Does Favorable Selection Among Medicare Advantage Enrollees Affect Measurement of Hospital Readmission Rates?

Literature indicates favorable selection among Medicare Advantage (MA) enrollees compared with fee-for-service (FFS) enrollees. This study examined whether favorable selection into MA affected readmission rates among Medicare-eligible veterans following hospitalization for congestive heart failure in the Veterans Affairs Health System (VA). We measured total (VA + Medicare FFS) 30-day all-cause readmission rates across hospitals and all of VA. We used Heckman's correction to adjust readmission rates to be representative of all Medicare-eligible veterans, not just FFS-enrolled veterans. The adjusted all-cause readmission rate among FFS veterans was 27.1% (95% confidence interval [CI] = 26.5% to 27.7%), while the adjusted readmission rate among Medicare-eligible veterans was 25.3% (95% CI = 23.6% to 27.1%) after correcting for favorable selection. Readmission rate estimates among FFS veterans generalize to all Medicare-eligible veterans only after accounting for favorable selection into MA. Estimation of quality metrics should carefully consider sample selection to produce valid policy inferences.

Duke Scholars

Author Matthew Leonard Maciejewski Population Health Sciences