Clinical determinants of hospital treated deliberate self-harm repetition: A time to recurrent event analysis

Interpersonal violent injury and subsequent risk of suicide and deliberate self-harm: a register-based national cohort study from Norway, 2010-2018

Background

Interpersonal violence is a leading cause of morbidity, with potentially severe adverse consequences for the mental health of the injured persons. The extent to which violent injury is associated with subsequent suicidal behavior, however, remains unclear. This study aimed to examine how violent injury was associated with subsequent deliberate self-harm and death by suicide.

Methods

This retrospective cohort study used nationwide longitudinal registry data from Norway to identify all individuals presenting to emergency services in 2010-2018 with a violence-related injury, along with sex- and age-matched control individuals from the general population. The primary outcomes were any emergency visit for deliberate self-harm (DSH) and suicide death, observed through 31 December 2018. Rates of each outcome were compared between violence-injured patients and comparison individuals using stratified multivariable Cox regression models, controlling for sociodemographic characteristics as well as history of psychiatric treatment and DSH. Secondary analyses tested for moderation by sex, age, and prior psychiatric treatment.

Findings

Violence-injured patients (n = 28,276) had substantially higher rates of DSH (946.7 per 100,000 person-years) and suicide death (74.5 per 100,000) when compared to controls (n = 282,760; 90.0 and 15.2 per 100,000, respectively). The hazard ratios (HRs) remained significantly higher even after accounting for covariates (HRadj for DSH: 5.11; 95% CI: 4.62, 5.66; HRadj for suicide: 2.40; 95% CI: 1.78, 3.24). Sex differences in this association were negligible, but the association between violence injury and DSH increased with age. Violence-injured patients with prior psychiatric treatment had the highest risk of suicidal behavior.

Interpretation

Violence-injured patients experience significantly excess rates of suicidal behavior, a finding with potential to inform both clinical intervention and population-level suicide prevention strategies.

Funding

Fulbright Norway Scholarship.

Psychiatric disorders among adult deliberate self-harm patients and subsequent risk of dying by suicide, mental and behavioural disorders and other external causes

INTRODUCTION

Deliberate self-harm (DSH) treated in general hospital is a well-established risk factor for suicide and other cause mortality. However, few studies have used population data to investigate the differential impact of specific psychiatric disorders on the risk of subsequent suicide, by sex and age of the patient in the context of previous DSH episodes.

METHOD

All patients aged 18 and older treated for DSH in general hospitals during the period 2008-2018 were identified through national registers. Cox proportional hazards regression was used to ascertain the associated risk of death by suicide, mental and behavioural disorder and other external causes.

RESULTS

The cohort consisted of 39 479 patients of which 878 died by suicide, 461 by mental and behavioural disorders and 1037 by other external causes. Overall, schizophrenia spectrum disorders, affective disorders and personality disorders increased the risk of suicide. Large gender and age differences were identified in the risk of suicide associated with personality disorders and affective disorders. Alcohol use disorders and dementia increased the risk of dying by mental and behavioural disorders and alcohol use disorders and other substance use disorders increased the risk of death by external causes.

CONCLUSION

Schizophrenia spectrum disorders, affective disorders and personality disorders increased the risk of suicide among DSH patients, but the effect varied by gender, age and history of previous DSH. Psychiatric evaluation of all DSH patients and treatment tailored to the patient's specific needs is essential to reduce the risk of premature death.

Clinical determinants of hospital treated deliberate self-harm repetition: A time to recurrent event analysis

INTRODUCTION

Psychiatric disorders are strongly associated with hospital treated deliberate self-harm (DSH). However, the effect of specific disorders on risk for DSH repetition in sex-age-subgroups is understudied. The present study aims to assess the influence of various specific psychiatric disorders on risk for subsequent DSH repetition by way of time to recurrent event analysis on a national cohort of DSH patients.

MATERIAL AND METHODS

Individuals aged 18 and older presenting to somatic hospital for DSH during the period 2008-2018 was identified through national registers. A parametric shared frailty survival analysis was used to investigate the impact of various psychiatric disorders on risk of DSH repetition.

RESULTS

The cohort consisted of 39,508 individuals of which 8634 (21.8%) presented with 24,028 repeated episodes of hospital treated DSH. Borderline personality disorder increased the risk of DSH repetition in females (adjusted HR 1.49, CI 1.41-1.57), while alcohol use disorder (HR 1.12, CI 1.04-1.19) and substance use disorders (adjusted HR 1.22, CI 1.14-1.32) increased the risk of repetition in males. The strongest impact of psychiatric disorder on risk of repetition was found among the elderly. Previous history of DSH was associated with the highest increased risk of repetition.

CONCLUSION

Prior history of DSH was strongly associated with DSH repetition, but the influence of psychiatric disorder varied significantly by specific diagnoses and by sex and age of the patients. Efforts to prevent DSH repetition should be age and gender specific and designed to meet the needs of people with different specific psychiatric disorders.