High-throughput, non-invasive prenatal testing for fetal Rhesus D genotype to guide antenatal prophylaxis with anti-D immunoglobulin: a cost-effectiveness analysis.

ABSTRACT

OBJECTIVE: To evaluate the cost-effectiveness of high-throughput, non-invasive prenatal testing (HT-NIPT) for fetal Rhesus D (RhD) genotype to guide antenatal prophylaxis with anti-D immunoglobulin compared with routine antenatal anti-D immunoglobulin prophylaxis (RAADP). DESIGN: Cost-effectiveness decision-analytic modelling. SETTING: Primary care. PARTICIPANTS: A simulated population of 100 000 RhD-negative women not known to be sensitised to the RhD antigen. METHODS: A decision tree model was used to characterise the antenatal care pathway in England and the long-term consequences of sensitisation events. The diagnostic accuracy of HT-NIPT was derived from a systematic review and bivariate meta-analysis; estimates of other inputs were derived from relevant literature sources and databases. Women in whom the HT-NIPT was positive or inconclusive continued to receive RAADP, whereas women with a negative result received none. Five alternative strategies in which the use of HT-NIPT may affect the existing postpartum care pathway were considered. MAIN OUTCOME MEASURES: Costs expressed in 2015GBP and impact on health outcomes expressed in terms of quality-adjusted life-years over a lifetime. RESULTS: The results suggested that HT-NIPT appears cost saving but also less effective than current practice, irrespective of the postpartum strategy evaluated. A postpartum strategy in which inconclusive test results are distinguished from positive results performed best. HT-NIPT is only cost-effective when the overall test cost is £26.60 or less. CONCLUSIONS: HT-NIPT would reduce unnecessary treatment with routine anti-D immunoglobulin and is cost saving when compared with current practice. The extent of any savings and cost-effectiveness is sensitive to the overall test cost. TWEETABLE ABSTRACT HT-NIPT is cost saving compared with providing anti-D to all RhD-negative pregnant women.