Killer Congestion: Temperature, Healthcare Utilization and Patient Outcomes

Extreme heat imperils health and results in more emergency department (ED) visits and hospitalizations. Since temperature affects many individuals within a region simultaneously, these health impacts could lead to surges in healthcare demand that generate hospital congestion. Climate change will only exacerbate these challenges. In this paper, we provide the first estimates of the health impacts from extreme heat that unpacks the direct effects from the indirect ones that arise due to hospital congestion. Using data from Mexico’s largest healthcare subsystem, we find that ED visits rise by 7.5% and hospitalizations by 4% given daily maximum temperatures above 34◦C. As a result, more (and sicker) ED patients are discharged home, and deaths within the hospital increase. While some of those hospital deaths can be directly attributed to extreme heat, our analysis suggests that approximately over half of these excess deaths can be viewed as spillover impacts due to hospital congestion. Additional analyses also reveal an increase in the share of deaths occurring outside hospitals, consistent with congestion-related health harms arising from the discharge of sicker patients from the ED. Our findings highlight an important new avenue of adaptation to climate change. If hospital congestion contributes to excess health damages from a changing climate, then expanding labor and capital investments and improving surge management tools can help reduce those damages.