Transfusion rates are increasing following total hip arthroplasty: risk factors and outcomes.

Despite attempts to minimize exposure to allogeneic blood, there are little data on recent nationwide trends in transfusion following total hip arthroplasty (THA) and no consensus on indications. The purpose of this study was to examine the rate, predictors, and inpatient outcomes associated with transfusion after primary THA. This retrospective cohort study analyzed the data collected from US Nationwide Inpatient Sample (NIS) for each year during the period 2005-2008 to assess the trends in transfusion in patients who underwent elective primary THA. Logistic regression models were used to evaluate the predictive risk factors for blood transfusion. The University Hospital Consortium (UHC) database was also queried to examine the variability in rates of transfusion at different academic medical centers. A total of 129,901 patients were identified in the NIS database. The transfusion rates following THA consistently increased from 18.12% in 2005 to 21.21% in 2008 (P<0.0001). Hospitals in the Northeast and Midwest region had the highest and lowest rates of transfusion, respectively. Significant risk factors for blood transfusion were female gender (odds ratio, OR 2.1), age above 85 (OR 2.9), African-American race (OR 1.7), Medicare payor status (OR 1.6), being at a hospital in the Northeast Region (OR 1.4), the presence of preoperative anemia (OR 1.6), having at least one comorbidity (OR 1.3), and a high Charlson Index score (OR 2.2). Patients receiving blood transfusions had increased in-hospital mortality, longer lengths of stay, and higher total charges compared to non-transfused patients (P<0.001). The UHC database demonstrated that transfusion rates vary widely across different institutions from <5% to >80%. The incidence of blood transfusion has recently increased following total hip arthroplasty and there is great variability in practice. We identified several patient risk factors along with the morbidity and mortality independently associated with transfusion following THA. Further work is needed to standardize the approach to blood conservation and minimize exposure to allogenic blood.