Impact of time from discharge to readmission on outcomes: an observational study from the US National Readmission Database

Background The Hospital Readmission Reduction Programme (HRRP) was created to decrease the number of hospital readmissions for acute myocardial infarction (AMI), chronic obstructive pulmonary disease (COPD), heart failure (HF), pneumonia (PNA), coronary artery bypass graft (CABG), elective total hip arthroplasty (THA) and total knee arthroplasty. Objectives To analyse the impact of the HRRP on readmission rates from 2010 to 2019 and how time to readmission impacted outcomes. Design Population-based retrospective study. Setting All patients included in the US National Readmission database from 2010 to 2019. Patients We recorded demographic and clinical variables. Measurements Using linear regression models, we analysed the association between readmission status and timing with death and length of stay (LOS) outcomes. We transformed LOS and charges into log-LOS and log-charges to normalise the data. Results There were 31 553 363 records included in the study. Of those, 4 593 228 (14.55%) were readmitted within 30 days. From 2010 to 2019, readmission rates for COPD (20.8%–19.8%), HF (24.9%–21.9%), PNA (16.4%–15.1%), AMI (15.6%–12.9%) and TKR (4.1%–3.4%) decreased whereas CABG (10.2%–10.6%) and THA (4.2%–5.8%) increased. Readmitted patients were at higher risk of mortality (6% vs 2.8%) and had higher LOS (3 (2–5) vs 4 (3–7)). Patients readmitted within 10 days had a mortality 6.4% higher than those readmitted in 11–20 days (5.4%) and 21–30 days (4.6%). Increased time from discharge to readmission was associated with a lower likelihood of mortality, like LOS. Conclusion Over the last 10 years, readmission rates decreased for most conditions included in the HRRP except CABG and THA. Patients readmitted shortly after discharge were at higher risk of death.