Monitoring the Health Costs of Heat-Related Illnesses and Deaths in Arizona

Extreme weather events including heat waves, wildfires, dust storms, flooding, and drought, along with adverse air quality events, are climate-sensitive public health hazards in Arizona. These environmental events pose risks to human health and can be affected by long-term changes in temperature, precipitation, and other weather conditions. Arizona’s extreme heat is a chronic issue that sustains 100 F degree daily maximum temperatures from May to September. These extreme heat events are projected to become more frequent and severe over time. Additionally, with an aging population and rapid population growth of city centers that contribute to the urban heat island effect, a larger vulnerable population is expected to be exposed to risk factors which could lead to heat exhaustion, heat stroke, and heat-related deaths. Extreme heat is the number one weather-related cause of death in Arizona and preventing heat illness has been a public health activity for many health organizations within the state. Stakeholders of the heat community in the state have identified that monitoring trends in heat illness and deaths would be beneficial to evaluate the effectiveness of interventions.

This analysis builds upon data collected by the Arizona Environmental Public Health Tracking (EPHT) program by utilizing hospital discharge data and vital records death data to quantify morbidity and mortality costs associated with exposure to excessive natural heat. Cases are ascertained using International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) diagnosis codes prescribed by the U.S. Centers for Disease Control and Prevention’s (CDC) National Environmental Public Health Tracking Network Nationally Consistent Data Measures. Arizona’s hospital discharge database, which contains billing information on total charges associated with hospital stays, emergency department visits, and payer types, is used to estimate the health care cost burden of these cases. Additionally, mortality costs will be derived using the Environmental Protection Agency’s Value of Statistical Life (VSL) estimates. A descriptive epidemiological analysis of charges for heat illnesses and deaths will be discussed for years 2008-2018.

In 2018, Arizona had 251 heat-related deaths. Additionally in that same year, Arizona hospitals saw 2,989 heat-related emergency department visits and 750 inpatient admissions. This analysis aims to characterize the economic cost of morbidity and mortality due to heat-related illnesses and deaths in Arizona over time. Information from this analysis is meant to build a baseline methodology for summarizing the cost-benefit of public health interventions implemented for preventing heat illness against health outcome treatment costs. Furthermore, the goal of this work is to bring awareness to this issue through prevention programs and further the adoption of public health adaptation activities across local organizations in Arizona.