A Cost-Effectiveness Analysis of Screening Strategies involving Noninvasive Prenatal Testing for Trisomy 21
Abstract In the trends of increasing advanced maternal age (AMA) and decreasing cost of Noninvasive Prenatal Testing (NIPT), we investigated the benefits and cost effectiveness of NIPT as primary or contingent strategies for trisomy 21 (T21). A theoretical model involving 1,000,000 single pregnancies was established. We presented five screening scenarios, primary NIPT (Strategy 1), contingent NIPT after traditional triple serum screening higher than 1/300 or 1/1000 (Strategy 2-1 or Strategy 2-2) and age-based (Strategy 3). Strategy 3 was stratified, in which 1) for advanced maternal age (AMA) of 40 and more, prenatal diagnosis was offered, 2) for AMA of 35 to 39, NIPT was introduced, 3) if younger than 35, contingent strategy with screening risk higher than 1:300 (Strategy 3-1) or 1:1000 (Strategy 3-2) will be offered NIPT. Parameters were referred to publications or on-site verification. The primary outcome was incremental cost analysis for each strategy on baseline and alterative assumptions, which take aging society, reducing cost of NIPT and compliance into consideration. The second outcomes were total cost, cost-effect and cost-benefit analysis. If the incremental cost was less than 0.215 million US$, which was cost for raising one T21 child, or the benefit-to-cost ratio over 1, then the strategy was defined as “cost-effective”. The anticipated prenatal diagnosis was significantly reduced in Strategy 1 and 2, most notably in Strategy 2-1. For the incremental costs, strategy 2-1 was set as baseline. All other strategy costed more than raising one T21 except 3-1. In sensitivity analysis, strategy 1 costed the least when NIPT was lower than 47 US$. If NIPT less than 131 US$, the incremental cost of any strategy was less than 0.215 million US$. When the proportion of AMA accounted for more than 15% and 20% of population, incremental costs of strategy 3-1 and 3-2 were cost effective. In conclusion, contingent NIPT after traditional triple serum screening (risk higher than 1/300) was optimal in total cost (130 million US$), cost-effect (33.4 thousand US$) and cost-benefit (ratio=4.90) analysis of the model. Age-based strategy was optimal as AMA proportion and NIPT acceptance increased. The primary NIPT was most effective for certain price.
