Prevalence of abnormal glucose tolerance following a transient ischemic attack or ischemic stroke

Background: Despite current preventive therapies, patients with transient ischemic attack (TIA) and ischemic stroke remain at high risk for recurrent brain disease and cardiovascular events. In an effort to develop new therapies, abnormal glucose tolerance has recently been proposed as an interventional target. Among persons not otherwise known to be diabetic, impaired glucose tolerance (IGT) and diabetic glucose tolerance (DGT) are each associated with an increased risk for incident vascular disease, vascular disease mortality, and all-cause mortality. We conducted this study, to determine if IGT and DGT are sufficiently common among patients with TIA and ischemic stroke to warrant therapeutic trials of antihyperglycemic agents. Methods: Men and women older than 45 years were recruited from 3 hospitals in south central Connecticut. Eligibility, criteria included a recent TIA or nondisabling ischemic stroke, no history of physician-diagnosed diabetes mellitus, and a fasting plasma glucose level less than 126 mg/dL (< 7.0 mmol/L). After an overnight fast, subjects were admitted to a clinical research center for a standard 75-g oral glucose tolerance test. Impaired glucose tolerance was defined by a 2-hour plasma Glucose value of 140 to 199 mg/dL (7-8-11.0 mmol/L) and DGT by a value of 200 mg/dL or greater (greater than or equal to 11.1 mmol/L). Results: Between June 2000 and August 2003, we enrolled 98 eligible patients. The average time from TLA or stroke to measurement of glucose tolerance was 105 days (range, 24-180 days) and the median age was 71 years. Twenty-seven subjects (28%) had IGT and 24 (24%) had diabetes. In a forward stepwise logistic regression model, only a fasting plasma glucose level of 110 mg/dL or greater (greater than or equal to 6.1 mmol/L) and lower waist circumference were associated with an increased risk for IGT or DGT. Conclusions: Impaired glucose tolerance and DGT are present in most persons with a recent TIA or ischemic stroke who have no history of diabetes and a fasting plasma glucose level less than 126 mg/dL (< 7.0 mmol/L). Our findings bring new urgency to the initiation of research to examine the effectiveness of antihyperglycemic therapies among patients with cerebrovascular disease and abnormal glucose tolerance.