Will CGM Be for the Masses or Just the Highly Motivated?

by james s. hirsch

Continuous glucose monitoring may be our most promising technology in diabetes management, but will it be for the type 1 masses or just for the highly motivated?

Let’s consider the device itself. As one who’s used a CGM, I believe that what the technology actually does – deliver real-time glucose data, trend lines, and warning signals – is far less important than what it demands. If diabetes is a daily battle, continuous glucose monitoring changes the terms of engagement. It forces patients to be more involved, more vigilant, more attuned to the vagaries of glucose levels and to their own bodies. When the sensor needs to be replaced, when a glucose reading spikes to 300, when a low blood-sugar alarm sounds – all demand a response.

Even on “good days,” when your glucose trend line lazily drifts through your target range like a creek through a mountain ravine, you still have to check and double check that the apparatus is working, that you’re responding correctly to the numbers, and that all is steady in your glycemic world.

This is the great virtue of continuous glucose monitoring. And its greatest liability. The constant demands of this technology impel its users to improved control, but those very demands can also turn people away.

We already know that the acceptance of a technology or a drug often has less to do with efficacy than with ease of use or tolerability. Consider conventional home glucose monitoring. Prick finger, get a drop of blood, read the meter. It isn’t sexy. It isn’t exciting. And it isn’t perfect. But since it became available about 30 years ago, it has revolutionized type 1 diabetes. It’s simple, affordable (with insurance), and essentially painless. For most individuals with type 1 diabetes, the question is not whether they’ll test their blood sugar, but how often. (People with type 2 diabetes also test their blood sugar, but not in the same percentages or frequency.)

Now consider the insulin pump. I saw my first insulin pump more than 30 years ago – it was the size of a World War II walkie-talkie – and its advocates thought the pump would eventually dominate the market and revolutionize care. The pumps have indeed become far better – smaller, sleeker, more powerful – but the majority of people with type 1 diabetes continue to use syringes or pens. (The numbers are imprecise, but an estimated 25 to 30 percent of individuals with type 1 diabetes use pumps and a very small percentage of other columns.) Why haven’t pumps become more popular? For those without insurance, they may be too expensive. Aesthetics and body image are also factors. No matter how small or discreet the pump, some people will always resist having an electronic gadget attached to their body.

Further, pumps are simply more difficult, complicated, and demanding than a syringe or a pen. Both my nine-year-old son and I have been using pumps for the last five years, so I can affirm their flexibility and their power. But I can also affirm that a pump requires more time, more trouble-shooting, and more expertise (programming the pump, changing insertion sites, calculating carbs). Some people don’t have those resources.

Indeed, to maximize the pump, you probably need the support of your healthcare provider who can help you program and fine tune the device and then make adjustments. Unfortunately, that requires time that your provider is already short of and expertise that he or she may not have – and, one more thing, your provider won’t receive any extra money for the effort. 

In other words, a complicated technology, no matter how effective, is ill-suited for our healthcare system.

Which brings us to CGM, which amplifies the benefits and the challenges of the pump. To use a CGM, you have to be willing to invest the time, energy, and resources into mastering the technology. That includes interpreting the reams of data – your blood sugar numbers – that are now literally at your fingertips. There is no doubt that individual patients who are willing to do that will achieve superior outcomes. The technology forces you to be part of your own care in a way that is inevitably beneficial.

But for some people with diabetes – who knows how many – the technology is daunting, and the investment in time and energy unreasonable (not to mention huge financial burdens if your insurer doesn’t cover it). And even if you are willing to make that commitment, will your healthcare provider download, graph, and interpret thousands of numbers? And if you’re using a pump, will your doctor cross-reference your insulin delivery patterns with your blood glucose readings to adjust your basal rates and insulin-to-carb ratios?

Here’s a hint: probably not.

The CGM makers understand the challenge. Like the pump makers, they are trying to make each new generation of their product more powerful but also easier to use and less intrusive, and the sooner they are able to integrate continuous monitoring with pumps, the more likely consumers will accept it. Their ultimate goal will be to make CGM as similar to finger pricks as possible – if not as fast and simple, at least close to it. And if they don’t come close, CGM will probably remain a product for only the most highly motivated patients.

I’m rooting for the CGM makers because I know this is true.

Master your technology.

Master your diabetes.