Understanding the impact of clinical characteristics and healthcare utilizations on suicide among cancer sufferers: a case-control study in Hong Kong

BACKGROUND: Few studies have investigated whether hospital utilization patterns of cancer sufferers are associated with their suicide. This study aims to explore whether clinical profiles and healthcare utilization patterns are related to suicide among cancer sufferers. METHODS: Verified suicide cases with cancer (2012-2016) were identified. Each case was matched with two non-suicide controls suffering cancer, by birthyear, sex, and admission year. Cancer-related information, physical and psychiatric comorbidities, opioid-based painkiller usage, the number and length of inpatient admissions, and the number of outpatient and Accident & Emergency (A&E) attendances, in the six months leading up to the suicide, were identified. Conditional logistic regression models were constructed to explore the influence of clinical profiles and hospital utilization on suicide. These models were stratified by age and cancer stage. OUTCOMES: 383 cases and 766 controls were included in the analyses. Overall, younger age, metastasis/recurrent status, suffering head and neck cancer, having psychiatric comorbidities, using opioid-based painkillers, and high frequency of A&E attendances and inpatient admissions increased the odds of suicide. Being diagnosed with liver cancer, consuming high numbers of outpatient attendances, and high numbers of inpatient days decreased the odds of suicide. Stratified analyses confirmed the influence of young age and metastatic/recurrent cancer status on risk of suicide. INTERPRETATIONS: Suicidal cancer sufferers had distinctive clinical profiles and hospital utilization patterns. Detecting and mitigating suicidal risk should be incorporated as an important component in treatment of cancer sufferers in the clinical setting. FUNDING: Li Ka Shing Foundation and Hong Kong Research Grants Council