How health care is like a thermostat

A urologist who specializes in prostate cancer, Dr. Peter C. Albertsen said he’s long been astounded at how many patients referred to him have had CT scans and bone scans performed that weren’t warranted.

So when he and colleagues at Yale and New York University began researching the use of imaging in prostate cancer patients, Albertsen figured they would find lots of inappropriate imaging.

“The data said, ‘Yeah, you’re partly right, but you missed something else,'” said Albertsen, chief of the UConn Health Center’s urology division and a professor of surgery.

In fact, the researchers found that areas of the country with high rates of inappropriate imaging also had high rates of imaging that was warranted, while areas that had lower rates of inappropriate imaging also had lower rates of the imaging that was appropriate.

“Imaging use appears to be determined strongly by regional practice patterns and affinity for imaging, rather than by medical indication,” the researchers wrote in an article published Monday in the journal Health Affairs.

They called the concept the “thermostat model” of health care usage: Rates of imaging, appropriate and inappropriate alike, go together in a particular region, as if they were set by a thermostat.

The authors, led by Dr. Danil V. Makarov, a professor at the NYU School of Medicine and NYU Wagner School of Public Service, warned that efforts to reduce unnecessary imaging could also inadvertently lead to a drop in imaging that is warranted, if the efforts are not properly tailored.

The study used data from 48,148 prostate cancer patients aged 66 to 85 who were diagnosed with prostate cancer in 2004 or 2005. The researchers defined appropriate and inappropriate imaging based on guidelines from the National Comprehensive Cancer Network.

As policymakers try to control health care costs by cutting back on inappropriate health care use, the authors noted, they should look to break the “thermostat-like relationship” between appropriate and inappropriate health care use to ensure that the right patients get the right tests and procedures. Some ways to get health care providers to reduce unnecessary care while still providing appropriate services could include profiling physicians who inappropriately overuse resources, linking payment to appropriate use, or rewarding physicians and organizations that use their resources appropriately, they wrote.

Albertsen said the further development and dissemination of guidelines for the use of imaging could help, although he noted that the more guidelines there are, the more difficult it can be for physicians to keep track of and follow them. The use of electronic medical records could improve things, he said, if they can notify physicians when they have ordered imaging for patients where guidelines would not recommend them.

Alternatively, he said, a system in which health care providers have a set budget for patient care could help by increasing the focus on avoiding unnecessary imaging, while underuse of imaging could be addressed by having quality standards.

The study was funded by the Robert Wood Johnson Foundation and the Department of Veterans Affairs.