Influence of Weather Patterns and Changes on Sickle Cell Disease Vaso-Occlusive Episodes and Acute Chest Syndrome: A Nationwide Sample Analysis

Abstract

Introduction: Vaso-occlusive episodes (VOE) in sickle cell disease (SCD) contribute to significant morbidity and healthcare costs due to repeated emergency department (ED) visits and hospital stays. Recurrent VOE's also often trigger serious sequelae, such as acute chest syndrome (ACS). Known risk factors for VOE include dehydration and infection. The effect of weather on the incidence of VOE has been studied in specific geographic locations with inconsistent results. Our study aims to determine the correlation between change in weather patterns and VOE nationwide using a large dataset. Methods: After IRB approval, the Pediatric Health Information System (PHIS) database was queried for SCD patients younger than 21 years of age evaluated in the ED or admitted for VOE and ACS from 2016-2021. The PHIS is a comparative database with clinical and resource utilization data for inpatient, ambulatory surgery, ED, and observation unit encounters for more than 49 children's hospitals nationwide. Patients with type HbSS, HbSC, Hb Sβ+, and Sβ(0) SCD were included. Demographic and clinical information was collected, including age, sex, race, geographic location, and inpatient length of stay. Weather information was collected via the National Climatic Data Center database. The weather variables included average temperature (Tavg), delta in temperature (TΔ), average precipitation, and average wind speed for every city in which a pediatric hospital within the PHIS database is located. Descriptive statistics were used to describe the demographics and weather characteristics. Population-averaged GEE analysis with negative binomial distribution with log link was performed with weekly counts of VOE admissions as the outcome, weather parameters as predictors, and hospitals as clusters. The weather parameters used were the averages of the daily units by week. Results from the regression analyses were reported as incidence rate ratios with 95% confidence intervals. A two-sided p-value less than 0.05 was considered as statistically significant for the analysis. Results: Of the total 79, 872 encounters included, 86% were diagnosed with VOE and 14% with ACS. Approximately, 52% of patients presented to hospitals in the southern region (Table 1). Regions (number of participating hospitals) include midwest (MW, 8), northeast (NE, 4), south (S, 11), and west (W, 5). Information from both the PHIS and weather database were available for 11,547 weeks. The south had the highest Tavg, TΔ, and precipitation. The MW had the highest wind speed and lowest Tavg. The NE had the lowest TΔ and Tavg. The west had the lowest wind speed and precipitation. The weather variables remained non-significant for ACS admissions. Overall, Tavg, TΔ, and wind speed were significant for VOE admissions while Tavg, precipitation, and wind speed were significant for VOE ED visits. Table 2 highlights the associations between overall VOE visits, weather variables, and regions. Conclusion: Our results show average temperature and delta in temperature (TΔ) is associated with the incidence of VOE admissions and ED visits. A positive association is observed in the midwest and northeast region for Tavg and negative association in the northeast region for TΔ. Future prospective studies will need to assess the effect of weather on VOE in a larger population, so specific weather-related guidelines can be developed for SCD patients and families. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal