Background and Purpose—The purpose was to assess the prevalence of disorders of glucose metabolism and insulin resistance in Japanese ischemic stroke patients with no history of diabetes by performing 75-gram oral glucose tolerance test (OGTT).

Methods—We recruited 427 ischemic stroke patients (atherothrombotic infarction, n=220; lacunar infarction, n=125; cardioembolic infarction, n=82). OGTT was used to evaluate disorders of glucose metabolism in stroke patients without previously known diabetes (n=113). We investigated the relationships among the prevalence of abnormal glucose metabolism, ischemic stroke subtypes, and the prevalence of insulin resistance using homeostasis model assessment for insulin resistance and immunoreactive insulin at 120 minutes after glucose loading (IRI₁₂₀).

Results—OGTT identified the presence of disorders of glucose metabolism in 62.8% of ischemic stroke patients without previously known diabetes, including diabetes (24.8%) and impaired glucose tolerance (lone impaired glucose tolerance and impaired fasting glucose plus impaired glucose tolerance, 34.5%). The prevalence of newly diagnosed diabetes and impaired glucose tolerance was the highest in the atherothrombotic infarction group (68.9%). The highest values of homeostasis model assessment for insulin resistance and immunoreactive insulin at 120 minutes after glucose loading were found in atherothrombotic infarction patients with abnormal glucose tolerance.

Conclusions—In this study, a significantly large percentage of Japanese patients with ischemic stroke and no history of diabetes were found to have disorders of glucose metabolism by OGTT. Impaired glucose tolerance and insulin resistance could play an important pathogenic role in the development of atherothrombotic infarction.