Accuracy of individual and combined risk-scale items in the prediction of repetition of self-harm: multicentre prospective cohort study.

Anna Kathryn Taylor,David Gunnell,Nav Kapur,Sarah Steeg,Leah Quinlivan,Keith Hawton

doi:10.1192/bjo.2020.123

Abstract

Individuals attending emergency departments following self-harm have increased risks of future self-harm. Despite the common use of risk scales in self-harm assessment, there is growing evidence that combinations of risk factors do not accurately identify those at greatest risk of further self-harm and suicide. To evaluate and compare predictive accuracy in prediction of repeat self-harm from clinician and patient ratings of risk, individual risk-scale items and a scale constructed with top-performing items. We conducted secondary analysis of data from a five-hospital multicentre prospective cohort study of participants referred to psychiatric liaison services following self-harm. We tested predictive utility of items from five risk scales: Manchester Self-Harm Rule, ReACT Self-Harm Rule, SAD PERSONS, Modified SAD PERSONS, Barratt Impulsiveness Scale and clinician and patient risk estimates. Area under the curve (AUC), sensitivity, specificity, predictive values and likelihood ratios were used to evaluate predictive accuracy, with sensitivity analyses using classification-tree regression. A total of 483 self-harm episodes were included, and 145 (30%) were followed by a repeat presentation within 6 months. AUC of individual items ranged from 0.43-0.65. Combining best performing items resulted in an AUC of 0.56. Some individual items outperformed the scale they originated from; no items were superior to clinician or patient risk estimations. No individual or combination of items outperformed patients' or clinicians' ratings. This suggests there are limitations to combining risk factors to predict risk of self-harm repetition. Risk scales should have little role in the management of people who have self-harmed.

Highlights

Individuals attending emergency departments following selfharm have increased risks of future self-harm
We used data from a multicentre prospective cohort study that examined the diagnostic accuracy for predicting repeat self-harm of five risk scales: the Manchester Self-Harm Rule,[19] ReACT SelfHarm Rule,[20] SAD PERSONS Scale,[21] Modified SAD PERSONS Scale[22] and Barratt Impulsiveness Scale.[23]
The following scale items performed better than the scale they originated from: previous suicide attempt (AUC 0.61, 95% CI 0.57–0.65) and previous psychiatric care (AUC 0.65, 95% CI 0.61–0.69) from the SAD PERSONS Scale, which had an overall Area under the curve (AUC) of 0.55 and previous suicide attempt or psychiatric care (AUC 0.65, 95% CI 0.61–0.69) from the Modified SAD PERSONS Scale

Summary

Introduction

Individuals attending emergency departments following selfharm have increased risks of future self-harm. The third annual progress report of England’s National Suicide Prevention Strategy highlighted self-harm as a key issue in its own right, including the need to recognise that people who present to hospital following self-harm are a high-risk group for later suicide.[1] Emergency departments in England treat more than 220 000 episodes of self-harm annually.[2] At least half of people who die by suicide have a history of self-harm.[3] in England self-harm is associated with a 50 times greater risk of suicide in the year after the episode, which may be higher for those who present repeatedly.[4,5,6]. The risk of further self-harm and specific follow-up care based on the needs of individuals should be considered as part of this assessment.[8,9]

Methods

Results

Conclusion