Age effects on case fatality rates of injury patients by mechanism

Abstract

Background: Case fatality from injury increases exponentially with age. The objective of this study is to identify age effects on case fatality of injury patients by injury mechanism.

Methods: This is an observational study using the Emergency Department-based Injury In-depth Surveillance data from 2007 to 2012. Eligibility was all injured patients, excluding those with unknown information for age, disposition after emergency department or admission, or injury mechanism. End point of this study was inhospital mortality. Injury mechanism was categorized into road transport injury (RTI), fall, collision, cut/pierce, burn, poisoning, and miscellaneous. Case fatality ratio was calculated to evaluate age effects on case fatality by injury mechanism and gender.

Result: Among 927011 injury patients, a total of 924755 patients were analyzed. Total case fatality rate was 0.9%, and rates by injury mechanisms were 4.4% in poisoning, 2.1% in RTI, and 0.8% in fall. By age and gender, the highest crude case fatality rate was 19.74% observed in older than 80-year-old men with poisoning. Case fatality ratios in both genders increased by age from 60- to 69-, 70- to 79-, to older than 80-year-old patients; ratios by injury mechanisms were 13.71, 20.76, and 22.29 (male) and 7.21, 11.18, and 13.05 (female) in poisoning; 5.46, 9.30, and 14.13 (male) and 3.90, 7.96, and 12.08 (female) in RTI; 1.22, 1.52, and 2.02 (male) and 1.14, 2.15, and 6.42 (female) in burn.

Conclusions: Case fatality rates of injury increased with age; however, the trends in increase differed by injury mechanisms and gender. Strategies for injury prevention and decreasing mortality should consider the age effects on case fatality of different injury mechanisms.