Factors Associated With Prolonged Inpatient Stay in Patients Undergoing Outpatient Allogeneic Stem Cell...

Allogeneic hematopoietic stem cell transplantation (HCT) in the outpatient setting has been previously shown to be safe and feasible. However, there is a paucity of data on the factors associated with prolonged inpatient stay for patients planned for outpatient allogeneic HCT. In this article, we enumerate the parameters associated with prolonged inpatient stay in patients undergoing allogeneic HCT done using an outpatient day hospital model. We conducted a retrospective study describing the outcomes of patients undergoing allogeneic HCTs administered from July 2021 to July 2024 through our outpatient day hospital. Factors associated with ≤5 days of inpatient admission were analyzed using a Mann-Whitney U test for continuous variables and a chi-squared test for categorical variables. Multivariate analysis to identify factors independently associated with prolonged inpatient admission (>5 days) was performed using binary logistic regression. A total of 213 patients who underwent outpatient allogeneic HCT during the study period were included. Females were 38% (n = 81) and median age at time of transplantation was 58 (range, 17-75) years. Myeloablative condition regimens were used in 57.3% (n = 122) and the most common donor for transplantation was a 10/10 HLA-matched unrelated donor (64.8%; n = 138) followed by an HLA-matched sibling donor (21.1%; n = 45). During transplantation, 13.3% (n = 29) patients were never admitted to the inpatient unit and 50.7% (n = 108) patients had 1 admission. The most common reasons for inpatient transfer were fever or suspected infection in 62.5% (n = 172) and severe mucositis in 9.1% (n = 25) patients. After multivariate regression, female sex (hazard ratio [HR], 2.01; P = .04), and pretransplant hemoglobin <100 g/L (HR, 2.81; P = .005), HCT-CI >2 (HR, 2.41; P = .04), conditioning regimens other than fludarabine/busulfan (RIC) regimen (HR, 2.77; P = .003), and any ABO mismatch between donor and recipient (HR, 2.21; P = .03) were associated with prolonged inpatient transplant admission. D+100 NRM of the overall outpatient HCT patient population was 5.3%, with <1% needing an intensive care unit transfer within 48 hours of inpatient transfer. Allogeneic HCT done through a day hospital saved an average of 22 days/patient inpatient hospital bed days during their transplant admission. Outpatient allogeneic HCT using an ambulatory day hospital is a viable and potentially cost-effective method of performing HCT. Knowledge of factors associated with prolonged inpatient admissions will help to predict patient outcomes, improving patient education and utilization of hospital resources.