In nondiabetic patients with acute myocardial infarction (AMI), acute hyperglycemia is associated with high risk of cardiovascular (CV) mortality but the prognostic value of glycosylated hemoglobin (HbA1c) remains uncertain.

In a large observational study, we aimed to identify the prognostic values of admission HbA1c and plasma glucose for acute MI in nondiabetic patients regarding in-hospital and one-year CV mortality.

From the RICO survey database all the consecutive nondiabetic patients with AMI (n=6884) from January 2001 to June 2016 were included. Cut off levels (high/low) were determined by ROC curve analysis for the prediction of CV one-year death (HbA1c: 5.9% and glucose: 156mg/dL) to set up 4 groups: low HbA1c/low glucose (n=3849), low HbA1c/high glucose (n=734), high HbA1c/low glucose (n=1802) and high HbA1c/high glucose (n=499).

Elevation of glucose or HbA1c was associated with elevated rate of hospital mortality, when compared to all other groups (Fig. 1). By multivariate logistic regression analysis, only high glucose remains a prognostic factor of hospital death [OR(95% CI): 1.59 (1.16–2.17)]. In survivors at discharge, group with elevated levels of both plasma glucose and HbA1c had a higher rate of one-year CV mortality compared to all other groups (P<0.001). High HbA1c was an independent predictive factor of one-year CV mortality, beyond high glucose [OR(95% CI): 1.75 (1.35–2.27) and 1.98 (1.49–2.61), respectively] and covariates (Fig. 1).

In our large population-based study in nondiabetic patients with AMI, high levels of admission HbA1c and/or plasma glucose give different prognostic information and were associated with increased risk of mortality at short or long term. Early mortality risk was mainly driven by acute hyperglycemia and one-year mortality by HbA1c, independently of plasma glucose. Our findings may help identifying high-risk patients to target for aggressive secondary prevention after AMI.