Australia’s Heat-Related Burden of CVD Holds Warnings for All

Approximately 7% of the CVD burden in Australia is related to high temperatures, with worrying projections suggesting that the number of people at risk will continue to increase unless urgent efforts are pursued to curb climate change and help humans adapt.

In the new study, published in the European Heart Journal, CVD attributable to hot weather was found to be responsible for approximately 49,483 years of healthy life lost annually, with 97% of that time lost due to fatal disease.

The findings have implications beyond Australia since global climate change accompanied by rising temperatures will only continue to challenge population health, including by raising the risk of CVD, senior author Peng Bi, MBBS, PhD (University of Adelaide, Australia), stressed to TCTMD.

Actions need to be taken now “to develop and implement both mitigation and adaptation strategies to minimize such risks to protect population health, especially for the most vulnerable groups such as the elderly, people with chronic diseases, outdoor workers, children, etc,” he said.

Other recent studies have detailed the impact of extreme heat on the risk of atrial arrhythmias in patients with cardiac implantable electronic devices and on the risk of CV mortality in various patient subgroups, with some suggestion that it also may be a factor in further widening health disparities.

In their paper, Bi and colleagues say they believe it is possible, based on their estimates, to reduce the impact of high temperatures, but it’s going to take a lot of work and it needs to start now.

“In terms of mitigation, we need to work together to reduce the emission of greenhouse gases,” Bi said. “For adaptations, we need to implement tailored actions for the most vulnerable populations. Medical and healthcare workforce capacity building and essential resources are important.” In addition, input from the community about behaviors and needs also will be essential to ensuring that strategies are truly tailored correctly for the populations they are intended to help, he said.

Hot Weather’s Impact

Using the Australian Burden of Disease database, investigators led by Jingwen Liu, MPH, MSc (University of Adelaide), calculated the burden of CVD attributable to high-temperature exposure. In their modeling and projections, they took into account the contribution of greenhouse gas emissions and looked at regional differences under a variety of scenarios.

For Australia, high temperatures were found to be responsible for 7.3% of the CVD burden, or the equivalent to 223.8 disability-adjusted life-years (DALYs) per 100,000 persons between 2003 and 2018. Among all the territories and states, South Australia had the highest heat-attributable burden of CVD at 11.9%, or the equivalent of 416.6 DALYs per 100,000 persons.

Areas with the largest population sizes coupled with large burdens of CVD saw the greatest number of heat-attributable DALYs overall.

In projection scenarios, the researchers found that the percentage increase in the total burden of CVD attributable to hot weather could increase by nearly 85% by the 2030s and by more than 180% by the 2050s. Those numbers could shift downward by 50% or more with implementation of effective human adaption strategies, the modeling suggests.

We need to work together to reduce the emission of greenhouse gases, [and] we need to implement tailored actions for the most vulnerable populations. Peng Bi

Importantly, the researchers note, the ability of populations to protect themselves from excessive heat often correlates with socioeconomic status and thus “financial support for cooling and subsidies for air conditioning/electricity costs may likely benefit those with fewest resources.”

Finally, the environment and extreme heat are among multiple potential patient-specific risk factors that should be considered in healthcare, Bi said.

He and his colleagues urge clinicians to think about this in the context of prevention for their patients with CVD, or at increased risk for it, and offer advice about increasing fluid intake and plant-based diets, reducing outdoor activity levels, and planning for safe storage of heat-sensitive medications during times of hot weather.

Finally, they say studies are urgently needed to understand how various adaptation strategies can attenuate the effects of temperature on CV illness and death, as well as plan which of those strategies work best for individual regions and populations.