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

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.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.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.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.