Time above 140 mg/dL on CGM tracked with cardiovascular risk in people without diabetes

Design

Cross-sectional analysis within the Framingham Heart Study, blinded CGM

Population

1,356 adults without diabetes or cardiovascular disease, mean age 59

Primary outcome

10-year PREVENT cardiovascular risk and cardiometabolic risk factors

Effect

Per 1 SD more time >140 mg/dL: +2% PREVENT risk, 21–26% higher odds of hypertension and dyslipidaemia

Framingham investigators fitted blinded Dexcom G6 Pro sensors for up to ten days in 1,356 participants without diabetes or cardiovascular disease (mean age 59, 93% non-Hispanic White). They related CGM measures and data-driven glycaemic profiles to 10-year PREVENT cardiovascular risk and individual risk factors.

Each one-standard-deviation increase in time spent above 140 mg/dL (about 15 percentage points of the day) was associated with a 2% higher PREVENT risk estimate and 21–26% higher odds of hypertension and dyslipidaemia, after adjusting for fasting glucose. Profiles with more CGM dysglycaemia did not map neatly onto prediabetes defined by fasting glucose and HbA1c, and were associated with 6–7% higher risk estimates.

This is cross-sectional and the outcome is a modelled risk score, not events. It says that CGM sees something HbA1c does not; it does not show that acting on it helps. It is a reason to take a high time-above-range seriously when a patient has already worn a sensor, not a reason to put sensors on people without diabetes.

• Do not use CGM to screen people without diabetes; this study does not support it.
• If a patient without diabetes shows you consumer CGM data with frequent excursions above 140 mg/dL, check blood pressure and lipids.
• A normal HbA1c does not rule out meaningful post-meal dysglycaemia.
• The cohort was 93% White; South Asian glycaemic patterns may differ and were not studied.

Why it matters

Patients are arriving with consumer CGM traces, and this gives a reason to look at their blood pressure and lipids rather than dismiss the data.

Don't overread it

This was a cross-sectional association with a modelled risk score — it cannot show that CGM-guided care prevents events.

The statistics, in plain English

The 2% figure is a relative increase in an estimated 10-year risk, so for someone at 10% it means about 10.2%, not 12%. The 21–26% higher odds of hypertension are more noticeable, but odds ratios overstate risk when the condition is common.

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