Hospital readmissions reduction program success might have been overstated by more than half, study says

Reductions in risk-adjusted readmission rates caused by the Hospital Readmissions Reduction Program (HRRP) may have substantially lower than previously reported, according to a new study in the journal Health Affairs. 

Published Monday, the study shows a change in billing forms used by Medicare that was introduced during the same time frame accounts for more than half the reduction in risk-adjusted readmission rates that was previously attributed to the HRRP.

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Christopher Ody, Ph.D., of the Kellogg School of Management at Northwestern University, said he and his coauthors initially dove into data from Medicare’s Research Identifiable Files in an attempt to identify the types of changes hospitals made to drive the reduction in readmission rates after program's introduction.

“We have these two pieces of evidence that had been used to say that this program had had a big effect,” Ody said. “One was this really dramatic time series decrease and the other one is these decreases were bigger for targeted conditions and targeted hospitals. We’ve made very small adjustments to how these prior studies were done, but it turns out that we can pull the rug out from underneath both pieces of these as evidence.”

When the team dug into the one-month time period that accounted for roughly half the total drop in readmissions, they found it coincided with a key change to the form hospitals use to submit data to Medicare. The change allowed hospitals to report up to 25 codes for a given patient, where they previously had been limited to nine. That generated an overall increase in patient risk scores, creating a higher baseline that would have generated lower readmission rates regardless of any additional intervention.

Whether the remaining decrease in readmission rates has to do with the HRRP is open to interpretation, Ody said.

“If you asked me what I thought, the most likely interpretation of our results would be that [the HRRP] didn’t work. And the reason for that is that I don’t think that there is any reason that there should be decreases in readmission rates in critical access hospitals because of this program,” he says.

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If the HRRP did result in some number of decreased readmissions, the mechanism producing those results remains unclear. So far, however, the preponderance of the evidence appears to suggest that if the HRRP did generate a meaningful decrease in readmission numbers, it didn’t do so in the originally intended fashion, and its effects have not been nearly as large as previously reported.

Taken alongside the findings of another recent study suggesting some of the program’s unintended consequences may actually cause harm to patients, the data to date highlight the difficulties confronting policymakers as they design and test the programs designed to drive the shift toward a value-based healthcare system.

The key takeaway here may be the importance of smaller-scale pilot programs rather than national rollouts, especially if they produce measurable differentiations in the data.

“Creating experimental variation is great both because it lets us measure the effect of these programs better, and it lets us then figure out within the different ways we can do things what’s working better and what’s working worse,” Ody said.