HbA1c is closely related to the risk of cardiovascular events

A retrospective analysis of more than 29000 U.S. patients found that patients with type 2 diabetes mellitus (T2DM) with similar overall levels of glycosylated hemoglobin (HbA1c) had significantly higher risk of cardiovascular disease (CVD) events than patients with type 2 diabetes mellitus (T2DM). Therefore, the authors suggest that HbA1c fluctuation in a specific period of time (e.g. 6 months to 1 year) should be taken as a supplementary target for blood glucose monitoring. 

The studys authors, Shen and colleagues from Pennington biomedical research center, included data from more than 100000 T2DM patients collected in the Louisiana experiment assessing diabetes outcomes (lead) study.

Excluding patients with CVD history and less than 4 HbA1c measurements in the first 2 years after diabetes diagnosis, 29260 patients were included for analysis. In the two years between the diagnosis of diabetes and the admission to the study, patients took an average of nine HbA1c measurements.

The main outcome of the study was CVD events (including coronary heart disease and stroke). During an average follow-up of 4 years, 3746 patients had CVD events. The researchers calculated the fluctuation level of A1c in each patient and then evaluated the correlation between the two.

Since there is "no standardized definition of HbA1c volatility", researchers have applied three different statistical methods to evaluate volatility, all of which produce consistent and statistically significant results.

Taking the basic standard deviation analysis as an example, after adjusting for multiple potential confounding factors, the incidence of CVD events in the quartile with the highest volatility of HbA1c was significantly higher than that in the quartile with the lowest incidence of HbA1c by 59%.

In addition, the incidence of CVD events increased steadily with the increase of HbA1c volatility. In general, after adjusting for confounding factors, the risk of CVD events increased significantly by 18% for each unit of HbA1c standard deviation.

"This study shows that monitoring the fluctuation of HbA1c in a specific period of time can be used as a supplement to the target of blood glucose. In clinical practice, it is recommended to adopt treatment methods that can reduce the fluctuation of HbA1c and reduce hypoglycemic events," the authors said