Impact of changes in specificity of data recording on cause-specific injury mortality in the United States, 1999–2010

BACKGROUND: We aimed to examine changes in the specificity of data recording and assess the impact on cause-specific injury mortality during 1999–2010. METHODS: A longitudinal study was designed to analyze injury mortality data of 1999-2010. Mortality rates for unspecified injury and for cause-specific injury were obtained using CDC’s Web-based Injury Statistics Query and Reporting System (WISQARS™). The proportion of unspecified injury was used to measure the specificity of injury data recording. We used the proportionate method to adjust data specificity and compared changes in cause-specific mortality before and after adjustment. RESULTS: Between 1999 and 2010, the age-adjusted mortality from unspecified injuries decreased from 3.4 to 2.5 per 100,000 persons for all ages. The proportion of unspecified unintentional injury decreased from 18.9% to 10.9% for the elderly ages 65+. The proportion of unspecified homicide significantly increased for all age groups except ages 25–44 years. After adjustment, increases in age-adjusted mortality rates from falls, poisoning and drowning were less (77 vs. 61%, 66 vs. 51%, and 9 vs. 0%) and decreases in injuries from motor vehicle crashes, suffocation, fire/burn, and natural/environmental disasters were greater (-30 vs. -37%, -17 vs. -24%, -23 vs. -24%, and -46 vs. -51%), respectively. The adjustment resulted in reversed changes in homicide by firearm (-1 vs. 5%) and cut/pierce (-5 vs. 2%), greater increases in homicide by suffocation (9 vs. 16%) for ages 45–64 years, and smaller decreases in all other age- and cause-specific homicide groups. CONCLUSIONS: During 1999–2010, the specificity of data recording changed significantly for homicide rates and elderly unintentional injury mortality and the changes altered trends in cause-specific injury mortality.