Differences in vascular risk factors between etiological subtypes of XXXX : importance of population-based studies.

@entity1 @entity64 @entity101 @entity6 @entity165 @entity385
BACKGROUND: To understand the mechanisms of @entity64 and to target prevention, we need to know how risk factors differ between etiological subtypes. Hospital-based studies may be biased because not all @entity64 @entity1 are admitted. If risk factors differ between @entity1 who are admitted and those who are not, then case-control studies will be biased. If the likelihood of admission also depends on @entity64 subtype, then case-case comparisons may also be biased. METHODS: We compared risk factors and @entity385 subtypes (TOAST classification) in hospitalized and nonhospitalized @entity1 in 2 population-based @entity64 incidence studies: the Oxford Vascular Study (OXVASC) and Oxfordshire @entity64 Project (OCSP). We also performed a meta-analysis of risk factor- @entity64 subtype associations with other published population-based studies. RESULTS: In OXVASC and OCSP, @entity64 subtypes differed between hospitalized (293 of 647) and nonhospitalized @entity1 (P<0.0001), with more @entity64 (odds ratio [OR], 1.8; 95% CI, 1.3 to 2.6) and fewer @entity64 (OR, 0.4; 95% CI, 0.3 to 0.7). Premorbid blood pressure and @entity165 were higher in hospitalized @entity1 (both P<0.0001). Risk factor- @entity64 subtype associations in hospitalized @entity1 were consequently biased (P=0.001). Meta-analysis of data from all @entity1 in OXVASC, OCSP, and 2 other studies demonstrated consistent risk factor- @entity64 subtype associations. However, contrary to previous hospital-based studies, there was only a weak (OR, 1.4; 95% CI, 1.1 to 1.8) and inconsistent (P(heterogeneity)=0.01) association between small-vessel @entity64 and @entity101 and no association with @entity6 (OR, 1.0; 95% CI, 0.7 to 1.3). CONCLUSIONS: Prevalences of risk factors and @entity64 subtypes differ between hospitalized and nonhospitalized @entity1 with @entity385 , which may bias hospital-based risk factor studies. Meta-analysis of population-based studies suggests that vascular risk factors differ between @entity64 subtypes.
