The findings raise questions about the effectiveness of financial incentives and the 'Choosing Wisely' campaign.
Despite efforts among physician groups to reduce the overuse of medical imaging, the rates of CT, MRI and other scans continues to rise, new research shows.
The study, published this week in the Journal of the American Medical Association, examined the use of more than 135 million imaging exams and found that the growth in imaging slowed in the early 2000s.
However, that trend has reversed in recent years for computerized tomography and magnetic resonance imaging across most patient age groups, with the exception of children, according to researchers at UC Davis, UC San Francisco and Kaiser Permanente.
The researchers looked at patterns of medical imaging between 2000 and 2016 among16-21 million adult and pediatric patients in seven U.S. health care systems and in the universal, publicly funded health care system in Ontario, Canada.
For the U.S. data, they included people receiving care in integrated healthcare systems such as Kaiser Permanente, and systems with mixed insurance including HMOs and PPOs with fee-for-service plans.
The researchers found that:
- Annual growth in CT, MRI and ultrasound were highest in earlier years (2000-2006), but utilization has continued to rise year over year. Between 2012 and 2016 there was a 1%-5% annual growth for most age groups and most tests in the U.S. and Ontario, Canada.
- The one exception was CT use in children, which declined in the U.S. from 2009 -2013 and remained stable since 2013.
- Rates of imaging accelerated after initially dropping in many cases. For example, the rate of growth in CT scans among the elderly was 9.5% in 2000-2005, dropped to 0.9% in 2006-2011, but then increased to 3% annual growth over the last five years.
- Imaging rates were slightly lower in integrated healthcare systems than in the mixed model.
Study lead author Rebecca Smith-Bindman, MD, a UCSF professor of radiology, epidemiology and biostatistics, and obstetrics and reproductive medicine, said that unnecessary or overuse of scanning can lead to patient harms such as incidental findings, overdiagnosis, anxiety and radiation exposure that is associated with an increased risk of cancer.
Although it is widely believed that imaging rates are declining due to payment and educational efforts that have targeted unnecessary imaging, the authors found a reacceleration in imaging use, with ongoing growth in the use of CT and MRI in adults.
"Like all aspects of medicine, it's important to make sure imaging is justified, and that the potential benefits are balanced against the potential harms," she said.
“Like all aspects of medicine, it's important to make sure imaging is justified, and that the potential benefits are balanced against the potential harms.”
Study lead author Rebecca Smith-Bindman, MD, UCSF
Annual growth in CT, MRI and ultrasound were highest in earlier years (2000-2006), but utilization has continued to rise year over year.
The one exception was CT use in children, which declined in the U.S. from 2009 -2013 and remained stable since 2013.
Rates of imaging accelerated after initially dropping in many cases.