Is mortality readmissions bias a concern for readmission rates under the Hospital Readmissions Reduction Program?

To determine whether the exclusion of patients who die from adjusted 30-day readmission rates influences readmission rate measures and penalties under the Hospital Readmission Reduction Program (HRRP).

100% Medicare fee-for-service claims over the period July 1, 2012, until June 30, 2015.

We examine the 30-day readmission risk across the three conditions targeted by the HRRP: acute myocardial infarction (AMI), congestive heart failure (CHF), and pneumonia. Using logistic regression, we estimate the readmission risk for three samples of patients: those who survived the 30-day period after their index admission, those who died over the 30-day period, and all patients who were admitted to see how they differ.

We identified and extracted data for Medicare fee-for-service beneficiaries admitted with primary diagnoses of AMI (N = 497 931), CHF (N = 1 047 552), and pneumonia (N = 850 552).

The estimated hospital readmission rates for the survived and nonsurvived patients differed by 5%-8%, on average. Incorporating these estimates into overall readmission risk for all admitted patients changes the likely penalty status for 9% of hospitals. However, this change is randomly distributed across hospitals and is not concentrated amongst any one type of hospital.

Not accounting for variations in mortality may result in inappropriate penalties for some hospitals. However, the effect of this bias is low due to low mortality rates amongst incentivized conditions and appears to be randomly distributed across hospital types.