Though patient survival rates have improved overall, the 'weekend effect' persists for cardiac arrest, study finds

Survival rates for patients who have a heart attack in the hospital have improved overall, but the odds are a bit better for patients who go into cardiac arrest on a weekday.

Researchers led by Uchenna Ofoma, M.D., a critical care physician at Geisinger Health System in Pennsylvania, analyzed data on more than 151,000 adults at 470 hospitals recorded between 2000 and 2014.  

They found that cardiac arrest survival rates in hospitals during weekdays increased from 16% to 25.2% over that period, while survival rates at hospitals on weeknights and weekends increased from 11.9% to 21.9%, according to data published in the Journal of the American College of Cardiology. 

About half of the patients in the study went into cardiac arrest in off-hours. The gap between survival rates for weekdays and off-hours remained roughly the same throughout the study period, the researchers found. 

RELATED: Press Ganey report links patient experience and patient safety 

Ofoma told CNN that overall hospital survival rates have improved over the past several years, so looking at trends like the "weekend effect" is important to address potential disparities. 

"We know that survival trends have improved in the last decade or so," Ofoma said. "The question now becomes … what happens to the disparities? Has it remained the same? Is it narrowing?" 

He said that a strategy to address the weekend effect is to take a look at the providers with the narrowest gap in survival rates between weekdays and off-hours and replicate what works for them. 

RELATED: Publishing mortality rates doesn't improve outcomes 

The weekend effect has been well-documented around the world, but recent research has called its true impact into question. A British study published in May 2016 found that death rates on the weekend may only be higher as fewer patients are hospitalized on those days, skewing the results. 

Another British study, published later that year, found that merely being admitted on a weekend may not increase a patient's chance of mortality, but that he or she may face greater risks if an emergency surgery is scheduled in off-hours. 

Ofoma told CNN that the patients in the study who flatlined in off-hours may have been sick beyond cardiac issues that were measured in the study, which may have an impact on their chance of survival. Their heart attacks were also less likely to be witnessed by someone else in the hospital if it occurred on the off-hours, he said.