JAMA Feature: CT, MRI use in ED spiked in last decade
 |
“We were quite surprised by the finding, particularly by the magnitude of the increase. It’s a pretty astronomical increase,” lead author Frederick Kofi Korley, MD, from the department of emergency medicine at Johns Hopkins University in Baltimore, told Health Imaging News.
Previous studies have established increased use of CT in emergency departments, but none had focused specifically on injury-related conditions. “Analyzing this trend is important because approximately 70 percent of injury-related visits are by persons who are younger than 45 years,” wrote Korley. This population faces the largest potential risk of oncological impacts from ionizing radiation.
Korley said the study provides the first quantitative reference of the use of advanced imaging for injury-related ED visits.
The researchers mined data from the National Hospital Ambulatory Medical Care Survey to determine national trends in the use of CT and MRI for injury-related ED visits from 1998 to 2007. The primary outcome was the proportion of injury-related visits for which a CT or MRI was ordered, and the secondary outcome was the proportion of visits with life-threatening diagnoses, according to the authors.
Approximately 22.4 million, or 20 percent of ED visits, between 1998 and 2007 entailed injury-related conditions. The researchers sampled visits from a mean of 370 hospitals for each year of the study and found that physicians ordered CT or MRI for 6 percent of injury-related visits in 1998. In 2007, 15 percent of injury-related visits entailed CT or MRI studies.
Compared with the 1998 group, patients who presented to the ED with an injury-related condition in 2007 were significantly more likely to receive CT or MRI, wrote Korley. CT accounted for the majority of the increase as MRI represented 0.2 percent of the combined data, added the researchers.
Other trends remained stable during the course of the study. Life-threatening diagnoses occurred in 1.7 percent and 2 percent of visits in 1998 and 2007, respectively. The proportion of injury-related visits that proceeded to hospital admission was 5.9 percent in 1998 and 5.5 percent in 2007.
Although there was no relationship between race and sex for advanced imaging orders, age was associated with advanced imaging. Patients age 60 years and older were more likely to receive a study than those between 18 and 45 years of age, who, in turn, were more likely to be referred for an advanced study than patients aged 18 years or younger, according to researchers. Among patients aged 3 to 18 years, the odds of referral to CT or MRI in 2007 were 2.16 times that in 1998, reported the authors. Patients presenting to academic EDs were more likely to undergo CT or MRI than patients presenting to nonacademic departments.
The mean difference in length of stay was 126 minutes longer for injury-related visits that involved a CT or MRI for visits from 2001 to 2007.
Korley and colleagues cited a variety of factors that may have contributed to increased CT use:
- Its superiority over x-ray for diagnosing cervical spine fractures and other conditions;
- Routine use of whole-body scanning at some trauma centers;
- Increased availability of CT;
- Proximity of CT to ED patient care areas;
- CT speed and decreased need for pediatric sedation; and
- Concerns about malpractice suits for a missed diagnosis.
Multiple issues
The increased use of CTs in injury-related ED visits is problematic from several perspectives. Discussions about the carcinogenic potential of ionizing radiation from CT have been minimal in the ED community, shared the authors, who wrote, “In a 2004 survey of emergency department physicians, only 9 percent were aware that CT can increase a patient’s lifetime risk of cancer.” One of the indirect effects of increased CT use is longer ED visits, which may contribute to overcrowding and increase risk of medical error, according to the authors. The trend also has financial repercussions. Annual spending on CT imaging swelled from $975 million in 2000 to $2171 million in 2007. “We can’t continue in that direction,” offered Korley.
“We’re just beginning to understand the problem,” said Korley. “We don’t know if it represents overuse or not.” That’s because patients who might have been admitted to the hospital without CT imaging may not have been admitted to the hospital after a CT exam.
“In the ED our first focus is on saving lives," said Korley. However, the study indicates that physicians “need to take time to ask if patients really need a study or not.”
Korley points to the potential of decision support. “Some existing decision support rules are accurate, but they are cumbersome and hard to remember on the fly. Advanced decision support that presents complex information at the decision-making point [will be helpful].”
Korley stressed that the emergency physician community is very early in its understanding of advanced imaging for injury-related visits and needs to understand all of the factors. The end goal, he said, “is to figure out how to best provide excellent emergency care in a cost-effective manner.”