Identifying and Tracking Gas Suicides in the U.S. Using the National Violent Death Reporting System, 2005-2012

Introduction: Identifying the source and specific type of gas used in suicides is difficult using most data systems owing to limitations in ICD-10 coding. The National Violent Death Reporting System (NVDRS), with its rich collection of both coded and free-text variables, has the potential to overcome these limitations. This study used a multipronged approach to identify gas-specific suicides in NVDRS and to track the incidence of these suicides over time.

Methods: Using suicide cases from the 16 NVDRS states that participated throughout 2005-2012, free-text and code searches were conducted for four types of variables-incident narratives, coroner/medical examiner cause-of-death statements, cause-of-death codes, and substance names-to identify suicides by carbon monoxide, helium, hydrogen sulfide, and four other gases. All analyses were conducted in 2015.

Results: Approximately 4% (3,242 of 80,715) of suicides recorded in NVDRS over the study period were the result of gas inhalation. Of these, the majority (73%) were carbon monoxide suicides (almost exclusively from motor vehicle exhaust and charcoal burning). Other types of gas (most notably helium), once rare, are now more common: At the start of the study period non-carbon monoxide gas suicides represented 15% of all gas suicides; at the end of the study period, they represented 40%.

Conclusions: Public health policies to reduce a suicidal person's access to more lethal suicide methods require a reliable source of surveillance data on specific methods used in suicide. Small changes to NVDRS could make it an efficient and nimble surveillance system for tracking these deaths.