Patients were about 40 percent less likely to survive the most severe heart attacks in the six coldest months of the year, according to research presented in June at the British Cardiovascular Society Conference.
Cardiologists at Leeds General Infirmary in the U.K. compared data on more than 4,000 patients who received primary percutaneous coronary intervention (PCI) following myocardial infarction at their hospital over a four-year period.
The risk of death within 30 days was similar in the winter versus the summer for less severe heart attacks. However, for patients who experienced cardiac arrest or cardiogenic shock, one-month mortality rates were 28 percent in the cold season and 20 percent in the warm season.
“Potential explanations could include longer time to treatment, prolonged hospitalization and delays to discharge, and increased prevalence of winter-associated infections, which in the sickest patients, could be potentially lethal,” lead researcher Arvin Krishnamurthy said in a press release. “Further studies interrogating the association between time of admission and outcomes, especially in the sickest and most vulnerable patients, are certainly warranted.”
The cold months in the study were defined as November through April. Other studies have also demonstrated higher rates of cardiovascular complications in the winter, including an increased risk of heart failure for elderly patients and more heart-related hospital admissions and mortality.
“You obviously can’t choose when you have a major heart attack, but it shouldn’t have such an impact on your chances of surviving,” said Metin Avkiran, DSc, PhD, the associate medical director at the British Heart Foundation. “It’s vital we carry out more research to find out why there are these differences, as well as continuing to do all we can to stop people having heart attacks in the first place.”