My Detailed Review of the MiniMed 670G from Medtronic

The MiniMed 670G from Medtronic is an insulin pump coupled with a glucose sensor.  It uses a computer program (called an “algorithm”) to automate certain aspects of insulin delivery.  I decided to try 670G partially out of professional interest (everybody and their great aunt has been asking for my opinion on the system), and partially out of personal interest, as my blood glucose control hasn’t been the greatest the past couple of years.

Let me start out by saying this:

Since I started using 670G, my overall blood glucose control is better.

I have to keep reminding myself of this non-consequential fact, because every day I find things about this system that I don’t particularly like.

To continue reading, click here.

Why I’m excited about Tandem’s X2 Dexcom G5 software update

By David Ahn, MD

In late August, the FDA approved Tandem Diabetes’ long-awaited first software update for their X2 Insulin Pump that enables Dexcom G5 integration. With a FREE simple software update performed in the comfort of their own home, thousands of X2 users can now display CGM data (from the Dexcom G5 Mobile System) directly on their Tandem pump screen.

In the world of smartphone apps and hybrid closed loops, viewing CGM data on a pump screen might not appear at first glance to be groundbreaking, but Tandem’s software update will provide meaningful benefits not only for Tandem customers, but for the entire industry of people affected by diabetes.

First time a software update has added a new feature to an insulin pump

“The pump that gets updated, not outdated” is appropriately Tandem’s marketing slogan for their X2 Insulin Pump. A longstanding frustration for pump owners has been that insurance companies will not replace or upgrade most insulin pump hardware until the 4 year warranty period expires.

Therefore, while you might be buying the latest and greatest pump on the market right now, it will likely be outdated within 18 months. By the time your 4 year warranty period expires, you might be two or three generations behind. And as we draw nearer to a fully closed-loop artificial pancreas, those two or three generations might make a huge difference.

However, Tandem’s X2 platform has been built with the future in mind. People who received the very first X2 pumps nearly one year ago now have the same new Dexcom G5 integration available in the latest version shipping today with a simple convenient software update. Adding completely new features via software update has never been done in an insulin pump before.

Tandem X2 is now the only pump that integrates with Dexcom G5

Dexcom integration with Tandem pumps might seem like old news because their T:Slim G4 pump (released in September 2015) similarly displayed CGM data from the Dexcom G4. However, the T:Slim G4 did not include the advanced software 505 algorithm, leading to less accurate readings than on a later Dexcom G4 or G5 model. Second, the T:Slim G4’s lack of bluetooth functionality prevented integration with the Dexcom G5 and its popular ability to transmit CGM data directly to smartphones.

Therefore, prior to this G5 software update, Tandem and Dexcom customers were stuck with a dilemma: purchase the older T:Slim G4 and forego the amazing smartphone feature OR go with an X2 and forego the ability to view CGM data on the pump. With the new G5 software update, this dilemma is solved and the X2 is the only pump that directly integrates with the Dexcom G5. (The Animas OneTouch Vibe Plus was planning to integrate with the G5 but Johnson and Johnson decided to exit the pump market).

Dexcom G5 integration is a godsend for many Android users

While G5 owners with iPhones have long enjoyed the luxury of viewing their CGM data on their phone or Apple Watch, Android users have only been recently granted access. And only Android users that use certain models. For example, owners of the highly-rated Google Pixel smartphone or other non-Samsung Android phones will not find the Dexcom app in their App Store. (Workarounds do exist, but are at your own risk).

Therefore, insulin pump users that own Android phones not supported by Dexcom would previously have to resort to carrying around their insulin pump controller AND their Dexcom receiver. Not fun.

With the latest software update, X2 owners can leave their Dexcom receiver at home AND take advantage of the advanced software algorithm and smartphone-sharing capabilities of the G5 Mobile.

The update points toward even better upgrades in the future

Tandem has already begun the pivotal study for their next significant software update, PLGS (predictive low glucose suspend). PLGS will allow the X2 pump to automatically suspend insulin delivery when its advanced software algorithm predicts that the blood sugar will sink below <80 mg/dL in the next 30 minutes, significantly reducing dangerous hypoglycemia. This feature also aims to reduce hyperglycemia as users will be less fearful of low blood sugars limiting proper bolusing.

Tandem Diabetes has indicated that the PLGS software update will apply to the current X2 pump, so all existing X2 owners will be able to add that feature when the company hopes it will be released in Summer of 2018. (Unlike the free G5 software update, the PLGS software update might require a one-time cost).

Conclusion: Pump competition is good for consumers

Unfortunately, the pump market is currently getting smaller with the exits of Asante, Roche, and Animas in the past several years. No matter which remaining pump company you find yourself rooting for, having options when it comes to insulin pumps is important for several reasons.

First, competition breeds innovation. In the smartphone market, if it weren’t for Google and Samsung, Apple would have very little reason to continue adding new features to the iPhone year after year. In fact, many features such as the “Plus” form factor and the rapid evolution of voice assistants such as “Ok Google,” Alexa, and Siri are likely a direct result of competition in the market.

In the insulin pump market, Medtronic pumps looked largely the same and only added minimal new features until other players in the market came along.

Second, competition brings down costs. The cost of living with Diabetes is already ridiculous as it is, the last thing we need is for a single company to monopolize the pump market. In fact, Tandem Diabetes is offering all owners of their previous T:Slim pump an upgrade pathway, costing $399-$799, which is dramatically lower than Medtronic’s upgrade cost of either $599 or $3100.

Lastly and most importantly, competition brings choice. People with diabetes aren’t all alike and their needs might change over time. When starting a new patient on a pump, I like to present the wide variety of pumps on the market, each with their own strengths and weaknesses. Medtronic has the only hybrid closed loop on the market; Insulet’s Omnipod is the only tubeless patch pump available; Tandem’s X2 has the only touchscreen pump.

With Tandem’s X2 ability to add new features via software update, patients have an option that will remain up-to-date over the next few years.



What could Apple’s “super secret” diabetes project be?

News broke earlier today from CNBC’s Christina Farr that Apple, Inc. has a small team of engineers working on creating sensors that can “non-invasively and continuously monitor blood sugar levels to better treat diabetes”. The project is allegedly far enough along in development that Apple is investigating possible regulatory pathways and performing feasibility trials at clinical sites in the Bay Area.

The article suggests that the project is a wearable sensor (either inside or worn in conjunction with a future version of the Apple Watch) that can track blood sugar non-invasively with optical sensors, similar to how the current Apple Watch can monitor heart rate. Such a non-invasive continuous glucose monitor would undoubtedly be a “holy grail” for diabetes, but can Apple succeed where so many other companies have so far failed to deliver?

Just for fun, let’s brainstorm potential possibilities for what this secret Apple Project could be. We’ll sort them by order of plausibility.

Most Likely Possibility: Health-focused Apple Watch “Pro” with an Invasive Glucose Monitor Partner


One question underlying this whole scenario is whether or not Apple really wants to be a medical device company. As Tim Cook himself pointed out to The Telegraph in November, 2015: “We don’t want to put the watch through the Food and Drug Administration (FDA) process. I wouldn’t mind putting something adjacent to the watch through it, but not the watch, because it would hold us back from innovating too much, the cycles are too long. But you can begin to envision other things that might be adjacent to it — maybe an app, maybe something else.”

Interestingly enough, he does mention the possible for an Apple-made companion device or software to the Apple Watch that might be a health device.


That being said, systems that closely resemble non-invasive continuous glucose monitors exist or are on the horizon. The Abbott Freestyle Libre Flash is approved in Europe for continuous glucose monitoring in diabetes, and does not require any calibration with a glucose meter.  (A short-term version called the Abbott Libre Professional is FDA-approved in the USA).


Similarly, Verily (part of Google) has partnered with DexCom to work toward a penny-sized continuous glucose monitor that would be usable for both Type 1 and Type 2 Diabetes and not require calibrations.


Also, implantable CGM should be here soon (Senseonics is currently filing for FDA approval), which is inserted under the skin and worn for 90+ days.
The common thread with all these devices is that they are invasive and all require some sort of display/reader to receive the readings.

Apple could potentially create an FDA-approved Healthcare-focused (as opposed to just fitness) Apple Watch “Pro” that is more robust and can communicate reliably with such sensors. If the wireless connection and stability of the device were medical-grade, removing extra middle-man devices would be a huge boon to patients. Users of such a “Pro” Watch might sacrifice some other features (small size?) or not get a model updated every year, but it would be reliable enough for medical use. (Such a health-stable PRO Watch would be quite useful for Artificial Pancreas projects too).

Most Interesting Possibility: Consumer-grade Optical (or Microneedle) Glucose Monitoring for Everyday Use

Combining my theory that Apple does not want to become a medical device company and the fact that accurate non-invasive glucose monitoring is a feat of titanic proportions, perhaps their top-secret glucose monitoring project is not for medical use at all.

As society becomes more health-conscious and sensor-driven, it’s only a matter of time before the general population starts monitoring glucose. In the diet and nutrition communities, sugar and carbohydrates have become the enemy, and some athletes (without Type 1 Diabetes) actually use invasive continuous glucose monitors while training to optimize their diet and exercise regimens.

Companies like Sano have been working toward non-invasive CGM for everyday use, and Apple has acquired companies (eg C8 Medisensors) working on various forms of non-invasive CGM. Some of these companies utilize optical sensors, and others use an array of microneedles to sample interstitial fluid.

With consumer-grade CGM, people could observe rough trends about their blood sugar. They’d be able to see first-hand how quickly certain foods (eg. cereal, white rice) can spike blood sugars, and how avoiding carbs can keep blood sugars relatively flat. Furthermore, widely prevalent sugar monitoring might not be accurate enough to dose insulin or diagnose diabetes, but it could help raise awareness and promote screening for Pre-Diabetes.

As an endocrinologist without diabetes, I’ve had the opportunity to wear CGM’s in the past, and they have been very enlightening. If I had the choice, I’d wear quite often.

Moonshot Possibility: Medical-grade Non-Invasive Glucose Monitoring for Diabetes

Now this is clearly what the original source is suggesting, but I also find it the least likely. The article itself recognizes the immensity of this challenge:

“Accurately detecting glucose levels has been such a challenge that one of the top experts in the space, John L. Smith, described it as ‘the most difficult technical challenge I have encountered in my career.’ The space is littered with failures, as Smith points out, but that hasn’t stopped companies from continuing to attempt to crack this elusive opportunity.”

Much like Verily’s partnership to measure glucose levels via a smart contact lens, a non-invasive continuous glucose monitor from Apple would be mind-blowing. However, the diabetes community is well-aware of other longshots that have promised much, but never delivered. (Exhibit A: the GlucoWatch).

In addition to the technical challenges, I’m also not sure what Apple’s end-game with such a medical device would be. Would they try to carve out their own niche in the diabetes glucose monitoring space, taking on Dexcom and Medtronic? Would they license their technology to these companies? Would they try to market directly to consumers?

All that being said, I am extremely excited that Apple is focusing their efforts and resources on glucose monitoring and diabetes. I can’t wait!

Medicare announces coverage criteria for Dexcom G5, but blocks use of smartphones?

Coming sooner than expected, Medicare recently clarified coverage criteria for the Dexcom G5, paving the way for Medicare to reimburse for people with both Type 1 and Type 2 Diabetes requiring intensive insulin dosing to use the Dexcom G5 mobile.

Dexcom and the diabetes community heralded the exciting news, as the lack of CGM coverage for Medicare patients had previously been a glaring oversight. Dr. Steven Edelman, founder of TCOYD, often joked about this, saying, “Good news! According to Medicare, Type 1 diabetes is cured when you turn 65!”

Despite the good feelings all around, a closer look at the Medicare document includes some concerning language that might forbid users to take advantage of one of the most useful features of the Dexcom G5: the ability to view sugars on your smartphone or smartwatch.

Recap of an exciting month for diabetes and technological innovation

Fall has come with a flurry of new products, FDA approvals, and announcements from the major players in diabetes technology. Don’t miss out by checking out a quick recap of what matters:

1. Tandem Diabetes begins shipping the forward-thinking T:Slim X2

Tandem X2

Thanks to an all-new bluetooth transmitter and its FDA-approved ability to add new features with software updates, the T:Slim X2 unifies and replaces Tandem Diabetes’ outgoing models, the T:Slim and T:Slim G4. (The T:Flex will remain as the primary option for users requiring higher doses of insulin).

While it currently closely resembles the outgoing T:Slim in form and function the T:Slim X2 will soon introduce (via free software update) the long-overdue ability to display data directly from the Dexcom G5 continuous glucose monitor (CGM). In addition to wirelessly receiving information from other devices like the G5, the T:Slim X2 can transmit data to other devices such as the iPhone. This two-way communication opens up the very likely possibility of smartphone apps to display information from (and possibly even control) insulin pumps and CGM’s.

Years down the road, the future-proof X2 platform will be able to incorporate “artificial pancreas” features such as predictive low glucose suspend and eventually fully autonomous closed loop systems.

Current owners of Tandem products can learn about upgrade options here.

2. FDA approves Medtronic 570G, the next step toward the Artificial Pancreas


The same month that the (underwhelming) 630G systems began shipping, the FDA surprised the diabetes community by approving the eagerly anticipated Medtronic 670G Hybrid Closed Loop system, including their next-generation CGM sensor.

The Medtronic 670G’s landmark feature is its SmartGuard HCL (Hybrid Closed Loop) technology, which automatically adjusts the pump’s insulin rate to target a blood sugar of 120. Much like a car with adaptive cruise control, the 670G will increase or decrease the basal rate of insulin delivery but will still require user intervention for notable events such as mealtime boluses. (We explore why this matters in a separate article.)

The 670G also comes with the updated design introduced in the 630G, and includes the new Guardian 3 sensor, featuring better accuracy and a 7 day wear period (up from 6 days).

Although Medtronic won’t ship the 670G until April 2016, the 670G’s FDA approval represents a pivotal step forward toward achieving the goal of a true Artificial Pancreas.

3. FDA Approves Abbott Freestyle Libre Pro System for Short-Term CGM Usage

Freestyle Libre Pro

Although the Abbott Freestyle Libre has been available for personal use in Europe for years, the hybrid-CGM comes stateside with limited functionality as a professional system (rather than for personal use). That means the Libre Pro System would be purchased by health care providers to be worn by their patients for a 14 day period. (This 14 day period improves upon the Medtronic iPro’s 4 day and Dexcom Professional’s 7 day period)

During that 14 day period, the patient will not have to do any calibrations, BUT they would also not have real-time access to their CGM readings. At the end of the period, the patient would review their CGM data with their provider to identify patterns.

While we’re still hoping that the FDA will eventually approve the version of the Freestyle Libre for long-term, personal use found in Europe, the Libre Pro System can still benefit patients in the USA whose insurance only covers short-term CGM trials. Also, the Freestyle Libre Pro System’s 14 day wear period and freedom from calibrations makes it an obvious upgrade over the Medtronic iPro.

4. Medtronic adds Android compatibility to Connect

Medtronic Connect for AndroidThe Connect is Medtronic’s answer to Dexcom’s Share, and comes in the form of a small dongle that helps transmit data to nearby smartphones. Also like the Dexcom’s smartphone connectivity, Medtronic had been limited to the Apple iPhone. Until now… With the release of MiniMed Connect in the Android Play Store, the Connect finally allows data from the 530G to be viewed from your smartphone, Apple or Android. (Dexcom plans to release a G5 app into the app store very soon).

Unfortunately, the Medtronic Connect platform is curiously not compatible with the aforementioned upcoming 670G and their current top-of-the-line 630G.



Why the Medtronic 670G Artificial Pancreas is a huge deal for diabetes

So you’ve read all the headlines about an artificial pancreas and how it’s supposed to change the world for diabetes, but what does it really mean? We understand the skepticism… Remember: Medtronic previously claimed to have released an artificial pancreas system back in 2013.

But this time, the Medtronic 670G actually is a big deal. It’s a major step forward towards the artificial pancreas, and scientific studies back up its bold claims. (Note: it is NOT a true artificial pancreas, though)

But instead of repeatedly saying how important it is, we’re going to tell you exactly why it matters.

An “artificial pancreas” is like a “self-driving car”


The quest toward an “artificial pancreas” closely parallels that of the “self-driving car.” The names do a good job in describing their futuristic vision, so long as you understand that the pancreas is the body organ that produces insulin. (In Type 1 diabetes, the pancreas no longer functions properly and stops making insulin, causing blood sugar to go out of control.)

So continuing the comparison, having Type 1 diabetes is like owning a car with just an engine; no steering wheel or brake. Not good. Thanks to modern medicine, people with diabetes have the opportunity to “drive their car” by checking their blood sugar and injecting insulin appropriately.

Much like a self-driving car, a true artificial pancreas would be an autopilot for navigating the highs and lows of blood sugar. With an artificial pancreas, the user would not have to devote any effort to controlling their blood sugar. It would take care of itself, just as a self-driving car would get you from point A to point B on its own.

But now the next question…

Is the Medtronic 670G an artificial pancreas?

No, but it’s halfway there. If a true artificial pancreas is like an autopilot for self-driving cars, the Medtronic 670G is similar to “adaptive cruise control.” (If you don’t know what that is, adaptive cruise control allows a car to automatically accelerate and decelerate to maintain a safe distance from the car in front of it). If you want to drive on a straight stretch of road without making any lane changes, adaptive cruise control requires virtually no user interaction.


Similarly, the Medtronic 670G’s breakthrough feature adjusts basal insulin delivery (by speeding it up or slowing it down) to maintain a normal blood sugar of 120 mg/dL. It might not be as obvious during the day with meals and periods of exercise, just as adaptive cruise control plays a more subtle role when making many turns during city-driving.

But overnight and between meals is when the 670G’s adaptive cruise control truly shines, when circumstances are relatively stable, without the need to “change lanes” for meals or exercise. And keep in mind, unlike a car that you only use for trips, people with diabetes live with their disease 24 hours a day, 7 days a week. So a significant portion of their day is spent during those in-between and overnight periods.

Medtronic 670G’s “Adaptive Cruise Control” Works

Studies have clearly shown that wearing the 670G improves sugar control by reducing time spent in both high and low blood sugar range and lowered average A1c from 7.4% to 6.9%.

People who have worn insulin pumps with “dynamic cruise control” features particularly rave about its benefits on improved sleep overnight. Restful sleep is a big deal (and why mattress/pillow companies make a killing!), and it’s even more elusive with Type 1 diabetes due to the fear of overnight hypoglycemia or hyperglycemia. It’s not uncommon to be woken up several times a week in the middle of the night to check blood sugar or to have to eat a snack to avoid hypoglycemia. And even when sleep is not interrupted, waking up with higher or lower sugars than desired can start the day off with a thud.

Medtronic 670G Artificial Pancreas

As you can see in the graph above, adults using the 670G algorithm (highlighted in red) had a much narrower range of blood sugars, especially at night, when compared to standard pump users (the shaded grey area). They also headed into their mornings closer to target, and with a more stable glucose trend.

Medtronic 670G is just the beginning…

The top reason we’re excited for April 2017 (when the Medtronic 670G becomes available) is that it is just the first of a wave in the movement towards a true artificial pancreas.

While Medtronic has the advantage of manufacturing both its CGM and insulin pump, many future competing artificial pancreas systems are partnering with Dexcom’s highly rated, iPhone-compatible continuous glucose monitors.


The long list of such artificial pancreas systems includes a variety of approaches such as Bigfoot’s iPhone-based user interface, the more altrustic public benefit company BetaBionics’ iLet, and collaborations between Tandem and TypeZero.

bigfoot-artificial-pancreasThese projects are in various stages of advanced development, most of which are being currently worn and tested in clinical trials and research labs. The initial feedback of test subjects has been exceedingly optimistic, and the future of the “self-driving” artificial pancreas is just around the corner.

No matter which company (or companies) win, the type 1 diabetes community is the biggest winner.

Stay tuned for more coverage of the Medtronic 670G and other artificial pancreas devices…




How to use watchSugar to view Dexcom on Apple Watch home screen

Released in October 2015, Apple Watch OS 2 introduced the ability to view third party app information as “complications” on the home screen watch face. While users with Continuous Glucose Monitor (CGM) users were salivating at the idea of viewing their Dexcom G4 and G5 information by simply glancing at their Apple Watch, FDA hurdles have delayed Dexcom’s officially introducing these features for Apple Watch.

Thankfully, indie app developer (and Type 1 PWD) Adam Wolf has come to the rescue and released watchSugar for iPhone and Apple Watch, which adds a complication to view blood sugar and trend information from your CGM directly on the watch face. From some preliminary testing, it works exactly as promised!

What it Does

Before watchSugar, there was no simple solution for viewing Dexcom CGM data directly on the watch face, in the same way you would view the weather forecast or stock information.

Apple Watch Complication for Dexcom CGM

With watchSugar, there are two complications (large and small) that are viewable in most of the Apple Watch faces. The larger complication also shows the timestamp for when the glucose was sampled, which is quite important.

How to Install watchSugar Apple Watch Complication:

  1. [Steps 1-4 are to be performed on the iPhoneInstall watchSugar via the App Storedownload watchSugar App Store
  2. Make sure the companion Apple Watch app is installed by opening the Watch app, tapping on watchSugar, and making sure “Show App on Apple Watch” is toggled on.watchSugar Watch App
  3. Launch the watchSugar app and log in using your Dexcom Share/Follow credentialswatchSugar Login
  4. You should see a confirmation screen as pictured above on the right.
  5. [Steps 5-9 are to be performed on the Apple WatchForce touch on ANY watch face (by pressing firmly in the center of the screen) to bring up the options for selecting and customizing watch watchface
  6. Swipe left and right to pick your watchface, then tap the CUSTOMIZE button. (I highly recommend the Modular watch face because it includes timestamp information)
  7. Swipe to the left or right to bring up the display for adjusting complications. Tap on the complication on the screen where you’d like to view your sugar. (In this example, tap in the middle of the screen)Screen for choosing your complication
  8. Using the digital crown knob on the side of the Apple Watch, scroll up and down until you see the watchSugar complication. watchsugar_complication
  9. Press the digital crown knob on the side of the Apple Watch twice to return to your watch face.
  10. Your Dexcom blood sugar complication should now be visible on your watch face. watchsugar for dexcom and apple watch

Important Caveats

First off, the watchSugar App Store item description states that “watchSugar is able to update every 17 minutes on average.” (This is due to a limitation of the Apple Watch complications, not due to Dexcom or the developer)

Since the Dexcom G4 and G5 samples blood sugars every 5 minutes, this means that the sugar displayed on the complication can be 2-3 readings behind. In my brief testing, I did not find this was an issue, but I would highly recommend using the larger complication so that you can see the time that the reading was checked. (in the above image, even though the time was 6:25, the blood sugar reading was sampled at 6:12PM)

Secondly, watchSugar receives blood sugar readings through the Dexcom Share/Follow system. This requires that you set yourself up as a “follower” using the Dexcom Share app. In addition, the complication requires an active internet connection.