AJR: Financial interest spurs imaging utilization

A new analysis verified and strengthened earlier studies that demonstrated the link between financial interest in imaging and greater utilization of imaging. The research, published in the November issue of American Journal of Roentgenology, led the authors to suggest that cost-containment efforts target financial interest in imaging.

Although previous studies have established a link between financial interest in imaging and utilization, skeptics have identified limitations and deficiencies in them. Mythreyi Bhargavan, PhD, of the American College of Radiology, and colleagues identified the limitations and designed an analysis to correct for them.

According to Bhargavan and colleagues, limitations in previous studies included:

• Emphasis on a limited range of illnesses and imaging techniques;
• Questionable identification of financial interest;
• Lack of adjustment for patient age and general health status;
• Lack of adjustment for severity of illness;
• Lack of examination of imaging-intense practice styles;
• Lack of analysis of total imaging utilization; and
• Lack of analysis of the impact of the Deficit Reduction Act (DRA).

The researchers adjusted for these limitations and used Symmetry’s Episode Grouper to analyze a random sample of 5 percent of healthcare claims of Medicare fee-for-service beneficiaries from 2004 to 2007. The analysis comprised 23 different combinations of medical conditions and imaging modalities.

Bhargavan et al explained that if almost all findings across the 23 combinations were the same, the findings could be generalized. They identified and applied four types of financial interest (self-referrer, imager, predominantly same-specialty referrer, predominantly self-referrer) in each analyses. Finally, the researchers accounted for patient age and health status, imaging-intensive practice style, use of alternate modalities and effects of the DRA.

The researchers confirmed the generalizability of their findings, and wrote, “On average, across all 23 condition-modality combinations and for all four definitions of physician financial interest for each of these 23 combinations, patients of physicians with a financial interest had 1.87 times the probability of having an imaging procedure as did patients of physicians without a financial interest.”

Age, health status and illness severity had little impact on utilization, accounting for a less than one percent difference in utilization.

The analysis indicated that physicians with practice styles that are naturally imaging intensive seemed to be more likely to acquire imaging equipment. The odds of imaging among this group averaged 1.29 times as high as others before they acquired financial interest. Financial interest increased this tendency as physicians’ odds of imaging increased 49 percent after they acquired financial interest.

Moreover, physicians with a financial interest tended to order more images in other modalities as well. Finally, the impact of the DRA was minimal and infrequently significant across analyses.

Bhargavan et al concluded by emphasizing the large impact of financial interest and wrote, “Unless empiric evidence related to the benefits of financial interest in imaging becomes available, we suggest that financial interest in imaging be considered as a focus for cost-containment efforts.”