Among adults with diabetes, HbA1c showed a consistent positive association with prevalent CVD across population-based (NHANES) and clinical cohorts, whereas the associations of FBG and TyG were less consistent.
HbA1c was independently associated with higher odds of prevalent CVD in the NHANES population-based cohort of adults with diabetes.
HbA1c was also independently associated with higher odds of prevalent CVD in the Chinese clinical cohort, with a larger effect size than in NHANES.
Fasting blood glucose (FBG) and the triglyceride-glucose (TyG) index were not significantly associated with prevalent CVD in fully adjusted logistic regression models.
Restricted cubic spline analyses showed different HbA1c–CVD dose-response shapes in the two cohorts.
TyG showed a significant nonlinear association with prevalent CVD in the NHANES cohort despite the lack of a significant association in the linear fully adjusted model.
Subgroup analyses did not show consistent evidence of effect modification of the glycemic biomarker–CVD associations across demographic and clinical characteristics.
The authors conclude that HbA1c, as a measure of long-term glycemic status, is relevant to prevalent CVD in diabetes, and that longitudinal studies are needed to clarify temporal relationships.
This study looked at whether three common blood-sugar-related measures were linked to existing heart and blood vessel disease in people with diabetes. The measures were fasting blood glucose (a snapshot of blood sugar), HbA1c (a marker of average blood sugar over the past two to three months), and the triglyceride-glucose index (a marker related to insulin resistance). Researchers analyzed two groups: about 3,400 U.S. adults with diabetes from a national health survey, and about 765 hospitalized patients with diabetes in China. In both groups, higher HbA1c was linked to higher odds of having cardiovascular disease, even after accounting for other factors such as age and other health characteristics. The link was modest in the U.S. survey and stronger in the Chinese hospital group. Fasting glucose and the triglyceride-glucose index did not show a clear, consistent link after adjustment. The shape of the relationship also differed, with some evidence that it was not a straight line in the hospital group. This research suggests HbA1c, which reflects longer-term blood sugar, may be more closely tied to cardiovascular disease in people with diabetes than a single fasting glucose reading. However, because the data were collected at a single point in time, the study cannot show that high HbA1c causes heart disease or that it comes first. Studies that follow people over time are needed to clarify this.
Zhang L, Liu M, Zhang Y, Zhao L, Liu Y, Wang R, et al.. (2026). Glycemic biomarkers and cardiovascular disease in diabetes: a comparative analysis of population-based and clinical cohorts.. Frontiers in endocrinology. https://doi.org/10.3389/fendo.2026.1995413