Mortality in people living with dementia who self-harmed: An Australian data linkage study

Objectives: This study aimed to examine mortality for people living with dementia/mild cognitive impairment who self-harmed. Methods: We conducted a retrospective cohort study in New South Wales, Australia, using data ranging from 2001 to 2015. From people who accessed hospital services in the study period, we identified 154,811 people living with dementia/mild cognitive impairment, 28,972 who self-harmed and 1511 who had a record of both dementia/mild cognitive impairment and self-harm. We examined rates, causes and predictors of death for people with dementia/mild cognitive impairment and/or self-harm diagnoses using flexible parametric survival analyses. We explored rates of repeat self-harm in people living with dementia who self-harmed. Results: Circulatory disorders accounted for 32.0% of deaths in people with a living with dementia who self-harmed, followed by neoplasms (14.7%), and mental and behavioural disorders (9.6%). Death was more likely for someone who had self-harmed if they developed dementia/mild cognitive impairment. Predictors of death included male sex, greater physical comorbidity, a history of delirium, more previous emergency department presentations and fewer previous mental health ambulatory service days. Greater engagement with outpatient mental health services predicted a decreased likelihood of repeat self-harm. Discussion: We found that mortality increases when people who self-harm develop dementia. We argue post-diagnosis support offers a potential opportunity to reduce mortality rates in people with both dementia and self-harm diagnoses.