Beta Blockers and Antiplatelet Drugs Tied to Heat-related MI Risk
During hot weather events, people taking beta blockers and antiplatelet medications such as aspirin could be at increased risk of a myocardial infarction (MI), amplifying the risk already present from hot weather.
A new study published in Nature Cardiovascular Research found that, among people suffering non-fatal MI associated with hot weather, a greater portion are taking these heart drugs.
“Patients taking these two medications have higher risk,” said Assistant Professor Kai Chen, first author of the study. “During heat waves, they should really take precautions.”
External environmental factors like air pollution and cold weather can trigger MIs, and there is growing evidence to suggest that hot weather can do so, too. But epidemiologists are still working to identify which groups of people are most vulnerable to these environmental extremes.
The authors looked at 2494 cases sourced from a registry, in which individuals experienced a non-fatal MI in Augsburg, Germany during the hot-weather months (May–September) between 2001 and 2014.
In previous research, they had shown that exposure to either heat or cold made heart attacks more likely, and they calculated that heat-related MI rates would rise once the planet has warmed by 2–3°C.
The current study built on that research by examining patients’ medication use prior to their MI.
They analysed the data in a way that let patients serve as their own controls, by comparing heat exposure on the day of the MI versus the same days of the week within the same month. That is, if a person had an NI on the third Thursday in June, the authors compared their temperature exposure that day to their temperature exposure on other, “control” Thursdays in June.
It turned out that users of beta-blockers or antiplatelet medications were likelier to have an MI during the hottest days compared to control days. Antiplatelet medication use was associated with a 63% increase in risk and beta-blockers with a 65% increase. People taking both drugs had a 75% higher risk. Non-users of those medications were not more likely to have a heart attack on hot days.
When researchers compared younger patients (25–59 years) to older ones (60–74 years), they found, as expected, that the younger ones were a healthier group, with lower rates of coronary heart disease. Yet younger patients taking beta-blockers and antiplatelet medications were more susceptible to heat-related heart attack than older patients, despite the older ones having more heart disease.
Another clue that these two medication types may render people more vulnerable is that, other heart medications generally didn’t show a connection to heat-related heart attacks. An exception was statins, which taken by younger people, were associated with an over threefold risk of a heart attack on hot days.
“We hypothesise that some of the medications may make it hard to regulate body temperature,” Asst Prof Chen said. He plans to find out why in future studies.
The results suggest that as climate change progresses, heart attacks might become a greater hazard to some people with cardiovascular disease.
Source: Yale School of Public Health
