By Gary M. Kaye
Editor, Tech50+ (www.tech50plus.com)
There are an estimated 86 million diabetics in the U.S. About 3 million of those have Type I Diabetes, an autoimmune disease in which the body stops producing insulin, and must inject this hormone to survive. Millions of the Type II diabetics are also on insulin replacement. Both diabetes sufferers can exist in what seems like an endless loop of highs and lows.
Now there’s at least a partial solution. Officially, it’s the Medtronic MiniMed 670G. Unofficially it’s been called the “artificial pancreas.” It’s the first (and so far only FDA approved) closed-loop system that constantly self-adjusts to automatically keep glucose levels in target range.
Old Tech + Old Tech = Breakthrough
The two components of the MiniMed System – the insulin pump and the continuous glucose monitor (CGM) – are not new. The first wearable insulin pump was invented by Dean Kamen in 1973 and came to market three years later. The first practical CGM came from MiniMed (later purchased by Medtronic) in 1999. However, linking them required complex algorithms that didn’t exist before, and a microprocessor-based platform capable of making the connection.
First approved by the FDA in the spring of 2017, this system was designed for Type I diabetics. It’s now also being used by some Type II diabetics on full insulin replacement, myself among them. I’ve been living with it for a couple of months and it has made it easier to control my blood glucose levels. But as with any first-generation technology, it has its warts.
How Does It Work?
The Medtronic MiniMed 670g is the first system in which a CGM can talk to an insulin pump. But note – it’s called a Continuous Glucose Monitor, not a Continuous Blood Glucose Monitor. Unlike finger sticks that measure glucose from blood, CGMs measures glucose in the interstitial fluid just under your skin. The readings will almost never match finger sticks, but come close. This reading is fed to the pump, where a smart chip to determine correct insulin dosage on almost a minute-by-minute basis based on the patient’s programmable targets. At mealtime, users set the pump to deliver an insulin dose based on expected carbohydrate intake.
Medtronic trainers work with diabetes professional to program a patient’s insulin pump, which can hold a three-to-four day supply. The system comes with a reservoir with a built-in needle to draw insulin from a vial (ordered through your prescription service). Once filled, the reservoir attaches to the infusion set, which includes tubing and a plastic needle you insert into your body with a device called a "serter.” Programming options allow you to adjust the pump to deliver a consistent level of base insulin throughout the day, with more options when it’s hooked to the CGM. The two devices should be positioned on the body so they can communicate, but not too close together.
The CGM consists of a rechargeable transmitter and a sensor that’s good for six to seven days. Attaching the transmitter and sensor is a bit more complex than the infusion pump, but it only takes a short time to get used to it.
When you start up the transmitter and sensor, it takes time to find the pump, then almost two hours to "warm up." Then you do a finger stick to calibrate the CGM, repeating the finger stick every 12 hours at minimum.
When things are working well, the system is in Auto Mode and a blue shield displays your current glucose value. When you need to calibrate the sensor – or the algorithm wants a new blood glucose reading – you'll see the Safe Mode screen until you make adjustments.
Quirks
This is first generation technology and does peculiar things – like waking you up in the middle of the night to check your blood glucose levels for no apparent reason. There are additional alerts, some you can control, others you can’t – like an alarm before you hit a low or a high. The techs on the 24/7 360G hotline are knowledgeable, though wait times can be long for help.
User Hostile Software
To track how you are doing, Medtronic created CareLink software. When it works it will take the data from your blood glucose monitor and your pump and give you a comprehensive report that you can share with your healthcare team. The problem – based on my experience, – is CareLink does not support many of the major browsers, including Google Chrome and some versions of Microsoft Internet Explorer. However, many diabetes professionals also have the software, so you can bring your pump and meter to them and get reports from them.
The Raw Deal for Medicare Patients
Though many private insurance plans cover the MiniMed 670g, Medicare does not, claiming the finger stick requirement makes it less desirable than CGMs from Dexcom and Libra.
I spoke with a Medicare official (CMS) who basically did not understand that these other CGMs are measurement devices, whereas the Medtronic Guardian Link transmitter and sensor is a communications device that instructs the pump on how much insulin to deliver.
And the MiniMed 670g costs are big – the pump is $7,249, the Guardian Link 3 Transmitter is $990 and sensors, which last about six days, are $50 each. For Medicare patients on a fixed income, the $11,000 to get going on the system puts the MiniMed 670g is pretty much out of reach.
Does It Work?
The MiniMed 670g Hybrid Closed Loop System means I am better able to manage my diabetes, with a lowering of my AIC levels. That makes it worth the hassles; though I’m not sure the peace of mind over blood glucose highs and lows is worth $11,000.
Two Facebook groups address MiniMed 670g use issues –the Medtronic 670G Support Group and the Medtronic 670g users. Medtronic also has its own blog, the Loop Blog.
Gary Kaye is the creator of Tech50+ (www.tech50plus.com), the leading website covering technology from the Baby Boomer perspective. Kaye has been covering high tech for more than 30 years with outlets including NBC, ABC, CNN and Fox Business. He is a regular contributor to AARP and other websites on issues regarding the nexus of technology, seniors and baby boomers.
