Cost-effectiveness of cell salvage and alternative methods of minimising perioperative allogeneic blood transfusion: a systematic review and economic model.

OBJECTIVES: To compare patient outcomes, resource use and costs to the NHS and NHS Blood Transfusion Authority (BTA) associated with cell salvage and alternative methods of minimising perioperative allogeneic blood transfusion.

DATA SOURCES: Electronic databases covering the period 1996-2004 for systematic reviews and 1994-2004 for economic evidence.

REVIEW METHODS: Existing systematic reviews were updated with data from selected randomised controlled trials (RCTs) that involved adults scheduled for elective non-urgent surgery. Any resource use or cost data were extracted for potential use in populating an economic model. Relative risks or weighted mean difference of each outcome for each intervention were assessed, taking into account the number of RCTs included in each outcome and intervention and the presence of any heterogeneity. This allowed indirect comparison of the relative effectiveness of each intervention when the intervention is compared with allogeneic blood transfusion. A decision analytic model synthesised clinical and economic data from several sources, to estimate the relative cost-effectiveness of cell salvage for people undergoing elective surgery with moderate to major expected blood loss. The perspective of the NHS and patients and a time horizon of 1 month were used. The economic model was developed from reviews of effectiveness and cost-effectiveness and clinical experts. Secondary analysis explored the robustness of the results to changes in the timing and costs of cell salvage equipment, surgical procedure, use of transfusion protocols and time horizon of analysis.

RESULTS: Overall, 668 studies were identified electronically for the update of the two systematic reviews. This included five RCTs, of which two were cell salvage and three preoperative autologous donation (PAD). Five published systematic reviews were identified for antifibrinolytics, fibrin sealants and restrictive transfusion triggers, PAD plus erythropoietin, erythropoietin alone and acute normovolaemic haemodilution (ANH). Twelve published studies reported full economic evaluations. All but two of the transfusion strategies significantly reduced exposure to allogeneic blood. The relative risk of exposure to allogeneic blood was 0.59 for the pooled trials of cell salvage (95% confidence interval: 0.48 to 0.73). This varied by the type and timing of cell salvage and type of surgical procedure. For cell salvage, the relative risk of allogeneic blood transfusion was higher in cardiac surgery than in orthopaedic surgery. Cell salvage had lower costs and slightly higher quality-adjusted life years compared with all of the alternative transfusion strategies except ANH. The likelihood that cell salvage is cost-effective compared with strategies other than ANH is over 50%. Most of the secondary analyses indicated similar results to the primary analysis. However, the primary and secondary analyses indicated that ANH may be more cost-effective than cell salvage.

CONCLUSIONS: The available evidence indicates that cell salvage may be a cost-effective method to reduce exposure to allogeneic blood transfusion. However, ANH may be more cost-effective than cell salvage. The results of this analysis are subject to the low quality and reliability of the data used and the use of indirect comparisons. This may affect the reliability and robustness of the clinical and economic results. There is a need for further research that includes adequately powered high-quality RCTs to compare directly various blood transfusion strategies. These should include measures of health status, health-related quality of life and patient preferences for alternative transfusion strategies. Observational and tracking studies are needed to estimate reliably the incidence of adverse events and infections transmitted during blood transfusion and to identify the lifetime consequences of the serious hazards of transfusion on mortality, health status and health-related quality of life.