Differing views explain why Medicare rejected CT colonography

May 28, 2009

Two radically different opinions have emerged to describe why the Centers for Medicare and Medicaid Services decided not to extend Medicare coverage to CT colonography screening. One credits a new policy requiring efficacy data that considers the effect of proposed medical applications specifically on a Medicare population. The other cites the influence of the U.S. Preventive Services Task Force.

Two radically different opinions have emerged to describe why the Centers for Medicare and Medicaid Services decided not to extend Medicare coverage to CT colonography screening. One credits a new policy requiring efficacy data that considers the effect of proposed medical applications specifically on a Medicare population. The other cites the influence of the U.S. Preventive Services Task Force.

A perspective touting CMS's new policy was highlighted in the May 28 New England Journal of Medicine. The article, "CMS's landmark decision on CT colonography-examining the relevant data," celebrates CMS's May 12 decision to deny coverage.

Critics of CMS policies concerning diagnostic imaging joined physicians directly involved with CMS policymaking to write the article.

Dr. Steve E. Phurrough, former director of coverage and analysis at CMS, was the chief author of the February 2009 proposed decision memo that determined that the clinical evidence for CTC was not strong enough to justify Medicare payment. Dr. Marcel E. Salive is director of CMS's medical and surgical services division.

Dr. Rita F. Redberg is a cardiologist at the University of California, San Francisco and a former member of the Medicare Coverage Advisory Committee, a group that evaluates the efficacy of new therapies and diagnostic techniques for the program. Dr. Sanket S. Dhruva, a UCSF medical resident, served as first author.

Dhruva and Redberg collaborated on a 2008 meta-analysis, published in the Archives of Internal Medicine, that concluded that many trials establishing the clinical efficacy of medical procedures proposed for Medicare coverage are based on experience of individuals who are too young to qualify for Medicare. The average age of subjects in 141 peer-reviewed cardiovascular imaging and therapeutic trials was 60.1 years. Women and minorities were severely underrepresented. In some cases, older patients, women, and patients with comorbid conditions were excluded.

In its CTC decision, CMS decided specifically to downgrade the influence of the American College of Radiology Imaging Network's National CT Colonography Trial by Dr. C. Daniel Johnson and other studies by Dr. Perry Pickhardt and Dr. David H. Kim because of a similar age disparity. The final decision notes that the average age of subjects in the three trials ranged from 57 to 58.3 years. The average age of Medicare beneficiaries in 2007 was 75.5 years.

It was the first time CMS used age disparity as a primary reason for rejecting a coverage application, said Redberg in an interview.

"It was an important decision because it acknowledged the importance of subgroup analysis and the need for data on women and the elderly," she said. "We hope it inspires more people to include those subgroups as well as race and ethnicity data when appropriate."

The decision does not mean that applicants for Medicare coverage will have to conduct trials specifically studying Medicare beneficiaries, Redberg said.

"But your study would have to include older patients and a subgroup analysis of older patients," she said.

Johnson would welcome that requirement. He is planning to break out the findings of more than 500 Medicare subjects from the ACRIN trial to answer questions posed in the final decision. In an interview with Diagnostic Imaging on May 15, Johnson expressed confidence that the subgroup findings will be published in the next 12 months.

Johnson also challenged CMS's conclusions about the reproducibility of ACRIN trial findings for Medicare beneficiaries.

"We know the biology and behavior of colorectal tumors are the same for seniors as for people under the age of 65," he said.

It is also unclear why CMS waited until the final decision to discuss its objections to the ACRIN trial design. Before patient recruitment, Johnson and other ACRIN trial researchers flew to Washington, DC, to discuss the study design with CMS and other government officials.

"This was to make sure the ACRIN trials answered all their concerns," he said.

Rather than questions about reproducibility, Johnson believes the U.S. Preventive Services Task Force's recommendation against CT colonography screening in 2008 was the key to CMS's ruling against Medicare coverage. The task force decision was made before ACRIN results were published in September.

"I think CMS was instructed that it was supposed to follow those guidelines," Johnson said.