Higher Fasting Insulin Tracked With Worsening Heart Function

Originally surfaced August 10, 2026, drawing on a Circulation: Heart Failure research article published the same day.

A new community cohort study found that higher fasting insulin and insulin resistance were associated with worsening diastolic heart function over four years. The paper asks whether metabolic dysfunction may affect the heart before overt hyperglycemia becomes the whole story.

That makes this a useful cardiometabolic finding, but not a new heart-failure screening rule. The study was observational. It shows that the markers traveled with later heart dysfunction and mortality risk, not that a high fasting insulin result caused either outcome.

What the researchers measured

The investigators analyzed 1,191 participants in the Olmsted County Heart Function Study. Their median age was 58.7 years. Participants had echocardiograms at baseline and again four years later, while fasting insulin and the homeostatic model assessment of insulin resistance, commonly called HOMA-IR, were assessed at baseline.

Diastolic dysfunction progression occurred in 7.5% of participants. After adjustment for age, creatinine, and NT-proBNP, each one-standard-deviation increase in log-transformed fasting insulin was associated with 65% higher odds of progression. The adjusted odds ratio was 1.65, with a 95% confidence interval of 1.33 to 2.07. HOMA-IR produced a similar adjusted odds ratio of 1.66.

The researchers also evaluated longer-term outcomes in 2,030 participants. Follow-up was a median 10.97 years for heart failure and 18.1 years for mortality. In the abstract's secondary analyses, each one-standard-deviation increase in insulin was associated with an 11% higher hazard of death from any cause and a 16% higher hazard of cardiovascular death. HOMA-IR produced similar estimates.

Those are adjusted population-level associations. They are not personal risk percentages and should not be applied to a single lab result.

Why the heart-function detail matters

Diastolic dysfunction means the heart has trouble relaxing and filling normally. It can precede heart failure with preserved ejection fraction, a form of heart failure in which the heart's pumping percentage may look normal even while filling pressures and symptoms become abnormal.

The study's result supports a possible metabolic link, but the design cannot establish the biological sequence by itself. Echocardiography, symptoms, medical history, blood pressure, kidney function, body composition, medication use, and other factors still shape the clinical picture.

Where fasting insulin fits

A fasting insulin test measures insulin after a fasting period. The study also used HOMA-IR, a calculated index that combines fasting insulin with fasting glucose. A fasting insulin result by itself is not HOMA-IR, and neither one is a stand-alone diagnosis of insulin resistance, diastolic dysfunction, or heart failure.

An A1c test answers a different question by estimating average blood glucose over roughly two to three months. The new paper is interesting precisely because its fasting-insulin signal was not interchangeable with a glucose-average result.

For self-pay testing, the defensible use is context. A measured fasting insulin value can add another data point to a metabolic discussion. It cannot replace an echocardiogram, diagnose a cardiac condition, or decide whether treatment is needed.

What not to overread

This study does not show that everyone should order fasting insulin to estimate heart-failure risk. It does not establish a universal fasting-insulin cutoff, prove that lowering insulin prevents diastolic dysfunction, or show that a normal A1c rules out the pattern the researchers observed.

The clean takeaway is narrower: in this community cohort, higher fasting insulin and insulin resistance were associated with worsening diastolic function and higher long-term mortality risk. That is a strong reason for more prospective research and a weak reason for anyone to treat one insulin result as a cardiac forecast.

This article is editorial commentary and is not medical advice. It has not been reviewed by a physician and should not be used to make decisions about insulin-resistance diagnosis, heart-failure evaluation, diabetes care, medication, or testing frequency.