The lethality of suicide methods: A systematic review and meta-analysis

Background: The use of suicide methods largely determines the outcome of suicide acts. However, no existing meta-analysis has assessed the case fatality rates (CFRs) by different suicide methods. The current study aimed to fill this gap. Methods: We searched Scopus, Web of Science, PubMed, ProQuest and Embase for studies reporting method specific CFRs in suicide, published from inception to 31 December 2020. A random-effect model meta analysis was applied to compute pooled estimates. Results: Of 10,708 studies screened, 34 studies were included in the meta-analysis. Based on the suicide acts that resulted in death or hospitalization, firearms were found to be the most lethal method (CFR:89.7%), followed by hanging/suffocation (84.5%), drowning (80.4%), gas poisoning (56.6%), jumping (46.7%), drug/liquid poisoning (8.0%) and cutting (4.0%). The rank of the lethality for different methods remained relatively stable across study setting, sex and age group. Method-specific CFRs for males and females were similar for most suicide methods, while method-CFRs were specifically higher in older adults. Conclusions: This study is the first meta-analysis that provides significant evidence for the wide variation of the lethality of suicide methods. Restricting highly lethal methods based on local context is vital in suicide prevention.