- Design
- Randomised controlled trial, 26 weeks, 22 primary care practices
- Population
- 283 adults with type 2 diabetes not on insulin, baseline HbA1c about 8.8%
- Primary outcome
- HbA1c at 26 weeks
- Effect
- 7.2% vs 8.0%; adjusted difference −0.9 points (95% CI −1.1 to −0.6)
The CONNECT trial, in NEJM (14 October), randomised 283 adults with type 2 diabetes not on insulin, at 22 US primary care practices, to continuous glucose monitoring or routine care for 26 weeks. Baseline HbA1c was about 8.8%.
HbA1c fell to 7.2% with a sensor and to 8.0% with routine care, an adjusted difference of 0.9 points. Time in range was 21 points higher with CGM, and time below range was slightly lower. There was no severe hypoglycaemia.
Most guidance has reserved CGM for people on insulin. This trial suggests the feedback itself — seeing what meals and missed doses do — drives a clinically meaningful HbA1c fall in people on tablets or GLP-1 drugs, at least while the sensor is worn. It was funded by a sensor manufacturer, ran for six months, and did not measure complications or what happens after the sensor stops.
Guidelines have not yet changed. In practice, a short sensor period with a structured review is worth discussing for people above target on oral or non-insulin injectable therapy, where cost allows. In India, sensor cost is the limiting step for most patients.
- Consider a sensor for people with type 2 diabetes not on insulin whose HbA1c remains above target
- Pair it with a structured review of the trace; the device alone is not the intervention
- Look for post-meal peaks and missed-dose patterns the HbA1c hides
- Agree beforehand how long the sensor period will last and what will change afterwards
- Discuss cost openly; a time-limited period may suit people paying privately
Why it matters
It challenges the assumption that CGM only earns its cost once insulin starts.
Don't overread it
Six months, industry funded, HbA1c only — it does not show fewer complications or a lasting effect after the sensor stops.
The statistics, in plain English
The 0.9-point difference (95% CI 0.6 to 1.1) is both statistically and clinically significant: the smallest plausible effect, 0.6 points, is still comparable to adding a second tablet. Participants started high, near 8.8%, so people closer to target would probably gain less.
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