Age of Packed Red Blood Cells Transfused to Patients with Acute Leukemia: A Descriptive Analysis

Background: Patients with acute leukemia frequently present with disease-related severe anemia (hemoglobin <8 g/dL). Packed red blood cell (PRBC) transfusions are standard of care for severe anemia, though cells' ability to transport oxygen decreases with prolonged storage time (maximum 42 days). Evidence exists to support a significant decline in available cells' ability to transport oxygen beyond 21 days, though no guidelines currently exist to inform use of PRBCs based on storage age. Characteristics of transfused PRBC units and hemoglobin (hgb) levels in patients treated for severe anemia during acute leukemia treatment has not been described.

Methods: We sought to characterize PRBC units transfused during intensive induction chemotherapy treatment and associated hemoglobin levels following the initial transfusion based on PRBC unit age. We performed a pilot study via retrospective secondary analysis of pre-existing data from the University of Alabama at Birmingham O'Neal Comprehensive Cancer Center patient database and associated blood bank records. We included patients 18 years or older who were newly diagnosed with acute leukemia and required intensive induction chemotherapy treatment between December 2021-March 2022, who had a documented hgb consistent with the World Health Organization definition of severe anemia (<8 g/dL) during hospitalization, and who received at least one unit of PRBCs.

Results: Patients (n=11) were primarily Caucasian (90.9%), female (72.7%), with a median age of 56 years (range 34-70) (Table 1). Most patients (72.7%) were diagnosed with acute myeloid leukemia. Median duration of hospital stay for induction chemotherapy treatment was 26 days (range 13-56 days). Median hgb level was 8.9 g/dL (range 3.7-11.5 g/dL) on hospital admission; prior to the initial PRBC transfusion, median hgb was 6.7 g/dL (range 3.7-8.7 g/dL). After initial PRBC transfusion, median hgb increased to 7.7 g/dL (range 5.6-9.6 g/dL), representing a median increase in hgb of 1.1 g/dL (range -0.9-3.2 g/dL). Median age of the initial PRBC unit transfused was 27 days (range 13-32 days). Patients received a median of 9.5 PRBC units (range 0-18) during the intensive induction chemotherapy treatment period; median age of all PRBC units transfused was 23 days (range 3-41 days). Moderate positive correlation was noted between the change in hgb pre- and post-initial transfusion and PRBC age (r=0.55). Across hospitalization, median hgb level was 7.7 g/dL (range 7.3-9.1 g/dL); final hgb level prior to discharge was a median of 7.8 g/dL (range 7.2-9.5 g/dL).

Conclusions: In our pilot study, patients undergoing intensive induction chemotherapy treatment for acute leukemia generally received older PRBC units (>21 days) both at their initial transfusion and throughout their hospitalization. PRBC unit age was positively associated with change in hgb. In general, patients did not achieve a normal hgb level prior to hospital discharge despite numerous PRBC transfusions. Our findings are limited by sample size and therefore not generalizable. It is possible that transfusion of older stored PRBCs may result in inadequately treated or prolonged anemia, impacting patients' physiological response to disease and treatment. Further investigation is needed to examine this relationship.

No relevant conflicts of interest to declare.