Saturday, March 14, 2020

by David Kliff, The Diabetic Investor

Insulin pump therapy has long been recognized as one of the most effective therapy options for both Type 1 and intensively managed Type 2 patients. There are hundreds if not thousands of studies that have shown how the use of an insulin pump improves patient outcomes. Over the years insulin pumps have made some substantial leaps in terms of usability features and benefits. While more complex than multiple daily injection (MDI) therapy, insulin pump therapy has also become more patients and physician friendly.

In this column we’ll examine the pros and cons of insulin pump therapy with a focus on the intensively managed Type 2 population. We’ll pay very close attention to the latest sensor augmented systems given the increasing usage of continuous glucose monitoring (CGM) Please also note, it’s pretty easy for an existing pump patient to switch from one system to another, therefore our comments here will focus more on patients initiating pump therapy for the first time. With that said, let’s begin.

The Pros

Thankfully, because of CGM technology initiating pump therapy has never been easier. In fact, we would go as far and state that no patient should initiate pump therapy without being on a CGM for at least 30 days (60 or 90 would be better). Why? Using the software that works with the existing CGM system it becomes simple to determine several of the factors that are used to program the pump. Factors such as:

1. Insulin time to action
2. Duration of action
3. Insulin to Carb Ratio’s

CGM data also provides a more detailed overview which allows for better pump programming. For example, given that pumps now allow for multiple basal rates, should a patient be experiencing dawn phenomenon, the pump can be programmed to deal with this issue.

owever Now thanks to technology we have two systems and soon a third where the CGM and pump are designed to work together. There is the 670G from Medtronic and the Control IQ from Tandem; Insulet will soon have the Horizon on the market sometime later this year. These hybrid closed loop systems offer several benefits; most notably is that the majority of the heavy lifting decisions that patients used to make are now being made by the system. Using sophisticated insulin dosing algorithms, these systems can almost be like an auto pilot on an airplane managing the patient’s insulin dosing.

These systems are designed to keep patients in a tighter range with the additional benefit of protecting patients from dangerous hypoglycemic events. Should the system detect a hypoglycemic event coming it automatically shuts down the delivery of insulin while warning the patient of pending low. On the flip side, should the system detect the patient’s glucose going outside their range on the high side it automatically delivers insulin keeping the patient in range.

Frankly the real-world results of these new systems has been astonishing with patients achieving Time In Range (TIR), a key new very important metric for measuring control, of greater than 70%. More astonishing is achieving these ranges with few adverse hypoglycemic events. Although the Control IQ has not been available for as long as the 670G, the real-world results are nothing short of fantastic with patients achieving TIR of greater than 85%.

Although we have yet to see detailed data on the coming Horizon system from Insulet, we suspect it will perform as well as the Control IQ as it works with the same CGM system, Dexcom and has a similar insulin dosing algorithm. The fact is when it comes to insulin pumps in today’s world the pump itself is just a piece of programmable hardware, the real work is done by the CGM and the insulin dosing algorithm. However, we should note that patients have indicated the user interface for the Control IQ is much more patient friendly than the 670G interface.

The Cons

Now as way cool and whiz bang as these new systems are, they do not come without drawbacks. First and foremost, they are medical devices, and unfortunately medical devices can and do malfunction. This is fact of life with any medical device and insulin pumps are no different. The big difference is these systems deliver insulin which is not just a life sustaining drug but also a lethal drug when incorrectly dosed. While deaths are very rare with these systems they have occurred.

Secondarily, as sophisticated as these systems have become, they do not function without patient interaction. Infusion sets needed to change every three days, reservoirs replaced and filled every three days, sensors replaced every 10 days, etc. The pump itself needs to charge with a typical charge lasting a day perhaps two. The reality is some patients just don’t want to do all this stuff and find it easier to inject even if that means injecting multiple times per day.

Third, there is training and an adjustment period for patients new to pump therapy. Yes, pumps are much smarter these days as they are basically minicomputers, but even with this advanced technology patients still need training. There is also an adjustment period as the patient transitions from MDI to insulin pump therapy. A period which not only impacts their outcomes but mindset as well. Some patients experience a feeling of relief or freedom when put on these systems no longer worrying about having their insulin with them or having to inject in a public place. Others feel somewhat anxious as they realize they are attached to a machine which for all practical purposes has control over their lives and until they trust the system this anxiety will remain. Obviously, each patient is different which is why we recommend patients new to pump therapy also work with a CDE who can help them deal with these issues.

The Costs

Now no discussion of insulin pump therapy would be complete without discussing the financial ramifications. With the exception of the OmniPod system from Insulet, pump therapy is not cheap and does require ongoing costs to the patient. Add in the cost of a CGM and it’s understandable why some patients chose to excuse the expression stick with MDI.  Even the OmniPod which requires no upfront cost nor any costs for pump supplies does require an ongoing cost.

Before advising any patient on whether to implement pump therapy we’d highly recommend a discussion on this issue of cost. As we all know diabetes besides being a chronic disease is also a costly disease and given the complexities of health insurance coverage the cost of diabetes sometimes can and does interfere with the management of diabetes. No one likes this situation however it is better to address this issue up front.

There is no question that insulin pump therapy has made tremendous advancements these past few years. However, this does not in any way mean insulin pump therapy is for everyone. As we have noted there are several critical issues that may prevent a patient from transitioning from MDI to pump therapy. Still, given the results we are seeing in the real world with the newer sensor augmented systems, it’s hard to ignore the potential of insulin pump therapy.