The interaction effect between low income and severe illness on the risk of death by suicide after self-harm

Background: Previous Western studies have reported that the prevalence of death by suicide within 1 year after self-harm was 0.5-2%; however, no studies have focused on the Far East. Aims: To calculate the prevalence of death by suicide after self-harm over different lengths of follow-up time and to determine the predictors of death by suicide after self-harm. Method: Our study was based on 3,388 inpatients hospitalized between 2000 and 2007 in any of the 1,230 hospitals in Taiwan. Death by suicide after self-harm among the members of this cohort was tracked after 3 months, 6 months, and 1-8 years. The tracking continued until December 31, 2008. We analyzed the prevalence and risk factors of death by suicide after self-harm using Cox's regression model. Results: Of the 3,388 individuals with a history of self-harm included in the study, 48 (1.4%) died by suicide after self-harm within 3 months and 97 (2.9%) within 1 year. In all, 144 (4.3%) died by suicide after self-harm within 8 years. The predictors of death by suicide were violent methods (such as hanging, drowning, firearms, and jumping), low income, and severe illness. Moreover, an interaction effect was noted between low income and severe illness on the outcome (death by suicide). Conclusion: It seems that effective healthcare for individuals who engage in self-harming behavior would benefit from supplementing medical care with social assistance, such as the support of a social worker.