O3214: Trends and outcomes of heat-related illnesses at a tertiary children's hospital system in the southern United States, 2012-2023

Background: As extreme summer temperatures become more frequent due to a changing climate, there is an increased risk of heat-related morbidity and mortality, particularly in vulnerable populations such as children. Heat-related illnesses represent a clinical spectrum of disorders ranging from heat cramps to heat stroke and may be complicated by end-organ injury such as rhabdomyolysis. Pediatric data on trends and outcomes of heat-related illness are lacking. This study aims to examine trends in heat-related illness over time and describe differences in patient characteristics and outcomes for children with "heat-specific" diagnoses compared to rhabdomyolysis.

Methods: We conducted a retrospective study at a pediatric health care system with two large children’s hospitals to identify Emergency Department (ED) encounters with a heat-related ED diagnosis during warm months (May through September) from 2012 to 2023. We included ED diagnoses corresponding to “excessive natural heat” (ICD-10 X30) and “effects of heat and light” (T67) (“heat-specific” diagnoses) and rhabdomyolysis (M62.82). We analyzed aggregate heat-related monthly ED encounters over time (Mann-Kendall) and association with maximum temperature (Pearson correlation). We described differences in “heat-specific” vs rhabdomyolysis encounters using Chi-square.

Results: There were 542 heat-related ED encounters. Aggregate heat-related encounters, as a proportion of total ED encounters, increased by 170% from 2012 (4.3 per 10,000) to 2023 (11.6 per 10,000) (p=.01). Summer months with higher peak temperatures were associated with higher heat-related ED volume (r=0.66, p<.001) (Figure 1).

Of all heat-related encounters, 418 (77%) had heat-specific diagnoses, and 131 (24%) had a rhabdomyolysis diagnosis. Compared to the rhabdomyolysis group, the heat-specific group was younger, more likely to be Hispanic, use government-based insurance, and live in an area with a lower Child Opportunity Index score. Most heat-specific encounters resulted in an ED discharge (96%), while most rhabdomyolysis encounters resulted in hospital admission (63%) (Table 1).

Conclusion: Heat-related illness ED volume is associated with higher temperature and is increasing over time. Rhabdomyolysis, compared to other heat-related illnesses, is associated with different patient characteristics, lower frequency, and higher severity. Given the rise in healthcare utilization from heat-related illness, it is essential for all pediatricians to understand the health implications of our changing climate.