Effect of HbA1c on Stroke Risk Among Patients With Diabetes and Atrial Fibrillation

A team of investigators sought to identify the effect of glycemic control on risk for stroke among patients with atrial fibrillation.

Glycated hemoglobin (HbA1C) was found to be associated with risk for stroke in a dose-dependent manner among patients with diabetes and comorbid atrial fibrillation, according to the results of a study published in the American Journal of Cardiology.

Data for this historical cohort study were sourced from the Clalit Health Services database of electronic medical records from Israel. Patients (N=44,451) who were diagnosed with nonvalvular AF between 2010 and 2016 and had comorbid diabetes (n=17,753) were followed through 2017 to identify incidence rates of ischemic stroke and all-cause mortality. Patients were stratified according to HbA1c value: low (<7%; n=8818), intermediate (7% to <9%; n=5677), and high (≥9%; n=1686).

Compared with individuals with low HbA1C, those with high HbA1C were younger and had lower socioeconomic status, and more were of Arab ethnicity.

The incidence rates of ischemic stroke were 1.90, 2.37, and 2.72 per 100 person-years and all-cause mortality rates were 14.27, 13.61, and 14.45 per 100 person-years among the low, intermediate, and high HbA1C cohorts, respectively.

After adjusting for age, gender, socioeconomic status, body mass index, estimated glomerular filtration rate, comorbidities, use of medications, and mortality, risk for ischemic stroke was increased among the intermediate (adjusted hazard ratio [aHR], 1.32; 95% CI, 1.12-1.56) and high (aHR, 1.69; 95% CI, 1.32-2.16) HbA1C cohorts compared with the low HbA1C group.

Risk for all-cause mortality was elevated among the high HbA1C cohort (aHR, 1.17; 95% CI, 1.07-1.28) but not the intermediate HbA1C group (aHR, 1.02; 95% CI, 0.96-1.08).

This study may have been limited by missing data as 8.8% of the patients with diabetes did not have HbA1C information available before the index atrial fibrillation diagnosis.

The study authors concluded that “in this observational cohort of patients with incident nonvalvular [atrial fibrillation], HbA1c levels were associated with an increased risk of stroke in a dose-dependent manner even after accounting for other recognized risk factors and the use of oral anticoagulation. Whether intensive glucose control would decrease the frequency of stroke and death in patients with [atrial fibrillation with diabetes mellitus] beyond that offered by oral anticoagulant treatment, as seen in patients with coronary artery disease and [diabetes mellitus], awaits further testing in randomized controlled trials.”

Disclosure: This research was supported by Pfizer. 


Kezerle L, Haim M, Akriv A, et al. Relation of hemoglobin A1C levels to risk of ischemic stroke and mortality in patients with diabetes mellitus and atrial fibrillation. Am J Cardiol. Published March 29, 2022. doi:10.1016/j.amjcard.2022.02.024

This article originally appeared on Endocrinology Advisor