Racial/ethnic differences in age and cause of death among males with Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a neuromuscular disease characterized by progressive muscle weakness and early mortality. The lack of a unique diagnosis code for DMD on death certificates prevents the use of standard mortality databases for DMD reporting. Using a restricted National Center for Health Statistics database containing the exact text manually written on death certificates from all 50 states between 2003 and 2007, we report on the deaths of 775 males with DMD indicated on the death certificate. Overall, median age of death was 21 years; 77% of deaths were cardiac- and/or respiratory-related; 27% of DMD deaths occurred before age 18. Race/ethnicity was significantly correlated with age of death (p=.0002, Kruskal-Wallis): non-Hispanic Whites (n=571; median death age=21 yrs); non-Hispanic Blacks (n=79; median death age=19 yrs); and Hispanics (n=93; median death age=20 yrs). Non-Hispanic Whites (77%) were more likely to survive to adulthood than non-Hispanic Blacks (58%, p=.0005, Χ²) and Hispanics (67%, p=.04, Χ²). Race/ethnicity was also significantly associated with causes of death: non-Hispanic Blacks were more likely to die from cardiac complications than non-Hispanic Whites (70% vs. 43%, p<.0001, Χ²) and Hispanics were more likely to die from respiratory complications than non-Hispanic Whites (63% vs. 47%, p=.0035, Χ²). These data parallel recently reported racial differences among deaths from all types of muscular dystrophy and provide a base for monitoring trends of racial/ethnic disparities in DMD mortality.