Bridging assessment and treatment for repeat suicidality in prisons: development and validation of a risk model

Background Suicidal thoughts and behaviours are common in people in prison and associated with poor health outcomes, including suicide, injury and repeat self-harm. Objective To develop and validate a model to stratify risk of repeat suicidality up to 3 months in people in prison. Methods In seven English prisons, we identified 754 people aged over 17 who had been placed on a suicide risk management plan after a self-harm episode or elevated risk. We developed a multivariable model to stratify risk of repeat suicidality at 3 months using routinely collected sociodemographic, clinical and prison-related factors, which were tested using Cox proportional HR models. In a prospective validation sample of 390 people from 13 prisons, we tested this model to assess risk of repeat suicidality at 3 months across a range of performance measures. Findings Of the overall sample of 1144 people in prison (n=966 men or 84%, mean age 33 years), 22% had the outcome of repeat suicidality over 3 months. The final risk model consisted of nine factors, including sex, calendar age and features of recent suicidal behaviour. Calibration and discrimination were similar in both development and validation samples, with O:E ratio=1.09 (95% CI 0.88 to 1.35) and c-statistic=0.66 (95% CI 0.60 to 0.72) in external validation. At a 25% cut-off, sensitivity was 58% (50 to 66) and specificity was 72% (68 to 75) in external validation. The tool (Risk Assessment for people in Prison at risk of Self-harm and Suicide, RAPSS) is available as an online risk calculator at https://oxrisk.com/rapsstrial/. Interpretation A novel assessment approach for repeat suicidality can provide an evidence-based approach to stratify risk and better allocate resources.