Medicare Advantage beneficiaries run higher risk of readmission compared with traditional Medicare

Medicare Advantage users had higher risk-adjusted 30-day hospital readmission rates compared to traditional Medicare beneficiaries. Hospital admissions were compared for three common medical conditions. Findings from a retrospective population-based analysis are published in Annals of Internal Medicine.

Hospital readmissions are common and cost Medicare $26 billion annually. Reducing readmission rates has become a priority for clinicians, hospitals, and payers, particularly Medicare. As such, the Medicare Hospital Readmissions Reduction Program penalizes hospitals with worse than expected 30-day-readmission rates. However, readmission rates are calculated using data for traditional Medicare beneficiaries only, and not from those enrolled in the rapidly growing Medicare Advantage program.

Researchers from Brown University School of Public Health linked data from the Medicare Provider Analysis and Review (MedPAR) file with the Healthcare Effectiveness Data and Information Set (HEDIS) to investigate whether Medicare Advantage enrollees hospitalized for heart failure, pneumonia, or acute myocardial infarction had lower readmission rates than traditional Medicare enrollees. They found that, between 2011 and 2014, HEDIS data underreported hospital admissions for the medical conditions studied, and admissions that were incorrectly excluded had higher readmission rates than those that appeared in HEDIS data. Despite this, in analyses using the linkage of HEDIS and MedPAR, Medicare Advantage beneficiaries had higher 30-day risk-adjusted readmission rates than did traditional Medicare beneficiaries.

Based on previous studies, many policy observers have suggested that Medicare Advantage beneficiaries have better post-acute care outcomes than traditional Medicare beneficiaries. The authors say their study found no evidence that this happens with regard to readmission rates for three common medical conditions.

The authors of an accompanying editorial from the University of Minnesota School of Public Health suggest that while the study methodology is rigorous, the results should be interpreted with caution. The diagnosis codes on hospital claims were used for case-mix adjustment and may be subject to variation. In addition, the study included a cross-sectional comparison of Medicare Advantage versus traditional Medicare enrollees. If there were differences in the attributes between the enrollees in both programs that were related to both the choice of program coverage and hospital readmissions that are not captured by case-mix adjustment, then the estimates in the study may not capture the causal effect of Medicare Advantage enrollment.