Heatstroke is when the body’s temperature becomes concerningly high. It is accompanied by symptoms like nausea, headache, dizziness, and an accelerated heart rate. In severe cases, heatstroke can lead to loss of consciousness, organ damage, or death. In this article, we considered the risk factors of heatstroke death.
Heatwave in France
In the summer of 2003, France reported incredibly high temperatures. The high temperatures were accompanied by a spike in illnesses and deaths related to the heat. Researchers wanted to learn more about the risk factors for heatstroke death.
Source: Mortality of patients with heatstroke admitted to intensive care units during the 2003 heat wave in France: A national multiple-center risk-factor study*
The mortality rate of patients admitted to critical care units for heatstroke was 62.6% that summer. All of the patients used external body cooling methods, and nearly all patients were on ventilation to help them breathe.
“Patients managed without air conditioning had a 76% increased risk of death.”
Nearly half of the patients were treated in an ICU with air conditioning. This was found to be a predictor of survival. Additional risk factors included clinical indicators of organ failure and the use of drugs to raise blood pressure.
Heatwave in Chicago
In 1999, Chicago experienced one of its deadliest heatwaves. Researchers studied this incident to find further risk factors for heatstroke mortality in this population.
Source: Heat-related mortality during a 1999 heat wave in Chicago
Factors that increased the odds of heatstroke death included a preexisting heart condition, psychiatric illness, and living conditions. Living alone, not leaving the house daily, living on the top floor of a building, and having an annual income of less than $10,000 were initially found to be risk factors.
Factors that reduced the odds of heatstroke death included having a working home air conditioner, participating in group activities, having a pet in the home, and taking extra showers or baths.
The study said that these main risk factors were strongly associated with heatstroke mortality. However, we do not know exactly how strong. The odds described were the researcher’s best estimate, not the true value.
To explain further, the odds of heatstroke death were estimated to increase by over 8 times if the patient lived alone. However, the researchers are confident that the real value lies somewhere within 1.4 - 48.1 times. So, they are confident that living alone is a risk factor for heatstroke death, but they just don’t know exactly how big of a risk factor it actually is.
All this to say, a larger number of heatstroke patients in the study would ideally narrow the range of possible odds. The bigger the sample, the more confident researchers can be about their results.
Importance of air conditioning
An air conditioning system was an important factor in both studies. Whether in the critical care unit or at home, the data suggest that an air conditioner offers some level of protection from heatstroke mortality.