Long-term risk of repeat hospital admission involving self-harm by Aboriginal and non-Aboriginal people: A retrospective cohort study

Background: Identify risk factors for repeat hospitalisation involving self-harm by Aboriginal and non-Aboriginal people in the Northern Territory (NT), Australia. Methods: A retrospective cohort study of hospitalisations involving suicidal ideation and/or self-harm between 1 July 2001 and 31 December 2013 followed up to 31 December 2018. Survival analyses identified demographic and clinical characteristics associated with repeat hospitalisation involving self-harm. 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, 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. Limitations: The use of routinely collected administrative data limits analysis to only coded diagnoses and does not represent the full burden of self-harm and suicidal ideation in hospitals. Conclusion: The similarities and differences in long-term risk of repeat hospitalisation involving self-harm between Aboriginal and non-Aboriginal people pose distinct challenges for clinical management and prevention. The results emphasise the importance of comprehensive psychosocial assessment to properly understand the interplay of individual and contextual influences and highlights the need to better understand the availability and effectiveness of culturally tailored clinical interventions and community-based solutions.