Outpatient Care Dynamics after Allogeneic Transplantation: Reasons for Hospitalization and Early Mortality in a Latin American Transplant Center

Background: The outpatient model in the practice of hematopoietic stem cell transplantation (HSCT) has been accepted for its positive results in terms of effectiveness and safety. Its main advantages include shorter hospital stays, lower risk of infections, and higher patient satisfaction. However, there are associated risks, such as increased potential for rapid disease progression without immediate medical intervention, difficulties in managing severe complications, and the challenge of ensuring adequate patient and caregiver education to recognize early signs of complications. In developing countries, the reality of outpatient care can be very different from those in developed countries, often driven by necessity due to resource constraints and lack of available beds. Understanding the dynamics of hospitalization after the infusion in this setting is crucial for improving patient care and outcomes.

Objectives: To analyze the dynamics of post allogenic hematopoietic stem cell transpalntation (Allo-HSCT) hospitalization in patients from an outpatient transplant program. Identify the reasons for hospitalization and assess the treatment-related early mortality.

Methods: This retrospective cohort study included patients who underwent Allo-HSCT in our outpatient transplantation program in northeastern Mexico between January 2020 and January 2024. The unit operates from 8 am to 5 pm, and outside these hours, patients must communicate with doctors via a 24-hour hotline and seek emergency department care if necessary. Data were gathered from medical records, including patient demographics and hospitalization information such as the length of hospital stay, reason for hospitalization, need for critical care, use of mechanical ventilation, and mortality. Early transplant-related mortality was defined as death occurring within the first 30 days post-HSCT.

Results: Out of 157 patients who underwent allogeneic HSCT, 146 (92.9%) were planned as outpatient transplants. Within the first 30 days post-transplant, 56 patients (38%) required hospitalization. Among those hospitalized, 12 (21%) had matched sibling donors (MSD) and 44 (78.5%) had haploidentical HSCT. The median age was 29 (range, 16-68). Of the patients who required hospitalization, 35 (62.5%) were transferred from the outpatient clinic to the inpatient area during outpatient operating hours, while the remaining 21 (37.5%) were admitted directly through the emergency department outside outpatient clinic hours. The median length of stay was 8.5 days (range, 2-46). The primary reasons for hospitalization included febrile neutropenia in 37 patients (66%), cytokine release syndrome in 8 patients (14%), and diarrhea in 6 patients (10.7%). Acute kidney injury was present in 9 patients (16%), and hypotension at admission was noted in 16 patients (28.5%). Vasopressors were required for 10 patients (17%), and mechanical ventilation was necessary for 5 patients (8.9%). Mortality within the first 30 days post-transplant occurred in 10 patients (17.85%), with causes of death including septic shock (n=7, 70%), bleeding (n=2, 20%), and uremia (n=1, 10%). Only higher age was associated with early death (p=0.02), with a median age of 42.8 years (range, 16-68) in those who died early compared to 28 years (range, 16-68). The type of transplant, diagnosis, reason for admission, admission outside outpatient clinic hours, and presence of shock at admission were not associated with early death.

Conclusion: The dynamics of hospitalization in our outpatient program presented significant challenges, with hospitalizations primarily driven by complications such as febrile neutropenia and CRS. A substantial number of patients required transfer to inpatient care from outpatient facilities outside the outpatient clinic operating hours. Enhancing outpatient care infrastructure and early intervention strategies could significantly improve patient outcomes in this setting. This study underscores the need for tailored approaches to manage patients in outpatient allogeneic programs in resource-constrained settings.

Future efforts should focus on strengthening outpatient care capabilities, coordination with inpatient and emergency services training healthcare providers and navigators, and developing protocols for early detection and management of complications to reduce hospitalizations and improve survival rates.

Gomez-De Leon:Abbvie: Honoraria; Amgen: Honoraria; bms: Honoraria; Novartis: Honoraria; Pfizer: Honoraria; Janssen: Honoraria; Sanofi: Honoraria, Other: Advisory board; Janssen: Other: Advisory board. Gomez-Almaguer:BMS: Consultancy, Other: Advisory board, Speakers Bureau; Roche: Speakers Bureau; Amgen: Consultancy, Other: Advisory board, Research Funding, Speakers Bureau; AbbVie: Research Funding, Speakers Bureau; Seattle Genetics: Research Funding; Incyte: Research Funding; Astex Pharmaceuticals: Research Funding; Tevas: Speakers Bureau; Takeda: Consultancy, Other: Advisory board, Research Funding, Speakers Bureau; Janssen: Consultancy, Other: Advisory board, Speakers Bureau; Novartis: Consultancy, Other: Advisory board, Speakers Bureau; Blueprint Medicines: Research Funding; Sanofi: Speakers Bureau; Kartos Therapeutics: Research Funding; Gilead/Forty Seven: Research Funding; ConstellationPharmaceuticals: Research Funding.