This study examined the clinical and economic impact of introducing a restrictive transfusion strategy to reduce transfusion-attributable severe acute complications in high-risk patients in the intensive care unit. The authors concluded that the restrictive transfusion strategy, with a transfusion trigger at haemoglobin levels of 7g/dL, was more effective and less expensive than a liberal strategy. The study was transparently carried out using clear methodology. The authors’ conclusions appear to be valid and enhanced by the extensive sensitivity analysis.

Cost-effectiveness analysis

The aim was to examine the clinical and economic impact of introducing a restrictive transfusion strategy to reduce transfusion-attributable severe acute complications (TSACs) in high-risk patients, who are receiving packed red blood cells (pRBC), in the intensive care unit (ICU).

This study considered a switch from a liberal transfusion strategy (transfusion required at haemoglobin levels of approximately 8.5g/dL) to a restrictive transfusion strategy (transfusion required at 7g/dL).

USA/critical care, ICU.

Analytical approach: This economic evaluation was based on a decision analytic model which simulated the reduction in TSACs and potential cost savings associated with a restrictive transfusion strategy. The time horizon of the analysis appears to have been one year. The authors stated that the perspective of the hospital was adopted.

Effectiveness data: The clinical data were derived from known, relevant studies, which were selected by the authors. The number of TSACs with restrictive and with liberal transfusion strategies was obtained from two randomised controlled trials (RCTs). Epidemiological studies were used to obtain the number of high-risk patients in ICUs in the USA. Other sources were used for other model parameters, but these were not described in detail. The authors’ assumptions and the approach used to select these data from the available sources were reported. Some calculations were also made in order to adapt the data from published sources to the decision model.

Monetary benefit and utility valuations: None.

Measure of benefit: The summary benefit measure was the number of additional TSACs prevented.

Cost data: The economic analysis was restricted to the cost of a unit of pRBC. The quantities of resources used were derived from the published literature, while the unit cost was obtained from a previous report, the details of which were not given. The costs were in US dollars ($) and the price year was 2005.

Analysis of uncertainty: Monte Carlo simulations and univariate sensitivity analyses were carried out to assess how robust the base-case findings were to variations in model inputs. The plausible ranges of values were derived from the literature or were based on authors’ opinions.

In the population of 1,020,800 adults who might be at risk for a late transfusion each year, the restrictive strategy prevented 39,246 additional TSACs. Due to the reduction in use of pRBC, the restrictive strategy saved $821,109,699 annually. Thus, the restrictive strategy was dominant (more effective and less costly).

The sensitivity analysis corroborated the base-case findings because the restrictive strategy was less expensive and more effective, even in the worst-case scenario.

The authors concluded that a restrictive transfusion strategy, with a transfusion trigger at 7g/dL, in appropriate high-risk ICU patients, was more effective and less expensive than a liberal strategy.

Interventions: The selection of the comparators, liberal versus restrictive transfusion strategies, was appropriate given their relevance in the authors’ setting.

Effectiveness/benefits: The sources of data appear to have been selected. The authors provided some information on the design of these sources. They discussed and justified the selection of the clinical evidence from the available data, and their justification appears to have been appropriate. They pointed out some limitations to the studies used to derive some clinical inputs. In particular, it was noted that the linear relationship between pRBC transfusion amounts and the adverse outcomes had not been confirmed in prospective studies. Furthermore, the data on complications associated with liberal transfusion were derived from a single study, which may not reflect treatment patterns in other settings nor real-world practice in general. Finally, the use of two trials to obtain data on the risk of TSACs for the liberal and restrictive strategies could have introduced some bias due to potential differences in patient population between the two studies. Extensive sensitivity analyses were conducted on these parameters to address these issues.

Costs: The analysis of costs was restricted to the hospital’s viewpoint, which appeared to include only the cost of transfusion products. The unit costs and resource quantities were reported. The cost associated with TSACs was not included due to the limited published evidence. The price year was given. In general, the economic analysis was carried out in a transparent fashion, enhancing the possibility of replicating the analysis for other settings and time periods. The use of discounting was not relevant given the one-year horizon of the model.

Analysis and results: A synthesis of costs and benefits was not required given the dominance of one strategy over the other. The costs and benefits were appropriately reported. The issue of uncertainty was satisfactorily addressed in the sensitivity analysis, the results of which were clearly presented. The authors noted that the robust sources of data used in the analysis strengthened the validity of the study findings. Furthermore, when assumptions were required, a conservative approach was adopted.  Finally, it was noted that the transparent framework of the model should ensure the applicability of the results to concrete clinical settings. The authors acknowledged, as potential limitations to their analysis, the paucity of the published studies and the fact that TSAC costs were not included.

Concluding remarks: On the whole, the study was transparently carried out using clear methodology. The authors’ conclusions appear to be valid and enhanced by the extensive sensitivity analysis.

Not stated.

Hebert PC, Wells G, Blajchman MA, et al. A multicenter, randomized, controlled clinical trial of transfusion requirements in critical care. N Engl J Med 1999;340:409-17.

Corwin HL, Gettinger A, Pearl RG, et al. Efficacy of recombinant human erythropoietin in critically ill patients: a randomized controlled trial. JAMA 2002;288:2827-35.

Shermock KM, Horn E, Lipsett PA, et al.  Number needed to treat and cost of recombinant human erythropoietin to avoid one transfusion-related adverse event in critically ill patients. Crit Care Med 2005;33:497-503.