Diabetes is a risk factor for both incident and recurrent stroke. Stroke etiology in persons with diabetes is similar to that in the general population and is often associated with large artery atherosclerosis, cardioembolism, and cerebral small vessel disease. A unique feature of stroke in persons with diabetes is that they tend to have more subclinical strokes and different magnetic resonance imaging characteristics of stroke, including more white matter hyperintensities, lacunar infarcts, and other evidence of small vessel disease in the brain. Standard vascular risk factors, including hypertension, smoking, dyslipidemia, and atrial fibrillation, increase the risk of stroke among individuals with both type 1 and 2 diabetes, and treatment of hypertension is a cornerstone of stroke prevention in persons with diabetes. Diabetes-specific stroke risk factors include hyperglycemia, glycemic variability, metabolic syndrome and insulin resistance, albuminuria, and diabetic retinal diseases. Other predictors of stroke risk among persons with diabetes include proteomic biomarkers, obstructive sleep apnea, and autonomic neuropathy.
While epidemiologic studies have found an association between hyperglycemia and stroke risk, randomized clinical trials of intensive glycemic control have not demonstrated a reduction in stroke risk. However, specific glycemic control agents, including the glucagon-like peptide-1 analogues semaglutide and dulaglutide, have been shown to reduce stroke risk in high-risk persons with type 2 diabetes. Further, a thiazolidinedione has been shown to reduce risk of recurrent stroke among persons with type 2 diabetes (PROactive trial) and to prevent recurrent cardiovascular disease events in patients with recent stroke or transient ischemic attack with insulin resistance but not diabetes. Diabetes is associated with higher post-stroke mortality and worse neurologic and functional outcomes, although results have not been consistent across all studies. Despite higher degree of hyperglycemia being associated with worse outcomes in epidemiologic studies, intensive glucose control following an acute ischemic stroke has not been shown to improve outcomes compared with standard glucose control.