OBJECTIVES

Down syndrome (DS) is the most frequent fetal chromosomal abnormality and different prenatal screening strategies are used for determining risk of DS worldwide. New non-invasive prenatal testing (NIPT) using cell free fetal DNA in maternal blood can provide benefits due to its higher sensitivity and specificity compared with conventional screening tests. This study aimed to assess the cost-effectiveness of using population-level NIPT in fetal aneuploidy screening for DS.

METHODS

We developed a microsimulation decision-analytic model to perform a probabilistic cost-effectiveness analysis (CEA) of prenatal screening and diagnostic strategies for DS. The model followed each simulated pregnant woman through the pregnancy pathway. The comparators were serum only screening, contingent NIPT (NIPT as a second-tier screening test) and universal NIPT (NIPT as a first-tier screening test). To address uncertainty around the model parameters, the expected values of costs and quality-adjusted life-years (QALYs) in the base case and all scenario analyses were obtained through probabilistic analysis from a Monte Carlo simulation.

RESULTS

Base case and scenario analyses were conducted by repeating the micro-simulation 1,000 times for a sample of 45,605 pregnant women per the population of British Columbia, Canada (N=4.8 million). Preliminary results of the sequential CEAs showed that contingent NIPT was a dominant strategy compared to serum only screening. Compared with contingent NIPT, universal NIPT at the current price of test was not cost effective with an incremental cost-effectiveness ratio over $100,000/QALY. Contingent NIPT also had the lowest cost per DS case detected among these three strategies.

CONCLUSIONS

Including NIPT to existing prenatal screening was shown to be beneficial over conventional testing. However, at current prices, implementation of NIPT as a second-tier screening test is more cost-effective than deploying it as a universal test.