Associations between ABO non-identical platelet transfusions and patient outcomes-A multicenter retrospective analysis

Abstract

Background: Due to platelet availability limitations, platelet units ABO mismatched to recipients are often transfused. However, since platelets express ABO antigens and are collected in plasma which may contain ABO isohemagglutinins, it remains controversial as to whether ABO non-identical platelet transfusions could potentially pose harm and/or have reduced efficacy.

Study design and methods: The large 4-year publicly available Recipient Epidemiology and Donor Evaluation Study-III (REDS-III) database was used to investigate patient outcomes associated with ABO non-identical platelet transfusions. Outcomes included mortality, sepsis, and subsequent platelet transfusion requirements.

Results: Following adjustment for possible confounding factors, no statistically significant association between ABO non-identical platelet transfusion and increased risk of mortality was observed in the overall cohort of 21,176 recipients. However, when analyzed by diagnostic category and recipient ABO group, associations with increased mortality for major mismatched transfusions were noted in two of eight subpopulations. Hematology/Oncology blood group A and B recipients (but not group O) showed a Hazard Ratio (HR) of 1.29 (95%CI: 1.03-1.62) and intracerebral hemorrhage group O recipients (but not groups A and B) showed a HR of 1.75 (95%CI: 1.10-2.80). Major mismatched transfusions were associated with increased odds of receiving additional platelet transfusion each post-transfusion day (through day 5) regardless of the recipient blood group.

Discussion: We suggest that prospective studies are needed to determine if specific patient populations would benefit from receiving ABO identical platelet units. Our findings indicate that ABO-identical platelet products minimize patient exposure to additional platelet doses.

Keywords: ABO; platelet transfusion.

Figure 1:

Study Flow Chart depicting subject and encounter inclusion and exclusion criteria.

Figure 2:

Example Encounter Schematic Encounters initiate with a platelet transfusion defined as shown in Supplemental Table 1. Upon subsequent platelet transfusion, encounters were reclassified in an escalating manner of identical to major or minor to bidirectional. Examples are not all-inclusive.

Figure 3:

Risk of mortality associated with exposure to ABO non-identical platelet transfusions by recipient blood group and diagnosis category: Forest plots of Hazard ratio (HR) and 95% Confidence Intervals (95% CI) from Cox proportional hazards model relative to identical only platelet transfusions, see Methods. Left panel: blood group O recipients. Right panel: blood groups A and B recipients. Diagnostic categories were assigned based on ICD9/10 codes. An encounter may fall into more than one diagnostic category.

Figure 4:

Risk of mortality associated with exposure to an increasing number of ABO non-identical platelet transfusions by recipient blood group and diagnosis category: Forest plots as described in Figure 3 in a dose-dependent response. For blood groups A and B, bidirectional exposures are included in both the major and minor categories.

Figure 5:

Risk of sepsis associated with exposure to ABO non-identical platelet transfusions by recipient blood group and diagnosis category: Forest plots as described in Figure 3 except with an endpoint of sepsis. Trauma and Intracerebral Hemorrhage were not analyzed due to an insufficient number of events.

Figure 6:

Odds Ratio for receiving a subsequent platelet transfusion following a non-identical platelet transfusion: Odds Ratio and 95% Confidence Intervals from a multivariable logistic model for a subsequent platelet transfusion following a non-identical platelet transfusion relative to identical only platelet transfusions for each 24-hour period after receipt of a platelet transfusion. Blood group O following a major mismatch platelet transfusion is represented by the filled square, dotted line. Blood groups A and B following a major mismatch is the filled circle, dashed line, minor mismatch is the filled diamond, long dashed line and bidirectional is the filled triangle, dot/dashed line. Values are offset for clarity.