The number of heat-related emergency department visits in the northwestern United States spiked during the last week of June, reflecting the heat wave’s “sizeable public health impact,” according to a report released last week by the Centers for Disease Control and Prevention (CDC).
“Record high temperatures are occurring more frequently in the United States, and climate change is causing heat waves to become more intense, directly impacting human health, including heat-related illnesses and deaths,” the report authors note. A previous study by CDC researchers found that in 2004 through 2018, an average of 702 heat-related deaths occurred in the United States annually.
In the new study, published in the Morbidity and Mortality Weekly Report, the researchers analyzed data from the National Syndromic Surveillance Program, a collaboration between the CDC and other federal agencies, local and state health departments, health care facilities, independent clinical laboratories, and a university-affiliated research center. They looked for patterns in heat-related emergency department visits during the June 2021 heat wave—when most of Oregon and Washington were under a National Weather Service excessive heat warning—and the preceding month in US Department of Health and Human Services (HHS) Region 10, an area that includes Alaska, Idaho, Oregon, and Washington.
In May and June, the region had 3504 visits for heat-related illness; 2779 (nearly 80%) of these visits occurred during June 25 to 30. Because these figures do not include individuals who sought medical treatment in settings other than emergency departments, they likely underestimate the actual prevalence of heat-related illness during the dates studied, the authors note.
Region 10 accounted for approximately 15% of heat-related emergency department visits nationwide during June, even though the area has only about 4% of the total US population. The average daily number of such visits in Region 10 during June 25 to 30 (424 visits) was 69 times higher than that during the same days in 2019 (6 visits), when no heat advisory was in effect.
The highest daily count of heat-related emergency department visits occurred on June 28, with 1038 visits, compared with just 9 visits on the same date in 2019.
The areas in Region 10 that were most affected by the record-breaking heat were Oregon and Washington, particularly the Portland metropolitan area, where temperatures soared as high as 116 °F (46.7 °C), 42 °F (5.6 °C) higher than the average daily maximum temperature in June.
When the researchers examined the rates of visits by age group and sex, they found that adults aged 75 years or older (1094 per 100 000 visits) and men (862 per 100 000 visits) were disproportionately affected.
The report did not include information about the number of deaths that occurred during the heat wave. However, the Washington State Department of Health tallied 91 heat-related deaths in the state from June 26 through July 10, and news reports said that the Oregon health authorities counted 116 heat-related deaths.
Southwestern Canada also experienced record-breaking high temperatures during the same period. From June 25 through July 1, the British Columbia Coroners Service counted 808 deaths in the province, and though the number of those fatalities directly caused by the extreme temperatures has not yet been determined, the average number of deaths reported during the same period over the previous 5 years was 198.
The authors of the CDC report said that to prepare for such catastrophic heat waves, health departments can develop and implement heat response plans, open cooling centers, identify neighborhoods and populations that are especially at risk, and use data “to guide public health policy and action to protect their communities from heat-related illness and deaths, especially among disproportionately affected populations.”
In addition, the report notes that environmental emergencies require having timely mechanisms for tracking health information, and that syndromic surveillance helps meet this need “through near real-time monitoring of health conditions to trigger response, guide policy, allocate resources, and save lives.”
Published: July 20, 2021. doi:10.1001/jamahealthforum.2021.2569
Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2021 Stephenson J. JAMA Health Forum.
Corresponding Author: Joan Stephenson, PhD, Consulting Editor, JAMA Health Forum (Joan.Stephenson@jamanetwork.org).
Conflict of Interest Disclosures: None reported.
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Stephenson J. Record High Temperatures in US Northwest Led to Surge in Heat-Related Emergency Department Visits. JAMA Health Forum. 2021;2(7):e212569. doi:10.1001/jamahealthforum.2021.2569