CMS introduced the Hospital Readmissions Reduction Program in 2010 to encourage lower readmissions by penalizing hospitals with high rates.
Hospital responses to incentives under the Medicare value-based purchasing program have been linked to recent declines in 30-day readmission rates (from 17.5 percent in 2009 to 15.6 percent in 2014), but a decline in hospitalizations may offer another explanation for the lower readmissions, according to a new study published in Health Affairs.
"We found that because the probability of an admission occurring soon after another is lower when there are fewer admissions per patient, the reduction in admission rates may explain much of the reduction in readmission rates," the study's authors wrote.
To examine the relationship between readmission and admission rates, researchers at Boston-based Harvard Medical School conducted a simulation analysis using 2009–14 fee-for-service claims data for a 20 percent sample of Medicare beneficiaries. They removed random samples of admissions from the claims data and recalculated readmission rates from the data with fewer admissions. The analysis included 6.4 million admissions among 2.6 million Medicare beneficiaries.
Assuming readmissions are not related to care received in preceding admissions, the study found that the adjusted 30-day readmission rates matched the actual change.
"Our analysis demonstrates how factors responsible for declining hospital admission rates may have explained much of the recent reduction in readmission rates," the study authors said.
The authors said they cannot quantify the exact effect of declining admission rates on readmission rates, "but it was likely substantial because most admissions occurring within thirty days of another are probably not caused by lapses in quality during the preceding admission."
More information about the study is available here.