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Diagnostic Mammography Use in United States Drops 39%


 

CHICAGO — The use of mammography has increased dramatically in the United States, but that growth has come in two distinctly different phases, Dr. David C. Levin said at the annual meeting of the Radiological Society of North America.

Between 1996 and 2004, the total utilization rate of mammography, both screening and diagnostic, increased 48% from 282 to 418 per 1,000 female Medicare beneficiaries. Virtually all growth occurred in the late 1990s when a number of public health initiatives were directed at women to increase the awareness of periodic breast cancer screening. But from 2000 to 2004, the growth trend essentially flattened.

This may reflect decreased access due to a shortage of breast imagers or the closure of breast imaging centers as a result of low reimbursement rates, said Dr. Levin, professor of radiology, Jefferson Medical College, Philadelphia. It could also be a result of fewer public health initiatives related to breast cancer detection.

“I think that the issue of why fewer radiologists are willing to do mammography is a multifaceted problem,” he said in an interview. “The three main things are that it is perceived as being poorly compensated, it has a high malpractice exposure, and [it] is a stressful environment.”

While the use of screening mammography mirrored the overall growth trend, diagnostic mammography trended downward. From 1996 to 2004, the rate of utilization of diagnostic mammography dropped 39% from 153 to 93 per 1,000 women, while the rate for screening mammography increased 157% from 113 to 291 per 1,000 women.

Coding changes demanded by the Health Care Financing Administration could explain the decline in diagnostic mammography claims, Dr. Levin said. In the late 1990s, there was a blurred distinction between screening and diagnostic mammograms in that a lot of radiologists were asking for additional views during a screening mammogram and coding those visits as diagnostic mammograms. But HCFA said if there are no signs or symptoms, it has to be coded as a screening mammogram, he said.

There has been a continued rise in use of breast ultrasound in the United States, such that it is now used more than once for every three diagnostic mammograms. From 1996 to 2004, the number of breast ultrasounds more than doubled from 15 to 33 per 1,000 women, reported Dr. Levin and colleagues who conducted their research through the university's Center for Research on Utilization of Imaging Services.

The use of breast magnetic resonance imaging is very low, but it has begun to show an exponential growth trend in recent years. Just 0.02 per 1,000 women received a breast MRI in 1996, while 0.29 did so in 2004, a 1,350% increase.

The investigators calculated utilization rates based on CPT codes for mammography, breast ultrasound, and breast MRI in Medicare Part B databases for 1996 through 2004. During data tabulation, only global and professional claims were counted, but not technical claims, as this would have led to double counting, Dr. Levin said. Providers of all specialties were included. The analysis did not include the utilization of digital vs. film mammography, because specific codes were not available for digital mammography for the entire study period.

Radiologists continue to perform most (93%) breast imaging for women. Radiologists carried out 94% of mammograms, 89% of breast ultrasounds, and 93% of breast MRIs, according to the study, which was funded in part by the American College of Radiology.

Meanwhile, from 1996 to 2004, breast ultrasounds more than doubled from 15 to 33 per 1,000 women. DR. LEVIN

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