{"doi":"10.1111/acem.13919","title":"The Impact of Heat Waves on Emergency Department Visits in Roanoke, Virginia","abstract":"Extreme heat, often coupled with high humidity, is a source of environmental stress to the human body. The resulting strain can lead to morbidity or mortality. Prior heat-related research has emphasized the impact of heat events on mortality, but there is a growing interest in understanding the influence of heat on emergency department (ED) visits, hospitalizations, and other disease metrics.1, 2 With increasing global temperatures, the number and/or intensity of heat events is likely to increase. Because heat is underreported as a potential cause of morbidity, traditional data set filtering by heat stress codes results in a significant underestimate of the actual heat impact. Furthermore, short-term surges in ED visits associated with heat can overtax the delivery of health services and place patients at undue risk. Given the ability of meteorologists to accurately forecast heat waves and the potential to use that knowledge in ED scheduling, understanding the relationship between heat wave events and ED visits is a potentially important, yet often unconsidered, factor in ED staffing. The purpose of this study was to determine the extent to which ED visits were associated with heat waves. In addition to the total daily ED visit count, we examined age, demographic (race/sex) groups, and discharge diagnoses and their relationship to heat waves. This retrospective study utilized daily ED visit encounters from 2010 to 2017 for residents of the Roanoke, Virginia, region who visited hospitals operated by Carilion Clinic, a six-hospital system in southwest Virginia. The Carilion Clinic Institutional Review Board deemed this study as having minimal risk to study subjects and did not require individual subject consent. Patient-level data acquired from an electronic data patient archive included basic demographic data (age, sex, race/ethnicity), zip code, date of service, and discharge diagnosis. To be included in the study data set, patients must have lived in Roanoke or the surrounding area during the study period. Inclusion was based on the patient zip code tabulation area (ZCTA) of residence. The full data set was subdivided by age class, sex, and race/ethnicity. The latter variable was coded as white/nonwhite given that small sample sizes for specific nonwhite groups impacted statistical robustness. We examined CCS level one discharge diagnoses (17 categories) based upon the appropriate ICD-9 or ICD-10 code. ICD-9 codes were converted to the appropriate ICD-10 code using publicly available tools (http://www.icd10codesearch.com). When code comparisons were unclear, they were mapped to the closest clinically appropriate term. Weather data were downloaded from archived measurements taken at the Roanoke airport (station code ROA) by the National Weather Service. We identified 54 ZCTAs in the vicinity of the ROA weather station that covered an area of approximately 2400 km2. Weather data were retrieved at the observation time closest to 1 p.m. local standard time and included air temperature, wet bulb temperature, and dew point temperature. Apparent temperature (AT) was calculated from the raw data. AT is a combination of air temperature and humidity used to estimate the added stress placed on the body during hot conditions based on the efficiency of evaporative cooling. AT is commonly used in heat-health studies and is statistically equivalent to the popular “Heat Index.”2, 3 We used a time-stratified case-crossover approach in which ED visit counts during heat waves (with lags of up to 2 days) were compared to a prior control period that was not part of any heat wave. We defined heat waves as 3 or more days exceeding a 1 p.m. AT threshold of 33°C with no more than 1 intervening day below the threshold.2 The 33°C threshold was chosen based on the overall warm-season AT distribution and prior research in the region.2 The 33°C AT was exceeded 9.3% of the time from April to September at ROA. Total ED visits during heat waves were compared","journal":"Academic Emergency Medicine","year":2020,"id":72790,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":14,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9629,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":370594,"name":"Margaret E. Houck","orcid":null,"position":1,"is_corresponding":false},{"id":369864,"name":"Erin S. Markle","orcid":"0000-0003-2137-9024","position":2,"is_corresponding":false},{"id":370593,"name":"Sara Windoloski","orcid":null,"position":3,"is_corresponding":false},{"id":370595,"name":"Kyle B. Enfield","orcid":null,"position":4,"is_corresponding":false},{"id":369865,"name":"Hyojung Kang","orcid":"0000-0001-7429-1101","position":5,"is_corresponding":false},{"id":369866,"name":"Robert C. Balling","orcid":"0000-0003-3555-0654","position":6,"is_corresponding":false},{"id":369867,"name":"Damon Kuehl","orcid":"0000-0001-9052-8412","position":7,"is_corresponding":false},{"id":370596,"name":"John H. Burton","orcid":null,"position":8,"is_corresponding":false},{"id":370597,"name":"Wilson Farthing","orcid":null,"position":9,"is_corresponding":false},{"id":370598,"name":"Edmundo Rubio","orcid":null,"position":10,"is_corresponding":false},{"id":369868,"name":"Wendy M. Novicoff","orcid":"0000-0002-5146-7706","position":11,"is_corresponding":false},{"id":369863,"name":"Robert E. Davis","orcid":"0000-0002-3969-878X","position":0,"is_corresponding":true}],"reference_count":10,"raw_metadata":null,"created_at":"2026-07-18T21:45:09.279825Z","pmid":"31950572","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}