Association between Transplant Volumes and 30-Day Readmissions Following Allogeneic Hematopoietic Cell Transplantation (allo-HCT) in the US

Abstract Background: Readmissions within 30 days after index hospitalization is a quality and cost-containment metric. Financial penalties to hospitals with high rates of risk-adjusted readmissions have been expanded beyond medical conditions like heart failure and pneumonia. Published data show significant heterogeneity in readmission rates and recent data from elderly Medicare beneficiaries reported a 17.8% readmission rate for targeted conditions. Allo-HCT is a widely used therapeutic strategy in the management of various hematologic disorders like acute myelogenous (AML) and lymphoblastic leukemia (ALL). However, allo-HCT readmission rates are poorly described, and limited to single center studies only. The association between institution HCT volume and 30-day readmission metric has not been examined. Methods: In this observational study, we used the 2012-2014 Nationwide Readmission Database (NRD) to identify hospitals with established allo-HCT programs. Patients ≥18 years of age, discharged from hospital following an allo-HCT (identified using ICD-9 procedure code of 41.02, 41.03, 41.05, 41.06, or 41.08) were included. Annual hospital case volume was calculated as the sum of all discharges with allo-HCT within the calendar year; low, medium, and high annual case volume groups were created based on (survey weighted) tertiles of patients (pts.) in the analytic data domain (Figure 1). Rates, causes, and costs of 30-day readmissions were compared between low-, medium-, and high-volume hospitals. The analysis was limited to urban teaching hospitals and pts. admitted during month of December were excluded. The primary outcome, was the unplanned 30-day re-admission following allo-HCT. Multiple logistic regression was used to model each 30-day readmission outcome including hospital case volume with other predictors (age, sex, disease type, stem cell source, co-morbidity index, primary insurance, length of stay, infection and acute graft-versus-host-disease (aGVHD) at index admission, discharge disposition and median income quartile). Results: A total of 17,214 (weighted) allo-HCTs were performed during the time period. Baseline characteristics of pts. in low ( 158 allo-HCTs/yr.) hospitals were comparable as shown in Table 1. The overall rates of readmissions were significantly higher in low volume centers (24.7.4%; SE, 1.5) compared to medium (21.4% (1.7) and high volume (9.5% (1.8), centers (p=0.03). The mean time to readmission in low vs. medium vs. high volume centers was, 11.6 [0.39] days vs. 12 [0.26] days vs. 11.5 [0.57] days respectively, (p Readmission rates in low volume and medium volume centers compared to high volume centers were: adjusted odds ratio (aOR) 1.39, 95% CI 1.08-1.77; p =0.01 and 1.18, 95% CI, 0.89-1.55; p=0.23, respectively. Other significant predictors of readmission included disease type (ALL vs. AML): aOR 1.32, 95% CI 1.07-1.63; p= 0.009), type of primary insurance (Medicare vs. private): aOR 1.17, 95% CI 1.01-1.35; p=0.02; Elixhauser co-morbidity index (≥1 vs. 0): aOR 1.4, 95% CI 1.2-1.7; p= 0.001 and stem cell source (cord blood vs. peripheral blood; aOR 2.4, 95%CI 1.85-3.2, p Conclusions: The likelihood of readmission after allo-HCT is elevated in centers performing Disclosures Dhakal: Amgen: Honoraria; Takeda: Honoraria; Celgene: Consultancy, Honoraria. Shah: Geron: Equity Ownership; Lentigen Technology: Research Funding; Juno Pharmaceuticals: Honoraria; Oncosec: Equity Ownership; Miltenyi: Other: Travel funding, Research Funding; Exelexis: Equity Ownership. D'Souza: Prothena: Consultancy, Research Funding; Takeda: Research Funding; Celgene: Research Funding; Merck: Research Funding; Amgen: Research Funding. Hari: Celgene: Consultancy, Honoraria, Research Funding; Janssen: Honoraria; Bristol-Myers Squibb: Consultancy, Research Funding; Kite Pharma: Consultancy, Honoraria; Sanofi: Honoraria, Research Funding; Amgen Inc.: Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Spectrum: Consultancy, Research Funding. Hamadani: Sanofi Genzyme: Research Funding, Speakers Bureau; MedImmune: Consultancy, Research Funding; Celgene Corporation: Consultancy; Takeda: Research Funding; Cellerant: Consultancy; ADC Therapeutics: Research Funding; Ostuka: Research Funding; Janssen: Consultancy; Merck: Research Funding.