Diabetes Mellitus

Ischemic stroke incidence is increased 2-6 fold in patients diagnosed with type 1 or type 2 diabetes mellitus compared to patients with normal glucose levels. In DM the body is unable to produce or respond properly to insulin. DM is defined as a fasting plasma glucose ≥ 126 mg/dL or HbA1c ≥ 6.5%. It is estimated that more than 10% of the adult U.S, population has diagnosed or undiagnosed diabetes. Even when glucose levels are considered “well controlled,” diabetes is associated with a 1-3 fold increased the risk of stroke in adults. Identifying and treating diabetic patients will significantly reduce their risk of many other vascular complications of diabetes. However, since diabetes puts these patients at high risk for stroke, it is particularly important to control any of their additional risk factors for stroke, such as blood pressure. In diabetic hypertensive individuals, aggressive treatment of hypertension has been associated with significant reduction in stroke risk.

Populations at special risk

In the U.S., there is a disproportionately high prevalence of diabetes among non-Hispanic blacks (almost twice as high as whites), and in Mexican Americans.

Relationship to stroke pathogenesis

Diabetes increases the risk of ischemic strokes through several interrelated mechanisms that favor (and accelerate) the formation of atherosclerotic plaque. In patients with diabetes, plaque is much more common in the smaller branches of cerebral arteries than in non-diabetics. The narrowing of these smaller vessels can directly increase the risk of stroke.