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Diabetes Comes to HealthKit
2014-09-15 22:07:34 -0400

It's the idea too obious to pass up. It's something diabetics have been hoping for for years. Thanks to iOS 8 and HealthKit, it might finally be coming true.

Let me back up a bit:

##The Reality of Glucose Monitoring

When the rumors started about an Apple Watch, everyone jumped to the health-related tricks it might pull off. Among the more laughable ones was the rumor that it would be able to check your blood sugar.


As someone who just a few months ago started using a Continuous Glucose Monitor (CGM), let me tell you right now that such a thing just isn't possible at this point. The CGM, itself, is notoriously unreliable, but it's a great boon for managing my diabetes, anyway.

This is the gadget that's taped to the back of my arm 24 hours a day and seven days a week:

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(The penny is there to show you the scale.)

The white plastic piece you see is the transmitter. It's plugged into a thing that I inject into my arm, leaving behind a small filament-looking thing that is then taped down to stay on my arm for six days at a time. Sometimes, I put a second piece of tape on top of the transmitter to hold everything together even more securely.

Every five minutes, the CGM checks my interstitial sugar levels. The sample isn't taken from my blood, which we can now test with a fair level of reliability but which involves a finger prick. It's taken from the tissues in my arm. You can also put one of these in your abdomen, if you like. Since I already put my insulin pump in there, I put the CGM in my arm.

The reliability of the number the CGM gives you is suspect. It's tough to take a good reading from the interstitial tissues still, as it turns out. In fact, you calibrate that number by checking your blood sugar and syncing the numbers up. The CGM is great at giving you the trend of your sugar level, though, so it's an indispensible tool for me now.

Measuring sugar levels off of lights flashing on your skin from the back of a watch from Apple is ludicrous.

##Displaying That Data

Take note that the transmitter doesn't have a screen on it. With it polished white surface, it might look like a nano device from Apple, but it's not a tiny iPod and it has no way of displaying your readings. Instead, you need a second device to view those numbers. The transmitter can use its extremely and absurdly low-powered radio signal to send those numbers to the other device. (How low-powered is it? If the CGM is in my left arm and that other device is in my right pants pocket, it often temporarily loses the signal.)

In my case, with the Medtronic system, the insulin pump can read the signals from the transmitter and display them on its screen, complete with a little line chart to show you your last 24 hours of readings. There's also space there for an arrow or two to tell you when your levels are increasing or decreasing rapidly.

That's the system.

##HealthKit to the Rescue?

My system isn't the best. It works great and I love it, but every review ever written will tell you that the better CGM is made by a company called Dexcom. It does not interface directly with the pump. You need to carry a second device -- like a small iPod -- around with you, instead. It has a much nicer screen, but it's still a second device to keep track of. You're starting to lose pants pockets now.

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The Great White Hope in diabetes land is that, one day, these proprietary systems would open up and we'd be able to capture those numbers through a smart phone. That would give Dexcom users one less device to tote around, and everyone the chance to have a better view into their numbers.

Imagine how useful a phone app would be in showing you the numbers both in real time and historical? Maybe third parties could come in and grab up all that data and present it in a better way than Medtronic or DexCom might think of. (Medtronic's CareLink system is pretty nifty, but the data visualization is barebones, to put it nicely.)

Thanks, at last, to iOS 8's HealthKit, we might finally be getting to the dream:

DexCom Inc , which makes blood sugar monitoring equipment, is in talks with Apple, Stanford, and the U.S. Food and Drug Administration about integrating with HealthKit, said company Chief Technical Officer Jorge Valdes. [...]

Under the new system, HealthKit can scoop up the data from DexCom, as well as other app and device makers.

Data can be uploaded from HealthKit into Epic's "MyChart" application, where it can be viewed by clinicians in Epic's electronic health record.

YES! That's what we want, from everyone. Open up the systems, let a thousand apps bloom. Let's see who can come up with the most helpful charts and graphs.

##Reality (Read: Regulation) Check

Now, the trick here is that the FDA is involved. These pump systems are all incredibly regulated. Case in point: Medtronic just got clearance from the FDA to allow the use OS X Mavericks with its website, a month or two before it's replaced by Yosemite. Terrific.

A thousand apps blooming is unlikely. The manufacturers will want to keep their systems proprietary and benefit from them themselves. They've done a lot of work to get here and have helped a whole lot of people. It's tough to find fault with that. But, still, it doesn't hurt to dream, right?

This is a great first step. If Dexcom can work with an iPhone, can Medtronic afford to fall too far behind on that one? I hope not. I only have two fears with this: First, it'll require a new device with a new transmitter. Second, it'll take at least a year before the FDA approves anything.

At last, though, we have progress. The flat-out obvious idea that everyone has asked for might finally be coming true. At least, it's a promising start.

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