Trends of emergency department presentations with a mental health diagnosis by age, Australia, 2004–05 to 2016–17: A secondary data analysis

Objectives: The present study aims to explore for Australia: (i) the trends of ED presentations with a mental health (MH) diagnosis by age group; and (ii) whether those trends differ from all ED presentations. Methods: ED presentations to Australian public hospitals, 2004–05 to 2016–17 were captured in the National Non-Admitted Patient Emergency Department Care Database. We assessed total change and annual rate of change in the number and rates of presentations per 10 000 population for all presentations and those with a MH principal diagnosis (ICD-10-AM F00 to F99, MH_dx). Multivariable regression was used to assess the trend of the proportion of MH_dx presentations. Results: Between 2004–05 and 2016–17, children (0–14 years), followed by older persons (≥65 years) had the highest ED utilisation; while youth (15–24 years) and younger adults (25–34 years) predominated for MH_dx presentations. As a proportion of all presentations, MH_dx presentations were lowest in children, and highest in people 35–44 years (13.2-times higher than for children). The rate of increase in MH_dx presentations was higher than for all presentations in all age groups, reaching almost four times higher for children. Conclusion: The Australian Institute of Health and Welfare should consider expanding the breadth of MH diagnoses they report to better identify the impact of MH on ED presentations. Between 2004–05 and 2016–17, high ED utilisation by children and older persons, and the increasing burden of MH_dx presentations for youth, younger adults and children suggest that healthcare planning strategies for urgent and emergency care cannot afford to overlook the growing impact of these sub-groups.