Pavilion Publishing and Media Ltd
Blue Sky Offices Shoreham, 25 Cecil Pashley Way, Shoreham-by-Sea, West Sussex, BN43 5FF, UNITED KINGDOM
Tel: +44 (0)1273 434 943
Email: [email protected]
Researchers have discovered a strict relationship between hot temperatures and weight loss in heart failure patients, an indicator that their condition is worsening.
The authors of the study, published in ESC Heart Failure, say that a global rise in temperature and more frequent periods of extreme heat could therefore lead to worse outcomes for heart failure patients.
This is because weight loss in heart failure patients may lead to low blood pressure (particularly when standing up) and renal failure, which can be life-threatening.
The study’s authors say the findings should prompt discussions between clinicians and patients so that people with heart failure are aware that they may be at increased risk of poor outcomes during periods of hot weather.
Why is weight important in heart failure?
In patients with heart failure, the heart does not pump blood around the body as well as it should. Waste products accumulate, causing shortness of breath and fluid build-up in the lungs, legs and abdomen. Weight is the cornerstone of monitoring because weight gain is related to congestion, the main reason for hospital admission.
Diuretics are used to increase urine output and reduce breathlessness and swelling. ESC guidelines recommend educating patients to increase their diuretic dose or alert their healthcare team if they experience an increase in breathlessness or swelling or a sudden unexpected weight gain of more than 2kg in three days. However, weight loss has received less attention.
Weight dropped as temperature rose
To address this gap in research, the authors of the study looked at population data in France between 1 June and 20 September 2019, a period in which two heatwaves occurred.
The analysis included 1,420 patients with chronic heart failure. The median age was 73 years, 28% were women, and the average weight was 78 kg.
Participants weighed themselves daily using a scale that automatically sent measurements to clinic and reported symptoms (such as oedema, fatigue, breathlessness and cough) by answering questions on a personal device, with answers sent automatically to the clinic.
Daily temperatures (at noon) were obtained using data from the closest weather station to each patient’s home.
The researchers analysed the association between patient weight, ambient temperature on the same day, and temperature two days prior to the weight measurement.
The relationship between temperature and weight was very strong, with weight dropping as temperature rose. The strongest relationship was found with temperatures two days prior to the weight measurement.
Heart failure patients may need to adjust diuretic medication during heat waves
Professor Roubille said: “The weight loss we observed during the heatwave was clinically relevant. Patients weighing 78 kg lost 1.5 kg in a short period of time.”
He added that the team were surprised at the outcome of the study, as the team initially predicted patients would gain weight when temperatures rose.
The researchers are now calling for greater awareness about the risks of weight loss in heart failure patients during heat waves.
Given the expectation of more heatwaves, telemonitoring systems also need to alert clinicians of weight loss in heart failure patients. In addition, systems could notify patients losing weight that it may be due to the heat and they should contact their healthcare provider about reducing the dose of diuretics.
For heart failure patients not monitored remotely, a good rule of thumb would be to contact a healthcare professional if weight drops by 2 kg during a heatwave for advice on adjusting diuretic medication. Reacting early should help us to prevent complications, said Prof Roubille.