Can clinical guidelines reduce variation in transfusion practice? A pre–post study of blood transfusions during cardiac surgery

Background and Objectives: Previously published studies have consistently identified significant variation in red blood cell (RBC) transfusions during cardiac surgery. Clinical guidelines can be effective at improving the average quality of care; however, their impact on variation in practice is rarely studied. Herein, we estimated how variation in RBC use across cardiac surgeons changed after the publication of national patient blood management guidelines. Materials and Methods: We performed a pre–post study estimating change in variation in RBC transfusions across 80 cardiac surgeons in 29 hospitals using a national cardiac surgery registry. Variation across surgeons was estimated using fixed-effects regressions controlling for surgery and patient characteristics and an empirical Bayes shrinkage to adjust for sampling error. RBC use was measured by three metrics—the total number of units transfused, the proportion of patients transfused and the number of units transfused, conditional on receiving RBC. Results: The primary analysis utilized 35,761 elective cardiac surgeries performed between March 2009 and February 2015 and identified a 24.5% reduction (p < 0.0001) in mean total units transfused accompanied by a 37.2% reduction (p = 0.040) in the variation across surgeons. The reduction in mean total units was driven by both the proportion of patients transfused and the number of units transfused, conditional on receiving RBC, while the reduction in variation was only driven by the latter. Conclusion: In our study of RBC transfusions across cardiac surgeons, the surgeons who used more RBC in the pre-guideline period experienced larger reductions in RBC use after the guidelines were published.