Differences in Vascular Risk Factors Between Etiological Subtypes of Ischemic Stroke

Abstract

Background— To understand the mechanisms of stroke and to target prevention, we need to know how risk factors differ between etiological subtypes. Hospital-based studies may be biased because not all stroke patients are admitted. If risk factors differ between patients who are admitted and those who are not, then case-control studies will be biased. If the likelihood of admission also depends on stroke subtype, then case-case comparisons may also be biased. Methods— We compared risk factors and ischemic stroke subtypes (TOAST classification) in hospitalized and nonhospitalized patients in 2 population-based stroke incidence studies: the Oxford Vascular Study (OXVASC) and Oxfordshire Community Stroke Project (OCSP). We also performed a meta-analysis of risk factor–stroke subtype associations with other published population-based studies. Results— In OXVASC and OCSP, stroke subtypes differed between hospitalized (293 of 647) and nonhospitalized patients (P<0.0001), with more cardioembolic strokes (odds rati...