Australian Suicide Prevention using Health-Linked Data (ASHLi): Protocol for a population-based case series study

INTRODUCTION: In Australia, suicide is the leading cause of death for people aged 15–44 years. Health professionals deliver most of our key suicide prevention strategies via health services, but other efficacious population-level strategies include means restriction and public awareness campaigns. Currently, we have no population-level data allowing us to determine which individuals, in what parts of Australia, are likely to use our most promising interventions delivered by health services. The aims of this study are to describe: (1) health service utilisation rates in the year prior to death by suicide, and how this varies by individual case characteristics; (2) prescribed medicines use in the year prior to death by suicide, medicines used in suicide by poisoning and how this varies by individual case characteristics. METHODS AND ANALYSIS: This is a population-based case series study of all suicide cases in Australia identified through the National Coronial Information System (NCIS) from 2013 to 2019. Cases will be linked to administrative claims data detailing health service use and medicines dispensed in the year before death. We will also obtain findings from the coronial enquiry, including toxicology. Descriptive statistics will be produced to characterise health service and prescribed medicine use and how utilisation varies by age, sex, method of death and socioeconomic status. We will explore the geographical variability of health service and medicine use, highlighting regions in Australia associated with more limited access. ETHICS AND DISSEMINATION: This project involves the use of sensitive and confidential data. Data will be linked using a third-party privacy-preserving protocol meaning that investigators will not have access to identifiable information once the data have been linked. Statistical analyses will be carried out in a secure environment. This study has been approved by the following ethics committees: (1) the Justice Department Human Research Ethics Committee (REF: CF/17/23250), (2) the Western Australian Coroners Court (REF: EC 14/18 M0400), (3) the Australian Institute of Health and Welfare (REF: EO2017/4/366) and (4) NSW Population & Health Services Research Ethics Committee (REF: 2017/HRE1204). Findings will be published in peer-reviewed journals, presented at conferences and communicated to regulatory authorities, clinicians and policy-makers.