George Howard, Claudia S. Moy, Virginia J. Howard, Leslie A. McClure, Dawn O. Kleindorfer, Brett M. Kissela, Suzanne E. Judd, Fredrick W. Unverzagt, Elsayed Z. Soliman, Monika M. Safford, Mary Cushman, Matthew L. Flaherty, Virginia G. Wadley

At age 45 years, blacks have a stroke mortality ≈3× greater than their white counterparts, with a declining disparity at older ages. We assess whether this black-white disparity in stroke mortality is attributable to a black-white disparity in stroke incidence versus a disparity in case fatality. We first assess if black-white differences in stroke mortality within 29 681 participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort reflect national black-white differences in stroke mortality and then assess the degree to which black-white differences in stroke incidence or 30-day case fatality after stroke contribute to the disparities in stroke mortality. The pattern of stroke mortality within the study mirrors the national pattern, with the black-to-white hazard ratio of ≈4.0 at age 45 years decreasing to ≈1.0 at age 85 years. The pattern of black-to-white disparities in stroke incidence shows a similar pattern but no evidence of a corresponding disparity in stroke case fatality. These findings show that the black-white differences in stroke mortality are largely driven by differences in stroke incidence, with case fatality playing at most a minor role. Therefore, to reduce the black-white disparity in stroke mortality, interventions need to focus on prevention of stroke in blacks.