Isolated post-challenge hyperglycaemia and risk of cardiovascular events: Tehran Lipid and Glucose Study

Abstract

Objective: To evaluate the risk of cardiovascular events in diabetes defined by isolated post-challenge hyperglycaemia (IPH). Methods: We followed 3794 subjects aged ≥40 years without known history of diabetes or cardiovascular disease (CVD) at baseline for CVD events. Participants were categorized as subjects without diabetes [fasting plasma glucose (FPG) < 126 mg/dL and 2-h post-challenge plasma glucose (2-hPG) < 200 mg/dL], IPH (FPG < 126 mg/dL and 2-h PG ≥ 200 mg/dL) and fasting hyperglycaemia (fasting blood glucose (FBS) ≥ 126 mg/dL). Hazard ratios (HRs) were calculated with the use of Cox proportional-hazards regression models to evaluate the risk of CVD events. Results: At baseline, of 486 subjects with newly diagnosed diabetes, 190 (39%) had IPH. Over the next 8 years, age and sex-adjusted HR for incident CVD was 1.77 (95% confidence interval (CI): 1.19–2.64; p = 0.005) in subjects with IPH compared with subjects without diabetes. After further adjustment for potential confounders, the HR for CVD was not significant [1.32 (95% CI: 0.88–1.99; p = 0.2)]. Conclusions: IPH in middle-aged adults adds nothing for identifying CVD risks when other risk factors are taken into account. Associated metabolic risk factors seem to be more important than hyperglycaemia per se.