Background: WASID showed that Blacks with symptomatic intracranial atherosclerosis are at higher risk of recurrent stroke and have a greater vascular risk factor burden than whites. We sought to determine if aggressive medical management (AMM) in SAMMPRIS resulted in equal control of risk factors in Blacks vs. other races and eliminated the racial disparity in outcome.
Methods: Data on all 451 SAMMPRIS patients receiving AMM were used to determine risk factor control in Blacks vs. Others. SBP, LDL, and exercise were recorded throughout the trial, averaged (from baseline until primary endpoint), and dichotomized as in/out of target. Chi-square and t-tests were used to compare risk factor control in Blacks vs. Others. For outcome analyses, data from 227 patients randomized to AMM only were used. Time to event curves for the primary endpoint were compared between Blacks vs. Others using the log-rank test and hazard ratios were calculated with Cox proportional hazards regression.
Results: There were no differences between the percentage of Blacks (n=104) vs. Others (n=347) that were in-target for SBP (57.1% vs 62.3%, p=0.36), LDL (40.4% vs 48.5%, p=0.14), or exercise (40.4% vs 43.2%, p=0.61) and no difference in mean SBP (135.2 vs 133.3 mm Hg, p=0.19), LDL (80.7 vs 76.3 mg/dL, p=0.19), or PACE exercise score (3.6 vs 3.8, p=0.27). There was a numerically higher primary endpoint rate among Blacks, but no statistically significant difference in outcome (Figure). However, power to detect a HR of 1.5 for Black race (the HR for the primary endpoint in WASID) was only 20%.
Conclusions: Control of SBP and LDL, and exercise, which were highly associated with a good outcome in SAMMPRIS, were not different between Blacks and other races. However, the study lacked sufficient power to detect a difference in outcome between blacks and other races and therefore we cannot conclude that reducing racial disparities in risk factor control will lead to reducing disparities in outcome.