Original ContributionDiagnostic imaging rates for head injury in the ED and states' medical malpractice tort reforms
Introduction
Diagnostic imaging has increased significantly over the past 2 decades and contributes substantially to overall medical costs [1], [2], [3]. According to the Centers for Medicare and Medicare Services, the growth in the volume of imaging services per Medicare beneficiary outstripped the growth of all other services [4], [5]. Many factors have contributed to the increase in imaging, including improvements in imaging technology, greater availability of computed tomography (CT) and magnetic resonance (MR)[6], and increased patient- and physician-generated demand, resulting in a lowering in the threshold for its use. Physicians' fears of being sued also may lead to defensive medical practices, such as ordering nonindicated medical imaging [7], [8], [9]. Thus, some of the increase in imaging may be driven by physicians' fears of malpractice lawsuits and their adoption of defensive, medically nonindicated test ordering to avoid lawsuits [7], [8], [9].
Defensive medicine has been reported frequently in the United States [8], [9], [10]. In a 1992 Gallup pole, 84% of physicians said that the threat of medical liability suits causes them to order tests they might consider unnecessary [10], and a recent survey of physicians practicing within 6 high-risk medical specialties found nearly all physicians reported defensive medical practices [9]. Ordering of more diagnostic tests than was medically indicated was the most frequently reported defensive medical practice, and emergency department (ED) physicians were significantly more likely than other specialists to report nonindicated medical test ordering [9]. Other reports have also found that ED physicians are particularly likely to report defensive medical practices [8], [11].
There have been few studies on the association between specific tort reforms and indirect malpractice costs, such as those that result from so-called defensive medical practices. The US Office of Technology Assessment concluded it is impossible to accurately measure the costs of defensive medicine [8], but it is widely believed to account for a much larger percentage of health care costs than the direct costs. For example, whereas the direct costs (such as premiums and award payouts) associated with malpractice are estimated to represent approximately 1% of health care costs [8], indirect costs, such as those that result from defensive medical practices, are estimated to account for a much higher proportion of health care costs, and as much as 5% of health care costs, or $5 to $50 billion dollars annually [12], [13], [14], [15].
To assess defensive medical test ordering, we investigated the association between states' medical liability tort reforms and neurologic imaging rates for patients seen in the ED with head trauma. We studied neurologic imaging among head trauma patients; because it is a prevalent condition [16], guidelines exist for the use of imaging in this setting allowing at least crude separation between indicated and nonindicated imaging [17], [18], and ED physicians are specialists who experience high levels of litigation and report frequent defensive test ordering [9]. We hypothesized that imaging rates would be higher when imaging was indicated but that imaging rates would also vary by the specific tort reforms enacted.
Section snippets
Methods
Medicare billing claims provide a convenient source of information to evaluate the use of neurologic imaging among elderly adults. A representative 5% sample of Medicare-eligible adults 65 years and older living in 10 US states (Table 1), representing approximately 14% of the US population, was used to complete this study. These data were originally obtained for an unrelated project evaluating breast cancer screening and treatment [19], [20], thus limiting the sample to female Medicare
Results
Among the 274 590 Medicare beneficiaries in our cohort, 8588 women (3.1%) were evaluated in an ED for head injury between 1992 and 2001, including 1835 who had a severe injury (Table 2). Neurologic imaging increased substantially over the study period (Fig. 1). Imaging increased approximately 22% among patients with severe injury (73% to 89%) and 79% among patients with a mild-moderate injury (38% to 68%) over the 9-year period.
In the unadjusted analyses, patient age and income were not
Discussion
The American College of Emergency Physicians has developed guidelines for neurologic imaging for patients seen in an ED with head injury [17]. These guidelines recommend that imaging should be obtained when there is a severe injury, but that imaging should be considered discretionary in other cases, as the risk of detecting significant or treatable disease is low [18]. Although the guidelines are relatively recent, they provide a reasonable way to separate situations where imaging is clearly
Acknowledgment
The authors would like to thank Dr James Brenner for his helpful comments on an earlier version of the manuscript.
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