First, some hospitals "may actually go in another direction, and start giving chemical (anti-clotting medication) prophylaxis to really low-risk patients, where the risk/benefit ratio doesn't favor that. That may increase the risk of bleeding and other complications.
"We don't want to do things that are outside the guidelines simply to address a faulty measure," Bilimoria says.
Second, "the worst thing is if a hospital's physicians think, 'Oh, I can drop my rate for VTE by looking less,' then they'll miss one, they won't get away with it, and that will be a deadly event."
In a nutshell, the problem is this: hospitals do imaging studies to look for blood clots in patients, even when they're asymptomatic. So hospitals that do more imaging studies find more blood clots than hospitals that don't do as many.
Some hospitals with trauma or burn units, or large orthopedic and cancer services, where surgical patients may be at higher risk for blood clots, and certainly academic medical centers, may look for clots in every patient after surgery, performing ultrasound or CT imaging tests to screen for any potential blood clot that could get into the lung and impair breathing.
Bilimoria and colleagues at Northwestern University's Feinberg School of Medicine who did this research believe the measure is so seriously flawed, that CMS should not be publicly reporting rates by hospital.
"The fact that it's being publicly reported should bother people," Bilimoria says.
Nor should it be using PSI-12 as a pay-for-performance measure, though it serves as such under authority of two sections of the Patient Protection and Affordable Care Act, he says.