Infectious Morbidity and Hospitalization Requirements of Patients with Acute Myeloid Leukemia Receiving Intensive Outpatient Consolidation.
Authors: Benke Stan , Bow E. J. , Schacter B. , Loughery J. , Benjaminson P. , Seftel M. D. , Rubinger M. 
Published: April 2020

Abstract
Limited inpatient resources have focused interest upon the outpatient administration of intensive post-remission consolidation of acute myeloid leukemia (AML). Experience is limited in this regard (Blood 2002, 100:766a). In August 2001 a program of post-remission outpatient consolidation was instituted in our centre. A total of 68 cycles were administered to 35 patients with AML over 36 months. Standard prophylaxis included ciprofloxacillin and acyclovir. Our study was designed to look at infectious complications and requirement for hospitalization. Median age of patients was 54.5 years (range 20–77). Chemotherapy consisted of either high-dose cytarabine (1.5gm/m2 q12 hours x 12 doses in patients &lt; 60 yrs) in 39 cycles, or intermediate-dose cytarabine (0.5gm/m2 q12 hours x 12 doses in patients &gt;60 yrs) in 29. Upon completion of chemotherapy, patients continued to be evaluated daily on an ambulatory basis. Granulocyte colony stimulating factor was initiated on day eight of each cycle, along with blood product support. Median time to an absolute neutrophil count of ≥0.5 x 109/L, was 19.8 days (15–35). Only 26/68 (38%) required admission, with a median hospital stay of 19.7 days (5–96). A febrile neutropenic event (FNE) occurred in 46/68 (68%) cycles of outpatient consolidation, with blood cultures revealing a causative microorganism in 27/46 (59%). Viridans group Streptococci were the most common pathogen isolated, accounting for 12 cases, while Gram negative organisms were found in 5 patients. 15/46 (33%) patients were admitted to hospital at the onset of their FNE with 3 requiring inotropic support and endotracheal intubation. All three had septic shock and acute respiratory distress syndrome with documented Streptococcus mitis bacteremia; one of these patients died while the other two recovered fully. 31/46 (67%) cases of FNE were treated initially with outpatient antimicrobial therapy. The most commonly used empiric antibiotic regimen was vancomycin and ceftriaxone. 23/46 (50%) episodes of FNE were treated entirely on an outpatient basis; 8/46 (17%) failed outpatient antibiotics and required some inpatient care. Three patients were admitted for reasons other than FNE (psychosocial support, 1; relapse of AML, 1; central venous catheter infection, 1). Overall mean duration of hospitalization for each cycle of consolidation given was 7.5 days. The mortality of 2.9% seen in our group compares favorably with other published data (NEJM, 1994; 331:896). In conclusion intensive outpatient consolidation for AML is feasible, as it is associated with acceptable infectious morbidity, with the majority of cases (62% of cycles) being managed entirely on an ambulatory basis. The short mean duration of hospitalization of only 7.5 days per cycle, compares favorably with published data (NEJM 1995 332:217) and is likely economically advantageous. A comprehensive cost-analysis of outpatient versus inpatient costs for AML consolidation is under evaluation at our institution.