Evaluation of 30-Day Hospital Readmission and Mortality Rates Using Regression-Discontinuity Framework

Abstract

Background: The Hospital Readmissions Reduction Program (HRRP) has been associated with reduced 30-day readmissions for acute myocardial infarction (AMI) and heart failure (HF). Objectives: The purpose of this study was to test whether this 30-day readmission reduction is a manifestation of practices that defer or avoid hospitalizations beyond the 30-day period. Methods: At all U.S. hospitals under HRRP, the authors calculated daily readmission rates for elderly Medicare fee-for-service beneficiaries through day-60 post-discharge following a hospitalization for AMI and HF—the 2 target cardiovascular conditions—as well as pneumonia in July 2008 to June 2016. The authors applied a robust bias-corrected nonparametric regression approach to evaluate for discontinuities in rates around day 30. Results: The authors identified 3,256 eligible hospitals, with median readmission rates in the days 1 to 30 and 31 to 60 post-discharge of 19.6% (interquartile range [IQR]: 16.7% to 22.9%) and 7.8% (IQR: 6.5% to 9.4%) for AMI, 23.0% (IQR: 20.6% to 25.3%) and 11.4% (IQR: 10.2% to 12.6%) for HF, and 17.5% (IQR: 15.4% to 19.8%) and 8.3% (IQR: 7.3% to 9.3%) for pneumonia, respectively. Daily readmission rates decreased across most of the 60 post-discharge days, with no discontinuities in the local polynomial regression for readmission at the 30-day mark, with a >95% power to detect 0.1% difference for each outcome across post-discharge day 30. Similarly, there was no discontinuity in mortality at 30 days post-discharge, or for either outcome at hospitals that incurred readmission penalties. Conclusions: There was no evidence that clinicians adopted strategies that specifically deferred admissions or affected mortality in the 30-day period after discharge. The findings are consistent with the institution of strategies that generally affected readmission risk after discharge.