CGM engagement linked to bigger A1c drops
- A May 6 Managed Healthcare Executive briefing spotlighted a JAMA Network Open study tying frequent CGM use in type 2 diabetes to larger A1c drops. - The key number was sensor wear on more than 270 days a year — that group cut A1c by 1.52 points versus 0.63 without CGM. - The bigger shift is from device access to device engagement — especially around the 3- to 6-month point.
Continuous glucose monitoring is turning into a behavior story, not just a gadget story. That matters because type 2 diabetes care has long had a familiar gap — getting people access to better tools does not guarantee better control. The new wrinkle is that a large 2025 JAMA Network Open analysis, now being pulled into clinical practice discussions, shows the biggest A1c gains came from people who kept using CGM consistently, not just people who started it. Managed Healthcare Executive’s May 6 discussion zeroed in on that point and on the moment when engagement often starts to fade. ### What actually changed? The news is not that CGM can help — that was already clear. The useful update is that researchers looked at 9,258 adults with type 2 diabetes and sorted outcomes by how often they actually wore sensors over 12 months. The people with the heaviest use — more than 270 days — had GLP-1 drugs, SGLT2 inhibitors, and insulin regimens. ### How big was the difference? Pretty big. The highest-use group dropped HbA1c by 1.52 percentage points at 12 months, versus 0.63 points in matched patients who did not use CGM. The study also showed that the biggest reductions happened around 3 months, which fits the real-world idea that people learn from glucose. ### Why does “engagement” matter so much? Because CGM is only useful if the person changes something after seeing the data. A separate 2026 mixed-methods study helps explain the mechanism: people who reported stronger self-efficacy — basically, feeling more capable of managing diabetes day to day — had much higher engagement. The feedback loop is. ### Why is 6 months a big deal? Turns out that is where the easy wins may already be gone. The Managed Healthcare Executive discussion framed 6 months after CGM start as an inflection point — early behavior fixes have happened, novelty has worn off, and “tech follow-up” through the first year instead of assuming the device will carry the whole load by itself. ### Does this make HbA1c less important? No — but it does make HbA1c less sufficient on its own. HbA1c is still useful as a 2- to 3-month average, but it can mislead in anemia, pregnancy, some hemoglobin variants, recent blood loss, and kidney or liver disease. In those cases, CGM adds something
