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September 5th, 2003 Previous studies have greatly underestimated the cost-effectiveness of Solvent Detergent treated plasma A paper1 published in the August 2003 edition of the prestigious journal Vox Sanguinis claims that previous analyses have greatly underestimated the cost-effectiveness of SD-FFP. Past studies assessing cost-effectiveness of solvent-detergent treated plasma (SD-FFP) have produced a wide variety of costs per quality-adjusted life year (QALY) estimates ranging from US$ 289,000 - 9,743,000. However, they considered only rare infective complications such as HIV, HBV and HCV infection and ignored the relatively common non-infective events such as transfusion related acute lung injury (TRALI). In contrast, the new publication by Riedler et al used a comprehensive, robust economic model, comparing the costs of both infective and non-infective complications of fresh frozen plasma and SD-FFP. Relative risks, costs and mortality rates associated with transfusion-related complications were incorporated and the final analysis of incremental cost per life year saved for SD-FFP compared with untreated FFP was performed from a UK health service budget perspective. The life expectancy of hypothetical patients ranging in age from neonates to 70 years was evaluated using a decision-tree model. In one arm of the model patients received SD-FFP, whilst in the other they received untreated FFP. A proportion of patients in each arm experienced adverse events, as indicated by probabilities documented in the literature. For each event short and long term costs were accrued and any associated mortality was applied. Acute and recurring costs were based on either published UK cost surveys or studies. The most important driver of cost-effectiveness was TRALI on account of its relatively high incidence and mortality The cost per life year saved in the UK for SD-FFP was £22,728 (€32,843) for neonates and £98,468 (€141,981) for patients 70 years or older. Cost-effectiveness ratio was below £50,000 (€72,094) / life year saved for patients less than 48 years of age and below £30,000 (€43,256) for those aged 21 or under. In patients with a good short term prognosis the cost effectiveness was significantly better [ranging from £12,335 (€17,785) for neonates to £61,692 (€88,952) for 70 year olds] These figures are substantially lower than the ratios estimated previously for SD-FFP. The cost-effectiveness ratios are also lower than those for many other preventative strategies routinely employed in transfusion medicine such as autologous blood transfusion and HCV NAT. The authors note that if a value of £50,000 (€77,094) / life year saved is taken as “acceptable” then SD-FFP is a cost-effective treatment for all patients aged 48 and under as well as for older patients with a good clinical prognosis. Additionally, they speculate that if all untreated FFP used for transfusion in the UK were to be replaced with SD-FFP:
Finally, the authors also note that their model used a number of conservative assumptions. They did not for example take into account a reduction of febrile or anaphylactic reactions with SD-FFP, even though there is published evidence to suggest a lower risk than that for untreated FFP. Similarly their assumed costs for hepatitis transmission were based purely on the drug costs for acute infection and took no account of treatment for chronic infections or liver failure. Similarly the assumed incidence of TRALI was based on that for all blood components although it is known that the risk may be higher for FFP than for red cells or platelets. |