There is considerable variability in the rates of transfer of heart attack patients among hospitals that do not perform catheterization procedures, according to a study published online Dec. 2 in JAMA Internal Medicine.

Medicare patients initially admitted to nonprocedure hospitals that transfer many heart attack patients tended to undergo more invasive cardiac procedures compared with patients in hospitals with lower transfer rates; however, the higher number of transfers did not necessarily improve outcomes.

Researchers led by Jose August Barreto-Filho, MD, PhD, of the University of Sergipe in Arcaju, Sergipe, Brazil evaluated the transfer rates of 55,692 Medicare patients admitted to 901 U.S. nonprocedure hospitals that admitted more than 25 patients per year for acute MI. They compared the rates of invasive procedures (catheterization, PCI and CABG) during the index hospitalization (which included the time at both hospitals if patients were transferred), within 60 days of the index hospitalization and within from the time of discharge to 60 days after the index hospitalization. As outcomes, they assessed mortality at 30 days and one year.

Transfer rates were categorized as low (less than or equal to 20 percent), mid-low (more than 20 to 30 percent), mid-high (more than 30 to 40 percent) and high (more than 40 percent). On average, 29.4 percent of patients were transferred and rates ranged from zero to 81.3 percent.

There were higher rates of procedures among patients from hospitals with high transfer rates, but a higher number of procedures did not translate into lower mortality rates or lengths of stay. Investigators also compared hospital characteristics across these four categories, including bed size, location, ownership status and teaching status.

“The extensive variability among transfer rates suggests that clinical needs have not been a primary driver of this process of care,” the authors wrote.

They also argued that their findings suggest that the transfer process warrants a closer look.

“Our data and those from other studies illustrate the complexity surrounding the standardization of transfer practice at the hospital level, further suggesting the importance of scrutinizing the effectiveness of this process to improve institutional outcomes,” they wrote.