Outcomes of Reduced-Intensity Conditioning Allogeneic Hematopoietic Cell Transplantation Performed in the Inpatient versus Outpatient Setting.

Allogeneic hematopoietic cell transplantation (allo-HCT) with reduced-intensity conditioning (RIC) is commonly performed as an inpatient procedure. The feasibility and outcomes of RIC allo-HCT in the outpatient setting is not known. We performed a single-center retrospective cohort study of patients aged ≥ 18years with hematologic malignancies who underwent RIC allo-HCT either in the inpatient or outpatient setting. Donor types included HLA-matched sibling and well-matched unrelated donors. The objectives were to compare the survival, complications, charges, and incidences of relapse, nonrelapse mortality (NRM), and acute and chronic graft-versus-host disease (GVHD) between the 2 groups. Between 2014 and 2017, 151 eligible patients were included, with 116 undergoing RIC allo-HCT in the inpatient setting and 35 patients undergoing RIC allo-HCT in the outpatient setting. Baseline characteristics were comparable between the 2 groups except for a higher proportion of patients with myeloma in the outpatient cohort (inpatient 15.5% versus outpatient 37.1%). The cumulative incidence of grades II to IV acute GVHD (inpatient 25.2% versus outpatient 25.7%), grades III to IV acute GVHD (inpatient 10.4% versus outpatient 8.5%), chronic GVHD (inpatient 38.3% versus outpatient 51.6%), NRM at 1 year (inpatient 10.8% versus outpatient 3.2%), and relapse (inpatient 24.8% versus outpatient 33.2%) did not significantly differ between the 2 cohorts. One-year progression-free survival (inpatient 64.4% versus outpatient 63.6%, P = .39) and overall survival (inpatient 73.8% versus outpatient 82.8%, P = .93) were also not significantly different between the 2 groups. The proportion of patients who developed neutropenic fever (inpatient 25.8% versus outpatient 8.5%, P = .03) and mucositis (inpatient 50.8% versus outpatient 8.5%, P < .001) and who required total parenteral nutrition (inpatient 20.6% versus outpatient 5.7%, P = .04) were more frequent in the inpatient cohort. About 51.5% of the outpatient cohort never required hospital admission in the first 100days. Outpatient HCT resulted in significantly lower charges than inpatient HCT in the first 100days (median charges: inpatient $339,621 versus outpatient $247,334; P < .001). On multivariate analysis the site of the HCT (outpatient versus inpatient) was not a significant predictor of either overall or progression-free survival. Outpatient RIC allo-HCT is feasible and safe with daily outpatient evaluation and aggressive supportive care resulting in outcomes comparable with those who received the transplant in the inpatient setting.