Readmission Rate
Readmission rate is the percentage of patients who return to an inpatient setting within 30 days of discharge — a key quality and cost indicator tracked by CMS, The Joint Commission, and value-based payment programmes.
What is Readmission Rate?
A hospital readmission occurs when a patient is discharged from an acute care hospital and returns for another inpatient admission within a defined period — most commonly 30 days. The 30-day window is used by CMS because it balances clinical relevance (most preventable readmissions occur within 30 days) with statistical reliability. The national all-payer 30-day readmission rate is approximately 15.5%, though Medicare-specific rates are higher, typically ranging from 17–20%.
All-Cause vs Condition-Specific Readmissions
Readmission metrics can be all-cause (any readmission within 30 days regardless of reason) or condition-specific. The CMS Hospital Readmissions Reduction Programme (HRRP) focuses on six specific conditions: acute myocardial infarction (AMI), heart failure (HF), pneumonia, chronic obstructive pulmonary disease (COPD), elective primary total hip/knee arthroplasty (THA/TKA), and coronary artery bypass graft surgery (CABG). Each condition has its own benchmark readmission rate and risk-adjustment model.
CMS Excess Readmission Ratio (ERR)
CMS calculates the Excess Readmission Ratio (ERR) for each HRRP condition. ERR = (Predicted readmissions ÷ Expected readmissions). An ERR greater than 1.0 indicates worse-than-expected performance after risk adjustment. The risk adjustment accounts for patient age, sex, principal diagnosis, and comorbidities — but notably does NOT adjust for socioeconomic status, though CMS now reports dual-eligible stratified rates separately. An ERR above 1.0 for any HRRP condition triggers a penalty of up to 3% of all Medicare base operating payments for that fiscal year.
Preventable vs Unavoidable Readmissions
Not all readmissions are preventable. Studies suggest 27–28% of readmissions are preventable. High-impact interventions include: medication reconciliation at discharge, patient education on warning signs, scheduled follow-up within 7 days of discharge (shown to reduce readmissions by 20–30%), Transitional Care Management (TCM) services, and care coordinator calls within 48–72 hours. Identifying which readmissions were clinically avoidable — versus necessary acute deterioration — requires detailed case-level review that analytics tools can support.