Abstract P381: Factor VIII and Incident Hypertension in Black and White Adults: The REasons for Geographic and Racial Differences in Stroke (REGARDS) Cohort Study

Abstract

Background: Black adults have a disproportionate hypertension burden. While some excess risk is mediated by diet and sociodemographics factors (e.g., income, education) much remains unexplained. Pro-thrombotic and pro-inflammatory states are associated with hypertension risk; higher coagulation factor VIII (FVIII) is associated with thrombosis, inflammation, and cardiovascular disease. Black adults have higher FVIII than White adults. We sought to estimate incident hypertension risk among Black and White REGARDS adults by FVIII level, and determine if FVIII mediates some of the excess hypertension burden in Black REGARDS participants. Methods: Hypertension was use of blood pressure (BP)-lowering medications or 140/90 mm Hg BP threshold. We included Black and White participants from REGARDS without Visit 1 (2003-2007) hypertension, and hypertension assessment at visit 2 (2013-2016), and Visit 1 ELISA-measured FVIII. Modified Poisson regression estimated risk ratios (RR) of incident hypertension by FVIII level in models controlling for known confounders, stratified by race given a significant race*FVIII interaction on incident hypertension. Inverse odds ratio weighting estimated % mediation of the Black-White hypertension risk in each model that was due to FVIII. Results: Among the 1,870 included participants, mean (SD) age was 62 (8), 51% were female and 36% were Black participants. Relative to White participants, Black participants had higher mean FVIII level (114% vs. 103%; P<0.001) and 46% greater hypertension risk (95% CI 30-65%) in the crude model. Higher FVIII did not associate with greater hypertension risk in any model ( Figure ). Factor VIII did not mediate excess burden of hypertension among Black participants in any models. Conclusions: FVIII was not associated with greater hypertension risk and did not mediate any of the excess burden of incident hypertension seen among Black participants.