AMHERST, Mass. - In the first nationwide study to directly address the associations between high-deductible insurance plans and the use of diagnostic imaging, researchers including Kimberley Geissler at the University of Massachusetts Amherst found that patients enrolled in such health plans use about 7.5 percent fewer diagnostic tests such as MRI, X-rays and CT scans, than patients without such plans. Details appear in an early online edition of Medical Care.
Geissler says, "I think what we found most surprising is the large reductions in imaging use among people with high deductibles. We had hoped to find that patients were reducing use of low-value imaging, but we found they reduced all use similarly. It seems patients are not informed enough to discern which tests are more optional and which are medically necessary."
She notes that more Americans are enrolling in high-deductible insurance plans in recent years because they offer relatively low monthly premiums but higher out-of-pocket costs; most plans on the newly created health insurance exchanges are high-deductible insurance plans. It is estimated that from 2000 to 2014 Medicare spending for imaging almost tripled from $3.6 to $10 billion.
Geissler is the senior author of the study and an assistant professor of health policy and management at the School of Public Health and Health Sciences at UMass Amherst. She and co-authors point out that "as diagnostic imaging can have important downstream care and cost implications, having the right level of high-value utilization is an important policy priority."
For this study, the researchers considered insurance plans with an annual deductible of at least $1,200 for individuals and $2,400 for families to be high deductible. To investigate three main outcomes, they used a 2010 insurance database including more than 21 million adults to compare use rates and costs of imaging studies such as X-rays, CT or MRI scans, among others, for patients with and without high-deductible plans.
They define low-value imaging tests as being less critical, such as diagnostic MRIs for lower back pain, and point out that high use of "low-value diagnostic imaging," such as with "marginal medical benefit and potential patient harms," or "use of expensive diagnostic imaging when less expensive ones would be medically appropriate, may promote a cycle of increasing medical intervention conferring little or no benefit."
After controlling for age, sex, geographic location and health status, the study found that people enrolled in high-deductible plans used 7.5 percent fewer imaging studies than those in other plans. "This difference in imaging utilization corresponded to a 10.2 percent difference in imaging payments," the researchers write.
Patients in high-deductible plans were less likely to undergo any diagnostic imaging, a difference of 1.8 percentage points. However, once a patient had at least one imaging test, being in a high-deductible plan had little effect on their total use of imaging studies.
First author Sarah Zheng took part in the study of patient cost sharing and how it influences use of services as part of her doctoral work. She and colleagues recommend that future health care policy moves toward reducing diagnostic imaging should be combined with efforts to improve patient awareness and education, because at present people do not know what they should and should not do.
Overall, the researchers say results raise concerns that high-deductible health plans "may be a blunt instrument reducing all diagnostic imaging, rather than helping physicians and patients choose high-value imaging."
Medical Care is the official journal of the Medical Care Section of the American Public Health Association and is published by Wolters Kluwer.