Very High Hospital Admission Rate after Outpatient Non-Myeloablative Allogeneic Stem Cell Transplant Using Fludarabine and Low Dose TBI.
Authors: Bolwell Brian , Rybicki Lisa , Kalaycio Matt , Pohlman Brad , Andresen Steven , Brown Stacey , Kuczkowski Elizabeth , Bates Jennifer , Bernhard Laura , Cherni Kelly , Baker Janet , Sobecks Ronald 
Published: April 2020

Abstract
One of the theoretic advantages of non-myeloablative (“mini”) preparative regimens such as fludarabine and low dose total body irradiation (TBI) is that the transplant can be performed as an outpatient. Data is surprisingly sparse concerning the later hospital admission rate of such transplanted patients. We transplanted 71 patients from 1/1/00 to 6/15/05 using a “mini” preparative regimen of fludarabine and TBI (200cGy, n=53, 400cGy, n=18) and examined the rates of admission after transplant. All transplants and preparative regimens were delivered as an outpatient. The admission rate was similar between those receiving 200cGy and 400cGy, and the two groups were combined for this analysis. Median patient age was 52 (range, 15–65). Diagnoses included NHL (n=16 [23%]), AML (n=13, [18%]), myeloma (n=7, [10%)]), CML (n=7, [10%]), MDS (n=7, [10%], myelofibrosis (n=6, [8%]), CLL (n=4, [6%]), other (n=11, [15%]). Approximately 40% had resistant or untreated disease at transplant. 63 of 71 patients (89%) were admitted within 1 year of their original transplant. Rates of admissions were similar for related donor transplants (41/47, 33%) and unrelated donor transplants (22/24, 92%). Of 63 patients admitted to the hospital after their outpatient transplant, 52 (83%) were admitted within 3 months of the transplant. The most common reason for admission was fever (n=30, [58%]). Four patients were admitted for cardiac events (chest pain, tachycardia, possible MI and atrial fibrillation) and 7 patients were admitted for acute graft vs host disease. Of the 30 patients with fever at the time of transplant, the absolute neutrophil count was 0.94 k/μL (range, 0–16.49), and 9 had an absolute neutrophil count &lt;500 k/μL. 11 patients were admitted to the hospital between 3 and 12 months after their initial transplant, most commonly because of either acute graft vs host disease or infection. The median number of all post-transplant hospitalizations for matched related transplants was 2 (range, 0–8) and for matched unrelated transplants was 3 (range, 0–11). The median time from transplant to the first admission to the hospital was Day +22 for matched related transplants, and Day +6 for matched unrelated transplants. Median length of stay for the admissions was 6 days for the entire group. 32/71 (45%) of patients were admitted to the hospital at least 3 or more times within 18 months of their original transplant. Patients admitted to the hospital 0 or 1 time had a superior survival than those admitted 2 or more times, (overall survival 54% vs 24%, p value = 0.022) In conclusion, while the delivery of a “mini” transplant preparative regimen and the infusion of hematopoietic stem cells may safely be given as an outpatient, our experience suggests that the vast majority of patients have at least one hospital admission for various complications within 3 months of the transplant. This data does not support the concept that non-myeloablative allogeneic transplants can be performed as an outpatient in their entirety.