DOES THE TIME FROM DISCHARGE TO READMISSION IMPACT OUTCOMES?

Background: In 2012, as part of Value based purchasing program, CMS instituted the Hospital Readmission Reduction program (HRRP). This aimed to decrease the number of unplanned readmission to the hospital for six conditions: Acute myocardial infarction(AMI),chronic obstructive pulmonary disease( COPD), Heart Failure (HF), Pneumonia ( PNA) , Coronary bypass graft(CABG), Elective total hip arthroplasty (THA) and total knee arthroplasty ( TKA) . We aimed to analyze the impact of this rule on readmission rates and analyze whether time to readmission was associated with outcomes.

Methods: We performed a retrospective study of inpatient records included in the National Readmission database from 2010 to 2019. We recorded information on AMI, COPD, HF, PNA, CABG, TKA and THA and analyzed association between readmission status, timing of readmission and the outcomes: Death, Hospital Charges and Length of stay. We performed Univariate and Multivariate analysis.

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% to 19.8%) , HF ( 24.8 % to 21.9%) , PNA ( 16.4% to 15.1%) , AMI ( 15.6% to 12.9%) and TKR (4.1% to 3.4%) decreased whereas CABG ( 10.2% to 10.6%) and THR 4.2% to 5.8%) increased over time. Readmission likelihood increased with Male gender ( OR 1.07, 95% CI 1.068 – 1.072) ,teaching hospitals (OR 1.02, 95% CI 1.016 – 1.021) and Medicare (compared to Medicaid (OR 1.09, 95% CI 1.085 – 1.093), but was lower in Medium ( OR 0.98, 95% CI 0.976 – 0.981) and Small size (OR 0.95, 95% CI 0.945 – 0.951) compared to Large size hospitals, and with higher income brackets and higher age. Later admission year was also associated with less readmissions. Readmitted patients were at higher likelihood of dying ( 6% vs 2.8%) had a higher LOS (3[2-5] vs 4[3-7] but similar hospital charges compared to non-readmitted patients. When compared by Quartile, patients readmitted within 10 days had a mortality to 6.4% higher than those readmitted in 11-20 days ( 5.4%) and 21-30 days(4.6%). Increased time from discharged to readmission was associated with lower death likelihood, lower Hospital charges but similar LOS.

Conclusions: Over the last 10 years, readmission rates decreased for the all conditions included in the HRRP except CABG and THR. It is unclear what impact HRRP had , since those rates started to decrease prior its institution. Patients readmitted shortly after discharge were at higher risk of death and had higher hospital charges compared to those readmitted later.