Racial/ethnic variation in stroke rates and risks among patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE), which is associated with increased stroke risk, is more prevalent and often more severe among Blacks, Asians, and Hispanics than Whites. We examined racial/ethnic variation in stroke rates and risks, overall and by hemorrhagic versus ischemic subtype, among SLE patients.

Within Medicaid (2000-2010), we identified patients aged 18-65 with SLE (≥ 3 ICD-9 710.0 codes, ≥ 30days apart) and ≥12 months of continuous enrollment. Subjects were followed from index date to first stroke event, death, disenrollment, or end of follow-up. Race/ethnicity-specific annual event rates were calculated for stroke overall and by subtypes (hemorrhagic vs. ischemic). We used Cox proportional hazard models to estimate hazard ratios (HR) of stroke by race/ethnicity, adjusting for comorbidities and the competing risk of death.

Of 65,788 SLE patients, 93.1% were female. Racial/ethnic breakdown was 42% Black, 38% White, 16% Hispanic, 3% Asian, and 1% American Indian/Alaska Natives. Mean follow-up was 3.7 ± 3.0years. After multivariable adjustment, Blacks were at increased risk of overall stroke (HR 1.34 [95%CI 1.18-1.53), hemorrhagic stroke (HR 1.42 [1.00-2.01]), and ischemic stroke (HR 1.33 [1.15-1.52]) compared to Whites. Hispanics were at increased risk of overall stroke (HR 1.25 [1.06-1.47)] and hemorrhagic stroke (HR 1.79 [95% CI 1.22-2.61]), but not ischemic stroke, compared to Whites.

Among SLE patients enrolled in Medicaid, we observed elevated stroke risk (overall and by subtype) among Blacks and Hispanics compared to Whites, suggesting the importance of early recognition and screening for stroke risk factors among Blacks and Hispanics.