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Overview
Exposure to higher temperatures is one of the more direct impacts related to extreme weather driven by climate change. Climate scientists project that most communities in Oregon will experience an increase of more than 30 days over 90°F by mid-century[1].
Extreme heat events can cause loss of internal temperature regulation and conditions including heat cramps, heat exhaustion, heat stress, heat stroke, and death[2].
In the United States, extreme heat causes more deaths annually than all other weather events combined[3]. Investments to mitigate temperature increases and support climate adaptation can reduce heat-related deaths[4]. Therefore, where there are risks, there are opportunities to support mitigation and adaptation efforts to save lives.
The Pacific Northwest has seen an increase in average annual temperatures of 1.5°F compared to the first half of the 20th century, and a further increase of 4-9°F is expected by the end of this century[5]. In 2024, summer temperatures continued to be warmer than average. A majority of the tri-county region experienced mean temperatures throughout the month of July that were in the top 10% of mean temperatures recorded over the past century[6]. In Portland, Troutdale, and Hillsboro, several daily maximum temperatures were set in early July, and early September. This indicates increasingly severe heat at the peak of summer, and an extending summer season[7].
Elevating Equity
Heat exposure and the ability to adapt to that exposure are dependent on social and environmental conditions. In a comprehensive study of health impacts from heat, the U.S. Global Change Research Program synthesized evidence on populations most at risk[8]. The study found evidence that the following groups face higher risk from extreme heat:
Adults over the age of 65
People experiencing houselessness
People with chronic medical conditions that reduce thermoregulation (like heart disease or poor blood circulation)
People with few social connections and limited social networks
Children
Pregnant people
People living, working, or going to school in an urban heat island
People from some racial and ethnic groups affected by structural environmental racism with limited access to protective factors (e.g. homeownership)
People with mental, behavioral, or cognitive disorders that are exacerbated by heat, or who rely on medications that interfere with thermoregulation
People with no access to cooling systems at home
References
[1]Oregon Watershed Enhancement Board(2023). Observed and Projected Climate Changes. Oregon Government Website. Published September 2023. Accessed May, 2025. https://www.oregon.gov/oweb/Documents/climate-R3-variables.pdf. ↩︎
[2] Bell, J. E., S. C. Herring, L. Jantarasami, C. Adrianopoli, K. Benedict, K. Conlon, V. Escobar, J. Hess, J. Luvall, C. P. Garcia-Pando, D. Quattrochi, J. Runkle, and C. J. Schreck III, 2016: Ch. 4: Impacts of extreme events on human health. The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment., U.S. Global Change Research Program, Washington, DC, 99–128. doi:10.7930/J0BZ63ZV occri.net/ocar4 ↩︎
[3]National Weather Association.Weather Related Fatality and Injury Statistics.Nation Weather Service National Oceanic and Atmospheric Administration. Published 2025. Accessed May 2025. https://www.weather.gov/hazstat. .↩︎
[4]Romanello M, Napoli CD, Green C et. al.The 2023 report of the Lancet Countdown on health and climate change: the imperative for a health-centred response in a world facing irreversible harms. Lancet. 2023 Dec 16;402(10419):2346-2394. doi: 10.1016/S0140-6736(23)01859-7. Epub 2023 Nov 14. PMID: 37977174; PMCID: PMC7616810. ↩︎
[5] Lo, Y. T.. E., Mitchell, D. M., Gasparrini, A., Video-Cabrera, A. M., Ebi, K. L., Frumhoff, P. C., Millar, R. J., Roberts, W., Sera, F., Sparrow, S., Uhe, P, & Williams, G. (2019). Increasing mitigation ambition to meet the Paris Agreement’s temperature goal avoids substantial heat-related mortality in U.S. cities. Science Advances. 5; p 1-9. ↩︎
[6]National Weather Service(2024). Month in Review- July 2025. National Weather Service National Oceanic and Atmospheric Administration Website. Published July 2024. Accessed May, 2025. https://www.weather.gov/media/pdt/PDT%20Month%20in%20Review%20-%20July%202024.pdf#:~:text=Average%20temperatures%20during%20July%20were%20much%20above,Washington%2C%20most%20notably%20in%20the%20Blue%20Mountains. ↩︎
[7] National Weather Service. Climate Graphs. Previous Monthly Charts and Tables,2024. National Weather Service National Oceanic and Atmospheric Administration Website. Accessed May, 2025. https://www.weather.gov/pqr/CliPlot. ↩︎
Trends
This section looks at Emergency Department and Urgent Care (ED/UC) visits, hospitalizations, and deaths due to extreme heat. Heat is dangerous to our health, especially when:
Temperatures are higher
Heat lasts for consecutive days (two or more)
It doesn’t cool down enough at night
It’s earlier in the summer and our bodies aren’t used to the heat yet
The National Weather Service (NWS) uses these factors to set a Heat Risk Index [8], which you can see below. The Heat Risk Index lets us see how much we were exposed to dangerous heat. These data look at the months of September – May, referred to as the “warm season”.
Calendar Heat Risk
In recent years there have been more days with major heat risk and more consecutive (two or more) days of heat risk. Source: Environmental Protection Agency (EPA)
Calendar that shows the highest NWS heat risk level in the tri-county region during the warm season from 2018 – 2024.
Heat-related illness ED/UC visits since 2021 have been much higher than in 2020.
Number of ED/UC visits for heat-related illness during the 2020 – 2024 warm seasons by county and year of visit.
The rate of heat-related illness ED/UC visits compared with total ED/UC visits peaked during the year of the heat dome in summer 2021, but has since remained higher than most previous years.
Rates of ED/UC visits for heat-related illness per 100,000 total ED/UC visits by county and year for 2016-2024 warm seasons. *The denominator is all ED/UC visits since the same person can visit facilities multiple times.
Hospitalizations
Rates and yearly counts of hospitalizations for heat-related illness each year are compared with all hospitalizations from May to September for the region and each county.
Hospitalizations for heat-related illness were highest in summer 2021 and present in recent years for all three counties.
Number of hospitalizations for heat-related illness during 2020 – 2024 warm seasons by county and year of admission
The rates of heat-related illness hospitalizations compared with all hospitalizations peaked during the year of the heat dome in summer 2021, but remained higher than previous years.
Rates of hospitalizations for heat-related illness per 100,000 hospitalizations by county and year for 2016 to 2024 warm seasons.
Most heat-related deaths happened during the 2021 heat dome, summers since the heat dome have had more deaths than expected and have not returned to pre-heat dome levels.
Number of heat-related deaths during 2020 – 2024 warm seasons by county and year of admission.
The rate of heat-related deaths among all deaths was greatest in Multnomah County from 2021-2023 but has been slightly greater in Washington County in recent years
Rates of heat-related deaths per 100,000 deaths by county and year during 2014-2024 warm seasons.
This section looks at demographic information for heat-related illness Emergency Department and Urgent Care (ED/UC) visits, hospitalizations, and deaths.
Visits are given as a percentage for age, race/ethnicity, and sex.
A larger percentage of heat-related illness ED/UC visits are by males, seniors, and people identifying as white when compared to all ED/UC visits.
Demographic comparison of heat-related illness ED/UC visits and all ED/UC visits in the tri-counties during the 2021 – 2024 warm seasons.
Rates of heat-related illness ED/UC visits compared with all ED/UC visits have increased among adolescents, young adults, seniors ages 65 – 74, both men and women, and nearly all racial and ethnic identities in recent years. Rates decreased among people ages 75+. 2019–2022 and 2023–2024
Rate of heat-related illness ED/UC visits per 100,000 all visits for 2019–2022 and 2023–2024 warm seasons by patient age, race/ethnicity, and sex in the region.
A larger percentage of hospitalizations for heat-related illness are by males, and people over 45 years of age when compared to all hospitalizations
Demographic comparison of hospitalizations for heat-related illness and all hospitalizations in the region during the 2021 – 2024 warm seasons.
Rates of heat-related illness hospitalizations compared with all-cause hospitalizations have increased among younger adults, males, nearly all racial and ethnic identities, but decreased among people ages 45 years and older, females, and people identified as white alone. 2019–2022 and 2023–2024
Rate of heat-related illness hospitalizations per 100,000 total hospitalizations for 2019–2022 and 2023–2024 warm seasons by patient age, race/ethnicity, and gender in the region.
Compared to all-cause deaths, a larger percentage of heat-related deaths are by males and people ages 45-74.
Demographic comparison of heat-related deaths and all deaths in the region during the 2021 – 2024 warm seasons.
Risk Factors for Emergency Department and Urgent Care Visits
Risk factors for heat exposure (vehicle, outdoor activity, occupational activity, intoxication, and houselesness) and arrival by ambulance (representing severity of illness) for HRI ED/UC visits from summer 2024 were identified by manual reviews.
We used keywords from our manual reviews to develop codes that automatically search for those that mention each risk factor based on information from the visit records.
Codes that correctly identified 70% or more of manually-identified risk factors in the 2024 data were then applied to historical data from 2016-2024 to show trends over time. Results from identified codes are presented in the section risk factors over time.
Risk Factors Counts
A large number of ED/UC visits during warm season 2024 mentioned outdoor activities (e.g., yard work, sports/recreation).
Number of heat-related illness visits with description of heat exposure identified in manual review of written notes during warm season 2024.
Risk Factors Percentages
Across all three counties, a large percentage of heat-related illness ED/UC visits during summer 2024 mention heat exposure in outdoor and occupational settings.
Percentage of heat-related illness visits with description of heat exposure in written notes during 2024 warm season.
Ambulance
Arrival by ambulance is an indicator of potential barriers to transportation, access to care, as well as severity of health condition. Additionally, ambulance use can create a financial burden for patients.
A majority of heat-related illness ED/UC visits during summer 2024 in Clackamas and Multnomah Counties mention arrival by ambulance, indicating high severity of illness.
Percentage of heat-related illness ED/UC visits that mention arrival in ambulance during 2024 warm season.
Risk Factors Over Time
Occupational exposure was the most frequently identified risk factor in heat-related illness ED/UC visits in the entire region
Percentage of heat-related illness ED/UC visits with mention of specific risk factors from 2016 – 2024. This data is derived from automated codes, and numbers slightly differ from those found by manual review for summer 2024
Notes
Data details
Daily Heat Risk data is from National Weather Services (NWS). The data on Air Quality Index (AQI) comes from the Environmental Protection Agency (EPA), and the number of Emergency Department and Urgent Care visits (ED/UC) for heat-related illness came from the Electronic Surveillance System for the Early Notification of Community-based Epidemics (ESSENCE) in Oregon.
The number of hospitalizations was obtained by request from the Office of Health Analytics at Oregon Health Authority Health Policy and Analytics Division.
Data on deaths that occurred in the region come from death certificates from Oregon Vital Statistics from 2019-2024. Vital records data captures information on the cause and manner of death, and demographic information about the decedent. Deaths have one underlying cause and up to twenty contributing causes that are recorded by a medical professional or the county medical examiner. The underlying cause is the disease or injury that initiated the chain of events leading to death and contributing causes contribute to death but are not to the ultimate direct cause. Both underlying and contributing causes of death are translated into codes (ICD-10, or International Statistical Classification of Disease, 10th revision) which can then be queried to find heat related deaths.
For causes of hospitalizations and death(underlying and contributing) the ICD 10 codes used are X30 and T67.
These data are for the months of May-September from 2019-2024.
Methods
Quantitative
We obtain data for heat-related emergency department and urgent care visits (ED/UC visits) of county residents, heat-related hospitalizations of county residents, and heat-related death occurring within each county (See table of heat-related health indicators). We aggregate indicators per summer season and present annual number of events (ED/UC visits, hospitalizations, or deaths) for the region and each county in bar graphs. We calculate annual rates of each heat-related indicator.
Rates for heat-related illness ED/UC visits and hospitalizations are among all ED/UC visits and all hospitalizations for the same time period. We do not calculate visit percent or rates by census population data because some visits and hospitalizations can be by the same person. Urgent care facilities reporting to ESSENCE can also change over time. Therefore, the percentage of heat-related illness among all ED/UC visits and hospitalizations provides a consistent way to track changes in the burden of climate-related care over time and identify differences between who typically seek care. Rates for heat-related deaths are among all deaths in the region (place of injury) for the same time period.
Heat-related Health Indicators
Health Outcome
Data Source
Query Details
Heat-related illness (ED/UC Visits) (Heat-related illness refers to a variety of conditions resulting from elevated body temperatures such as heat stroke, heat syncope (fainting), heat exhaustion, and heat cramps.)
Oregon ESSENCE (Electronic Surveillance System for the Early Notification of Community-Based Epidemics)
Keywords in patient records that suggest heat illness, such as:
• "heat stroke"
• "heat exhaustion"
• "too hot"
• "hyperthermia"
• "sunstroke"
• "heat cramps"
• and other variations like "hot" with "fatigue," "exposure," or "cramps."
ICD 9 and 10 Codes:T67, 992
Excludes people whose symptoms are clearly unrelated to heat, such as:
• People saying they "feel hot" without other signs
• Pain in body parts (e.g., limb, back, jaw) not related to heat
• Descriptions involving heating pads, heat packs, or dental pain
• Non-medical uses of "heat" (e.g., "hot tea", "hot grease", "heater", "hot flash")
• Mentions of fever, alcohol, burns in the mouth, or psychological symptoms
Heat-Related Hospitalizations among Tricounty Residents
Office of Health Analytics: Hospital Reporting Program
ICD 10 Codes:X30, T67, and P81.0
Heat-Related Deaths that occurred in Tri County
Oregon Vital Records
ICD 10 Codes:X30, T67, and P81.0
Note: All queries were conducted for the period October to March, 2016-2024
QualitativeRisk Factors Identified by Manual Review
We used existing queries and reviewer guides from our region to develop a guide for manual review of all heat-related illness queries from summer 2024. Each county had two people independently review triage notes, chief complaints, and discharge diagnosis for evidence of the risk factors below. Disagreements were resolved through discussions toward consensus.
Risk Factors Identified by Manual Review
Concept
Description for Manual Review
Vehicle
We aim to capture heat exposure in vehicles that can rapidly become overheated. These include exposures that occur in private or occupational vehicles (e.g., car, RV, delivery truck) for reasons such as lack of AC, overheating, or more.
Outdoor
We aim to capture when injury/illness was likely sustained outdoors. These include heat exposures from living, working or participating in any outdoor activity such as attending events, doing yard work, or recreation.
Occupation
We aim to capture when injury/illness was likely sustained on the job through extended periods of time in the heat. Occupational heat exposure includes working outdoors during extreme heat, and indoors without adequate cooling (e.g., kitchens, manufacturing)
Mental Health
We aim to capture cases where there was evidence that mental health disability/conditions were exacerbated by heat or made people more vulnerable to heat's impact.
Intoxication
We aim to capture substances that can impair people's judgement such as stimulants, opioids, and alcohol, and cause physiologic effects impacting the ability to cool one's body.
Signs of Houselessness
People experiencing houselessness are vulnerable to extreme heat due to their living conditions, co-occurring health issues, and lack of resources. Signs of houselessness include direct mention of the patient being houseless/homeless and context-dependent notes, such as being found in the streets/in a tent, being brought in from a shelter, needing shelter, living in car/RV.
Ambulance arrival
Transport by ambulance represents the burden on Emergency Management Services, and patient illness severity and access to transportation and healthcare.
Note: These concepts are used to categorize heat exposure cases during manual review of records
Risk Factors Identified by Automated Text Search
Automated text queries that are codes with a set of search criteria were used to identify yearly visits with mention of houselessness, intoxication, and occupation during May to September from 2016-2024. Based on HRI visit data for summer 2024, the queries used to identify houselessness, intoxication, and occupational heat exposure correctly identified at least 70% (Sensitivity>70% & Specificity>70%) of visits identified by manual review (referent value) for these risk factors.
Risk Factors and Automated Text Queries
Risk Factor
Automated Text Query
Houselessness
Keywords in patient records that suggest houselessness, such as:
• "Homeless"
• "Houseless"
• "Sleeps in his vehicle"
• "Sleeps in her vehicle"
• "Sleeps in vehicle"
• "Unsheltered"
• "Sleep out"
• "Sleeping out"
• "Live out"
• "Living out"
• "Sleep in car"
• "Sleep in RV"
• "Live in RV"
• "No housing"
• "Lack of housing"
• "Without housing"
ICD 10 Codes: Z590 and Z591
Intoxication
Keywords in patient records that suggest intoxication, such as:
• "Intoxic"
• "Alcohol"
• "Marijuana"
• "Fentan"
ICD 10 Codes: F19, F10, F11, and F12
Occupation
Keywords in patient records that suggest occupation, such as:
• "Occupation"
• "Construction"
• "Employer"
• "Landscape"
• "Employee"
• "Employed"
Note: These queries are used to automatically identify risk factors in patient records
Extreme Heat Overview
Exposure to higher temperatures is one of the more direct impacts related to extreme weather driven by climate change. Climate scientists project that most communities in Oregon will experience an increase of more than 30 days over 90°F by mid-century. Extreme heat events can cause loss of internal temperature regulation and conditions including heat cramps, heat exhaustion, heat stress, heat stroke, and death.
In the United States, extreme heat causes more deaths annually than all other weather events combined. Investments to mitigate temperature increases and support climate adaptation can reduce heat-related deaths. Therefore, where there are risks, there are opportunities to support mitigation and adaptation efforts to save lives.
The Pacific Northwest has seen an increase in average annual temperatures of 1.5°F compared to the first half of the 20th century, and a further increase of 4-9°F is expected by the end of this century. In 2024, summer temperatures continued to be warmer than average. A majority of the tri-county region experienced mean temperatures throughout the month of July that were in the top 10% of mean temperatures recorded over the past century. In Portland, Troutdale, and Hillsboro, several daily maximum temperatures were set in early July, as well as early September. This indicates increasingly severe heat at the peak of summer, as well as an extending summer season.
Elevating Equity
Heat exposure and the ability to adapt to that exposure are dependent on social and environmental conditions. In a comprehensive study of health impacts from heat, the U.S. Global Change Research Program synthesized evidence on populations most at risk. The study found evidence that the following groups face higher risk from extreme heat:
Adults over the age of 65
People experiencing houselessness
People with chronic medical conditions that reduce thermoregulation (like heart disease or poor blood circulation)
People with few social connections and limited social networks.
Children
Pregnant people
People living, working, or going to school in an urban heat island.
People from some racial and ethnic groups affected by structural environmental racism with limited access to protective factors (e.g. homeownership)
People with mental, behavioral, or cognitive disorders that are exacerbated by heat, or who rely on medications that interfere with thermoregulation.
People with no access to cooling systems at home
Trends
This section looks at Emergency Department and Urgent Care (ED/UC) visits, hospitalizations, and deaths due to extreme heat. Heat is dangerous to our health, especially when:
Temperatures are higher
Heat lasts for consecutive days (two or more)
It doesn’t cool down enough at night
It’s earlier in the summer and our bodies aren’t used to the heat yet
The National Weather Service (NWS) uses these factors to set a Heat Risk Index, which you can see below. The Heat Risk Index lets us see how much we were exposed to dangerous heat during the warm seasons (May to September) in 2018 – 2024.
Calendar Heat Risk
Key Takeaway: “In recent years there have been more days with major heat risk and more consecutive (two or more) days of heat risk. Source: National Oceanic Atmospheric Administration NOAA”
Alt Text: “Calendar that shows the highest NWS heat risk level each day in the tri-county region from May to September 2018 to 2024. Heat risk is coded by color, ranging from little to none, minor, moderate, major, and extreme.” Emergency Department and Urgent Care Visits
Heat-Related Illness Emergency Department and Urgent Care (ED/UC) visits
ED/UC visits for heat-related illness (HRI) from May to September for the region and by county.
Annual Count
Key Takeaway: “Heat-related illness ED/UC visits since 2021 have been much higher than in 2020.”
Alt Text: “Vertical bar chart showing yearly number of heat-related illness ED/UC visits from 2020 to 2024 warm season for Clackamas, Multnomah, and Washington Counties, and the entire region.”
Rates
Key Takeaway: “The rate of heat-related illness ED/UC visits compared with total ED/UC visits peaked during the year of the heat dome in summer 2021, but has since remained higher than most previous years.”
Alt Text: “Line graph of annual rate of heat-related illness ED/UC visits among all visits during 2016 – 2024 warm seasons.”
Heat-Related Hospitalizations
Rates and yearly counts of hospitalizations for heat-related illness each year are compared with all hospitalizations from May to September for the region and each county. Percentage of hospitalizations from summers 2016 – 2024 are presented by age, race/ethnicity, and sex.
Annual Count
Key Takeaway: “Hospitalizations for heat-related illness were highest in summer 2021 and present in recent years for all three counties.”
Alt Text: “Vertical bar chart showing yearly number of heat-related illness hospitalizations from 2020 – 2024 warm seasons for Clackamas County, Multnomah County, Washington County, and the entire region.”
Rates
Key Takeaway: “The rates of heat-related illness hospitalizations compared with all hospitalizations peaked during the year of the heat dome in summer 2021, but remained higher than previous years.”
Alt Text: “Line graph of yearly rate of heat-related illness hospitalizations among all hospitalizations during 2016 to 2024 warm seasons.”
Heat-Related Deaths
Rates and yearly counts of deaths from heat-related illness (link to data details) from May – September for the region and by county.
Annual Count
Key Takeaway: “Most heat-related deaths happened during the 2021 heat dome, summers since the heat dome have had more deaths than expected and have not returned to pre-heat dome levels.”
Alt Text: “Vertical bar chart showing yearly number of heat-related deaths from 2020 – 2024 warm seasons for Clackamas County, Multnomah County, Washington County, and the entire region.”
Rates
Key Takeaway: “The rate of heat-related deaths was greatest in Multnomah County from 2021 – 2023 but has been slightly higher in Washington County in recent years.”
Alt Text: “Line graph of yearly rates of heat-related deaths compared with all deaths during 2016 – 2024 warm seasons.” Risk Factors for Emergency Department and Urgent Care Visits
Heat-Related Demographics
This section looks at demographic information for heat-related Emergency Department and Urgent Care (ED/UC) visits, hospitalizations, and deaths. Visits are given as a percentage for age, race/ethnicity, and sex.
Heat-Related Emergency Department and Urgent Care Visits
Key Takeaway: “Males, seniors, and people identifying as white have a higher percentage of heat-related illness ED/UC visits.
Alt Text: “Horizontal bar chart comparing percentage of heat-related illness ED/UC visits and all ED/UC visits for 2016 – 2024 warm seasons by age, race/ethnicity, and sex.”
Category
Sub-Category
Heat Related ED/UC Visits
All ED/UC Visits
Sex
Male*
0.61
0.45
Sex
Female*
0.39
0.55
Age
Younger Adult (18-44)
0.39
0.40
Age
Older Adult (45-64)
0.25
0.25
Age
Senior (65-74)*
0.14
0.11
Age
Older Senior (75+)*
0.13
0.11
Age
Adolescence (10-17)*
0.04
0.06
Age
Preschool (0-4)*
0.03
0.05
Age
Childhood (5-9)*
0.02
0.03
Race Alone
White alone*
0.72
0.64
Race Alone
Hispanic or Latino*
0.09
0.12
Race Alone
Other Race*
0.09
0.11
Race Alone
Black or African American alone*
0.05
0.07
Race Alone
Asian alone*
0.03
0.05
Race Alone
American Indian or Alaska Native alone
0.01
0.01
Race Alone
Native Hawaiian or Pacific Islander alone
0.01
0.01
Rates by Demographic
Key Takeaway: “Rates of heat-related illness ED/UC visits compared with all ED/UC visits have increased among adolescents, young adults, and seniors ages 65 – 74 in recent years. Rates decreased among people ages 75+. Rates have increased among both men and women in recent years. Rates have increased among nearly all racial and ethnic identities.”
Alt Text: “Barbell chart that shows rate of heat-related illness visits per 100,000 all visits for 2019 – 2022 compared with rate from 2023 – 2024 by patient age, race and ethnicity, and sex”
Heat-Related Hospitalization
Key Takeaway: “A larger percentage of hospitalizations for heat-related illness are by males, and people over 45 years of age”
Alt Text: “Horizontal bar chart comparing heat-related hospitalizations and all hospitalizations for 2016 – 2024 by age, race and ethnicity, and sex”
Category
Sub-Category
Heat-Related Hospitalizations
All Hospitalizations
Sex
Male*
0.60
0.47
Sex
Female*
0.40
0.53
Age
Older Senior (75+)*
0.32
0.22
Age
Older Adult (45-64)*
0.29
0.21
Age
Senior (65-74)
0.20
0.16
Age
Younger Adult (18-44)
0.17
0.21
Age
Adolescence (10-17)
0.01
0.02
Age
Childhood (5-9)
0.00
0.01
Age
Preschool (0-4)*
0.00
0.18
Race Alone
White alone
0.70
0.65
Race Alone
Black or African American alone
0.07
0.05
Race Alone
Asian alone
0.06
0.05
Race Alone
Refused/Unknown/NA
0.06
0.11
Race Alone
Hispanic or Latino*
0.04
0.09
Race Alone
Other Race alone
0.03
0.04
Race Alone
American Indian or Alaska Native alone
0.02
0.01
Race Alone
Native Hawaiian or Pacific Islander alone
0.00
0.01
Rates by Demographics
Key Takeaway: “Rates of heat-related illness hospitalizations compared with all-cause hospitalizations have increased among younger adults but decreased among people ages 45 years and older. Hospitalization rates for males have increased and females have decreased. Rates have increased among nearly all racial and ethnic identities but decreased among people identifying as white or any other race alone.”
Alt Text: “Barbell chart that shows rate of heat-related hospitalizations per 100,000 total hospitalizations for 2019 to 2022 compared with rate from 2023 to 2024 by patient age, race and ethnicity, and sex.”
Heat-Related Deaths
Key Takeaway: “Males and people ages 45 – 74 have a higher percentage of heat-related deaths.”
Alt Text: “Horizontal bar chart comparing percentage of heat-related deaths and all deaths for 2016 – 2024 by age, race and ethnicity, and sex.
Category
Sub-Category
Heat-Related Deaths
All Deaths
Sex
Male*
0.70
0.54
Sex
Female*
0.30
0.46
Age
Older Adult (45-64)*
0.34
0.19
Age
Senior (65-74)*
0.34
0.21
Age
Older Senior (75+)*
0.28
0.51
Age
Younger Adult (18-44)
0.04
0.08
Age
Preschool (0-4)
0.01
0.01
Race Alone
White alone
0.85
0.85
Race Alone
Black or African American alone
0.05
0.04
Race Alone
Hispanic or Latino
0.04
0.05
Race Alone
American Indian and Alaska Native alone*
0.03
0.01
Race Alone
Asian alone
0.02
0.04
Risk Factors
Reviewers manually identified risk factors for summer 2024. An automated text query, searching for keywords among visits during the warm season was used to present risk factors mentioned over time.
Key Takeaway: A large number of ED/UC visits in Clackamas, Multnomah, and Washington Counties describe outdoor activity leading to heat illness.
Alt Text: Horizontal bar graph that shows number of visits with description of heat exposure by Clackamas, Multnomah, and Washington County.
Key Takeaway: Across all three counties, a large percentage of heat-related illness ED/UC visits describe heat exposure in outdoor and occupational settings.
Alt Text: Horizontal bar graph showing percentage of visits with description of heat exposure by county.
Key Takeaway: A majority of heat-related illness ED/UC visits in Clackamas and Washington Counties mention arrival in ambulance during 2024 warm season.
Alt Text: Pie charts showing percentage of ED/UC visits with mention of arrival in ambulance.
Key Takeaway: “Occupational exposure was the most frequently identified vulnerability factor in heat-related illness ED/UC visits in the three counties”
Alt Text: “Line graph that shows yearly percentage of heat-related illness ED/UC visits with mention of intoxication, occupation, or houselessness from 2016 to 2024.”
Notes
Data details
Daily Heat Risk data is from National Weather Services (NWS). The data on Air Quality Index (AQI) comes from the Environmental Protection Agency (EPA), and the number of Emergency Department and Urgent Care visits (ED/UC) for heat-related illness came from the Electronic Surveillance System for the Early Notification of Community-based Epidemics (ESSENCE) in Oregon.
The number of hospitalizations was obtained by request from the Office of Health Analytics at Oregon Health Authority Health Policy and Analytics Division.
Data on deaths that occurred in the region come from death certificates from Oregon Vital Statistics from 2019-2024. Vital records data captures information on the cause and manner of death, and demographic information about the decedent. Deaths have one underlying cause and up to twenty contributing causes that are recorded by a medical professional or the county medical examiner. The underlying cause is the disease or injury that initiated the chain of events leading to death.
Contributing causes contribute to death but are not to the ultimate direct cause. All causes of death are translated into codes (ICD-10, or International Statistical Classification of Disease, 10th revision) which can then be queried to find heat related deaths.
For Hospitalizations and Deaths the ICD 10 codes used are X30 and T67.
These data were for the months of May-September from 2019-2024.
Methods
Quantitative
We obtain data for heat-related emergency department and urgent care visits (ED/UC visits) of county residents, heat-related hospitalizations of county residents, and heat-related death occurring within each county (See table of heat-related health indicators). We aggregate indicators per summer season and present annual number of events (ED/UC visits, hospitalizations, or deaths) for the region and each county in bar graphs. We calculate annual rates of each heat-related indicator.
Rates for heat-related illness ED/UC visits and hospitalizations are among all ED/UC visits and all hospitalizations for the same time period. We do not calculate visit percent or rates by census population data because some visits and hospitalizations can be by the same person. Urgent care facilities reporting to ESSENCE can also change over time. Therefore, the percentage of heat-related illness among all ED/UC visits and hospitalizations provides a consistent way to track changes in the burden of climate-related care over time and identify differences between who typically seek care. Rates for heat-related deaths are among all deaths in the region (place of injury) for the same time period.
Heat-related Health Indicators
Health Outcome
Data Source
Query Details
Heat-related illness (ED/UC Visits) (Heat-related illness refers to a variety of conditions resulting from elevated body temperatures such as heat stroke, heat syncope (fainting), heat exhaustion, and heat cramps.)
Oregon ESSENCE (Electronic Surveillance System for the Early Notification of Community-Based Epidemics)
Keywords in patient records that suggest heat illness, such as:
• "heat stroke"
• "heat exhaustion"
• "too hot"
• "hyperthermia"
• "sunstroke"
• "heat cramps"
• and other variations like "hot" with "fatigue," "exposure," or "cramps."
ICD 9 and 10 Codes:T67, 992
Excludes people whose symptoms are clearly unrelated to heat, such as:
• People saying they "feel hot" without other signs
• Pain in body parts (e.g., limb, back, jaw) not related to heat
• Descriptions involving heating pads, heat packs, or dental pain
• Non-medical uses of "heat" (e.g., "hot tea", "hot grease", "heater", "hot flash")
• Mentions of fever, alcohol, burns in the mouth, or psychological symptoms
Heat-Related Hospitalizations among Tricounty Residents
Office of Health Analytics: Hospital Reporting Program
ICD 10 Codes:X30, T67, and P81.0
Heat-Related Deaths that occurred in Tri County
Oregon Vital Records
ICD 10 Codes:X30, T67, and P81.0
Note: All queries were conducted for the period October to March, 2016-2024
QualitativeRisk Factors Identified by Manual Review
We used existing queries and reviewer guides from our region to develop a guide for manual review of all heat-related illness queries from summer 2024. Each county had two people independently review triage notes, chief complaints, and discharge diagnosis for evidence of the risk factors below. Disagreements were resolved through discussions toward consensus.
Risk Factors Identified by Manual Review
Concept
Description for Manual Review
Vehicle
We aim to capture heat exposure in vehicles that can rapidly become overheated. These include exposures that occur in private or occupational vehicles (e.g., car, RV, delivery truck) for reasons such as lack of AC, overheating, or more.
Outdoor
We aim to capture when injury/illness was likely sustained outdoors. These include heat exposures from living, working or participating in any outdoor activity such as attending events, doing yard work, or recreation.
Occupation
We aim to capture when injury/illness was likely sustained on the job through extended periods of time in the heat. Occupational heat exposure includes working outdoors during extreme heat, and indoors without adequate cooling (e.g., kitchens, manufacturing)
Mental Health
We aim to capture cases where there was evidence that mental health disability/conditions were exacerbated by heat or made people more vulnerable to heat's impact.
Intoxication
We aim to capture substances that can impair people's judgement such as stimulants, opioids, and alcohol, and cause physiologic effects impacting the ability to cool one's body.
Signs of Houselessness
People experiencing houselessness are vulnerable to extreme heat due to their living conditions, co-occurring health issues, and lack of resources. Signs of houselessness include direct mention of the patient being houseless/homeless and context-dependent notes, such as being found in the streets/in a tent, being brought in from a shelter, needing shelter, living in car/RV.
Ambulance arrival
Transport by ambulance represents the burden on Emergency Management Services, and patient illness severity and access to transportation and healthcare.
Note: These concepts are used to categorize heat exposure cases during manual review of records
Risk Factors Identified by Automated Text Search
Automated text queries that are codes with a set of search criteria were used to identify yearly visits with mention of houselessness, intoxication, and occupation during May to September from 2016-2024. Based on HRI visit data for summer 2024, the queries used to identify houselessness, intoxication, and occupational heat exposure correctly identified at least 70% (Sensitivity>70% & Specificity>70%) of visits identified by manual review (referent value) for these risk factors.
Risk Factors and Automated Text Queries
Risk Factor
Automated Text Query
Houselessness
Keywords in patient records that suggest houselessness, such as:
• "Homeless"
• "Houseless"
• "Sleeps in his vehicle"
• "Sleeps in her vehicle"
• "Sleeps in vehicle"
• "Unsheltered"
• "Sleep out"
• "Sleeping out"
• "Live out"
• "Living out"
• "Sleep in car"
• "Sleep in RV"
• "Live in RV"
• "No housing"
• "Lack of housing"
• "Without housing"
ICD 10 Codes: Z590 and Z591
Intoxication
Keywords in patient records that suggest intoxication, such as:
• "Intoxic"
• "Alcohol"
• "Marijuana"
• "Fentan"
ICD 10 Codes: F19, F10, F11, and F12
Occupation
Keywords in patient records that suggest occupation, such as:
• "Occupation"
• "Construction"
• "Employer"
• "Landscape"
• "Employee"
• "Employed"
Note: These queries are used to automatically identify risk factors in patient records
Other Sections of the Report
You can find the rest of the report in the following links:
