Emergency department (ED) visits increased 60 percent faster than population growth from 2001 to 2008, while ED crowding outpaced the surge in visits, according to a study published in the July issue of Annals of Emergency Medicine. The authors linked the increase to a 140 percent growth rate in advanced imaging. However, imaging had a smaller net effect on crowding than other diagnostic tests and clinical procedures.

Stephen Pitts, MD, MPH, of the department of emergency medicine at Emory University in Atlanta, and colleagues sought to evaluate trends in ED crowding and potential causes by analyzing trends in ED occupancy.

The researchers mined the National Hospital Ambulatory Medical Care Surveys from 2001 to 2008 to generate estimates of visits and calculate mean and hourly occupancy in the ED.

“Crowding,” wrote Pitts et al, “has been associated with higher rates of medical errors, more frequent complications and increased mortality rates among critically ill patients.”

The researchers found the number of ED visits increased 1.9 percent per year during the study period, and mean occupancy, a surrogate for crowding, increased 3.1 percent per year. Pitts and colleagues evaluated a host of factors associated with crowding and reported use of advanced imaging increased most, by 140 percent.

Advanced imaging also was linked with longer visits. In 2008, the median length of visit for ED visits involving advanced imaging was 253 minutes. For other ED visits, median length was 137 minutes.

The numbers, however, don’t tell the entire story. The magnitude of effect of advanced imaging on crowding was less than other factors, such as more frequent ordering of blood tests, administration of IV fluids, performance of clinical procedures and visits with two or more medications mentioned, according to Pitts and colleagues.

The researchers offered several possible causes for and outcomes of their findings. They noted increasing treatment intensity may be tied to the aging population that present with complex medical issues. It also may reflect an increasingly interventionist practice style that might be attributed to a push for higher quality care, financial incentives for higher intensity care or defensive medicine, according to Pitts et al.

One possible positive point is that longer ED stays are less costly than preventable hospitalizations.

However, given the association between ED crowding and higher rates of medical errors, more frequent complications and increased mortality rates among critically ill patients, the authors sounded an alarm, and wrote, “These findings have ominous implications for patient safety and access to emergency care in the U.S.”