Impact of completeness of ascertainment of minor stroke on stroke incidence: implications for ideal study methods.

Background and Purpose— Reliable comparisons of stroke incidence are important. To determine the impact of systematic assessment of patients referred with transient ischemic attack on the measured incidence and severity of stroke, we compared 2 population-based studies. Methods— Patients with first-ever stroke ascertained during 2006 through 2010 from the Dijon Stroke Registry and the Oxford Vascular (OXVASC) Study were studied. Both studies comply with the criteria for ideal incidence studies, but the OXVASC Study also systematically assessed all patients referred with transient ischemic attack. Stroke severity was measured by the National Institutes of Health Stroke Scale. Results— Among…