Chronic obstructive pulmonary disease symptoms worsen in hotter weather, US researchers report today.
Dr Supkash Gupta, a pulmonary and critical care fellow at the University of Washington, USA, is to present data this Sunday at the online European Respiratory Society International Congress. This shows that about two days after an increase in ambient temperatures, there was a rise in COPD exacerbations.
He said the findings raise concerns of climate change increasing the risk of exacerbations.
Dr Gupta and colleagues analysed data from 1,177 current and former smokers, whose average age was 64, who had enrolled in the SubPopulations and InteRmediate Outcome Measures in COPD Study (SPIROMICS) between 2010 and 2015. All had had at least one COPD exacerbation since joining the study.
The researchers assessed the risk of COPD exacerbations based on local, ambient temperatures recorded on the day of the exacerbation and in the preceding seven days.
The average time to the first exacerbation was 603 days and the risk of exacerbations increased with increasing temperatures during the preceding six days, with the highest risk two days after temperatures rose.
The researchers adjusted their results to take account of humidity levels, which have been implicated in the risk of exacerbations.
Dr Gupta says: “We found that each one-degree Celsius increase in ambient temperature was associated with a 2% increase in the likelihood of COPD exacerbations in the following two days among this group of patients.
“This study is one of the few to explore the impact of ambient temperature on the risk of COPD exacerbations in a group of people with established COPD for whom we have detailed medical information. Overall, it contributes to the emerging body of knowledge regarding ambient temperature and risk of COPD-related health problems.
“Other studies have shown a connection between extreme heat exposure and increased risk of health problems and death in people with COPD. There are concerns that these problems will accelerate with the ongoing and worsening climate crisis.
“Therefore, it is important to quantify the health risks associated with changes in ambient temperature, while also determining who is most at risk to inform policy-makers and healthcare providers.
“Our findings raise concerns about the risk of increased exacerbations with climate change. While not conclusive, the study suggests that those living with COPD may want to avoid exposure to adverse and extreme environmental conditions by limiting outdoor activities during periods of elevated temperatures relative to normal.”
Although the mechanisms involved in the link between heat and COPD exacerbations are not completely known, it is believed it may include hyperventilation, which increases the possibility dynamic hyperinflation.
At its extreme, dynamic hyperinflation could lead to increased pressure in the chest cavity and a subsequent decrease in blood flow back to the heart.
Effects of ambient temperature on COPD symptoms and exacerbations in the SubPopulations and InteRmediate Outcome Measures in COPD Study (SPIROMICS) cohort, presented by Supaksh Gupta. Environment and respiratory health session. 5 September 2021
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