A new study of cities hosting the largest US marathons has found that the odds of dying from acute myocardial infarction (MI) or cardiac arrest jump 13 percent the day the race is run.
The authors think that it is because blocked streets and traffic congestion add precious minutes to the time it takes for rescue units to get to the hospital.
On marathon days, it added more than four minutes in the 11 cities they studied. For people who drive themselves or have someone drive them, the delay is potentially much longer.
"The data are believable and the results important," said Brown University's Alpert Medical School in Providence, Rhode Island's Dr. Selim Suner who was not involved in the research. "This will probably open the eyes of some of the planners for the events,"
Blocked streets and traffic congestion add precious minutes to the time it takes for rescue units to get to the hospital.
"Most people have not thought of this as unintended consequence of marathons and other public events," said an associate professor of health care policy at Harvard Medical School in Boston and study coauthor, Dr Anupam Jena. Discussions with officials in the cities revealed "a lot of variability in terms of their awareness of this being a potential issue," he noted.
Jena and his colleagues looked at Medicare data from cities where marathons were run from 2002 through 2012, comparing death rates on the day of the race to rates in the five weeks before and the five weeks after. He and his team also compared rates in the host cities to those in surrounding zip codes that were unaffected by the race.
They found that the presence of the race in a city did not alter the number of cases of MI or cardiac arrest among people over age 64, but it did increase their rate of death within 30 days of the cardiac event from 24.9 percent when a marathon wasn't being run to 28.2 percent when it was.
In addition, the rates of MI combined with cardiac arrest were twice as high among beneficiaries hospitalized on marathon dates as among similar beneficiaries hospitalized on non-marathon dates, “a finding that is consistent with delayed care," the researchers wrote in the New England Journal of Medicine yesterday.
When they focused on ambulance transport times in the morning - when the races are usually run - they found that while it typically took 13.7 minutes to get to a hospital, the time increased to 18.1 minutes on marathon days.
"Several things could be done to address the problem," Suner said. "Special routes could be preassigned for emergency medical services for different locations or planning could include rerouting to other hospitals."
"The second issue here, which is more challenging to solve, is we found about 25 percent of people admitted with cardiac arrest or heart attack actually came in by themselves," Jena said. "They were not brought in by ambulance, and those individuals probably experienced very large delays in transport time."
"A solution could be to advise the public that if you have chest pains or shortness of breath, or symptoms that are alarming, the best thing to do anytime or particularly on a marathon day is to call the emergency services and not drive to the hospital yourself," he added.
In all, the researchers evaluated 1,145 hospitalizations on marathon dates and 11,074 on non-marathon dates in Boston, Chicago, Honolulu, Houston, Los Angeles, Minneapolis, New York, Orlando, Philadelphia, Seattle and Washington, D.C. There were not enough data to see if the death rates were lower in some marathon cities than others.
The study team also tried to exclude marathon participants from their tally.
Director of the disaster medicine and emergency preparedness department at Brown, Suner, cautioned that "the authors did not look at daily temperature or ozone levels which may have been higher on marathon days accounting for increased death in this population. Also, there may have been increased volume in the emergency departments during marathon days, making the care for people with myocardial infarction less than ideal."