Cold Waves Increase The Mortality Risk Of People With Heart Failure By 37%

A new global analysis published in the journal Circulation, found that being exposed to heatwaves or extremely cold weather accounted for additional cardiovascular disease deaths which occurred in 567 cities in 27 countries from 1979 to 2019. The researchers further observed that people with heart failure were the most vulnerable to high temperatures as they were at a 12% higher risk of a sudden death during heatwaves as compared to days with mild weather. But exceedingly cold weather put them at a 37% higher risk of dying.

“While we do not know the reason why temperature effects were more pronounced with heart failure patients it could be due to the progressive nature of heart failure as a disease,” said study co-author Haitham Khraishah, a cardiovascular disease fellow at the University of Maryland School of Medicine, in a press release. “One out of four people with heart failure are readmitted to the hospital within 30 days of discharge, and only 20% of patients with heart failure survive 10 years after diagnosis.”

In their study, the researchers closely analyzed 32 million cardiovascular deaths globally over a period of four decades. They got access to this data from the Multi-Country Multi-City (MCC) Collaborative Research Network — a group of experts from diverse fields who have been studying the public health impacts of climate change and how environmental stressors increase mortality risks. The team then further developed this data to carry out their investigations.

They observed that in Baltimore, for every 1000 cardiovascular deaths, extreme cold days accounted for a little over nine additional deaths. But heat-related deaths were attributed to only 2.2 additional deaths.

Although climate change is widely known to be the main cause of heatwaves, a lesser known fact is that warmer global temperatures can also result in extreme cold weather events in the Northern Hemisphere — specifically in East Asia, North America and Europe. While the Arctic is currently warming three times faster than the rest of the world — thanks to high greenhouse gas emissions from burning fossil fuels — the polar vortex which is a traditional weather pattern has become highly unstable.

This, in turn, results in extremely cold weather migrating out of the Arctic and making regions in lower latitudes far colder than before during winters. A 2021 Lancet study reported that in 2019, the average mortality rates that were linked to extremely low temperatures in nine countries exceeded heat-related deaths. Another study published a year later in Environmental Health Perspectives revealed almost 9% of deaths were associated with cold weather in Switzerland compared to only 0.28% of heat-related deaths from 1969 to 2017.

A Science study released in 2021 detailed how rapidly melting ice in the Barents and Kara seas (which are extensions of the Arctic Ocean) lead to increased snowfall over Siberia until the extremely cold weather flew down to the U.S. and might have led to the Texas cold wave in February 2021, according to scientists.

“It underscores the urgent need to develop measures that will help our society mitigate the impact of climate change on cardiovascular disease,” added Khraishah.