Risk of Coronary Heart Disease in Different Criterion of Impaired Fasting Glucose: A Meta-Analysis

The cut-point for diagnosing impaired fasting glucose (IFG) had been dispute, as reports about the associated clinical events are inconsistent. This meta-analysis evaluated the risk of coronary heart disease (CHD) in association with different criterion of IFG according to the American Diabetes Association (ADA) or the World Health Organization (WHO) Expert Group. We included prospective cohort studies with multivariate-adjusted data on IFG and CHD for analysis. The relative risks (RRs) of CHD were calculated and reported with 95% confidence intervals (95% CIs). Seventeen prospective cohort studies, comprising 527,021 individuals were included. The risks of CHD were increased in both participants with IFG defined as the ADA or WHO criterion (RR 1.11, 95% CI 1.02–1.21; and RR 1.18, 95% CI 1.10–1.28, respectively). Subgroup analyses showed that in both definition of IFG, the risk of CHD was only increased in studies with possibility of enrolling patients with increased 2 hours plasma glucose (2-h PG), or in studies with inadequate adjustment, but not in studies excluded participants with increased 2-h PG or in those with adequate adjustment of other risk factors. Our meta-analysis demonstrates that the presence of IFG was significantly associated with future risk of CHD. The risk of CHD was increased when fasting plasma glucose was as low as 100 mg/dL according to the lower cut-point of IFG by the ADA criterion. However, the risk maybe confounded by the undetected increased 2-h PG or other cardiovascular risk factors.