Hypothermia-related Deaths: A 10-year Retrospective Study of Two Major Metropolitan Cities in the United States*

Hypothermia-related deaths affect vulnerable populations and are preventable. They account for the vast majority of weather-related deaths in the United States. The postmortem diagnosis of hypothermia can be challenging, as there are no pathognomonic signs. The electronic databases of the New York City Office of Chief Medical Examiner and Harris County Institute of Forensic Sciences were searched for all fatalities where the primary cause of death included hypothermia, between January 2009 and July 2019. There were 139 hypothermia deaths in New York City (NYC) with an average annualized rate of 1.7 per million. During this same time, there were 50 hypothermia deaths in Houston with an average annualized rate of 2.4 per million. Males were more likely to die of hypothermia compared to females in both cities. The rate ratio (RR) in NYC was 3.55 (95% CI 2.40, 5.25), while the RR in Houston was 2.83 (95% CI 1.50, 5.32). Age- and sex-specific standardized hypothermia mortality rates were 18.2 (95% CI 15.1, 21.2) per million in NYC and 30.1 (95% CI 21.7, 38.6) per million in Houston. The comparative hypothermia death ratio was 1.66 (95% CI 1.19, 2.30), indicating hypothermia mortality in Houston was 66% higher than in NYC. There was no correlation between zip code poverty rates and hypothermia-related deaths. The most consistent autopsy finding was Wischnewski spots (56.6%), and ethanol was the most common toxicological finding (36.5%). Local agencies can use this data to target these higher-risk populations and offer appropriate interventions to try to prevent these deaths.