New research says we might not know as much as we think about heat-related deaths in the U.S. — including in Greater Cincinnati.
An investigation by NPR in partnership with Boston University found the Centers for Disease Control could be undercounting heat-related deaths by as many as 5,000 a year across the country.
The research found the largest likely number of unreported heat deaths is in places where extreme heat lingers longest. Harris County, Texas (where Houston is located) has as many as 244 uncounted heat-related deaths a year, according to the NPR investigation. Los Angeles County, California could have as many as 220.
Our region, with its more moderate climate, didn't have nearly that many. But the statistical model researchers used suggests at least a few heat-related deaths across Greater Cincinnati go uncounted annually.
Hamilton County reports 3.6 heat-related deaths a year on average, according to the county health department. NPR and BU's model suggests the actual number of heat deaths is likely closer to six or seven.
Complex conclusion, limited time
Hamilton County Public Health Medical Director Dr. Stephen Feagins says it's hard to know exactly how many deaths extreme heat causes each year because many times heat is a hidden contributor to a more obvious cause of death, like respiratory issues or a heart attack.
"Are there many more heat-related deaths than are being reported? Absolutely," he says, noting that goes for lots of other contributing factors to someone dying as well. "You have an immediate cause of death, and even that isn't as easy as it sounds. You do your best. Then you have contributing factors, other significant conditions that contributed to death. And sometimes you know those, and sometimes you don't."
Feagins says one factor is the nature of how deaths are investigated. It's rare for a death to trigger an autopsy unless a crime is suspected. Those non-criminal investigation autopsies usually only happen when a family requests and pays for one.
In addition to that, Feagins says state law requires a death certificate be issued soon after a person dies. And sometimes, the person signing off on that death certificate isn't the same person who was on shift when the patient came in. That means they have to rely on the patient's records.
For busy physicians in an emergency room or other setting where they're actively practicing medicine, that puts constraints on how much investigation can happen.
Feagins says human bodies are a complex collections of systems, and many deaths require a fair amount of subjective interpretation.
"You really have 72 hours for some certifying physician to complete a death certificate," Feagins said. "So death certificates are really a best estimate that has to be made pretty quickly."
The few deaths that do get reported as heat-related often involve bodies found in un-airconditioned environments or with other obvious signs heat was at play, Feagins said. But severe distress from heat isn't always immediately apparent.
How do heat-related deaths get reported to the CDC?
Hamilton County Public Health Epidemiologist Alex Woroncow says data about a person's death goes through several steps before it gets to the CDC. Other entities like the county coroner and funeral homes will contribute any additional information they have.
The Hamilton County Coroner's Office says when its staff investigates a death scene, they collect the deceased person's core body temperature, the ambient temperature of the environment around the body and whether there are fans or air conditioners operating in the space.
"All of the local information that is legally needed for the death certificate gets compiled together, and then that is sent up to the Ohio Department of Health," Woroncow says. "Once the Ohio Department of Health gets their records together, everything is sent to the National Center for Health Statistics to run through their algorithms."
From there, the CDC standardizes the data and analyzes various demographic and other statistics, then sends it back to state health departments, which publish it.
"That is what we pull from for our statistics," he said. "So it's sort of a circular approach."
Even after all that input, it's unusual for the cause of death initially reported on a death certificate to change, Feagins said.
"In all my years, this has only happened once or twice," he said. "It is a major deal to change a cause of death once it's been certified."
Local data on heat-related death and illness
Epidemiologist Woroncow says there isn't a clear trend when it comes to heat-related deaths in Hamilton County over the last decade due to the small number of deaths reported each year.
But he says another, related data set shows the increasing toll rising temperatures might be taking on county residents. Woroncow said heat-related emergency room visits have increased 14% in recent years.
He says it's hard to know why exactly that is in a nailed-down, statistically-backed way.
"Speaking anecdotally as a human being who walks outside, it's hotter," he says.
But there's more to consider than that.
"Without any population-scale data looking specifically at peoples' experiences of heat, it's hard to tell if that's based on increased availability of resources, utilization of emergency department resources, or if it's due to actual increases in heat."
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