Comparing Confirmed Sodium Nitrite Suicide Deaths With Poison Center Surveillance Estimates.

Importance: Sodium nitrite is a curing agent increasingly used for self-harm and suicide, and multiple locales have reported increasing cases. However, approaches to forensic investigation of these cases are not standardized, and current modes of surveillance in the United States may be inadequate. Objective: To define a potential standard approach for identifying sodium nitrite deaths based on forensic confirmation, and compare findings based on this standard to poison center surveillance. Design, Setting, and Participants: This retrospective case series of sodium nitrite exposures and deaths was conducted in 2 urban medical examiner jurisdictions in New York State from 2000 to 2022. The population-based sample included individuals from (1) medical examiner reports of decedents where the cause of death was sodium nitrite and (2) poison center reports of intentional exposures to sodium nitrite. Exposure: Sodium nitrite as either cause of death (medical examiner reports) or intentional exposure (poison center reports). Main Outcomes and Measures: Medical examiner determination of sodium nitrite deaths was considered the criterion standard and relied largely on confirmatory blood nitrite testing. Poison center records were assessed for intentional exposures to sodium nitrite. Results: In this case series of 36 decendents, median (range) age was 28 (20-57) years; 23 (63.8%) were male; 6 (16.7%) were African-American, 5 (13.9%) were Chinese, 13 (36.1%) were White, and 4 (11.1%) had unknown race; and 6 (16.7%) were Hispanic. No deaths were found from 2000 to 2018, and yearly increases in deaths from 2019 to 2022; these deaths were largely missed by local poison center surveillance. Most cases (83.3% [n = 30]) had postmortem blood nitrite concentrations available, and multiple decedents had evidence of suicide kit recommendations from internet sources. Conclusions and Relevance: In this case series of decedents in 2 New York medical examiner jurisdictions, sodium nitrite deaths increased yearly, and the medical examiners were able to obtain confirmatory nitrite concentrations in most cases. These findings suggest that poison center surveillance underestimates confirmed deaths from sodium nitrite; public health authorities should rely on multiple data sources when analyzing this problem, and forensic analyses should be standardized.