Abstract 12202: Pandemic-Related Diminished Pollution and ST-elevation Myocardial Infarctions

Abstract

Introduction: The reason for the reduction in ST-elevation myocardial infarctions (STEMI) during the coronavirus disease 2019 (COVID-19) pandemic remains a mystery. Increased particulate matter 2.5 (PM 2.5) is a known risk factor for ST-elevation myocardial infarctions (STEMI), although evidence of the reciprocal relationship (decreased PM 2.5 associated with decreased STEMI incidence) has not been shown. We sought to perform a natural experiment to determine if decreased PM 2.5 during the COVID-19 pandemic was associated with a decrease in STEMIs. Methods: We abstracted daily STEMI events between January 1, 2019 to April 30, 2020 (shelter-in-place [SIP] orders began in March) from the National Emergency Medical Services (EMS) Information System (NEMSIS) database. Incidence rates (events per 10,000 person-years) were calculated using US Census population denominators by US Census Divisions We abstracted average daily PM 2.5 data from across the US from the Environmental Protection Agency (EPA) website. Negative binomial regression models were used to estimate the relationship between levels of PM 2.5 and STEMI rates, adjusting for US Census Division, calendar day of week, calendar month, and calendar year. Results: There were 60,722 total STEMI events recorded during the study period. After multivariable adjustment, there were 6% less STEMIs per each 10 μg/m 3 reduction in PM 2.5 (rate ratio 0.94, 95% CI 0.90-0.99, p = 0.016; Figure ). Using the same multivariate adjustment, there were 373.8 less STEMIs per 10,000 person-years for each 10 μg/m 3 decrease in PM 2.5 (95% CI 69.4-678.1). Conclusions: Pandemic-related declines in PM 2.5 levels were associated with significantly less STEMIs across the US. While more pollution is known to increase STEMI risk, this demonstration of the reciprocal relationship provides the most direct evidence that efforts to reduce ambient pollution can prevent the most severe forms of myocardial infarctions.