Drivers of transfusion decision making and quality of the evidence in orthopedic surgery: a systematic review of the literature.

Reasons for variation in transfusion practice in orthopedic surgery are not well understood. This systematic review identified and appraised the quality of the literature in this area to assess the impact of factors associated with the use of allogeneic red blood cell (RBC) transfusion in orthopedic procedures. MEDLINE and EMBASE databases were searched for relevant English language publications. Articles containing a range of MeSH and text terms regarding "blood transfusion," "predictors," and "multiple logistic regression" were retrieved. Articles that focused on patients undergoing orthopedic procedures and that met prespecified inclusion criteria were appraised in terms of potential bias and the appropriateness of statistical approach. A total of 3641 citations were retrieved, and 29 met the inclusion criteria for the review. Articles reported on a range of orthopedic procedures including total hip arthroplasty; total knee arthroplasty, total shoulder arthroplasty, and spinal surgery. Most studies were conducted in the United States (n = 12) or Canada (n = 5). Study quality was moderate; 50% or more of the quality criteria were assessed in 15 articles. Particular areas of concern were the lack of prospective studies, lack of clarity in defining the time interval between risk factor assessment and transfusion outcome, and lack of model validation. A narrative synthesis found that 2 factors consistently influenced the use of RBC transfusion-decreased hemoglobin (n = 25) and increased patient age (n = 18). Increased surgical complexity (n = 12), low body weight (n = 9), presence of additional comorbidities (n = 9), and female sex (n = 7) were also important factors. The general quality of the studies in the field is weak. However, low hemoglobin and increasing age were consistently identified as independent risk factors for RBC transfusion in orthopedic practice. Additional or alternative analytical approaches are required to obtain a more comprehensive, holistic understanding of the decision to transfuse RBCs to patients undergoing orthopedic surgery.