Purpose: To assess the cost effectiveness of prophylactic blood transfusion as primary stroke prevention for children with sickle cell disease (SCD) identified, using transcranial Doppler (TCD) ultrasonography, to be at high risk of stroke.
Method: Electronic databases were searched for economic evidence up to May 2011. A de novo economic Markov model was developed which estimated changes in blood velocity, stroke incidence and SCD-related complications. The model was run twice for the lifetime of a hypothetical cohort of 1000 2-year old patients: intervention scenario, in which blood transfusion was provided as treatment for children with high blood velocity (≥200cm/s); and non-intervention scenario, in which blood transfusion was not provided. The model adopted a UK NHS perspective and costs and outcomes were discounted at 3.5%. Incremental cost-effectiveness ratios (ICERs) were calculated in terms of cost per quality adjusted life years (QALYs) gained.
Result: No relevant economic evaluations were identified. Data for the model were obtained through expert clinical opinion and published clinical-effectiveness evidence. Much of the latter was only available from US publications. Modelling suggested that blood transfusion plus TCD scans for SCD patients at high risk of stroke aged ≥2 years (compared with just TCD scans) may be good value for money. The intervention had an ICER of £24,075 per QALY gained and helped avoid 82 strokes over the lifetime of a population of 1000 patients. The intervention cost an additional £13,751 per patient and generated 0.6 extra years of life in full health per patient. All estimated ICERs were subject to significant uncertainty due to limitations in the clinical and cost effectiveness data available (e.g. no data for some parameters and some differences in treatment protocols between the UK and USA). However, sensitivity analyses and validation against existing data and expert opinion provided some reassurance that the model conclusion, that blood transfusions are cost effective, was reliable.
Conclusion: Use of TCD ultrasonography to identify children at high risk of stroke, and treating these children with prophylactic blood transfusions appears to be cost effective when compared to TCD ultrasonography only. Given limitations in the data available, further UK research is required to verify this conclusion.
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