Self-harm hospitalised morbidity and mortality risk using a matched population-based cohort design

Objective: Prior and repeated self-harm hospitalisations are common risk factors for suicide. However, few studies have accounted for pre-existing comorbidities and prior hospital use when quantifying the burden of self-harm. The aim is to quantify hospitalisation in the 12 months preceding and re-hospitalisation and mortality risk in the 12 months post a self-harm hospitalisation. Method: A population-based matched cohort using linked hospital and mortality data for individuals ⩾18 years from four Australian jurisdictions. A non-injured comparison cohort was matched on age, gender and residential postcode. Twelve-month pre- and post-index self-harm hospitalisations and mortality were examined. Results: The 11,597 individuals who were hospitalised following self-harm in 2009 experienced 21% higher health service use in the 12 months pre and post the index admission and a higher mortality rate (2.9% vs 0.3%) than their matched counterparts. There were 133 (39.0%) deaths within 2 weeks of hospital discharge and 342 deaths within 12 months of the index hospitalisation in the self-harm cohort. Adjusted rate ratios for hospital readmission were highest for females (2.86; 95% confidence interval: [2.33, 2.52]) and individuals aged 55–64 years (3.96; 95% confidence interval: [2.79, 5.64]). Conclusion: Improved quantification of the burden of self-harm-related hospital use can inform resource allocation for intervention and after-care services for individuals at risk of repeated self-harm. Better assessment of at-risk self-harm behaviour, appropriate referrals and improved post-discharge care, focusing on care continuity, are needed.