Chinese scientists evaluate NIPT effectiveness

Researchers from China analyzed the cost-effectiveness of various methods of prenatal screening for Down Syndrome and concluded that while NIPT (non-invasive prenatal testing) is a more effective and safer method, CMSS (conventional maternal serum screening) is unlikely to be replaced due to at a better price.

Down Syndrome (Trisomy 21) is the most common genetic cause of significant mental retardation. According to the International Information Center for Birth Defects, its frequency is 1.7 cases per 1000 newborns in the world. The incidence of Down Syndrome in China is between 23,000 and 25,000 new cases per year. According to a 2003 study in China, the average financial cost over the life of a child with Down syndrome from the family and society ranged from $ 47,000 to $ 55,000.

Currently there is no cure for Down Syndrome, but it can be detected during pregnancy using prenatal screening technology followed by invasive diagnostic testing if the screening result is positive. Traditional maternal serum screening (CMSS) in China includes measurements of serum AFP, hCG and uE3 in the second trimester, also called triple screening, and has a detection rate of approximately 69% with a 5% false positive in the general pregnant population. CMSS can also help detect not only Down Syndrome, but also other abnormalities, such as neural tube defects.

The recent introduction of non-invasive prenatal testing (NIPT), which analyzes extracellular DNA (cfDNA) in maternal plasma and uses a new generation of sequencing technology, has improved detection of Down Syndrome and has been shown to have a very low false positive rate. In addition, the detection of pathology is possible as early as 10 weeks of pregnancy, and it also helps to reduce the number of miscarriages caused by invasive diagnostic testing.

The rules governing NIPT in China were absent until 2014, as many blood samples were tested without the necessary genetic counseling, which led to their overuse or misuse. Subsequently, in 2015, the National Commission on Health and Family Planning initiated a pilot project in which 108 hospitals could conduct NIPT as an experiment. However, during this period, little information was published on the effectiveness, including economic, and the safety of NIPT for China.

Scientists from Fudan University (Shanghai) conducted a study designed to evaluate the cost-effectiveness of NIPT in detecting Down syndrome in China.

Simulated efficacy in a cohort of 10,000 pregnant women showed that the CMSS strategy, selective screening strategy, and universal screening strategy can prevent the birth of 3.03, 7.53, and 9.97 children with Down syndrome, respectively. In terms of reducing the number of births of children with Down syndrome, the universal screening strategy was most effective. The CMSS strategy, selective screening strategy, and universal screening strategy can result in 0.89, 0.07, and 0.14 fetal loss due to complications of amniocentesis. Thus, from a safety point of view, the selective screening strategy was the best, the authors of the study write.

In terms of cost-effectiveness, the cost-effectiveness ratio of the sampling screening strategy was the lowest.

Thus, scientists concluded that NIPT has great advantages as a screening method, but it is unlikely to take the place of CMSS due to the higher cost of NIPT. Selective screening - NIPT for high-risk pregnant women by CMSS - may be the appropriate strategy for balancing efficacy and financial costs. Recall that earlier the study of the economic efficiency of NIPT was carried out on the example of Belgium. It showed the advantages of this screening method while reducing its cost and the number of false-positive results.

The study is published in the Journal of Technology Assessment in Health Care. International Journal of Technology Assessment in Health Care.