Americans admitted to the hospital for heart failure have a 6% higher risk of dying than patients admitted in the spring.
Hospitalizations and death due to heart failure are higher during the winter in the United States, according to a pair of studies presented at the American College of Cardiology’s 66th Annual Scientific Session.
Prior research has shown that heart attacks, sudden cardiac death, and cholesterol levels tend to increase during the winter months in the United States, but these studies are the first to examine seasonal trends in heart failure hospitalizations and deaths in the states.
“Over 5 and a half million people live with heart failure in the US, and it’s one of the leading causes of hospitalization,” said Emmanuel Akintoye, MD, lead author of one of the studies. “But little to nothing has been known about how seasonal variation impacts hospitalization outcomes national.”
For the first study, the investigators examined data from approximately 600,000 hospital admissions for heart failure collected between 2011 and 2013 from the Nationwide Inpatient Sample.
The results of the study showed that the likelihood of dying during hospitalization for heart failure spiked during the winter, in addition to the cost and length of stay. A patient admitted to the hospital for heart failure during the winter months had a 6% higher risk of dying than a patient admitted in the spring, and 11% higher than a patient admitted in summer or fall.
The median cost for heart failure-related hospitalizations was $7459 in the winter and $7181 in the summer.
Akintoye noted that the study design prevented them from determining an explanation for the mortality and cost increases, but the increased prevalence of comorbidities, such as respiratory infections in winter, most likely play a role. Additionally, cold temperatures can lead to increased heart rate and blood pressure, which puts added stress on an already overworked heart.
Similar results were found in a second study led by Soumya Patnaik, MD.
The investigators examined data from almost 2 million hospitalizations for heart failure between 2002 and 2011 from the National Institutes of Health database. The results of the analysis showed that hospitalizations and deaths from heart failure while in the hospital were highest in the winter and lowest in late summer.
Heart failure hospitalizations by geographical region was also examined, and the investigators found that the South had the largest number of overall admissions for heart failure. The Northeast had the highest mortality, with 4.3% of admitted patients who died compared with the national average of 3.8%. The risk of death was found to be highest in January and February, even in areas of the country with overall warmer temperatures.
“Based on our findings, it’s fair to suggest that heart failure patients should take extreme caution in wintertime—–being extra cautious about taking timely medications, not getting exposed to cold [temperatures] if it’s not necessary, and being careful about their diet as well, such as limiting salt and not overindulging over the holiday season,” Patnaik said.
Patnaik stressed that clinicians should counsel their patients about medication and diet compliance during winter, and implement more frequent follow-up for heart failure patients at high risk of hospitalization, if appropriate.
Increased awareness of these heart failure admissions trends could enable health care providers and policymakers to plan ahead for the expected surge in hospitalizations and poorer outcomes during the winter months, according to the authors.
“Once we understand the causes, we can work towards trying to address the problem and increase survival for patients with heart failure,” Akintoye said.