Recurrence of Overdose Suicide Attempt index: a novel scoring system for predicting the recurrence of intentional overdose

Repeated suicide attempts through intentional overdose are not infrequent, but little is known about the risk factors associated with intentional overdose. We investigated these risk factors within 1 year of discharge from hospital and developed an index predicting recurrence. This retrospective observational study included 419 patients admitted to our hospital between 2011 and 2018 due to intentional overdose. Of these, 43 (10.0%) repeated an overdose within 1 year of discharge. The risk factors with the highest odds ratios from multivariate logistic regression analyses were used to develop an index assessing Recurrence of Overdose Suicide Attempt. The following variables were significantly associated with recurrence and were included in the index: anxiety and/or insomnia at discharge; use of five or more psychotropic medications; diagnosis of an ICD-F4 anxiety disorders; and female sex (odds ratios: 4.24; 5.52; 2.41; and 3.41, respectively). The area under the receiver operating characteristic curve of the index was 0.797. Sensitivity, specificity, and positive and negative predictive values for Recurrence of Overdose Suicide Attempt >4 points (out of 6) were 72.1%, 75.8%, 25.4%, and 96.0%, respectively. Our novel index predicted the recurrence of intentional overdose with a good negative predictive value and may therefore be a useful screening tool for this high-risk population.