Association between extreme heat exposure and Seattle, Washington pediatric hospital services, 2006 to 2023

Introduction: Climate change has led to a rise in global temperatures, resulting in more frequent and severe heat waves. These heat events pose significant threats to public health, especially among vulnerable populations such as children. Despite this, research on the specific health impacts of extreme heat on children, especially in Washington state, remains limited. We investigated the association between extreme heat exposure and pediatric hospitalizations. Methods: We conducted a case-crossover analysis of more than 300,000 clinical encounters at Seattle Children’s Hospital from May to September 2006 to 2023. Daily maximum humidex, a measure of temperature and relative humidity, was calculated by zip code using a spatiotemporal model. We performed conditional logistic regression to estimate the association between a 99th percentile extreme heat day and the odds of emergency department (ED) visits and inpatient/observational admissions for same days and prior single day lag effects. Results: Our analysis included 327,641 hospital encounters with a total of 8,170 extreme heat days. The overall odds of an ED visit on an extreme heat day were 3% (95% Confidence Interval (CI): 0%, 6%) higher than a non-extreme heat day, with continued significant increase in odds on lag days 2, 3, and 5. Conversely, the overall odds of an inpatient/observational admission on a heat day were 4% (95% CI: -9%, 0%) lower than on a non-extreme heat day. The fever-related diagnosis group for ED visits showed pronounced increase in odds on an extreme heat day at 15% (95% CI: 3%, 27%) higher odds for presenting to the ED. For the infectious-related diagnosis group, the odds of an inpatient/observational admission were 16% (95% CI: 1%, 34%) higher on extreme heat days and was notably higher for ED visits on lag days 2, 3, and 5. Discussion: Our results suggest that extreme heat is associated with an increase in ED visits for children, especially for fever-related conditions and an increase in infectious-related conditions for ED visits and inpatient/observational admissions for same day encounters and lagged days. Extreme heat may be inversely associated with overall inpatient/observational admissions for same day admissions. Pediatric practitioners should be aware that heat impacts children’s health outcomes and hospitals should be aware of increased ED load during periods of extreme heat for multiple health related causes.