Lower or higher doses for prophylactic platelet transfusions: results of a meta-analysis of randomized controlled trials.

BACKGROUND: There are conflicting data regarding the optimal platelet (PLT) dose to transfuse prophylactically to patients with thrombocytopenia. A meta-analysis has been performed to summarize the results of different randomized controlled trials (RCTs). STUDY DESIGN AND METHODS: RCTs reported through December 2005 were retrieved; five of them met the criteria for meta-analysis. Weighted mean difference (WMD) of posttransfusion PLT count increment (x10(9)/L) and transfusion interval (days) and summary odds ratio (OR) of bleeding in higher PLT dose group (HDP) versus lower PLT dose group (LDP), according to the authors, were calculated across studies.
RESULTS: The use of HDP was associated with an increase in the transfusion interval (WMD, 1.04 days; 95% confidence interval [CI], 0.89-1.19; p < 0.00001) when compared with the use of LDP. When the studies that guaranteed the ABO compatibility of the PLT transfusions were combined, the use of HDP was statistically associated with an increase in the posttransfusion PLT count increment when compared with the LDP group (WMD, 23.6 x 10(9)/L; 95% CI, 18.28 x 10(9) to 28.92 x 10(9)/L; p < 0.00001). When bleeding was studied, data were available in only three studies and the hypothesis of homogeneity was rejected, in 4 of 10 subgroups analyses.
CONCLUSION: Few RCTs have addressed the issue of PLT dose for transfusion. It is shown that the transfusion of higher doses of PLTs is statistically associated with an increase in the transfusion interval and in the posttransfusion PLT count increment. A well-designed study of enough power is essential to establish the most effective and efficient dose for prophylactic PLT transfusions.