Which deliberate self-poisoning patients are most likely to make high-lethality suicide attempts?

Background: The risk/rescue rating scale (RRRS) assesses the lethality of a suicide attempt, which is defined as the probability of inflicting irreversible damage. We assessed the lethality of suicide attempts using the RRRS and identified the socio-demographic profiles of patients who achieved high lethality in deliberate self-poisoning (DSP). Methods: A retrospective study was conducted to evaluate DSP patients who visited the emergency department of a tertiary teaching hospital between 2000 and 2011. The data included socio-demographic information, clinical variables, risk factors (e.g., the method used, whether consciousness was impaired, toxicity, reversibility and whether treatment was required) and rescue factors (e.g., location, who initiated the rescue, the probability of discovery, the accessibility of rescue, and delay until discovery). The high-risk group consisted of patients with 11-15 risk points, whereas patients in the low-rescue group had 5-11 risk points. We examined the characteristics of high-lethality suicide attempts (high-risk/low-rescue group). Results: A total of 1114 patients were enrolled in this study. Pearson's correlation analysis showed that the total risk score for patients with DSP was negatively associated with the total rescue score (r = -0.201, p < 0.001). Of the total number of DSP patients, 42 were included in the high-risk/low-rescue group. The multivariate logistic regression analyses showed significant associations between high-lethality suicide attempts and male gender (OR 2.70, 95 % CI 1.41-5.18, p = 0.003), older age (OR 1.02, 95 % CI 1.01-1.04, p = 0.015), and unemployment (OR 2.98, 95 % CI 1.41-6.33, p = 0.004). Conclusion: This retrospective study demonstrates that male gender, advanced age, and unemployed status were associated with high-lethality suicide attempts in DSP patients.