Investigators have developed and validated a new risk calculator to help predict death by suicide in the 6-12 months after an episode of nonfatal self-harm, new research shows.
A study led by Seena Fazel, MBChB, MD, University of Oxford, England, suggests the Oxford Suicide Assessment Tool for Self-harm (OxSATS) may help guide treatment decisions and target resources to those most in need, the researchers note.
“Many tools use only simple high/low categories, whereas OxSATS includes probability scores, which align more closely with risk calculators in cardiovascular medicine, such as the Framingham Risk Score, and prognostic models in cancer medicine, which provide 5-year survival probabilities. This potentially allows OxSATS to inform clinical decision-making more directly,” Dr. Fazel told this news organization.
The findings were published online in BMJ Mental Health.
Targeted tool
Self-harm is associated with a 1-year risk of suicide that is 20 times higher than that of the general population. Given that about 16 million people self-harm annually, the impact at a population level is potentially quite large, the researchers note.
Current structured approaches to gauge suicide risk among those who have engaged in self-harm are based on tools developed for other purposes and symptom checklists. “Their poor to moderate performance is therefore not unexpected,” Dr. Fazel told this news organization.
In contrast, OxSATS was specifically developed to predict suicide mortality after self-harm.
Dr. Fazel’s group evaluated data on 53,172 Swedish individuals aged 10 years and older who sought emergency medical care after episodes of self-harm.
The development cohort included 37,523 individuals. Of these, 391 died by suicide within 12 months. The validation cohort included 15,649 individuals; of these people, 178 died by suicide within 12 months.
The final OxSATS model includes 11 predictors related to age and sex, as well as variables related to substance misuse, mental health, and treatment and history of self-harm.
“The performance of the model in external validation was good, with c-index at 6 and 12 months of 0.77,” the researchers note.
Using a cutoff threshold of 1%, the OxSATS correctly identified 68% of those who died by suicide within 6 months, while 71% of those who didn’t die were correctly classified as being at low risk. The figures for risk prediction at 12 months were 82% and 54%, respectively.
The OxSATS has been made into a simple online tool with probability scores for suicide at 6 and 12 months after an episode of self-harm, but without linkage to interventions. A tool on its own is unlikely to improve outcomes, said Dr. Fazel.
“However,” he added, “it can improve consistency in the assessment process, especially in busy clinical settings where people from different professional backgrounds and experience undertake such assessments. It can also highlight the role of modifiable risk factors and provide an opportunity to transparently discuss risk with patients and their carers.”
Valuable work
Reached for comment, Igor Galynker, MD, PhD, professor of psychiatry at the Icahn School of Medicine at Mount Sinai, New York, said that this is a “very solid study with a very large sample size and solid statistical analysis.”
Another strength of the research is the outcome of suicide death versus suicide attempt or suicidal ideation. “In that respect, it is a valuable paper,” Dr. Galynker, who directs the Mount Sinai Beth Israel Suicide Research Laboratory, told this news organization.
He noted that there are no new risk factors in the model. Rather, the model contains the typical risk factors for suicide, which include male sex, substance misuse, past suicide attempt, and psychiatric diagnosis.
“The strongest risk factor in the model is self-harm by hanging, strangulation, or suffocation, which has been shown before and is therefore unsurprising,” said Dr. Galynker.
In general, the risk factors included in the model are often part of administrative tools for suicide risk assessment, said Dr. Galynker, but the OxSATS “seems easier to use because it has 11 items only.”
Broadly speaking, individuals with mental illness and past suicide attempt, past self-harm, alcohol use, and other risk factors “should be treated proactively with suicide prevention measures,” he told this news organization.
As previously reported, Dr. Galynker and colleagues have developed the Abbreviated Suicide Crisis Syndrome Checklist (A-SCS-C), a novel tool to help identify which suicidal patients who present to the emergency department should be admitted to hospital and which patients can be safely discharged.
Funding for the study was provided by Wellcome Trust and the Swedish Research Council. Dr. Fazel and Dr. Galynker have no relevant disclosures.
A version of this article first appeared on Medscape.com.