Model-based analysis of costs and outcomes of non-invasive prenatal testing for Down's syndrome using cell free fetal DNA in the UK National Health Service

Diagnostic performance and costs of contingent screening models for trisomy 21 incorporating non-invasive prenatal testing

BACKGROUND

Contingent screening for trisomy 21 using non-invasive prenatal testing has the potential to reduce invasive diagnostic testing and increase the detection of trisomy 21.

AIM

To describe the diagnostic and economic performance of prenatal screening models for trisomy 21 that use non-invasive prenatal testing as a contingent screen across a range of combined first trimester screening risk cut-offs from a public health system perspective.

METHODS

Using a hypothetical cohort of 300 000 pregnancies, we modelled the outcomes of 25 contingent non-invasive prenatal testing screening models and compared these to conventional screening, offering women with a high-risk (1 > 300) combined first trimester screening result an invasive test. The 25 models used a range of risk cut-offs. High-risk women were offered invasive testing. Intermediate-risk women were offered non-invasive prenatal testing. We report the cost of each model, detection rate, costs per diagnosis, invasive tests per diagnosis and the number of fetal losses per diagnosis.

RESULTS

The cost per prenatal diagnosis of trisomy 21 using the conventional model was $51 876 compared to the contingent models which varied from $49 309-66 686. The number of diagnoses and cost per diagnosis increased as the intermediate-risk threshold was lowered. Results were sensitive to trisomy 21 incidence, uptake of testing and cost of non-invasive prenatal testing.

CONCLUSION

Contingent non-invasive prenatal testing models using more sensitive combined first trimester screening risk cut-offs than conventional screening improved the detection rate of trisomy 21, reduced procedure-related fetal loss and could potentially be provided at a lower cost per diagnosis than conventional screening.

First trimester contingent screening for trisomies 21,18,13: is this model cost efficient and feasible in public health system?

PURPOSE

To evaluate the effectiveness of three different first trimester screening models for trisomies 21, 18 and 13, in terms of detection rate, invasive test rate and final costs.

MATERIAL AND METHODS

We analyzed the distribution of risk for trisomies 21, 18 and 13 in a population of 20,831 singleton pregnancies based on maternal age, fetal heart rate, nuchal translucency, free beta human chorionic gonadotropin and pregnancy-associated plasma protein A (Combined test). On the basis of our data, we estimated the performance and cost of screening for trisomies using three different models at specific cutoffs: Combined test; Cell free DNA test and Contingent screening test.

RESULTS

Using Combined test, DR for major trisomies was estimated to be 94.92%, invasive test rate was 6.3%. cfDNA would result in a DR of 97.92%, with an invasive test rate of 3.64%. Contingent screening approach would result in an overall DR of 97.82, with a rate for invasive procedure of 1.36% and a final cost lower than other screening policies (2,338,433 euro vs 5,796,060 of cfDNA and 2,385,473 of Combined test).

CONCLUSIONS

Contingent screening test could be a cost-efficient and feasible first trimester screening test for aneuploidies in public health system.

Pregnancy Outcome following Prenatal Diagnosis of Chromosomal Anomaly: A Record Linkage Study of 26,261 Pregnancies

Previous studies have demonstrated the influence of changes in the age at which women give birth, and of developments in prenatal screening and diagnosis on the number of pregnancies diagnosed and terminated with chromosomal anomalies. However, we are unaware of any population studies examining pregnancy terminations after diagnosis of chromosomal anomalies that has included all aneuploidies and the influence of maternal factors. The aims of this study were to examine the association between results of prenatal tests and pregnancy termination, and the proportion of foetuses with and without chromosomal anomalies referred for invasive diagnostic tests over time. Diagnostic information of 26,261 prenatal invasive tests from all genetic service laboratories in Scotland from 2000 to 2011 was linked to Scottish Morbidity Records to obtain details on pregnancy outcome. Binary logistic regression was carried out to test the associations of year and type of diagnosis with pregnancy termination, while controlling for maternal age, neighbourhood deprivation and parity. There were 24,155 (92.0%) with no chromosomal anomalies, 1,483 (5.6%) aneuploidy diagnoses, and 623 (2.4%) diagnoses of anomaly that was not aneuploidy (including translocations and single chromosome deletions). In comparison with negative test results, pregnancies diagnosed with trisomy were most likely to be terminated (adjusted OR 437.40, 95% CI 348.19–549.46) followed by other aneuploid anomalies (adjusted OR 95.94, 95% CI 69.21–133.01). During the study period, fewer pregnancies that were diagnosed with aneuploidy were terminated, including trisomy diagnoses (adjusted OR 0.44, 95% CI 0.26–0.73). Older women were less likely to terminate (OR 0.35, 95% CI 0.28, 0.42), and parity was also an independent predictor of termination. In keeping with previous findings, while the number of invasive diagnostic tests declined, the proportion of abnormal results increased from 6.09% to 10.88%. Systematic advances in prenatal screening have improved detection rates for aneuploidy. This has been accompanied by a reduction in the rate of termination for aneuploidy. This may reflect societal changes with acceptance of greater diversity, but this is speculation, and further research would be needed to test this.

Uptake, outcomes, and costs of implementing non-invasive prenatal testing for Down's syndrome into NHS maternity care: prospective cohort study in eight diverse maternity units

OBJECTIVE

 To investigate the benefits and costs of implementing non-invasive prenatal testing (NIPT) for Down's syndrome into the NHS maternity care pathway.

DESIGN

 Prospective cohort study.

SETTING

 Eight maternity units across the United Kingdom between 1 November 2013 and 28 February 2015.

PARTICIPANTS

 All pregnant women with a current Down's syndrome risk on screening of at least 1/1000.

MAIN OUTCOME MEASURES

 Outcomes were uptake of NIPT, number of cases of Down's syndrome detected, invasive tests performed, and miscarriages avoided. Pregnancy outcomes and costs associated with implementation of NIPT, compared with current screening, were determined using study data on NIPT uptake and invasive testing in combination with national datasets.

RESULTS

 NIPT was prospectively offered to 3175 pregnant women. In 934 women with a Down's syndrome risk greater than 1/150, 695 (74.4%) chose NIPT, 166 (17.8%) chose invasive testing, and 73 (7.8%) declined further testing. Of 2241 women with risks between 1/151 and 1/1000, 1799 (80.3%) chose NIPT. Of 71 pregnancies with a confirmed diagnosis of Down's syndrome, 13/42 (31%) with the diagnosis after NIPT and 2/29 (7%) after direct invasive testing continued, resulting in 12 live births. In an annual screening population of 698 500, offering NIPT as a contingent test to women with a Down's syndrome screening risk of at least 1/150 would increase detection by 195 (95% uncertainty interval -34 to 480) cases with 3368 (2279 to 4027) fewer invasive tests and 17 (7 to 30) fewer procedure related miscarriages, for a non-significant difference in total costs (£-46 000, £-1 802 000 to £2 661 000). The marginal cost of NIPT testing strategies versus current screening is very sensitive to NIPT costs; at a screening threshold of 1/150, NIPT would be cheaper than current screening if it cost less than £256. Lowering the risk threshold increases the number of Down's syndrome cases detected and overall costs, while maintaining the reduction in invasive tests and procedure related miscarriages.

CONCLUSIONS

 Implementation of NIPT as a contingent test within a public sector Down's syndrome screening programme can improve quality of care, choices for women, and overall performance within the current budget. As some women use NIPT for information only, the Down's syndrome live birth rate may not change significantly. Future research should consider NIPT uptake and informed decision making outside of a research setting.

"I think we've got too many tests!": Prenatal providers' reflections on ethical and clinical challenges in the practice integration of cell-free DNA screening

BACKGROUND

The recent introduction of cell-free DNA-based non-invasive prenatal screening (cfDNA screening) into clinical practice was expected to revolutionize prenatal testing. cfDNA screening for fetal aneuploidy has demonstrated higher test sensitivity and specificity for some conditions than conventional serum screening and can be conducted early in the pregnancy. However, it is not clear whether and how clinical practices are assimilating this new type of testing into their informed consent and counselling processes. Since the introduction of cfDNA screening into practice in 2011, the uptake and scope have increased dramatically. Prenatal care providers are under pressure to stay up to date with rapidly changing cfDNA screening panels, manage increasing patient demands, and keep up with changing test costs, all while attempting to use the technology responsibly and ethically. While clinical literature on cfDNA screening has shown benefits for specific patient populations, it has also identified significant misunderstandings among providers and patients alike about the power of the technology. The unique features of cfDNA screening, in comparison to established prenatal testing technologies, have implications for informed decision-making and genetic counselling that must be addressed to ensure ethical practice.

OBJECTIVES

This study explored the experiences of prenatal care providers at the forefront of non-invasive genetic screening in the United States to understand how this testing changes the practice of prenatal medicine. We aimed to learn how the experience of providing and offering this testing differs from established prenatal testing methodologies. These differences may necessitate changes to patient education and consent procedures to maintain ethical practice.

METHODS

We used the online American Congress of Obstetricians and Gynecologists Physician Directory to identify a systematic sample of five prenatal care providers in each U.S. state and the District of Columbia. Beginning with the lowest zip code in each state, we took every fifth name from the directory, excluding providers who were retired, did not currently practice in the state in which they were listed, or were not involved in a prenatal specialty. After repeating this step twice and sending a total of 461 invitations, 37 providers expressed interest in participating, and we completed telephone interviews with 21 providers (4.6%). We developed a semi-structured interview guide including questions about providers' use of and attitudes toward cfDNA screening. A single interviewer conducted and audio-recorded all interviews by telephone, and the interviews lasted approximately 30 minutes each. We collaboratively developed a codebook through an iterative process of transcript review and code application, and a primary coder coded all transcripts.

RESULTS

Prenatal care providers have varying perspectives on the advantages of cfDNA screening and express a range of concerns regarding the implementation of cfDNA screening in practice. While providers agreed on several advantages of cfDNA, including increased accuracy, earlier return of results, and decreased risk of complications, many expressed concern that there is not enough time to adequately counsel and educate patients on their prenatal screening and testing options. Providers also agreed that demand for cfDNA screening has increased and expressed a desire for more information from professional societies, labs, and publications. Providers disagreed about the healthcare implications and future of cfDNA screening. Some providers anticipated that cfDNA screening would decrease healthcare costs when implemented widely and expressed optimism for expanded cfDNA screening panels. Others were concerned that cfDNA screening would increase costs over time and questioned whether the expansion to include microdeletions could be done ethically.

CONCLUSIONS

The perspectives and experiences of the providers in this study allow insight into the clinical benefit, burden on prenatal practice, and potential future of cfDNA screening in clinical practice. Given the likelihood that the scope and uptake of cfDNA screening will continue to increase, it is essential to consider how these changes will affect frontline prenatal care providers and, in turn, patients. Providers' requests for additional guidance and data as well as their concerns with the lack of time available to explain screening and testing options indicate significant potential issues with patient care. It is important to ensure that the clinical integration of cfDNA screening is managed responsibly and ethically before it expands further, exacerbating pre-existing issues. As prenatal screening evolves, so should informed consent and the resources available to women making decisions. The field must take steps to maximize the advantages of cfDNA screening and responsibly manage its ethical issues.

Time and travel costs incurred by women attending antenatal tests: A costing study

OBJECTIVE

to estimate the costs to women, their friends and family for different antenatal tests in the Down's syndrome (DS) screening pathway.

DESIGN

questionnaire-based costing study.

SETTING

eight maternity clinics across the UK.

PARTICIPANTS

pregnant women (n=574) attending an appointment for DS screening, NIPT or invasive testing between December 2013 and September 2014.

MEASUREMENTS

using data collected from the questionnaires we calculated the total costs to women by multiplying the time spent at the hospital and travelling to and from it by the opportunity costs of the women and accompanying person and adding travel and childcare costs. Assumptions about the value of opportunity costs were tested in one-way sensitivity analyses. The main outcome measure was the mean cost to the women and friends/family for each test (DS screening, NIPT, and invasive testing).

FINDINGS

mean costs to women and their family/friend were £33.96 per visit, of which £22.47 were time costs, £9.15 were travel costs and £2.34 were childcare costs. Costs were lowest for NIPT (£22), £32 for DS screening (£44 if combined with NIPT), and highest for invasive testing (£60). Sensitivity analysis revealed that variations around the value of leisure time opportunity costs had the largest influence on the results.

KEY CONCLUSIONS

there are considerable costs to women, their friends and family when attending different tests in the DS screening pathway.

IMPLICATIONS FOR PRACTICE

when assessing the cost-effectiveness of changes to this pathway, costs to women should be considered.

Non-invasive prenatal diagnosis (NIPD) for single gene disorders: cost analysis of NIPD and invasive testing pathways

Objective

Evaluate the costs of offering non‐invasive prenatal diagnosis (NIPD) for single gene disorders compared to traditional invasive testing to inform NIPD implementation into clinical practice.

Method

Total costs of diagnosis using NIPD or invasive testing pathways were compared for a representative set of single gene disorders.

Results

For autosomal dominant conditions, where NIPD molecular techniques are straightforward, NIPD cost £314 less than invasive testing. NIPD for autosomal recessive and X‐linked conditions requires more complicated technical approaches and total costs were more than invasive testing, e.g. NIPD for spinal muscular atrophy was £1090 more than invasive testing. Impact of test uptake on costs was assessed using sickle cell disorder as an example. Anticipated high uptake of NIPD resulted in an incremental cost of NIPD over invasive testing of £48 635 per 100 pregnancies at risk of sickle cell disorder.

Conclusion

Total costs of NIPD are dependent upon the complexity of the testing technique required. Anticipated increased demand for testing may have economic implications for prenatal diagnostic services. Ethical issues requiring further consideration are highlighted including directing resources to NIPD when used for information only and restricting access to safe tests if it is not cost‐effective to develop NIPD for rare conditions. © 2016 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd.

What's Already Known About This Topic?

Non‐invasive prenatal diagnosis (NIPD) for some single gene disorders has entered clinical practice and NIPD for other conditions is in development.

Studies exploring the costs and benefits of implementing NIPD for a range of single gene disorders have not been undertaken.

What Does This Study Add?

For single gene disorders where technical approaches are straightforward, NIPD was considerably cheaper than invasive testing, but for conditions that need more technically challenging approaches NIPD was more expensive.

The anticipated increase in test uptake following the introduction of NIPD will be a major contributing factor to the cost of a genetic service offering prenatal diagnosis for single gene disorders in clinical practice.

Prospective monitoring and audit of uptake following clinical implementation is required to allow full consideration of the economic, social and ethical issues that will arise.

Women's Experiences and Preferences for Service Delivery of Non-Invasive Prenatal Testing for Aneuploidy in a Public Health Setting: A Mixed Methods Study

Non-invasive prenatal testing (NIPT) for aneuploidy is currently only available in the UK through the private sector outside of the research arena. As part of an implementation study in the UK National Health Service we conducted a mixed methods study to assess women’s experience of being offered NIPT using validated measures of decisional conflict, decisional regret and anxiety. Clinical service preferences were also explored. Women with a Down syndrome screening risk >1:1000 were invited to take part in the study and offered NIPT, NIPT and invasive testing (for women with a risk above 1:150) or no further testing. A cross-sectional survey and semi-structured interviews were conducted at two time points; at the time of testing and one month following receipt of results (or equivalent for NIPT decliners). In total, 845 questionnaires and 81 interviews were analysed. The main motivation to accept NIPT was for reassurance (30.8%). Decisional conflict occurred in a minimal number of cases (3.8%), however, none of the participants experienced decisional regret. Around a third (29.9%) of women had elevated anxiety at the time of testing, including intermediate risk women who traditionally would not be offered further testing (54.4% high risk; 20.1% medium risk), a finding supported through the qualitative interviews where prolonged or additional anxiety was found to occur in some medium risk cases. Women were overwhelmingly positive about the opportunity to have a test that was procedurally safe, accurate, reduced the need for invasive testing and identified cases of Down syndrome that might otherwise have been missed. Reassurance was identified as the main motivator for accepting NIPT, particularly amongst medium risk women, with high risk women inclined to accept NIPT to inform decisions around invasive testing. The current turnaround time for test result was identified as a key limitation. All the women interviewed thought NIPT should be adopted as part of NHS clinical practice, with the majority favouring NIPT offered as a first-line test. Our study highlights the potential that NIPT has to positively impact women’s experience of prenatal testing for aneuploidy.

Non-invasive prenatal testing for fetal chromosome abnormalities: review of clinical and ethical issues

Genomics-based non-invasive prenatal screening using cell-free DNA (cfDNA screening) was proposed to reduce the number of invasive procedures in current prenatal diagnosis for fetal aneuploidies. We review here the clinical and ethical issues of cfDNA screening. To date, it is not clear how cfDNA screening is going to impact the performances of clinical prenatal diagnosis and how it could be incorporated in real life. The direct marketing to users may have facilitated the early introduction of cfDNA screening into clinical practice despite limited evidence-based independent research data supporting this rapid shift. There is a need to address the most important ethical, legal, and social issues before its implementation in a mass setting. Its introduction might worsen current tendencies to neglect the reproductive autonomy of pregnant women.

Screening for fetal aneuploidy

Screening is currently recommended in pregnancy for a number of genetic disorders, chromosomal aneuploidy, and structural birth defects in the fetus regardless of maternal age or family history. There is an overwhelming array of sonographic and maternal serum-based options available for carrying out aneuploidy risk assessment in the first and/or second trimester. As with any screening test, the patient should be made aware that a "negative" test or "normal" ultrasound does not guarantee a healthy baby and a "positive" test does not mean the fetus has the condition. The woman should have both pre- and post-test counseling to discuss the benefits, limitations, and options for additional testing. Rapid advancements of genetic technologies have made it possible to screen for the common aneuploidies traditionally associated with advanced maternal age with improved levels of accuracy beyond serum and ultrasound based testing. Prenatal screening for fetal genetic disorders with cell-free DNA has transformed prenatal care with yet unanswered questions related to the financial, ethical, and appropriate application in the provision of prenatal risk assessment.

A cost-effectiveness analysis of cell free DNA as a replacement for serum screening for Down syndrome

OBJECTIVE

The aim of this article is to determine the cost effectiveness of cell free DNA (cfDNA) as a replacement for integrated screening using a societal cost perspective.

METHOD

This study used Monte-Carlo simulation with one-way and probabilistic sensitivity analysis.

RESULTS

Cell free DNA is more effective and less costly than integrated screening. The incremental cost-effectiveness ratio for cfDNA relative to the integrated test was -$277 955 per case detected (95th percent confidence interval -$881 882 to $532 785).

CONCLUSION

Cell free DNA screening is a cost-effective replacement for maternal serum screening when the lifetime costs of Down syndrome live births are considered. The adoption of cfDNA screening would save approximately $277 955 for each additional case detected over integrated screening.

[Analysis of cell-free DNA in maternal blood for detection of fetal trisomy 21 in high-risk population: Couples acceptance and grounds for refusal]

OBJECTIVES

To assess the determinants associated with the use of analysis of cell-free DNA in maternal blood for detection of trisomy 21 in high-risk women.

MATERIALS AND METHODS

Prospective study conducted in a single center between July 15, 2014 and December 15, 2014 on 99 consecutive women with increased risk of trisomy 21 above 1/250.

RESULTS

Analysis of cell-free DNA in maternal blood for detection of fetal trisomy 21 was proposed to 95 women out of 99, among them, 43 women (45.3%) required the test. Among these 43 women, 17 (38.6%) had a higher socio-economic status versus 10 (19.2%) among the women who did not request the test (P=0.03). The most common reason given by the 52 women who did not request the analysis of cell-free DNA was the cost, for 30 of them (57.7%), then because the test was not providing certainty for the diagnostic of trisomy 21 for 23 women (44.2%).

CONCLUSION

Analysis of cell-free DNA on maternal blood for detection of trisomy 21 does not seem accepted by the majority of women. The cost is probably the main reason for not using this test, but it seems that the lack of diagnostic certainty is also an obstacle for some women.

Cell-Free Fetal DNA Testing for Prenatal Diagnosis

Prenatal diagnosis and screening have undergone rapid development in recent years, with advances in molecular technology driving the change. Noninvasive prenatal testing (NIPT) for Down syndrome as a highly sensitive screening test is now available worldwide through the commercial sector with many countries moving toward implementation into their publically funded maternity systems. Noninvasive prenatal diagnosis (NIPD) can now be performed for definitive diagnosis of some recessive and X-linked conditions, rather than just paternally inherited dominant and de novo conditions. NIPD/T offers pregnant couples greater choice during their pregnancy as these safer methods avoid the risk of miscarriage associated with invasive testing. As the cost of sequencing falls and technology develops further, there may well be potential for whole exome and whole genome sequencing of the unborn fetus using cell-free DNA in the maternal plasma. How such assays can or should be implemented into the clinical setting remain an area of significant debate, but it is clear that the progress made to date for safer prenatal testing has been welcomed by expectant couples and their healthcare professionals.

Non-invasive prenatal testing for aneuploidy and beyond: challenges of responsible innovation in prenatal screening

This paper contains a joint ESHG/ASHG position document with recommendations regarding responsible innovation in prenatal screening with non-invasive prenatal testing (NIPT). By virtue of its greater accuracy and safety with respect to prenatal screening for common autosomal aneuploidies, NIPT has the potential of helping the practice better achieve its aim of facilitating autonomous reproductive choices, provided that balanced pretest information and non-directive counseling are available as part of the screening offer. Depending on the health-care setting, different scenarios for NIPT-based screening for common autosomal aneuploidies are possible. The trade-offs involved in these scenarios should be assessed in light of the aim of screening, the balance of benefits and burdens for pregnant women and their partners and considerations of cost-effectiveness and justice. With improving screening technologies and decreasing costs of sequencing and analysis, it will become possible in the near future to significantly expand the scope of prenatal screening beyond common autosomal aneuploidies. Commercial providers have already begun expanding their tests to include sex-chromosomal abnormalities and microdeletions. However, multiple false positives may undermine the main achievement of NIPT in the context of prenatal screening: the significant reduction of the invasive testing rate. This document argues for a cautious expansion of the scope of prenatal screening to serious congenital and childhood disorders, only following sound validation studies and a comprehensive evaluation of all relevant aspects. A further core message of this document is that in countries where prenatal screening is offered as a public health programme, governments and public health authorities should adopt an active role to ensure the responsible innovation of prenatal screening on the basis of ethical principles. Crucial elements are the quality of the screening process as a whole (including non-laboratory aspects such as information and counseling), education of professionals, systematic evaluation of all aspects of prenatal screening, development of better evaluation tools in the light of the aim of the practice, accountability to all stakeholders including children born from screened pregnancies and persons living with the conditions targeted in prenatal screening and promotion of equity of access.

Contingent non-invasive prenatal testing: an opportunity to improve non-genetic aspects of fetal aneuploidy screening

BACKGROUND

Several countries today struggle with suboptimal performances in many aspects of the fetal aneuploidy screening process and consider introducing non-invasive prenatal screening (NIPT) as a solution. In this study, costs and benefits of different scenarios for contingent NIPT screening in Belgium are evaluated with respect to partial redistribution of the national screening budget into quality improving measures for those screening activities that will be maintained when full NIPT screening is implemented.

METHODS

Data from the Belgian National Institute for Health and Disability Insurance and the Study Centre for Perinatal Epidemiology were used in modeled calculations of medical and economic impact of NIPT after prior conventional screening (1) at thresholds 1:300 and 1:600, and (2) at current and improved screening sensitivity.

RESULTS

Contingent NIPT screening under current screening conditions would maintain today's 7.9(0)/000 live birth prevalence of Down syndrome (LBPD) at an 11% reduction of overall short-term costs. Lowering the screening threshold to 1:600 or increasing sensitivity by 10% would reduce LBPD to 7(0)/000 at a maximum 3% increase of overall short-term costs.

CONCLUSION

Today, in Belgium and in many other countries, full NIPT screening is considered too expensive for immediate introduction into the national fetal aneuploidy screening program. Contingent NIPT screening is both clinically and economically beneficial. A temporary contingent NIPT protocol allows for reinvesting economic savings into optimization of those screening aspects, which are to be maintained in parallel to full NIPT screening.

Noninvasive Prenatal Screening for Genetic Diseases Using Massively Parallel Sequencing of Maternal Plasma DNA

The identification of cell-free fetal DNA (cffDNA) in maternal plasma in 1997 heralded the most significant change in obstetric care for decades, with the advent of safer screening and diagnosis based on analysis of maternal blood. Here, we describe how the technological advances offered by next-generation sequencing have allowed for the development of a highly sensitive screening test for aneuploidies as well as definitive prenatal molecular diagnosis for some monogenic disorders.

An Economic Analysis of Cell-Free DNA Non-Invasive Prenatal Testing in the US General Pregnancy Population

OBJECTIVE

Analyze the economic value of replacing conventional fetal aneuploidy screening approaches with non-invasive prenatal testing (NIPT) in the general pregnancy population.

METHODS

Using decision-analysis modeling, we compared conventional screening to NIPT with cell-free DNA (cfDNA) analysis in the annual US pregnancy population. Sensitivity and specificity for fetal aneuploidies, trisomy 21, trisomy 18, trisomy 13, and monosomy X, were estimated using published data and modeling of both first- and second trimester screening. Costs were assigned for each prenatal test component and for an affected birth. The overall cost to the healthcare system considered screening costs, the number of aneuploid cases detected, invasive procedures performed, procedure-related euploid losses, and affected pregnancies averted. Sensitivity analyses evaluated the effect of variation in parameters. Costs were reported in 2014 US Dollars.

RESULTS

Replacing conventional screening with NIPT would reduce healthcare costs if it can be provided for $744 or less in the general pregnancy population. The most influential variables were timing of screening entry, screening costs, and pregnancy termination rates. Of the 13,176 affected pregnancies undergoing screening, NIPT detected 96.5% (12,717/13,176) of cases, compared with 85.9% (11,314/13,176) by conventional approaches. NIPT reduced invasive procedures by 60.0%, with NIPT and conventional methods resulting in 24,596 and 61,430 invasive procedures, respectively. The number of procedure-related euploid fetal losses was reduced by 73.5% (194/264) in the general screening population.

CONCLUSION

Based on our analysis, universal application of NIPT would increase fetal aneuploidy detection rates and can be economically justified. Offering this testing to all pregnant women is associated with substantial prenatal healthcare benefits.

A Cost-Effectiveness Analysis of First Trimester Non-Invasive Prenatal Screening for Fetal Trisomies in the United States

Background

Non-invasive prenatal testing (NIPT) is a relatively new technology for diagnosis of fetal aneuploidies. NIPT is more accurate than conventional maternal serum screening (MSS) but is also more costly. Contingent NIPT may provide a cost-effective alternative to universal NIPT screening. Contingent screening used a two-stage process in which risk is assessed by MSS in the first stage and, based on a risk cutoff, high-risk pregnancies are referred for NIPT. The objective of this study was to (1) determine the optimum MSS risk cutoff for contingent NIPT and (2) compare the cost effectiveness of optimized contingent NIPT to universal NIPT and conventional MSS.

Study Design

Decision-analytic model using micro-simulation and probabilistic sensitivity analysis. We evaluated cost effectiveness from three perspectives: societal, governmental, and payer.

Results

From a societal perspective, universal NIPT dominated both contingent NIPT and MSS. From a government and payer perspective, contingent NIPT dominated MSS. Compared to contingent NIPT, adopting a universal NIPT would cost $203,088 for each additional case detected from a government perspective and $263,922 for each additional case detected from a payer perspective.

Conclusions

From a societal perspective, universal NIPT is a cost-effective alternative to MSS and contingent NIPT. When viewed from narrower perspectives, contingent NIPT is less costly than universal NIPT and provides a cost-effective alternative to MSS.

Overview of the impact of noninvasive prenatal testing on diagnostic procedures

Noninvasive prenatal testing (NIPT) has had a profound influence in the field of prenatal diagnosis since the 1997 discovery of cell-free fetal DNA in maternal blood. Research has progressed rapidly, with clinical data supporting laboratory studies showing that NIPT is highly sensitive and specific for fetal aneuploidy, resulting in marked uptake in the high-risk patient population. The superior accuracy of NIPT compared with conventional screening methods has led to significant decreases in the number of invasive diagnostic procedures, in addition to a concomitant decrease in the number of procedure-related fetal losses. Yet, NIPT has been described as a 'disruptive innovation' due to the considerable changes the technology has commanded on current prenatal screening and diagnostic practices. This review summarizes both institutional and global experience with NIPT uptake, its effect on reducing diagnostic invasive procedures, and the unique challenges that reduced procedural volume may have on physician and trainee proficiency, cytogenetic laboratories, and neonatal outcome.

Incorporation of dried blood alpha fetoprotein into traditional first trimester Down syndrome screening service

Abstract

What’s already known about this topic?

What does this study add?

Performance of antenatal reflex DNA screening for Down's syndrome

OBJECTIVE

Maternal plasma DNA analysis has a high but imperfect antenatal Down's syndrome screening performance. We aimed to determine the effect of combining DNA testing with current tests.

METHODS

In our modelled screening protocol, women provide two samples, one serum sample for a Combined test, and a plasma sample for a possible DNA test. Women with a Combined test risk above a specified level have a DNA test using the plasma sample without the need to recall them for another sample and counselling (ie. in a reflex manner). Women with a failed DNA test after a second attempt using a fresh plasma sample have an Integrated test. Screening performance was estimated according to the proportion of women reflexed to DNA testing and compared with universal DNA testing.

RESULTS

Reflexing 10% of women to a DNA test yields a 91% detection rate (DR) for a 0.025% false-positive rate (FPR) and no failed tests, compared with a 98% DR, 0.2% FPR and a 2.5% test failure rate with universal DNA testing (94% for 0.046% if 20% reflexed). DNA test failure rate has little influence on screening performance

CONCLUSION

Reflex DNA testing substantially reduces the FPR with a relatively small loss in detection compared with universal DNA testing, and reduces patient anxiety by avoiding the recall of women for DNA testing.

Screening Performance and Costs of Different Strategies in Prenatal Screening for Trisomy 21

Objective: Cell-free fetal DNA (cffDNA) testing has opened new options in prenatal screening for trisomy 21. Due to the higher costs of cffDNA testing there is an ongoing debate on how to combine different screening strategies. Methods: For this study, a model-based approach was used to evaluate all births in Germany in 2012 together with the percentage of euploid and trisomic pregnancies. Detection rates (DR), false positive rates (FPR), the costs of different screening strategies for trisomy 21 and combinations of these strategies were compared. The number of fetuses with trisomy 21 at 12 + 0 weeks of gestation was estimated based on maternal age distribution. We examined the screening performance of a screening strategy based on maternal age, first trimester screening (FTS) and cffDNA testing as well as the combinations "maternal age and cffDNA" and "FTS and cffDNA". Results: In 2012 673 544 children were born. Median maternal age at delivery was 30.2 years (25th-75th quartile: 27.0-34.0). Based on maternal age distribution the expected number of fetuses with trisomy 21 at 12 weeks' gestation was 1788. Our study population therefore consisted of 675 332 pregnancies. Screening based only on maternal age or FTS or cffDNA resulted in detection rates of 63.3 %, 92.2 % and 99.0 % and false positive rates of 21.8 %, 8.0 % and 0.1 %, respectively. When maternal age was combined with cffDNA, cffDNA testing was only offered to women over a certain age; if a cut-off of 30 years was used, this resulted in a DR of 85.2 % and a FPR of 1.7 %. If primary screening consisted of FTS with cffDNA testing only done when the risk was between 1 : 10 and 1 : 1000, the detection rate was 96.7 % and the false positive rate was 1.2 %. Conclusion: In this model-based study we showed that prenatal screening for trisomy 21 can be improved even more by combining FTS and cffDNA. Further studies are necessary to examine whether these results can be reproduced in reality.

Comparing outcomes and costs between contingent and combined first-trimester screening strategies for Down's syndrome

OBJECTIVE

To compare a contingent strategy with a combined strategy for prenatal detection of Down's syndrome (DS) in terms of cost, outcomes and safety.

STUDY DESIGN

The contingent strategy was based on a simulation, removing measurement of the free beta subunit of human chorionic gonadotropin (free βhCG) and calculating the DS risk retrospectively in 32,371 pregnant women who had been screened with the combined strategy in the first trimester. In the contingent strategy, a risk between 1:31 and 1:1000 in the first trimester indicated further testing in the second trimester (alpha-fetoprotein, inhibin A, unconjugated oestriol and free βhCG). The cut-off risk values for the contingent and combined strategies in the first trimester were 1:30 and 1:250, respectively, and the cut-off risk value for integrated screening in the second trimester was 1:250. Costs were compared in terms of avoided DS births, and the ratio of loss of healthy fetuses following invasive procedures per avoided DS birth was calculated.

RESULTS

The combined strategy had sensitivity of 40/44 (90.9%) and a false-positive rate of 2.8%. Corresponding values for the contingent strategy were 39/44 (88.6%) and 1.3%, respectively. Only 11% of pregnant women required tests in the second trimester, and the approximate cost reduction for each avoided DS birth was 5000€. The ratio of lost healthy fetuses following invasive procedures per avoided DS birth improved by up to 0.65.

CONCLUSION

The contingent strategy has similar effectiveness to the combined strategy, but has lower costs and fewer invasive procedures.

Rates of prenatal screening across health care regions in Ontario, Canada: a retrospective cohort study

BACKGROUND

It is recommended that all pregnant women be offered screening for Down syndrome and open neural tube defects, but emerging prenatal tests that are not publicly insured may compromise access. We evaluated screening rates for publicly insured screening tests across health care regions in the province of Ontario and determined whether maternal, provider or regional characteristics are associated with screening uptake.

METHODS

We conducted a population-based retrospective cohort study involving pregnant women in Ontario who were at or beyond 16 weeks' gestation in 2007-2009. We ascertained prenatal screening rates using linked health administrative and prenatal screening datasets. We examined maternal, provider and regional characteristics associated with screening uptake. Rate ratios (RRs) were estimated.

RESULTS

Of the 264 737 women included in the study, 62.2% received prenatal screening; uptake varied considerably by region (range 27.8%-80.3%). A greater proportion of women initiated screening in the first rather than the second trimester (50.0% v. 12.2%). Factors associated with lower screening rates included living in a rural area versus an urban area (adjusted rate ratio 0.64, 95% confidence interval [CI] 0.63-0.66), receiving first-trimester care from a family physician or midwife versus an obstetrician (adjusted rate ratio 0.91, 95% CI 0.90-0.92, and 0.40, 95% CI 0.38-0.43, respectively) and being in a lower income quintile (adjusted RR for lowest v. highest 0.95, 95% CI 0.94-0.96). Being an immigrant or a refugee was associated with higher screening rates.

INTERPRETATION

There were significant maternal, provider and regional differences in the uptake of prenatal screening across the province. With discrepancies expected to increase with the emergence of noninvasive prenatal tests paid for out of pocket by many women, policy efforts to reduce barriers to prenatal screening and optimize its availability are warranted.

Non-invasive prenatal testing: a review of international implementation and challenges

Noninvasive prenatal genetic testing (NIPT) is an advance in the detection of fetal chromosomal aneuploidies that analyzes cell-free fetal DNA in the blood of a pregnant woman. Since its introduction to clinical practice in Hong Kong in 2011, NIPT has quickly spread across the globe. While many professional societies currently recommend that NIPT be used as a screening method, not a diagnostic test, its high sensitivity (true positive rate) and specificity (true negative rate) make it an attractive alternative to the serum screens and invasive tests currently in use. Professional societies also recommend that NIPT be accompanied by genetic counseling so that families can make informed reproductive choices. If NIPT becomes more widely adopted, States will have to implement regulation and oversight to ensure it fits into existing legal frameworks, with particular attention to returning fetal sex information in areas where sex-based abortions are prevalent. Although there are additional challenges for NIPT uptake in the developing world, including the lack of health care professionals and infrastructure, the use of NIPT in low-resource settings could potentially reduce the need for skilled clinicians who perform invasive testing. Future advances in NIPT technology promise to expand the range of conditions that can be detected, including single gene disorders. With these advances come questions of how to handle incidental findings and variants of unknown significance. Moving forward, it is essential that all stakeholders have a voice in crafting policies to ensure the ethical and equitable use of NIPT across the world.

First-trimester contingent screening for trisomies 21, 18 and 13 by fetal nuchal translucency and ductus venosus flow and maternal blood cell-free DNA testing

OBJECTIVE

To examine performance of screening for major trisomies by a policy of first-line assessment of risk according to maternal age, fetal nuchal translucency thickness (NT) and ductus venosus pulsatility index for veins (DV-PIV) followed by cell-free DNA (cfDNA) testing in pregnancies with an intermediate risk.

METHODS

We estimated the distribution of risks based on maternal age, fetal NT and DV-PIV in a dataset of 86 917 unaffected and 491 trisomic pregnancies undergoing prospective screening for trisomies. Performance of screening for trisomies by cfDNA testing was derived from a meta-analysis of clinical validation studies. We estimated performance and cost of screening for trisomies using different combinations of ultrasound screening and cfDNA testing.

RESULTS

Screening for trisomies 21, 18 and 13 according to a combination of maternal age, fetal NT and DV-PIV in all pregnancies, followed by invasive testing in the high-risk group (≥ 1:10) and cfDNA testing in the intermediate-risk group (1:11-1:3000) can potentially detect about 96%, 95% and 91% of cases, respectively, with a false-positive rate (FPR) of 0.8%. On the assumption that the costs for ultrasound screening, cfDNA testing and invasive testing are €150, €500 and €1000, respectively, the overall cost of such a policy would be about €250 per patient. The alternative policy, of universal screening by cfDNA testing, can potentially detect about 99%, 97% and 92% of cases of trisomies 21, 18 and 13, but at an overall cost of more than €500 per patient.

CONCLUSION

Incorporation of cfDNA testing into a contingent policy of early screening for the major trisomies, based on the risk derived from first-line screening by a combination of maternal age, fetal NT and DV-PIV, can detect a high proportion of affected cases with a low FPR.

Cell-free fetal DNA screening in the USA: a cost analysis of screening strategies

OBJECTIVES

To determine whether implementation of primary cell-free fetal DNA (cffDNA) screening would be cost-effective in the USA and to evaluate potential lower-cost alternatives.

METHODS

Three strategies to screen for trisomy 21 were evaluated using decision tree analysis: 1) a primary strategy in which cffDNA screening was offered to all patients, 2) a contingent strategy in which cffDNA screening was offered only to patients who were high risk on traditional first-trimester screening and 3) a hybrid strategy in which cffDNA screening was offered to all patients ≥ 35 years of age and only to patients < 35 years who were high risk after first-trimester screening. Four traditional screening protocols were evaluated, each assessing nuchal translucency (NT) and pregnancy-associated plasma protein-A (PAPP-A) along with either free or total beta-human chorionic gonadotropin (β-hCG), with or without nasal bone (NB) assessment.

RESULTS

Utilizing a primary cffDNA screening strategy, the cost per patient was 1017 US$. With a traditional screening protocol using free β-hCG, PAPP-A and NT assessment as part of a hybrid screening strategy, a contingent strategy with a 1/300 cut-off and a contingent strategy with a 1/1000 cut-off, the cost per patient was 474, 430 and 409 US$, respectively. Findings were similar using the other traditional screening protocols. Marginal cost per viable case detected for the primary screening strategy as compared to the other strategies was 3-16 times greater than the cost of care for a missed case.

CONCLUSIONS

Primary cffDNA screening is not currently a cost-effective strategy. The contingent strategy was the lowest-cost alternative, especially with a risk cut-off of 1/1000. The hybrid strategy, although less costly than primary cffDNA screening, was more costly than the contingent strategy.

Pregnancy associated plasma protein-A2: a novel biomarker for Down syndrome

INTRODUCTION

In an effort to improve prenatal screening for Trisomy 21, we evaluated pregnancy associated plasma protein-A2 (PAPP-A2) as a potential novel second trimester biomarker for Trisomy 21.

METHODS

Trisomy 21 and normal control mid-trimester placental samples were subjected to quantitative rt PCR analysis of seven genes we had previously found to be differentially expressed in Trisomy 21 placentae. The localization and differential expression of PAPP-A2 in second trimester placentae from normal and Trisomy 21 pregnancies was determined by immunohistochemistry. PAPP-A2 maternal serum protein levels in ten Trisomy 21 and ten diploid pregnancies were compared by Western blotting. Maternal serum PAPP-A2 levels were measured in 30 Down syndrome cases and 142 normal controls, using ELISA. Regression analysis was used to determine the correlation of PAPP-A2 with other existing markers of Trisomy 21.

RESULTS

PAPP-A2 (aka PLAC 3) mRNA and protein expression were both increased in Down syndrome placentae as compared to diploid placentae. PAPP-A2 was also increased in maternal serum from Down syndrome pregnancies as compared to diploid pregnancies. PAPP-A2 expression correlated weakly with established markers.

DISCUSSION

This work takes advantage of our previously performed systematic approach to the discovery of novel maternal serum biomarkers for Trisomy 21, using cDNA microarray analysis. Beginning with the validation of the microarray results, we have tracked PAPP-A2 overexpression in Down syndrome from placental mRNA to maternal serum protein.

CONCLUSION

PAPP-A2 could serve as an additional maternal serum marker in prenatal screening for Trisomy 21.

Implementation of whole genome massively parallel sequencing for noninvasive prenatal testing in laboratories

Noninvasive prenatal testing (NIPT) for fetal aneuploidies using cell-free fetal DNA in maternal plasma has revolutionized the field of prenatal care and methods using massively parallel sequencing are now being implemented almost worldwide. Substantial progress has been made from initially testing for (an)euploidies of chromosomes 13, 18 and 21, to testing for sex chromosome (an)euploidies, additional autosomal aneuploidies as well as partial deletions and duplications genome-wide. Although NIPT is associated with significantly reduced risks for the fetus in comparison to existing invasive prenatal diagnostic methods, it presents several implementation challenges. Here, we review key issues potentially influencing NIPT and illustrate them using both data from literature and in-house data.

Non-invasive prenatal testing: UK genetic counselors' experiences and perspectives

To date, NIPT in the UK has been predominately used in the health service for early sexing of pregnancies at known risk of sex-linked conditions. Developments in the technology are broadening its use to diagnostic testing for paternally inherited genetic conditions and for detection of aneuploidy. This study aimed to examine the experiences of UK genetic counselors with offering NIPT for sexing, and to explore their views on future uses of the technology. Twenty interviews with practicing GC's from four centres were audiotaped, transcribed, and analyzed using modified grounded theory. Participants all had experience of counseling patients around prenatal diagnosis and 18/20 had experience of offering NIPT. GCs reported initially feeling cautious about offering the test, although they saw it as a positive advance for their patients at genetic risk. Emphasis was placed on accuracy, adequate counseling provision and gatekeeping with concerns expressed about broadening its use in the routine antenatal setting. Findings indicate the genetics model for offering prenatal testing to high risk patients can incorporate NIPT and the profession may have a role in informing its implementation in wider healthcare settings. In a wider context this study highlights the challenges new technologies bring to genetic counselors' practice and service structure.

The consequences of implementing non-invasive prenatal testing in Dutch national health care: a cost-effectiveness analysis

OBJECTIVE

Non-invasive prenatal testing (NIPT) using cell-free fetal DNA in maternal plasma has been developed for the detection of fetal aneuploidy. Clinical trials have shown high sensitivity and specificity for trisomy 21 (T21) in both high-risk and average-risk populations. Although its great potential for prenatal medicine is evident, more information regarding the consequences of implementing NIPT in a national programme for prenatal screening is required.

STUDY DESIGN

A decision-analytic model was developed to compare costs and outcomes of current clinical practice in The Netherlands using conventional screening only, with two alternatives: implementing NIPT as an optional secondary screening test for those pregnancies complicated by a high risk for T21, and implementing NIPT as primary screening test, replacing conventional screening. Probability estimates were derived from a systematic review of international literature. Costs were determined from a health-care perspective. Data were analysed to obtain outcomes, total costs, relative costs and incremental cost-effectiveness ratios (ICERs) for the different strategies. Sensitivity analysis was used to assess the impact of assumptions on model results.

RESULTS

Implementing NIPT as an optional secondary, or as primary screening test will increase T21 detection rate by 36% (from 46.8% to 63.5%) and 54% (from 46.8% to 72.0%), simultaneously decreasing the average risk of procedure-related miscarriage by 44% (from 0.0168% to 0.0094% per pregnant woman) and 62% (from 0.0168% to 0.0064% per pregnant woman), respectively. None of the strategies clearly dominated: current clinical practice is the least costly, whereas implementing NIPT will cause total costs of the programme to increase by 21% (from €257.09 to €311.74 per pregnant woman), leading to an ICER of k€94 per detected case of T21, when utilised as an optional secondary screening test and by 157% (from €257.09 to €660.94 per pregnant woman), leading to an ICER of k€460 per detected case of T21, when utilised as primary screening test. However, implementing NIPT as triage test did result in the lowest expected relative costs per case of T21 diagnosed (k€141).

CONCLUSION

NIPT should be implemented in national health care as an optional secondary screening test for those pregnancies complicated by a high risk for T21.

Evaluation of non-invasive prenatal testing (NIPT) for aneuploidy in an NHS setting: a reliable accurate prenatal non-invasive diagnosis (RAPID) protocol

BACKGROUND

Non-invasive prenatal testing (NIPT) for aneuploidies is now available through commercial companies in many countries, including through private practice in the United Kingdom (UK). Thorough evaluation of service delivery requirements are needed to facilitate NIPT being offered more widely within state funded healthcare systems such as the UK's National Health Service (NHS). Successful implementation will require the development of laboratory standards, consideration of stakeholder views, an analysis of costs and development of patient and health professional educational materials.

METHODS/DESIGN

NIPT will be offered in an NHS setting as a contingent screening test. Pregnant woman will be recruited through six maternity units in England and Scotland. Women eligible for Down's syndrome screening (DSS) will be informed about the study at the time of booking. Women that choose routine DSS will be offered NIPT if they have a screening risk ≥ 1:1000. NIPT results for trisomy 21, 18, 13 will be reported within 7-10 working days. Data on DSS, NIPT and invasive testing uptake, pregnancy outcomes and test efficacy will be collected. Additional data will be gathered though questionnaires to a) determine acceptability to patients and health professionals, b) evaluate patient and health professional education, c) assess informed choice in women accepting or declining testing and d) gauge family expenses. Qualitative interviews will also be conducted with a sub-set of participating women and health professionals.

DISCUSSION

The results of this study will make a significant contribution to policy decisions around the implementation of NIPT for aneuploidies within the UK NHS. The laboratory standards for testing and reporting, education materials and counselling strategies developed as part of the study are likely to underpin the introduction of NIPT into NHS practice.

NIHR PORTFOLIO NUMBER

13865.

Non-invasive prenatal testing for trisomy 21: a cross-sectional survey of service users' views and likely uptake

OBJECTIVE

To assess the views and likely uptake of non-invasive prenatal testing (NIPT) for trisomy 21 among potential service users in the UK.

DESIGN

Cross-sectional survey.

SETTING

Four antenatal clinics in England and two websites.

SAMPLE

A total of 1131 women and partners.

METHODS

Questionnaire conducted with women (and partners) recruited through antenatal clinics, a random sample of members of the website Mumsnet, and viewers of the website and Facebook page of the support group Antenatal Results and Choices (ARC).

MAIN OUTCOME MEASURES

Factors impacting decision-making towards prenatal testing; views on NIPT, including service delivery and likely uptake; hypothetical scenarios, focused on current screening, invasive testing, and NIPT offered to women with a high-risk screening result.

RESULTS

The vast majority (95.7%; 1071/1119; 95% CI 94.4-96.8%) thought NIPT was a positive development in prenatal care, with 88.2% (972/1103; 95% CI 86.1-90%) indicating that they would use the test, including respondents who would currently decline trisomy 21 screening (P < 0.001). Of the respondents who would have NIPT, 30.7% (299/973; 95% CI = 27.8-33.7%) said that they were 'likely' to terminate an affected pregnancy (including those who would currently decline screening or invasive testing), and 36.5% (355/973; 95% CI 33.5-39.6%) were 'not likely' to terminate an affected pregnancy. Respondents overwhelmingly indicated that safety for the baby was the most important attribute of NIPT (70.1%; 712/1015; 95% CI 67.2-73%).

CONCLUSION

Respondents were overwhelmingly positive towards the introduction of NIPT. Uptake is likely to be high, and includes women who currently decline screening as well as those who will use the test for information only. Pre-test counselling to ensure that women understand the implications of the test result is essential.