Peripheral glucose levels and cognitive outcome after ischemic stroke: Results from the Munich Stroke Cohort

Introduction: The relationship between glucose metabolism and stroke outcome is likely to be complex. We examined whether there is a linear or non-linear relationship between glucose measures in the acute phase of stroke and post-stroke cognition, and whether altered glucose metabolism at different time intervals (long- and short-term before stroke, acute phase) is associated with cognitive outcome. Patients and methods: In all, 664 consecutively recruited patients with acute ischemic stroke and without pre-stroke dementia were included in this prospective observational study. Blood samples were taken at admission and fasting on the first morning after stroke. Duration of diabetes was assessed by interview. Cognitive outcome was assessed by the Telephone Interview for Cognitive Status 3 months post-stroke. Dose-response analyses were used to investigate non-linearity. Regression analyses were stratified by diabetes status and adjusted for relevant confounders. Results: Cognitive status was testable in 422 patients (81 with diabetes). There was a non-linear relationship between both admission and fasting glucose levels and cognitive outcome. Lower glucose values were significantly associated with lower Telephone Interview for Cognitive Status scores 3 months post-stroke in patients without diabetes with a similar trend in diabetic patients. There was an inverse association between duration of diabetes and Telephone Interview for Cognitive Status scores (linear regression: −0.10 (95% confidence interval: −0.17 to −0.02) per year increase of diabetes duration), whereas HbA_1c was not related to cognitive outcome. Results were supported by sensitivity analyses accounting for attrition. Conclusion: Lower glucose levels in the acute phase of stroke are associated with worse cognitive outcome but the relationship is non-linear. Long-term abnormalities in glucose metabolism are also related to poor outcome but this is not the case for shorter term abnormalities. Altered glucose levels at different stages of stroke may affect stroke outcome through different pathways.