Use of n-of-1 (single patient) trials to assess the effect of age of transfused blood on health-related quality of life in transfusion-dependent patients
BACKGROUND The impact of age of red blood cells on health-related quality of life (HRQL) in patients who require chronic transfusions is not known. We assessed this using n-of-1 trials in patient populations where large randomized trials have not been done to date. STUDY DESIGN AND METHODS Chronically transfusion-dependent adult patients were randomly assigned over time to four fresh (<7 days of storage) and four standard-issue (up to 42 days of storage) blood transfusions in prospective double-blinded multicrossover studies (n-of-1 trials). HRQL questionnaires were completed before and at 24 hours after each transfusion. Hemoglobin (Hb) levels were measured before each subsequent transfusion. RESULTS Twenty transfusion-dependent patients were enrolled, of whom nine (five myelodysplastic syndromes, two myelofibrosis, one beta-thalassemia major, one Diamond-Blackfan anemia) completed at least six transfusions. Mean ages of fresh and standard-issue blood transfused were 4.0 and 23.2 days, respectively. There were no significant differences in the effect of standard and fresh blood on follow-up Hb levels or the eight HRQL dimensions assessed in all analyses. CONCLUSIONS In chronically transfused patients, there were no significant differences in HRQL or Hb levels between fresh versus standard blood. While larger trials are needed, these results support current practices in hospital blood transfusion laboratories using a first-in, first-out model of blood utilization for these transfusion-dependent patients. Use of n-of-1 trials to determine the benefits of transfusions in single patients appears to be feasible.
A cluster-randomized controlled trial of a blood conservation algorithm in patients undergoing total hip joint arthroplasty
BACKGROUND The optimum strategy for reducing allogeneic blood transfusion in patients undergoing total hip joint arthroplasty (THJA) is unknown. STUDY DESIGN AND METHODS The effectiveness of a comprehensive blood conservation algorithm (BCA) was evaluated by means of a cluster randomization trial. Thirty hospitals performing primary THJA were randomly assigned to implement the algorithm or to continue with usual care (UC). Subsequently, the institutional rate of allogeneic transfusion was determined for 60 consecutive patients who underwent surgery at each site. The BCA consisted of patient and provider education, hemoglobin-based recommendations for specific blood conservation strategies (recombinant human erythropoietin [rHuEPO] or autologous blood donation [ABD]) and transfusion guidelines. The main outcome measure was the institutional allogeneic transfusion rate. RESULTS One hospital withdrew consent after randomization, resulting in 14 hospitals assigned to BCA and 15 to UC. In the BCA arm, the institutional rates of rHuEPO use and ABD participation were 20. 1 and 27. 1 percent compared to 0. 6 and 25. 8 percent, respectively, in the UC arm. The allogeneic transfusion rate was substantially reduced in hospitals assigned to the BCA group (p = 0. 02; absolute risk reduction, 9. 6% [26. 1% UC vs. 16. 5% BCA]). Multivariate analysis of patient-level data showed that assignment to the UC arm was an independent risk factor for allogeneic transfusion (p = 0. 037; odds ratio, 1. 8; 95% confidence interval, 1. 0-3. 1) when adjusted for other prognostic factors. No differences were observed in the use of autologous blood. CONCLUSION A comprehensive approach to blood conservation was superior to UC for reducing allogeneic transfusion in patients undergoing THJA.