Disparities in the diagnostic process of Duchenne and Becker muscular dystrophy

Purpose: To determine whether sociodemographic factors are associated with delays at specific steps in the diagnostic process of Duchenne and Becker muscular dystrophy. Methods: We examined abstracted medical records for 540 males from population-based surveillance sites in Arizona, Colorado, Georgia, Iowa, and western New York. We used linear regressions to model the association of three sociodemographic characteristics with age at initial medical evaluation, first creatine kinase measurement, and earliest DNA analysis while controlling for changes in the diagnostic process over time. The analytical dataset included 375 males with information on family history of Duchenne and Becker muscular dystrophy, neighborhood poverty levels, and race/ethnicity. Results: Black and Hispanic race/ethnicity predicted older ages at initial evaluation, creatine kinase measurement, and DNA testing (P < 0.05). A positive family history of Duchenne and Becker muscular dystrophy predicted younger ages at initial evaluation, creatine kinase measurement and DNA testing (P < 0.001). Higher neighborhood poverty was associated with earlier ages of evaluation (P < 0.05). Conclusions: Racial and ethnic disparities in the diagnostic process for Duchenne and Becker muscular dystrophy are evident even after adjustment for family history of Duchenne and Becker muscular dystrophy and changes in the diagnostic process over time. Black and Hispanic children are initially evaluated at older ages than white children, and the gap widens at later steps in the diagnostic process. Genet Med 2011:13(11):942-947.