Systematic review and meta-analysis of non-invasive prenatal DNA testing for trisomy 21: implications for implementation in China

An Auto-Reading probe system for detecting deletion mutations In liquid biopsy with direct quantification of mutation abundance

Background

Deletion mutations have been confirmed to be closely related to the occurrence and progression of different hereditary diseases and tumors. Specifically, the deletion of a small number of bases is more challenging to be captured and differentiated. In non-invasive prenatal testing (NIPT) and liquid biopsy targeting circulating tumor DNA, obtaining accurate mutation abundance in targeted DNA is a crucial step in the detection process. However, the quantification of mutation abundance with existing methods is not accurate enough.

Results

Herein, we developed the " Auto-Reading" probe detection system based on our previous work. Through theoretical modeling and experimental calculations, we verified the successful application of our system in NIPT and early cancer diagnosis, enabling effective discrimination of different mutant abundances.

Significance

Our method overcomes the interference of reaction concentrations on signal detection, allowing direct quantification of mutation abundance without the need for purification of PCR products. The detection system is cost-effective and feasible for laboratory use. We believe the system will facilitate broad applications in mutation detection.

Potential efficacy of digital polymerase chain reaction for non-invasive prenatal screening of autosomal aneuploidies: a systematic review and meta-analysis

BACKGROUND

Digital Polymerase Chain Reaction (dPCR) presents a promising approach for quantifying DNA and analyzing copy number variants, particularly in non-invasive prenatal testing. This method offers a streamlined and time-efficient procedure in contrast to the widely used next-generation sequencing for non-invasive prenatal testing. Studies have reported encouraging results for dPCR in detecting fetal autosomal aneuploidies. Consequently, this systematic review aimed to evaluate the effectiveness of dPCR in screening for trisomy 21, 18, and 13.

METHODS

A systematic search was conducted in PubMed, Web of Sciences, and Embase for relevant articles published up to December 30, 2023. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was utilized for the quality assessment of the included articles. Furthermore, a bivariate random-effect regression model was used to conduct a meta-analysis on the utility of dPCR for trisomy 21 screening.

RESULTS

A total of 9 articles were included in this review, with all of them assessing the utility of dPCR in trisomy 21 screening, and 2 and 1 studies conducting additional analysis on the screening abilities of dPCR for trisomy 18 and 13, respectively. A bivariate random-effects model calculated pooled sensitivity and specificity with a 95% confidence interval (CI). Meta-analysis of 6 studies comparing trisomy-21 screening with karyotyping demonstrated dPCR's pooled sensitivity of 98% [95% CI: 94 -100] and specificity of 99% [95% CI: 99 -100]. While conducting a meta-analysis for trisomy 13 and 18 proved impractical, reported values for sensitivity and specificity were favorable.

CONCLUSIONS

These findings suggest that dPCR holds promise as an effective tool for non-invasive prenatal testing, presenting a less time-consuming and intricate alternative to next-generation sequencing. However, further research is necessary to evaluate dPCR's applicability in clinical settings and to delineate its specific advantages over next-generation sequencing. This study contributes valuable insights into the potential of dPCR for enhancing prenatal screening methodologies.

TRIAL REGISTRATION

The protocol of this study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) on 7/3/2024, with a registration code of CRD42024517523.

Non-Invasive Prenatal Testing (NIPT): Reliability, Challenges, and Future Directions

Non-invasive prenatal testing was first discovered in 1988; it was primarily thought to be able to detect common aneuploidies, such as Patau syndrome (T13), Edward Syndrome (T18), and Down syndrome (T21). It comprises a simple technique involving the analysis of cell-free foetal DNA (cffDNA) obtained through maternal serum, using advances in next-generation sequencing. NIPT has shown promise as a simple and low-risk screening test, leading various governments and private organizations worldwide to dedicate significant resources towards its integration into national healthcare initiatives as well as the formation of consortia and research studies aimed at standardizing its implementation. This article aims to review the reliability of NIPT while discussing the current challenges prevalent among different communities worldwide.

Introducing the non-invasive prenatal testing for detection of Down syndrome in China: a cost-effectiveness analysis

OBJECTIVE

This study aimed to compare the health economic value of a non-invasive prenatal testing (NIPT) strategy against a second-trimester triple screening (STS) strategy for the detection of Down syndrome based on real-world data from China.

DESIGN

A decision-analytical model was developed to compare the cost-effectiveness of five strategies from a societal perspective. Cost and probability input data were obtained from the real-world surveys and published sources.

SETTING

China.

PARTICIPANTS

Women with a singleton pregnancy.

INTERVENTIONS

The five strategies for screening were: (A) maternal age with STS (no NIPT); (B) STS plus NIPT screening; (C) age-STS plus NIPT screening (the currently referral strategy in China); (D) maternal age with NIPT screening and (E) universal NIPT screening.

MAIN OUTCOME MEASURES

Incremental cost-effectiveness ratios (ICERs) per additional Down syndrome case terminated, univariate and probabilistic sensitivity analysis and cost-effectiveness acceptability curves were obtained.

RESULTS

Strategy A detected the least number of Down syndrome cases. Compared with the cheapest Strategy B, Strategy D had the lowest ICER (incremental cost, US$98 944.85 per additional Down syndrome case detected). Strategy D had the highest probability of being cost-effective at the willingness-to-pay level between US$110 000.00 and US$535 000.00 per additional Down syndrome case averted. Strategy E would not be cost-effective unless the unit cost of the NIPT could be decreased to US$60.50.

CONCLUSION

Introducing NIPT screening strategies was beneficial over the use of STS strategy alone. Evaluating maternal age in combination with the NIPT screening strategy performs better than China's currently referral strategy in terms of cost-effectiveness and safety. Lowering the price of NIPT and optimising payment methods are effective measures to promote universal NIPT strategies in China.

The Knowledge, Attitude, Practices, and Satisfaction of Non-Invasive Prenatal Testing among Chinese Pregnant Women under Different Payment Schemes: A Comparative Study

Non-invasive prenatal testing (NIPT) for aneuploidy screening has been widely applied across China, and costs can affect Chinese pregnant women’s choices. This study aims to assess the knowledge, attitude, practices (KAP) and satisfaction regarding NIPT among pregnant women in China, and to further explore the relationship between payment schemes and women’s acceptability of and satisfaction with NIPT. A questionnaire survey was performed in Shenzhen and Zhengzhou, China, which separately applied “insurance coverage” and “out-of-pocket” payment scheme for NIPT. The major differences between the two cities were compared using chi-square test, Wilcoxon rank sum test, and propensity score matched analysis. Logistic regression models were applied to explore predictors for women’s acceptability and satisfaction. Compared with Zhengzhou participants, a higher proportion of Shenzhen women had heard of NIPT (87.30% vs. 64.03%), were willing to receive NIPT (91.80% vs. 80.43%) and had taken NIPT (83.12% vs. 54.54%), while their satisfaction level was lower. Having NIPT-related knowledge was associated with higher acceptability, and receiving genetic counseling helped to improve satisfaction. Besides, women with higher annual household incomes were more likely to take and be satisfied with NIPT. In conclusion, more attention should be paid to health education, subsidies for NIPT, and genetic counseling.

Non-invasive prenatal testing: A diagnostic innovation shaped by commercial interests and the regulation conundrum

Non-invasive prenatal testing (NIPT) is grounded in the analysis of free circulating fetal DNA (cfDNA) in pregnant women's blood. The rolling out of this screening method was in large part driven by commercial firms, which hoped to reach a huge potential market by offering a test that was expected to be risk-free, reliable, inexpensive, and able to detect a wide range of genetic traits of the future child. To date, most predictions about the scope and uses of NIPT have not materialized: in 2020 NIPT detects only a limited number of genetic anomalies, while results have to be confirmed by amniocentesis. NIPT has become a commercial success. Nevertheless the implementation of NIPT has tended to diverge across different national settings. In countries that already have state-sponsored screening for Down risk, NIPT has been offered by the state health insurance to women defined as "high risk", using a variant of the test that detects only three autosomal aneuploidies: trisomy 21, 13 and 18. These countries effectively regulate the supply of NIPT on grounds of cost-effectiveness and reliability. In countries without state-sponsored screening for Down risk, in contrast, multiple versions of NIPT covering a wider range of birth defects are commonly available on the free market, and purchased by women at low as well as high risk of having an affected child. Market-based healthcare systems tend to present women who can afford to pay for NIPT with a largely unregulated choice of technologies - though reimbursement rules imposed by private insurance providers may serve in effect to regulate use by those consumers who cannot afford to pay for tests from their own pockets. This regulatory divergence is shaped by the presence or absence of prior state-sponsored screening programs for Down risk.

The role of information provision in economic evaluations of non-invasive prenatal testing: a systematic review

BACKGROUND

Technological progress has led to changes in the antenatal screening programmes, most significantly the introduction of non-invasive prenatal testing (NIPT). The availability of a new type of testing changes the type of information that the parent(s) require before, during and after screening to mitigate anxiety about the testing process and results.

OBJECTIVES

To identify the extent to which economic evaluations of NIPT have accounted for the need to provide information alongside testing and the associated costs and health outcomes of information provision.

METHODS

A systematic review of economic evaluations of NIPTs (up to February 2018) was conducted. Medline, Embase, CINAHL and PsychINFO were searched using an electronic search strategy combining a published economic search filter (from NHS economic evaluations database) with terms related to NIPT and screening-related technologies. Data were extracted using the Consolidated Health Economic Evaluation Reporting Standards framework and the results were summarised as part of a narrative synthesis.

RESULTS

A total of 12 economic evaluations were identified. The majority of evaluations (n = 10; 83.3%) involved cost effectiveness analysis. Only four studies (33.3%) included the cost of providing information about NIPT in their economic evaluation. Two studies considered the impact of test results on parents' quality of life by allowing utility decrements for different outcomes. Some studies suggested that the challenges of valuing information prohibited their inclusion in an economic evaluation.

CONCLUSION

Economic evaluations of NIPTs need to account for the costs and outcomes associated with information provision, otherwise estimates of cost effectiveness may prove inaccurate.

The epidemic of abnormal copy number variant cases missed because of reliance upon noninvasive prenatal screening

OBJECTIVE

To assess the implications of increasing utilization of noninvasive prenatal screening (NIPS), which may reach 50% with the concomitant decrease in diagnostic procedures (DPs) for its impact on detection of chromosomal abnormalities.

METHODS

We studied our program's statistics over 5 years for DPs and utilization of array comparative genomic hybridization (aCGH). We then modeled the implications in our program if DP had not fallen and nationally of a 50% DP and aCGH testing rate using well-vetted expectations for the diagnosis of abnormal copy number variants (CNVs).

RESULTS

Our DP fell 40% from 2013-2017. Utilization of aCGH for DP nearly tripled. We detected 28 abnormal CNVs. If DP had not fallen, we likely would have detected 60. With 4 million US births per year, 2 million DPs would detect 30 000 abnormal CNVs and 4000 standard aneuploidies. At a 1/500 complication-pregnancy loss rate, the detection/complication ratio is 8.5/1.

CONCLUSIONS

Noninvasive prenatal screening has significantly changed the practice of prenatal screening. However, while increasing the detection of Down syndrome, the concomitant decrease in DP and lack of aCGH results in missing many more abnormalities than the increase in Down syndrome and complications of DP combined. From a public health perspective, such represents a missed opportunity for overall health care delivery.

Fewer women aged 35 and older choose serum screening for Down's syndrome: Impact and implications

OBJECTIVE

To quantify changes in the proportion of women aged 35 and older choosing serum screening for Down's syndrome over time and the effect on false positive and detection rates.

METHODS

From Rhode Island hospital-based laboratory prenatal screening records (2013-2017) we extracted the test performed (Integrated, Combined, Quadruple), maternal age, and Down's syndrome risk; documented observed changes in maternal age distributions and false positive rates, and modelled the impact of varying proportions of older women choosing screening on each test's performance using the 2015 United States birth cohort as baseline.

RESULTS

Over five years, observed false positive rates for Integrated testing declined from 1.9 to 1.3% (-32%). The proportion of older women tested declined from 14.9 to 8.5%, from which modelling predicts a 16% decline in the false positive rate. This is lower than our observed change but consistent with a reduction driven by declining participation by older women. Modelling predicted a detection rate reduction from 89 to 87%. Larger detection rate impacts were predicted for Combined and Quadruple testing.

CONCLUSIONS

This study documents, for the first time, the declining proportion of older women choosing Down's syndrome serum screening and subsequent impact on screening performance. The American College of Obstetrics and Gynecology recommends offering cell-free DNA screening for these 'high risk' pregnancies and uptake may increase further. Screening programmes could consider increasing use of Integrated testing over other serum screening tests or lowering risk cut-offs so false positive rates approach those of 2012 to regain lost detection.

Prenatal cell-free DNA screening test failures: a systematic review of failure rates, risks of Down syndrome, and impact of repeat testing

PURPOSE

We systematically reviewed the published literature on test failure rates for the sequencing of cell-free DNA (cfDNA) in maternal plasma to identify Down syndrome.

METHODS

We searched peer-reviewed English publications with diagnostic results on all pregnancies that provided test failure rates. Data on the odds of failure in Down syndrome and euploid pregnancies and the impact of repeat testing were extracted. Random-effects modeling was then used to identify moderators that could explain variability.

RESULTS

Thirty articles satisfied the inclusion criteria for overall failure rates. Study location (Western and Asian with initial testing, and Western with repeat testing) were significant moderators with failure rates of 3.3, 0.6, and 1.2%, respectively (P = 0.001). The odds ratio for Down syndrome in successful versus failed tests was 0.98 (95% confidence interval: 0.62-1.55, I² = 0%). Repeat testing from 14 large clinical cohort studies found that 83% (range: 52-100%) of failures were repeated, with 79% (range: 46-97%) being successful.

CONCLUSION

Lower failure rates in Asian studies may be related to not routinely measuring the fetal fraction and to fewer obese women. Repeat cfDNA testing is effective in providing reliable results after initial failures. Protocols for primary cfDNA screening should focus on Down syndrome, with less common and more structurally abnormal trisomy 18 and 13 pregnancies treated as adjuncts.