Relationship Between Hospital Readmission and Mortality Rates for Patients Hospitalized With Acute Myocardial Infarction, Heart Failure, or Pneumonia

Study Questions:

What is the relationship between hospital 30-day, all-cause, risk-standardized mortality rates (RSMRs) and 30-day, all-cause, risk-standardized readmission rates (RSRRs) for acute myocardial infarction (AMI), heart failure (HF), and pneumonia?

Methods:

This was a retrospective analysis of Medicare fee-for-service beneficiaries discharged with AMI, HF, or pneumonia between July 2005 and June 2008. Hospital 30-day RSMRs and RSRRs were the main outcome measures. The correlation between hospital RSMRs and RSRRs was quantified using weighted linear correlation. To examine whether the relationship between RSMR and RSRR was consistent among subgroups of hospitals, the authors stratified the sample by hospital region, safety-net status, and urban or rural status.

Results:

Mean RSMRs and RSRRs, respectively, were 16.60% and 19.94% for AMI, 11.17% and 24.56% for HF, and 11.64% and 18.22% for pneumonia. The correlations between RSMRs and RSRRs were 0.03 (95% confidence interval [CI], -0.002 to 0.06) for AMI, -0.17 (95% CI, -0.20 to -0.14) for HF, and 0.002 (95% CI, -0.03 to 0.03) for pneumonia. While there was a significant negative linear relationship between RSMRs and RSRRs for heart failure, the shared variance between these two measures was only 2.9%, with the correlation most prominent for hospitals with RSMR <11%.

Conclusions:

Hospital-level 30-day risk-standardized mortality rates and readmission rates were not associated for patients admitted with an AMI infarction or pneumonia. There was a modest association for patients admitted with HF, but only for a limited range of the RSMR.

Perspective:

While it has been suggested that hospital mortality rates and readmission rates may have an inverse relationship, the current analysis would dispel those concerns. The limitations of the analysis aside, the study is a substantial contribution by emphasizing that mortality and readmission rates are distinct measures (particularly for AMI and pneumonia) that offer unique information. Hospital-level performance in reducing mortality rates may not necessarily dictate performance on readmission rates. The association, albeit modest and only within a certain range, between hospital-level RSMRs and RSRRs for HF, should not be discounted.

Keywords: Outcome Assessment (Health Care), Risk, Myocardial Infarction, Pneumonia, Hospital Mortality, Cardiovascular Diseases, Medicare, United States, Home Care Services, Hospital-Based


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