Risk factors for repeat self-harm hospitalisation following hospital admissions for suicidal ideation and self-harm among Aboriginal and non-Aboriginal people: a retrospective cohort study using linked administrative data

PURPOSE: The Northern Territory (NT) experiences the highest rates of hospitalisations involving self-harm in Australia, especially amongst Aboriginal people. Given self-harm is a strong predictor of suicide risk, it is important to identify the distinct risk factors for a repeat hospitalisation involving self-harm amongst Aboriginal and non-Aboriginal people in the NT hospitalised for suicidal ideation and self-harm. METHODS: A retrospective cohort study was designed to follow-up patients with a first hospital admission involving suicidal ideation and/or self-harm between 1 July 2001 and 31 December 2013. Survival analysis techniques were used to estimate probability of and risk factors for repeat hospitalisation involving self-harm up to 31 December 2018 for Aboriginal and non-Aboriginal people separately. RESULTS: The risk of repeat hospitalisation involving self-harm was higher (HR 1.39; 95% CI: 1.22-1.59) amongst Aboriginal (n = 2,304) than non-Aboriginal people (n = 2,087). Compared to suicidal ideation only at first hospital admission, a higher risk of repetition was observed for any self-harm method (aHR: 1.71; 95% CI: 1.37-2.12) amongst Aboriginal people and self-poisoning only (aHR: 1.45; 95% CI: 1.13-1.85) amongst non-Aboriginal people. Previous substance misuse was associated with a higher risk of repeat hospitalisation involving self-harm for Aboriginal (aHR: 1.7; 95% CI: 1.38-2.1) and non-Aboriginal (aHR: 1.6; 95% CI: 1.14-2.25) people. For non-Aboriginal people, several mental health diagnoses were associated with higher risks of repetition. CONCLUSION: The distinct risk factors for repeat hospitalisation involving self-harm between Aboriginal and non-Aboriginal people emphasises the importance of comprehensive psychosocial assessment and culturally tailored clinical interventions and community-based solutions to properly understand and address risk factors for each group.