Comparison of injury case fatality rates in the United States and New Zealand

Objective: To compare injury case fatality rates in the United States (US) with New Zealand (NZ) to guide future information collection, research, and evaluation. Design: Using NZ (1992–96) and US (1996–98) mortality censuses, NZ national 1992–96 hospital discharge censuses, and US 1996–98 National Hospital Discharge Survey data, the authors compared case fatality rates by mechanism and intent of injury and age group. The analysis was restricted to severe injuries (AIS⩾3). Subjects: NZ (1992–96) and US (1996–98) populations. Main outcome measures: Ratio of case fatality rates in NZ versus the US (RCFR(NZ:US)). Results: Overall, among cases meeting the study criteria, unintentional injuries were 1.57 times more likely fatal in NZ and intentional assault injuries were 1.14 times more likely to be fatal in the US. Firearms were involved in 50% of US assaults versus 8% of NZ assaults. By mechanism, cutting/piercing injuries were 1.86, firearm injuries were 1.41, and motor vehicle injuries were 1.44 times more to be likely fatal in NZ. Natural/environmental injuries (RCFRNZ:US = 0.57), unintentional poisonings (RCFRNZ:US = 0.26), and unintentional suffocations (RCFRNZ:US = 0.67) were significantly more likely to be fatal in the US. Conclusions: Possible reasons for the observed results include: differences in geography and proportion of population in rural areas, trauma system differences, road design and vehicle types, seat belt use, larger role of firearms in US assaults, coding practices, policies, and environmental factors. Disparities evoke hypotheses to test in future research that will guide priority setting and intervention.