Environment/Climate Change
Excess moderate temperature days increase the risk of hospitalizations for cardiovascular conditions in multiple states Shannon Zenk* Melanie Sona Erin Liedtke Kelly Jones
Background: While it’s known that extreme heat can affect cardiovascular health, the impact of moderately hot temperatures (below 37°C) is unknown.
Objective: Our study aims to quantify the relationship between exposure to moderately hot temperatures ranging from 27°C to 37°C and the risk of in-patient hospitalization for cardiovascular conditions. Additionally, we aimed to contextualize hospitalization risk variation within different climate regions.
Methods: Inpatient electronic medical record data for patients with cardiovascular conditions was obtained from the Healthcare Cost and Utilization Project (HCUP) database for Arizona (AZ), Mississippi (MS), and New York (NY) 2016-2019. Daily high temperature at the ZIP code level was used to explore the associations between temperature and rate of hospitalization. We performed Poisson regression, controlling for year and stratifying by state, to determine the change in risk associated with each additional day above moderately hot temperatures during the hottest season of the year (June-September).
Results: Our study comprised of a sample size of 2,079,043 cardiovascular-related inpatient hospitalization. An additional day at 27°C was linked to an increased risk in hospitalization for cardiovascular conditions in AZ (RR 1.30, 95% CI 1.28-1.32), MS (RR 1.24, 95% CI 1.23-1.25), and NY(RR 1.10, 95% CI 1.10-1.11). Furthermore, results demonstrate distinct temperature thresholds at which the risk of hospitalization markedly escalates compared to the risk observed at 27°C. Notably in NY (32°C, RR 1.23, 95% CI 1.22-1.23) and MS (36°C, RR 1.41, 95% CI 1.37-1.44). This observation underscores regional disparities in the impact of temperature on the rate of hospitalization.
Discussion: Recognizing that temperatures well below extremes do increase the risk of experiencing heat exacerbated or induced cardiovascular illness, resulting in inpatient hospitalizations, is critical to inform climate-appropriate heat warning policies.