Abstract 14410: Hemoglobin A1c and Major Adverse Cardiovascular Events in the VA Million Veteran Program: Evidence-Based Recommendation for Life’s Essential Eight Improvement

Abstract

Background: The American Heart Association (AHA) recently proposed the Life’s Essential 8 (LE8) score as an enhanced measurement tool for cardiovascular health. For the blood glucose metric in LE8, persons with diabetes mellitus (DM) and a hemoglobin A1c (HbA1c) <7% receive higher points (40 out of 100) and successively fewer with increasing HbA1c. However, some studies have found that having a HbA1c <6% in DM patients was associated with a higher risk of mortality, especially cardiovascular (CVD) death. Aim: We sought to categorize DM with HbA1c <7% into two groups (<6% vs . 6-6.9%) and compare their associations with risk for a major adverse cardiovascular event (MACE) to better inform DM HbA1c cut points and LE8 scoring. Methods: Prospective cohort study of 213,760 Veterans enrolled in the VA Million Veteran Program (MVP) (2011-2021) who had a HbA1c measurement and were free of 5 point-MACE (fatal CVD, non-fatal myocardial infarction [MI], non-fatal stroke, non-fatal heart failure and non-fatal atrial fibrillation [Afib]) at baseline. Results: During a mean follow-up of 4.9 years, we identified 38,151 instances of MACE, including 9,665 MI, 2,837 stroke, 5,523 fatal CVD, 16,543 heart failure, and 18,114 Afib. Compared to diabetic patients with HbA1c of 6-6.9%, diabetic patients with a very low HbA1c level (<6%) had significantly higher risk of MACE [Hazard Ratio (HR): 1.15; 95%CI: 1.09-1.21], which was comparable to diabetic patients with HbA1c of 7-7.9% [HR: 1.14 (95%CI: 1.09-1.18)]. Similar results were observed for the associations between HbA1c and risk for stroke, heart failure, Afib and fatal CVD (Figure 1). Conclusions: Our results confirm previous findings that a very low HbA1c level among diabetic patients was associated with a higher risk for MACE. Based on our findings, we suggest further categorization of diabetic patients with HbA1c below 7% (i.e., <6% and 6-6.9%) and subsequent adjustment in LE8 scoring (i.e., from 40 to 30 points) for HbA1c.