Posttransfusion platelet count increments after ABO-compatible versus ABO-incompatible platelet transfusions in noncancer patients: an observational study.

BACKGROUND: Major incompatible platelet (PLT) transfusions have been associated with inferior posttransfusion PLT count increments compared with ABO-compatible transfusions. However, most studies to date have been small and involved hematology/oncology patients. STUDY DESIGN AND METHODS: We conducted a prospective observational study in predominantly nononcologic patients to determine whether ABO-compatible (defined as ABO identical and minor incompatible) PLT transfusions resulted in superior posttransfusion PLT count increments. We collected data on consecutive inpatients at Hamilton General Hospital receiving a PLT transfusion during a 50-month period. We compared the absolute count increment (ACI) and corrected count increment (CCI) values in ABO-compatible versus incompatible PLT transfusions. Linear regression was performed to adjust for factors potentially affecting the posttransfusion PLT count response. Univariate models were applied to each explanatory variable with p values of less than 0.10 considered potentially significant. Multivariate models were applied to all potential explanatory variables of interest. p values of less than 0.05 were considered significant.
RESULTS: A total of 1030 transfusions were included in the primary analysis, 73.7% of which were ABO compatible. The median ACI was 35 (interquartile range [IQR], 18-55) for compatible transfusions versus 31 (IQR, 13-51) for incompatible transfusions (p = 0.1480). The median posttransfusion CCI (n = 686) was 18.6 (IQR, 10.2-28.4) for compatible transfusions versus 15.2 (IQR, 4.7-25.7) for incompatible transfusions (p = 0.0499).
CONCLUSIONS: ABO-compatible transfusions in nononcologic patients are associated with a significantly better CCI although the observed difference is small (approx. 20%) and may not be clinically significant.