Temperature extremes detrimental to heart failure patients

Short-term exposure to either low or high temperatures carries an increased risk of mortality in patients with heart failure (HF), as suggested in a study.

For the study, researchers used data from the Swedish National Patient Register and the Cause of Death Register and identified 250,640 HF patients who died from any cause (mean age at death 84.3 years, 48.3 percent female) between 2006 and 2021. They examined mortality in relation to ambient temperatures.

Daily mean ambient temperature was assessed at 1-by-1–km spatial resolution to get a precise reading of the average for each specific location where a patient lived. Temperature exposures were defined using municipality-specific percentiles, with low and high temperatures corresponding to the 2.5th and 97.5th percentiles, respectively.

A U-shaped association emerged between ambient temperatures and both all-cause and cardiovascular mortality. Specifically, short-term exposure to low and high temperatures was associated with 13-percent (odds ratio [OR], 1.130, 95 percent confidence interval [CI], 1.074–1.189) and 5-percent (OR, 1.054, 95 percent CI, 1.017–1.093) greater odds of all-cause mortality, respectively, and 16-percent (OR, 1.160, 95 percent CI, 1.083–1.242) and 8-percent (OR, 1.084, 95 percent CI, 1.014–1.159) greater odds of cardiovascular mortality, respectively.

Of note, the mortality risk associated with high temperatures was more pronounced during the 2014-2021 period than the 2006-2013 period.

The findings demonstrate that the risk of death associated with heat exposure is spreading beyond traditionally hot areas and serve as an urgent call for high-latitude countries like Sweden to implement proactive strategies to protect vulnerable populations from increasing heat exposure.