Racial/Ethnic Variation in White Matter Hyperintensity Progression in the ACCORDION MIND Study

Background: White matter hyperintensities (WMHs) are linked to cognitive decline and stroke. We investigate the impact of race on WMH progression in the Action to Control Cardiovascular Risk in Diabetes Memory in Diabetes (ACCORDION MIND) trial. Materials and Methods: The primary outcome is WMH progression in milliliters, evaluated by fitting linear regression to WMH volume on the month 80 magnetic resonance imaging (MRI) and including the WMH volume on the baseline MRI. The primary predictor is patient race, with the exclusion of patients defined as “other” race. We also derived predicted probabilities of our outcome for systolic blood pressure (SBP) levels. Results: We included 276 patients who completed the baseline and month 80 MRI, of which 207 (75%) were White, 48 (17%) Black, and 21 (8%) Hispanic. During follow-up, the mean number of SBP, low-density lipoprotein (LDL), and A1c measurements per patient was 21, 8, and 15. The median (IQR) WMH progression was 1.5 mL (0.5 to 3.9) for Black patients, 1.0 mL (0.4 to 4.0) for Hispanics, and 1.3 mL (0.5 to 2.7) for Whites (Kruskal-Wallis test, P=0.59). In the multivariate regression model, Black, compared with White, patients had significantly more WMH progression (β Coefficient 1.26, 95% confidence interval 0.45 to 2.06, P=0.002). Hispanic, compared with White, patients neither have significantly different WMH progression (P=0.392), nor was there a difference when comparing Hispanic to Black patients (P=0.162). The predicted WMH progression was significantly higher for Black compared with White patients across a mean SBP of 117 to 139 mm Hg. Conclusions: Black diabetic patients in Action to Control Cardiovascular Risk in Diabetes Memory in Diabetes (ACCORDION MIND) have a higher risk of WMH progression than White patients across a normal range of SBP.