Background and purpose: We examined the impact of hyperglycemia on ischemic and hemorrhagic stroke incidence comparing criteria based on fasting plasma glucose (FPG) and 2-hour plasma glucose (2-hour PG).
Methods: Data from 9 European cohorts comprising 18 360 individuals between 25 to 90 years of age were collaboratively analyzed. The maximum length of follow-up varied between 4.9 to 36.8 years. Hazards ratios (95% confidence intervals) for stroke incidence were estimated using Cox-proportional hazards model adjusting for known risk factors.
Results: In individuals without a prior history of diabetes, the multivariate-adjusted hazards ratio for ischemic stroke corresponding to 1 SD increase in FPG was 1.12 (1.02 to 1.22) and in 2-hour PG 1.14 (1.05 to 1.24). Adding 2-hour PG to the model with FPG significantly improved the prediction of the model for the incidence of ischemic stroke (chi(2)=4.72, P=0.03), whereas FPG did not improve the 2-hour PG model prediction (chi(2)=0.25, P=0.62). A significantly increased hazard ratio was also observed for previously diagnosed diabetes (2.26 [1.51 to 3.38]) and for screen-detected diabetes defined by FPG (1.48 [1.08 to 2.02]) and 2-hour PG (1.60 [1.18 to 2.16]). None of the criteria predicted hemorrhagic stroke.
Conclusions: Diabetes defined by either of the criteria predicted the future risk of ischemic stroke but not the hemorrhagic stroke. The prediction is stronger for elevated 2-hour PG than for FPG levels.