Relationship of initial glucose level and all-cause death in patients with ischaemic stroke: the roles of diabetes mellitus and glycated hemoglobin level

Background and purpose: Previous studies demonstrated that post-stroke hyperglycemia was associated with poor outcome in non-diabetic patients. However, evidence was inconclusive amongst patients with diabetes. The aim of this study was to evaluate the relationship between initial glucose levels and mortality amongst patients with acute ischaemic stroke, and further, to assess whether the association varied by diabetes mellitus and glycated hemoglobin (HbA1c) levels. Methods: Data were collected from the medical records of 1277 first-ever stroke patients admitted to the emergency room between January 1, 2008 and June 30, 2009. Cox regression analysis was performed to assess the relationship between initial glucose level and mortality. Results: Compared with the lowest quartile of initial glucose level, a significant association with all-cause death [hazard ratio (HR), 2.18; 95% CI, 1.363.48] and cardiovascular death (HR, 1.91; 95% CI, 1.013.61) was seen in the highest quartile. In non-diabetic subgroup, those patients within the highest quartile of initial glucose level had a 3.29-fold relative risks (RR) [95% confidence interval (CI), 1.626.68] for all-cause and a 2.54-fold RR (95% CI, 1.438.77) for cardiovascular death compared with those within the lowest quartile. However, the association between initial glucose levels and the risk of death was not significant amongst those with diabetes (P for interaction = 0.01). In addition, the risk amongst patients with diabetes varied by the HbA1c levels. Conclusions: A significant association was confirmed between initial glucose level and mortality in non-diabetic ischaemic stroke patients. The possible relationship between initial glucose level, HbA1c level, and mortality amongst ischaemic stroke patients with diabetes warrants further research.