A review of one radiology practice’s diagnostic lumbar spine MRI exams has shown that the number of negative findings is 86 percent higher on exams ordered by a physician with a financial interest in the MRI equipment used, adding fuel to the assertion that self-referrals lead to overutilization, according to a study published in the June issue of the American Journal of Roentgenology .
The study, authored by Matthew P. Lungren of Duke University Medical Center in Durham, N.C., and colleagues, also found the average age of patients referred for imaging was lower if the referring physician group had a financial interest. “These findings suggest that there may be a lower threshold for lumbar spine MRI referral in the financially incentivized ordering group compared with ordering physicians with no financial incentive in MRI equipment,” wrote the authors.
Lungren and colleagues noted that previous studies have demonstrated that the practice of imaging self-referral is increasing and that owners of diagnostic imaging equipment are more likely to refer their patients to facilities where they have a financial interest. To the authors' knowledge, though, no studies had compared the subsequent findings on imaging studies between self-referrers and physicians with no financial interest in the imaging equipment used.
The retrospective review consisted of 500 consecutive diagnostic lumbar spine MRI exams at a single radiology practice. All exams were ordered by one of two separate referring physician groups—one with a financial interest in the MRI equipment used and one without.
Results showed the negative scan frequency was 86 percent higher in the financial interest group and the average age of patients in this group was 49.8 years, compared with 56.9 years in the no-financial interest group. Notably, there were no significant differences in the average total number of lesions per scan in the positive exam group, suggesting the study cohorts were similar in terms of disease severity.
Although the results demonstrated a bias toward increased imaging utilization from self-referrers, Lungren et al stopped short of saying the review proves intentional overutilization for profit. “If, as we suspect, there is a bias toward more imaging in patients with milder symptoms in a financially incentivized setting, the bias may be unconscious. Furthermore, it is also possible that the practice pattern of a given physician group may be particularly imaging intensive, whereas that of a different group might be less so. This could be related to the comfort level or dependence on imaging for diagnosis or to a stronger belief in the benefits of imaging by the financially incentivized group.”
The authors noted the study also could be skewed by the abnormalities used to classify a positive exam or by the possibility that the financial interest group served a statistically significant younger population—though this is unlikely due to the referring groups’ close geographic proximity.
“Despite the limitations, we think that the inherent conflict of interest present when physicians both order and then perform and collect money for MRI scans is an important factor to consider whenever the matter of healthcare cost is raised as an issue,” wrote the authors.
Lungren and colleagues suggested future studies validate the findings on a wider scale, and they also wrote that this type of assessment could provide important imaging utilization appropriateness metrics. “Such metrics could be of particular potential utility in the emerging era of accountable healthcare delivery. We think that medical societies and government agencies are the ideal sponsors of what would necessarily be large studies establishing these standards.”