Which technology will better improve your blood sugar management and quality of life: an insulin pump, or a continuous glucose monitor (CGM)? While these two technologies have a marvelous potential to combine forces, the sad truth is that many people with diabetes cannot afford two expensive devices, if they can afford any at all.
It’s a question that has been thoroughly investigated and debated by doctors and academics. And it seems like the experts are beginning to agree: if you had to choose just one device, you’re better off with the CGM.
This new consensus is important news, and not just for patients that want to optimize their glycemic control. Insurance companies also want to know what devices will result in healthier (that is, less expensive) outcomes. If the medical establishment is seen to favor one technology over the other, it will have significant consequences for the way that these devices are priced and prescribed.
In recent weeks, two more studies have contributed to the growing literature on the subject.
The three-year ‘COMISAIR’ study out of Prague has been published in the latest edition of Diabetes Care. Researchers followed about 100 participants, split into four different groups: pump with CGM, pump without CGM, multiple daily injections (MDI) with CGM, MDI without CGM. Patients that used the CGM enjoyed both significantly lower A1C and lower incidence of hypoglycemia compared to those checking their blood sugar manually with fingersticks. What appeared to surprise researchers is that these improvements were comparable between the groups that used a CGM with an insulin pump, and without. That is to say, the method of insulin delivery appeared to be irrelevant.
The COMISAIR study was partially funded by Dexcom, so some readers may view the conclusions with skepticism. While it pays to be wary of industry-backed science, in this case I think that Dexcom’s interests more or less align with those of people with diabetes. It’s also worth reiterating that Dexcom’s customers, and the intended audience for such studies, is not patients but the insurers. The authors of the COMISAIR study clearly called the “payers” to notice when they estimated and underlined the cost savings associated with better glycemic control.
Meanwhile, in the August edition of Current Diabetes Reports, a team of American endocrinologists asks the question more pointedly: “which should come first: an insulin pump or a continuous glucose monitor?” Their conclusion is confident. After reviewing recent clinical trials and considering practical issues such as cost and quality of life, the authors definitively recommend the CGM as “first-line technology.”
This review considered a larger number of studies, which all showed more or less the same thing: that people using CGM technology invariably spent less time in a hypoglycemic state (<70 mg/dL) and usually also had a lower A1C. Insulin pumps showed no such benefits in comparison to utilizing multiple daily injections. Several of the studies looked specifically at participants with only the CGM or with only an insulin pump, and all concluded that the CGM offered superior blood sugar control.
Other factors also appear to favor the CGM. In comparison to an insulin pump, a CGM typically requires less training and can be more easily integrated into a patient’s management regimen. Protection against hypoglycemia reduces emotional distress, improving quality of life. What’s more, CGMs are usually less expensive, given the usually high cost of the insulin pump itself. Monthly costs for the Dexcom and Freestyle units are more or less competitive with some of the leading insulin pumps, but they don’t require the same initial outlay.
If you’ve used one of the newer CGM models, you may find the conclusions unsurprising. It seems almost self-evident that having reliable real-time glucose measurements would enable people with diabetes to better fine-tune their daily glucose management. But it’s worth remembering that the CGM experienced a somewhat rocky introduction. In our interview with Dexcom CEO Kevin Sayer, he noted that the many insurance companies are still trigger shy because patients tended to give up on their earlier CGM models, which were by comparison clunky and inaccurate. It is only in recent years, with the introduction of the Freestyle Libre and the Dexcom G5 and G6 systems, that patients have really taken enthusiastically to the technology. One of the remarkable aspects of the COMISAIR study was the very high rate of adherence: study participants overwhelmingly continued to use their CGMs for the entire three years of the study.
CGM manufacturers are extremely eager to have their technology recognized as the “standard of care” for people with Type 1 (and eventually Type 2) diabetes. These recent studies, which both recognize and strengthen the consensus in favor of the CGM, will hopefully help to make this potentially vital technology even more widely available and accessible.