Blacks with ankylosing spondylitis (AS) have more severe disease compared to either whites or Latinos, according to a recent study. Researchers assessed 925 AS patients (57 blacks, 805 whites, 63 Latinos) enrolled in the longitudinal Prospective Study of Outcomes in AS (PSOAS) for functional impairment, disease activity, and radiographic severity. Comparisons of clinical characteristics and HLA-B27 frequency for each group were performed in 2 multivariable regression models, and researchers compared the baseline Bath Ankylosing Spondylitis Radiographic Index (BASRI) and modified Stokes Ankylosing Spondylitis Spine Score (mSASSS) by ethnicity, adjusting for covariates. They found:

• Blacks had greater functional impairment (Bath Ankylosing Spondylitis Functional Index), higher disease activity (Bath Ankylosing Spondylitis Disease Activity Index), erythrocyte sedimentation rate, and C-reactive protein levels.
• Baseline BASRI and mSASSS were higher in blacks as compared to whites and Latinos, more significant as disease duration increased.
• HLA-B27 occurred in 62.5% of blacks, 85.3% of whites, and 86.7% of Latinos.