D-dimer and the risk of hypertension: The REasons for Geographic And Racial Differences in Stroke Cohort Study

Background: Reasons for increased risk of hypertension in Black compared with White people are only partly understood. D-dimer, a thrombo-inflammatory marker higher in Black individuals, is also higher in people with hypertension. However, the impact of D-dimer on racial disparities in risk of incident hypertension has not been studied.Objectives: To assess whether D-dimer is associated with the risk of incident hyper-tension, whether the association between D-dimer and the risk of incident hyperten-sion differs by race, and whether the biology reflected by D-dimer explains racial disparities in the risk of incident hypertension.Methods: This study included 1867 participants in the REasons for Geographic And Racial Differences in Stroke cohort study without baseline hypertension and with a second visit 9.4 years after baseline. Risk ratios of incident hypertension by baseline D-dimer level were estimated, a D-dimer-by-race interaction was tested, and the mediating effect of D-dimer (which represents underlying biological processes) on the association of race and hypertension risk was assessed.Results: The risk of incident hypertension was 47% higher in persons in the top quartile than in those in the bottom quartile of D-dimer (risk ratio [RR]: 1.47; 95% CI: 1.23-1.76). The association was partly attenuated after adjusting for sociodemographic and adiposity-related risk factors (RR: 1.22; 95% CI: 1.02-1.47). The association of D-dimer and hypertension did not differ by race, and D-dimer did not attenuate the racial dif-ference in the risk of incident hypertension. Conclusion: D-dimer concentration reflects pathophysiology related to the develop-ment of hypertension. Specific mechanisms require further study and may involve adiposity.