The evidence

Every number we use, traced to its study.

Original-source first: when a report cites another paper for a statistic, we cite the original paper — and we keep the studied population, treatment and diabetes type visible in every claim.

What CGM changes

Better glucose data, better outcomes.

Significantly improved HbA1c
Increased Time in Range (TIR)
Reduced severe hypoglycemia
Reduced glucose variability
Fewer diabetic ketoacidosis (DKA) episodes
Lower long-term complication risk

Confirmed in randomised trials and in national registries — the Swedish NDR and the German/Austrian DPV registry both show lower HbA1c and fewer severe hypoglycaemic events among CGM users.

The trials

Citation-ready claims.

Randomised trialC03

+3.6 hours a day in range

In MOBILE, adults with type 2 diabetes using basal insulin but not mealtime insulin gained about 3.6 more hours per day in range and a 0.4 percentage-point greater HbA1c reduction with CGM at 8 months.

Population: 175 US adults, HbA1c 7.8–11.5%, basal insulin without prandial insulin

Martens et al., JAMA 2021;325(22):2262–2272

Randomised trialC04

−0.6 points HbA1c at 16 weeks

In FreeDM2, UK adults using basal insulin alongside SGLT2- or GLP-1-based therapy had a 0.6 percentage-point greater HbA1c reduction with CGM at 16 weeks; the difference was 0.5 points at 32 weeks.

Population: 303 UK adults with suboptimal control on basal insulin plus newer therapies

Wilmot et al., Lancet Diabetes Endocrinol 2026;14(6):463–474

Randomised trialC13

43% less time below 70 mg/dL

In REPLACE, adults with type 2 diabetes on intensive insulin therapy spent 43% less time below 70 mg/dL with flash CGM than with finger-prick monitoring at 6 months — about 28 fewer minutes per day.

Population: 224 adults with type 2 diabetes on intensive insulin at 26 European centres

Haak et al., Diabetes Ther 2017;8(1):55–73

Meta-analysisC05

Benefit without insulin

A 2024 meta-analysis of six trials in people with type 2 diabetes not using insulin found an average 0.31 percentage-point HbA1c improvement and about 2.1 more hours per day in range with CGM.

Population: 407 participants, six short RCTs, non-insulin-treated type 2

Ferreira et al., Diabetes Technol Ther 2024;26(4):252–262

Beyond insulin

The evidence isn't only for insulin users anymore.

Reimbursement still draws its line at insulin. The science has moved past that line — modest but consistent glycemic gains, and much larger behavioural ones.

−0.29%

HbA1c reduction

Non-insulin subgroup — 12 RCTs, n=1,248 (I²=0%).

+6.4%

Time in Range

Same meta-analysis — CGM vs finger-prick.

75%

changed behaviour

2SENSE participants, after 14 days of wear.

Jancev et al., Diabetologia (2024) — doi.org/10.1007/s00125-024-06107-6

Economic evidence

Cost-effective, even at higher upfront cost.

United Kingdom

+0.731 QALYs at an ICER of £3,684/QALY — well below the NHS threshold.

France

+0.47 QALYs, cost-effective despite higher upfront cost, driven by fewer complications.

Denmark

+1.37 QALYs, with a >99% probability of being cost-effective.

Sweden

Lower DKA and kidney-complication costs alongside QALY gains.

The message for policymakers is the same everywhere: complications consume most of the spending, and prevention costs less than rescue. CGM should be assessed as a long-term investment, not a device line item.

Where the evidence stops

The claims we refuse to make.

Current randomised evidence does not establish that CGM reduces long-term microvascular complications, macrovascular events or mortality in type 2 diabetes.
Claims-database cost and hospitalisation figures are before-and-after associations from manufacturer-funded analyses, not proof of causal savings.
Health-economic figures are model estimates under stated assumptions — they do not observe savings in any specific health system.
Survey findings describe the people who answered. They are not population estimates, and they are not clinical outcomes.
Most of this evidence base is type 2 diabetes. Type 1, gestational and other groups need their own evidence streams.

For people without diabetes — the "wellness CGM" market — the evidence base is thin. Marketing has run ahead of the science. Our ask is targeted care, not a sensor on every arm.

Access & reimbursement

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