The Need for Overlapping Interventions: Just One Won't Do It

Looking through the MRI

In a prior posting, the Disease Management Care Blog was reminded that the U.S. health care system  is exceptionally complex and non-linear. Thanks to its many overlapping, contradictory, shifting and often non-medical inputs, it defies the simple logic of a single-cause-leading-to-a-single-effect. If economics is the dismal science, health care economics is its dubious spawn.

However, that doesn't mean that multiple coordinated inputs combined with some good luck won't push the health care weather vane in the right direction. For the latest example of this fundamental truism, check out David Lee and Frank Levy's Health Affairs article The Sharp Slowdown In Growth Of Medical Imaging: An Early Analysis Suggests Combination Of Policies Was The Cause.

By way of background, medical imaging has been a high profile issue for policy makers and a headache for insurers because, until recently, the rate of costly "high dollar" imaging studies has been growing much faster than other medical costs.  It has been blamed as one technology-laden driver of health care inflation.  In the meantime, physicians have pointed to a variety of causes (and, by the way, left others unmentioned).  

In this study, the authors examined 10 years' worth of insurance claims for advanced imaging MRI and CAT scans from two multi-state commercial insurance plans and another smaller single state plan.  These data were then pooled with a 5% national random sample of imaging claims from Medicare beneficiaries.  The authors also interviewed radiologists, health administrators, radiology benefit managers and physician recruiters.

The results?  From 2000 through 2005, CT scans grew at a whopping rate of 14.3% but then slowed to 1.4%. MRI slowed in the same periods from 14% to 2.6%. At the same time, starting salaries for radiology specialist physicians significantly declined.
 
What happened?  According to the authors:

1. An industry sprung up.  In another example of the adage that "need is the mother of invention," companies that prior authorize imaging studies for medical necessity (for example) were hired by many commercial insurers.  They had an impact.

2. Skin in the game. Deductibles, co-insurance and co-pays made consumers think twice about agreeing to a study that was going to result in some out-of-pocket spending.

3. Unilaterally imposed fee reductions. Medicare cut the amount it paid for CAT and MRI studies performed in freestanding centers and physicians' offices. Hospitals were left untouched.

4. Glow in the dark.  Media reports on the amount of radiation prompted patients to worry about the long term impact of all those x-rays.

In other words, there was no single lever. Instead, the reduction of high utilization of pricey imaging was due to the confluence of at least four mutually reinforcing trends.

As further evidence of the overlapping trends that extended beyond simple cause-and-effect, Medicare never relied on prior authorization, didn't alter the out of pocket testing expenses for beneficiaries and left the payments for hospital-based imaging untouched. Yet Medicare saw an across-the-board reduction. MRIs don't involve ionizing radiation (they use relatively harmless magnets), but their overall rate went down in concert with CAT scans..

This has important implications for other laudable policy targets.  Based on this experience, waiving out of pocket costs alone are unlikely to increase the use of preventive health care services. Simply paying for the medical home may not make that big a difference.  Quoting the DMCB may not be enough to convince your skeptical friends.  So on and so on.

The obvious implication for the population health management service companies is that if they're going to have a significant impact, the likelihood of a successful outcome is far greater if it is implemented concurrently with other supportive interventions.

Putting the CAT Scanner Cancer Risk Into Perspective: Risk Compared to What?

After listening to and reading the news media's alarmist interpretations of an Archives of Internal Medicine report on the risk of 'yikes cancer!' from computerized (axial) tomography (CT or CAT) scans, the ever curious Disease Management Care Blog decided to take a look at the basis for all the fuss. Amy Berrington de Gonzales and colleagues used radiation and cancer data to project the future national incidence of additional cancers that can be expected from today's CAT scanners. The bottom line can be found in this table from the paper. Basically, the highest calculated risk of 'yikes cancer!' runs from a high of 7 per thousand CAT scans (or 0.7%) to 1 per ten thousand CAT scans (or 0.01%). There is a companion article that indicates that the dose of radiation may be even higher, suggesting there will be even more cancer down the road.

That all may sound awful, but the DMCB likes to keep the following factors in mind:

1) The lifetime risk of cancer from exposure to the radiation from a CAT scan is highest among children, but that pales compared to the more immediate risks that come from sedating children to keep them from moving. In the real world of clinical practice, this risk threshold is already considered so high that the added 0.7% risk from the radiation is not much of an additional consideration. Informed guardians already have a powerful incentive to keep CAT scan use to an absolute minimum - and they generally do.

2) As for the grown-ups, stumbling over the assessment of the real magnitude of risk may be a function of innumeracy, but the DMCB believes it can be managed by asking 'compared to what?' So while a CAT scan can present a lifetime risk of hundreths to tenths of one percent:

- having high blood pressure gives 40 year old men an additional 4-5% (one in twenty) chance developing heart failure over a lifetime. The DMCB says know your blood pressure, get it treated if it's high and then smile when they take your picture with the CAT scan.

- the risk of a brain hemorrhage from taking daily aspirin is 2 per 10,000 per year which is on the same order of magnitude every year as the lifetime cancer risk from a CAT scan. The DMCB doesn't recall any alarmist media reports on this risk. Hmmm. Once again, take two aspirins and smile for the scanner in the morning.

- the risk of a dying in a car accident during an average life time, according to this report, is 1 in 83, which works out to be more than 1% for every man, woman and child in the U.S. today. The DMCB recommends wearing a seat belt when you drive to your CAT scan appointment.

3) One way of gauging the risk of any health threat that is reported in the media is to examine the number of reports: the greater their number, stridency and alarm, the lower the real risk. The hubub over CAT scans suggests this inverse relationship is holding up.

4) Yet, Radiology Benefit Managers (or 'RBMs') have long regarded the cancer risk associated with CAT scans (example here) as one factor in controlling their utilization. If unecessary CAT scans are 'denied' for coverage by managed care oganizations, is that now no longer evidence of 'evil' managed care putting profits before patients? Were they right all along?

The DMCB has always been less worried about the radiation dose from CAT scanners than their far more dangerous tendency to find abnormalities in the absence of disease. Asymptomatic spots, densities, signals and other lesions of dubious significance have always bedeviled physicians and their patients, leading to ever more sophisticated imaging studies. If patient fear over CAT scan radiation exposure leads to fewer scans with fewer of their inevitable false positives, that may ultimately be a good thing.