Chronic hyperglycemia and subclinical myocardial injury.

OBJECTIVES: The purpose of this study was to examine the association between hyperglycemia and subclinical myocardial injury in persons without clinically evident coronary heart disease (CHD).
BACKGROUND: Hyperglycemia is associated with an increased risk of cardiac events, but limited information is available on its relationship to subclinical myocardial damage. Elevated cardiac troponin T even below traditional detection levels can be detected by a novel high-sensitivity assay.
METHODS: We examined the association between baseline glycated hemoglobin (HbA1c) and high-sensitivity cardiac troponin T (hs-cTnT) in 9,661 participants free of CHD and heart failure in the ARIC (Atherosclerosis Risk in Communities) study. Multivariable logistic regression models characterized the association between clinical categories of HbA1c (<5.7%, 5.7% to 6.4%, and ≥6.5%) and our primary outcome of elevated hs-cTnT (≥14 ng/l).
RESULTS: Higher baseline values of HbA1c were associated in a graded fashion with elevated hs-cTnT (p for trend < 0.001). After adjusting for traditional risk factors, compared to persons with HbA1c <5.7%, the odds ratios of elevated hs-cTnT for persons with HbA1c 5.7% to 6.4% and ≥6.5% were 1.26 (95% confidence interval: 1.01 to 1.56) and 1.97 (95% confidence interval: 1.44 to 2.70), respectively.
CONCLUSIONS: Higher HbA1c is associated with elevated hs-cTnT among persons without clinically evident CHD, suggesting that hyperglycemia contributes to myocardial injury beyond its effects on development of clinical atherosclerotic coronary disease.