Associations between glycated haemoglobin and multi-modal imaging markers of early cardiac aging

Background: Glycated haemoglobin (HbA1c) is a well-established biomarker for diabetes diagnosis and management and is linked to risk of cardiovascular death. However, among adults without cardiovascular disease (CVD) and diabetes, the value of HbA1c in predicting distinct signatures of myocardial ageing has not been explored.

Methods: Subjects, from among older adults without CVD, underwent comprehensive cardiovascular and metabolic assessment. Transthoracic echocardiography measured left ventricular structure and function. Longitudinal left atrial (LA) strain comprising reservoir strain (Ɛs), conduit strain (Ɛe) and booster strain (Ɛa) and their corresponding peak strain rates (SRs, SRe, SRa) were measured using cardiac magnetic resonance (CMR). Blood sampling for biomarkers and cardiovascular examinations were performed.

Results: 247 subjects (mean age 71 years, 44.1% female, mean HbA1c 6.0%) were included. HbA1c was significantly associated with E/A ratio (p < 0.0001), conduit strain (Ɛe) (p < 0.0001), conduit strain rate SRe (p < 0.0001), and conduit strain rate to booster strain rate SRe:SRa ratio (p < 0.0001). Multivariate models adjusting for clinical variables such as body mass index, blood pressure, heart rate, diabetes mellitus, smoking, and associated cardiac parameters, demonstrated a persistent independent association. Each unit increase in HbA1c was associated with lower E/A ratio, lower Ɛe, higher SRe and lower SRe:SRa ratio. These associations remained significant after diabetic subjects were excluded.

Conclusion: Distinct associations were found between HbA1c and myocardial functions of interest in the ageing heart. HbA1c may be useful biomarker for stratifying risks associated with myocardial ageing, independent of diabetes status.

Trial registration: ClinicalTrials.gov Identifier: NCT02791139.