Is pre-diabetes a predictor of events in patients with atrial fibrillation?

Background: Diabetes mellitus (DM) increases the probability of presenting atrial fibrillation (AF) and it is a predictor of its ischemic stroke. There is limited information of the association between glycated hemoglobin (HbA1c) levels and ischemic, embolic or bleeding events in patients with pre-DM and AF.

Methods: To investigate whether the presence of pre-DM in patients with AF predicts ischemic or bleeding events, myocardial infarction or mortality, we performed a retrospective study with a final cohort of 2993 non-diabetic patients with AF and data of glycated hemoglobin (HbA1c). We divided the cohort in two groups: those with normal glucose (n = 1351) and those with pre-diabetes (n = 1642). Incidence rates were calculated as the number of events per 100 person-years and were then compared between groups. Competitive hazard regression analysis for non-fatal events(death as the competing event) and conventional Cox regression for mortality were performed.

Results: There was not difference between groups for incidence rates of the different events per 100 person-years. Even considering HbA1c as continuous variable, the unadjusted analysis showed no relation between levels of HbA1c and more risk of events. This association remained not significant after adjustment for CHADS-VASc score, HAS-BLED score and anticoagulation therapy.

Conclusion: In this study of 2993 non-diabetic patients with new-onset AF, we have not found an association between HbA1c and worse prognosis when it is in the range of pre-diabetes.