Factors related to absence of toxicological investigation following fatal injury: a retrospective quantitative review of Coronial records in New Zealand.

Abstract

The accuracy of cause of death certification is strongly influenced by the quality of post mortem investigations (autopsies). In New Zealand, this can include toxicological investigation at the discretion of the Coroner. Little is known both within New Zealand and internationally about potential selection biases related to Coronial cases not undergoing toxicology investigation. A retrospective review of eligible injury-related deaths referred to a Coroner in New Zealand in 2014 was undertaken. Using data collected from the Australasian National Coronial Information System and New Zealand's Mortality Collection, descriptive analyses were undertaken to understand patterns related to toxicology report requests and patterns within toxicology reports. In New Zealand in 2014, 25% of 744 Coronial cases for fatal injury in those under 85years of age did not have corresponding toxicological reports. Reports were more likely to be absent in females (adjusted Odds Ratio (aOR) 1.7, 95%CI 1.0, 2.7), and in decedents aged under 15 and over 65years (aOR 11.0 and 4.1 respectively). More than half (56%, 95% CI 45%, 67%) of the deaths due to falls did not receive toxicological investigation. Better understanding of selection biases in Coronial processes helps inform policymakers, researchers, and practitioners of the limitations of available toxicological evidence.