing at a rate of 2 mg/dl/min or more. Since mine is doing that what feels like most of the time, that's an issue.
While watching the set up thing in the tutorial, I noticed that the settings for the low alert now offers an option of a low alert at 85 mg/dl (currently Dexcom only offers these low alert options: OFF, 60 mg/dl, 70 mg/dl, 80 mg/dl, 90 mg/dl, and 100 mg/dl). Hopefully this means that there are now more options to choose from for both high and low alerts.
For alert settings, there are now alert "profiles". Rather than being able to individually set each alarm to off, vibrate only, or vibrate then beep, you now choose from one of five profiles, which are: Vibrate only, Alarm Softly, Normal, Loud (they have a special name for loud), and Hypo Repeat (which is Normal, except the hypo alarms get louder and louder). You'll notice there doesn't seem to be an off option. Except for the fact that there's a loud option (which it desperately needs) this does not strike me as much of an improvement.
The sensor looks the same. My guess is that it's really only different by the way that the transmitter attaches, because the transmitter is shaped slightly differently.

So now, I have a few questions in my mind.
 Question one is, what if my Dexcom 7+ receiver, which is almost out of warranty, breaks before I use up my remaining sensors (which will be in roughly 6 weeks)? Will I be able to pay for a new 7+ receiver without  having to pay the $400 upgrade price (which is what is being charged if you bought a 7+ system before September 2012 and want to upgrade).
Question two: There are three color options, pink, blue, and black. The pink doesn't look real macho. Should I get blue or black?
Question three: So, say my G4 transmitter dies. Will insurance really pay for two transmitters per year? Will Dexcom really replace it for a reasonable price?
Question four: Is the system really as basic as it looks in the training video???

Friday, October 05, 2012

Funny Song; I Got to Poke My Finger Every Day

  • I got to poke my fingers every day
    I got to poke my finger, got to poke my finger, got to poke my finger, every day.
    I got to get that needle and put it inside the device.
    An then I got to pull the thing back.
    An then put the device on my finger and push the button and then I go
    I go to check that sugar every day.
    I got to check that sugar every day.
    I got to check that sugar, check that sugar, check that sugar every day.
    That's why I poke my finger every day.
    That's why I poke my finger every day.
    That's why I poke my finger- poke my finger- poke my finger- reckon I do
    I stick the needle and POW and tek some blood
  • And I gotta poke my finger every day.
    I poke my finger, yes I poke my finger, yes I poke my finger every day.
    Every day I poke my finger, every day I draw some blood.
    I go to put the needle inside the device and put the device goes through my finger and then push the button and go POW WOW
    'cause I got to poke my finger every day.

Thursday, October 04, 2012

That ADA Ad

... the one that says Diabetes Kills More than AIDS and Breast Cancer Combined! is showing up on practically every webpage I visit right now and it's bugging me.

Numerically speaking in the United States, diabetes is listed on more death certificates than AIDS or breast cancer, neither of which is a big killer. But diabetes isn't even close to being a bigger killer in terms of "years lost", because people dying of diabetes are on average 73. People dying of HIV and breast cancer account for more years lost as computed by the CDC because they are substantially younger than people dying of diabetes.

But even if that weren't the case I don't like that ad.

Wednesday, October 03, 2012

I just got my flu vaccine

and if you're reading this blog, you should too.
Vaccines are not totally effective at preventing disease (any disease) because not everybody's immune system will respond. To protect the people with the weakest immune systems, everybody who comes into contact with them needs to be vaccinated. That means you.

This has been a public service announcement from Jonah.
What the CDC wants you to know about diabetes and influenza:
Evidence that diabetes is a risk factor for flu infections severe enough for hospitalization: (9 out of 162 people hospitalized for swine flu had type 1 diabetes in this one hospital study- I don't have to tell you that 9/162 is way more diabetics than you'll find in the general population)
What the ADA has to say: