Two-hour post-challenge glucose is a better predictor of adverse outcome after myocardial infarction than fasting or admission glucose in patients without diabetes

We evaluate prevalence of new abnormal glucose tolerance (AGT) in post-MI survivors without known diabetes (DM) if guidelines are followed and compare the ability of admission (APG), fasting (FPG) and 2-h post-load plasma glucose (2h-PG) to predict prognosis.

A total of 674 patients were followed up for 4 years for incidence of major adverse cardiovascular events (MACE) of cardiovascular death, non-fatal re-infarction or non-haemorrhagic stroke. Ability of models including APG, FPG and 2h-PG to predict MACE was compared.

Of the total, 93–96% of impaired glucose tolerance and 64–75% of DM would be missed with current guidelines. MACE was higher in the upper quartiles of 2h-PG. When 2h-PG and FPG were included simultaneously in models, only 2h-PG predicted MACE (HR 1.12, CI 1.04–1.20, p = 0.0012), all cause mortality (HR 1.17, CI 1.05–1.30, p = 0.0039), cardiovascular mortality (HR 1.17, CI 1.02–1.33, p = 0.0205) and non-fatal MI (HR 1.10, CI 1.01–1.20, p = 0.0291). Adding 2h-PG significantly improved ability of models including FPG (χ² = 16.01, df = 1, p = 0.0001) or FPG and APG (χ² = 17.36, df = 1, p = 0.000) to predict MACE. Model including 2h-PG only had the lowest Akaike’s information criteria and highest Akaike weights suggesting that this was the best in predicting events. Adding 2h-PG to models including FPG or APG with other co-variates yielded continuous net reclassification improvement (NRI) of 0.22 (p = 0.026) and 0.27 (p = 0.005) and categorical NRI of 0.09 (p = 0.032) and 0.12 (p = 0.014), respectively. Adding 2 h-PG to models including only FPG, only APG and both yielded integrated discrimination improvement of 0.012 (p = 0.015), 0.022 (p = 0.001) and 0.013 (p = 0.014), respectively.

AGT is under-diagnosed on current guidelines. 2h-PG is a better predictor of prognosis compared to APG and FPG.