Can repetition of deliberate self-harm be predicted? A prospective multicenter study validating clinical decision rules.

Background: Clinical decision rules have been developed to help identify patients at high risk of repeating deliberate self-harm actions. The objective of this study was to prospectively validate the clinical decision rules', Södersjukhuset Self-Harm Rule and Manchester Self-Harm Rule, ability to predict repetition of deliberate self-harm (DSH).
Methods: A consecutive series of 325 patients attending two large emergency departments in Stockholm, Sweden due to DSH were included and followed for six months. Predictive factors were collected from hospital charts at the emergency department. A nationwide register-based follow-up of new DSH within six months was used. We calculated the sensitivity and specificity to evaluate the different decision rules' ability to identify repetition of DSH. Main outcome measure repeated DSH within six months.
Results: The cumulative incidence for patients repeating within six months was 24.6% (95% CI: 19.9-29.3). Application of Södersjukhuset Self-Harm Rule yielded a sensitivity of 89% (95%CI: 79.2-94.4) and a specificity of 11% (95%CI: 7.9-16.2). Application of Manchester Self-Harm Rule to our material yielded a sensitivity of 94% (95%CI: 85.4-97.7) and a specificity of 18% (95%CI: 13.8-23.9).
Limitations: If data regarding predictive factors were missing it was not possible to investigate this further and in the statistical analysis missing data was classified as no. This would imply that the predicted risks may be underestimated.
Conclusion: Clinical decision rules could be used as a compliment providing important additional information regarding risk of repetition in an ED setting when focusing on high sensitivity.
(Copyright © 2013 Elsevier B.V. All rights reserved.)