• Posted September 6, 2023

VA Hospitals See Steep, Steady Rise in Heat-Related Illnesses

Heat domes and extreme heat waves have been battering the United States for years now, and a new study shows that increasing temperatures are doing real harm to humans.

A significant increase in heat-related illnesses like heat stroke and heat exhaustion has occurred during the past two decades among patients treated at U.S. Department of Veteran Affairs (VA) health facilities, VA researchers have found.

"There is now statistical evidence to show that heat-related illnesses are on the rise, all things considered, and those patients that are older and sicker are the most likely to have a poor outcome,"said study co-author Zachary Veigulis, chief data scientist for the VA's National Center for Collaborative Healthcare Innovation.

With a brutally hot summer still baking much of the United States, the findings are important. This week alone, a heat wave blankets Mid-Atlantic and Northeast states, and scorching temperatures persist in Texas and neighboring states.

VA diagnoses for heat illness nationwide increased from about 24 cases per 100,000 patients in 2002 up to 35 cases per 100,000 in 2019, according to results published in the July-August issue of the Journal of Climate Change and Health.

This was a "statistically significant and clinically important increase,"the researchers said, adding that people with multiple chronic illnesses were most at risk.

But the increase in heat-related illnesses hasn't been uniform across the nation, and states that have fared worse aren't always where one might expect, the study authors said.

"The incidence of heat-related illnesses is steadily going up and has been steadily going up, and more so for some areas of the country than others,"said lead researcher Dr. Thomas Osborne, director of the VA's National Center for Collaborative Healthcare Innovation.

"Some typically warmer U.S. states, including areas like New Mexico and Nevada and Louisiana, actually did not have a dramatic increase in heat-related illnesses, where others did,"Osborne said.

California, Florida and Texas were disproportionately affected by heat-related illnesses, as might be expected in sunny states, the study authors noted.

But there were notable increases in Missouri, Arkansas, Virginia, Ohio and New York, the results showed. Only one state, Wisconsin, experienced a nominal decrease in heat-related illnesses.

Osborne and his colleagues think this shows that some hotter states are better prepared for climate change, because they've already been dealing with heat waves.

"Some locations that don't traditionally see or commonly experience these hot weather conditions may not be as prepared because they don't expect it as much and they're getting caught off guard,"Osborne said.

That's the most important takeaway from this study, said Dr. Georges Benjamin, executive director of the American Public Health Association.

"We've known that people with chronic diseases have more problems with heat,"Benjamin said. "What is fascinating, what is really new here, is the state variation. One would have thought that that variation would have been the hotter states had more problems than the cooler states."

For this study, researchers reviewed the VA's national electronic health record database from 2002 through 2019, identifying 33,114 documented cases of heat-related illness affecting more than 28,000 patients. Their average age was 59.

Health problems like heat cramps, heat exhaustion and heat stroke occur because high temperatures overwhelm the body's ability to regulate itself, Osborne and Benjamin said.

"When it gets out of range, then bad things happen,"Osborne said of body temperature. "That's because all these critical chemical reactions for life, they need to be within a specific range. When you can't balance that range well because the heat is too extreme, then systems start to malfunction and shut down, which can lead to a cascade of negative events that can rapidly spiral into crisis."

People with chronic conditions like diabetes, high blood pressure or heart disease are at greater risk for heat-related illness, either because of their health problems or the medications they're on to treat them, Osborne said.

The study found that patients with multiple chronic illnesses experienced a steadily increased rate of heat-related illnesses, from about 10% in 2002 to 25% in 2019.

Patients with heart disease alone experienced a 50% increase in heat-related illnesses, from around 10% in 2002 to around 15% in 2019, the study found.

The rate of heat-related illness affecting homeless veterans actually provided some signs of hope, Osborne said.

Heat-related illness among the homeless steadily increased from 2002 to a peak in 2014, but then steadily declined through 2019.

"Around that time the VA was also implementing a lot of veteran homeless health and wellness programs,"Osborne said. "What we're seeing here is there's hope, that intentional efforts to improve the lives of veterans could have these positive consequences."

That extends to the typically hot states that saw a lower-than-expected increase in heat-related illnesses, Osborne said.

"Those traditionally warmer states have already seen these dangers and are taking evasive and proactive actions,"Osborne said. "They're reaching out to patients, and they're creating cooling centers where people can go if it's a hot day. Some of those areas that are probably dealing with it longer and have been thinking about it more have been leading the charge, or at least that's what we think."

Warmer states also have more experience dealing with extended heat waves, Benjamin added.

"If you're in a part of the country which doesn't get hot a lot, and now we're seeing longer and hotter heat waves, you start seeing more people get sicker,"he noted.

In the meantime, people who are older and have multiple chronic illnesses should be careful about exposing themselves to the heat, Benjamin said.

"We tell people with heart conditions and lung conditions not to go out when it's real hot because you're much more likely to have a heart attack,"Benjamin said. "We definitely tell people not to cut your grass, or if you have to work outside to stay well-hydrated and to take breaks when you're out working in the sun, to find some shade to cool down."

More information

HealthDay has more about working in extreme heat.

SOURCES: Zachary Veigulis, MS, chief data scientist, Veterans Affairs National Center for Collaborative Healthcare Innovation, Palo Alto, Calif.; Thomas Osborne, MD, director, VA National Center for Collaborative Healthcare Innovation, Palo Alto, Calif.; Georges Benjamin, MD, executive director, American Public Health Association; Journal of Climate Change and Health, July-August 2023