Suicidal/self-harm behaviors among cancer patients: a population-based competing risk analysis

Cancer patients had elevated risk of suicidality. However, few researches studied the risk/protective factors of suicidal/self-harm behaviors considering the competing risk of death. The objective of this study is to systematically investigate the risk of suicidal/self-harm behaviors among Hong Kong cancer patients as well as the contributing factors.

Patients aged 10 or above who received their first cancer-related hospital admission (2002-2009) were identified and their inpatient medical records were retrieved. They were followed for 365 days for suicidal/self-harm behaviors or death. Cancer-related information and prior 2-year physical and psychiatric comorbidities were also identified. Competing risk models were performed to explore the cumulative incidence of suicidal/self-harm behavior within 1 year as well as its contributing factors. The analyses were also stratified by age and gender.

In total, 152 061 cancer patients were included in the analyses. The cumulative incidence of suicidal/self-harm behaviors within 1 year was 717.48/100 000 person-years. Overall, cancer severity, a history of suicidal/self-harm behaviors, diabetes and hypertension were related to the risk of suicidal/self-harm behaviors. There was a U-shaped association between age and suicidal/self-harm behaviors with a turning point at 58. Previous psychiatric comorbidities were not related to the risk of suicidal/self-harm behaviors. The stratified analyses confirmed that the impact of contributing factors varied by age and gender.

Cancer patients were at risk of suicidal/self-harm behaviors, and the impacts of related factors varied by patients' characteristics. Effective suicide prevention for cancer patients should consider the influence of disease progress and the differences in age and gender.