Association of Heat Index and Patient Presentation Rate at a Stadium

A mass gathering is defined as an event that has the potential to strain the resources of the local health system. An onsite physician for mass gatherings can mitigate the strain on the local health infrastructure. One factor affecting onsite medical usage and patient presentation rates is the heat index, which is a calculated value of perceived heat exposure that combines air temperature and relative humidity. In this study we asked whether there was a positive association between heat index and patient presentation rates for onsite medical care at a bounded (large event in an enclosed location) professional stadium sporting event. We hypothesized that a positive correlation exists between these two variables and assess whether it might surpass current onsite resources.

We performed a prospective observational study with patients seeking medical care at a baseball stadium in a large northeastern city in the United States. The onsite physician collected information on patients who presented during games held at the stadium. Data on game attendance, temperature in degrees Fahrenheit (F), humidity, and heat index were collected using government and professional organization websites. We assessed the correlation between heat index and patient presentation rate with the Pearson product-moment correlation (PPMC) per 100,000 attendees at the game.

A total of 81 baseball games occurred at the studied stadium from April-September 2023, with eight games excluded due to incomplete data. The heat index ranged from 46°F to 91°F, with a mean (± SD) of 70.8°F (± 10.4°F). The number of patients varied from 0-5 per game, with a mean of 1.92 (± 1.13), and stadium attendance ranged from 25,007 to 47,295, with a mean of 40,824. The patient presentation rate per 100,000 in attendance was 5.04 (± 2.13). The PPMC was calculated to be 0.37 (P < .01), indicating a positive correlation between heat index and patient presentation rates. The most common reasons for seeking medical care were lightheadedness and musculoskeletal complaints.

In this study we found that the heat index was moderately associated with higher patient presentation rates at bounded mass gathering baseball events. No additional resources were needed, but this correlation could aid future event medical planning efforts as the climate continues to evolve.