Using HbA1c may not alter the effectiveness of screening for cardiovascular disease risk among adults with prediabetes, although CVD risk is greater among this group vs. those with lower HbA1c levels, according to findings published in Diabetes Care.

“People with prediabetes are on average much heavier, have higher blood pressure and more abnormal lipids than those without — these factors lead such people to be at greater risk for cardiovascular disease much more so than their slightly raised sugar levels. However, prediabetes is a strong risk factor for incident diabetes,” Naveed Sattar, MD, PhD, professor of metabolic medicine at the University of Glasgow in the U.K., told Healio. “This is why when we adjust analysis for usual risk CVD factors, risk for cardiovascular disease in those with prediabetes is only minimally increased. In other words, this confirms that the independent effect of a slightly raised glucose into the prediabetes range on CVD is very modest indeed.”

Sattar and colleagues evaluated HbA1c levels and CVD events from the QRISK3 risk score, American College of Cardiology/American Heart Association (ACC/AHA) guideline and European Systematic Coronary Risk Evaluation, such as coronary heart disease, stroke and transient ischemic attack, across 8.9 years of median follow-up in a cohort of 357,833 adults with data in the UK Biobank. The researchers found that an HbA1c of between 6% and 6.4% was identified for 11,665 participants, who were categorized as having prediabetes (mean age, 59.7 years; 54.7% women), and an HbA1c of 6.5% or more was identified for 2,573 participants, who were categorized as having undiagnosed diabetes (mean age, 57.9 years; 41.1% women). The remaining 343,595 participants had an HbA1c of less than 6% (mean age, 56 years; 55.9% women).

The researchers wrote that 3.6% of adults experienced CVD events from the QRISK3 risk score assessment, 1.9% experienced CVD events from the ACC/AHA guideline and 0.5% experienced CVD events from the European Systematic Coronary Risk Evaluation.

Using HbA1c may not alter the effectiveness of screening for cardiovascular disease risk among adults with prediabetes, although CVD risk is greater among this group vs. those with lower HbA1c levels.

Source: Adobe Stock

CVD risk was 1.83 times greater for adults with prediabetes vs. those without prediabetes (HR = 1.83; 95% CI, 1.69-1.97) 2.26 times greater for those with undiagnosed diabetes vs. without diabetes (HR = 2.26; 95% CI, 1.96-2.6). However, the researchers noted that these calculations were made before adjustments; when adjustments were added CVD risk was 1.11 times greater for individuals with prediabetes (HR = 1.11; 95% CI, 1.03-1.2) and 1.2 times greater for individuals with undiagnosed diabetes (HR = 1.2; 95% CI, 1.04-1.38).

“The added predictive gain from inclusion of HbA1c in risk prediction was modest,” the researchers wrote.

“If someone is picked up in practice with prediabetes, they should have their other CVD risk factors measured as, on average, they will be around 10 kg heavier than average, have 6 mm Hg higher systolic blood pressure and have more abnormal lipids. All these abnormalities should be used as further incentives to people to make lifestyle changes to lessen their risks not only of diabetes but also of associated cardiovascular disease,” Sattar said. “In some, preventive medications might be needed, but in most cases, these should be reserved [for] after people are given a real chance to make lifestyle changes. How we help people with lifestyle changes is improving, but we can do even better with good training.”