Combined first-trimester versus second-trimester serum screening for Down syndrome: a cost analysis

BACs-on-Beads technology: a reliable test for rapid detection of aneuploidies and microdeletions in prenatal diagnosis

The risk of fetal aneuploidies is usually estimated based on high resolution ultrasound combined with biochemical determination of criterion in maternal blood, with invasive procedures offered to the population at risk. The purpose of this study was to investigate the effectiveness of a new rapid aneuploidy screening test on amniotic fluid (AF) or chorionic villus (CV) samples based on BACs-on-Beads (BoBs) technology and to compare the results with classical karyotyping by Giemsa banding (G-banding) of cultured cells in metaphase as the gold standard technique. The prenatal-BoBs kit was used to study aneuploidies involving chromosomes 13, 18, 21, X, and Y as well as nine microdeletion syndromes in 321 AF and 43 CV samples. G-banding of metaphase cultured cells was performed concomitantly for all prenatal samples. A microarray-based comparative genomic hybridization (aCGH) was also carried out in a subset of samples. Prenatal-BoBs results were widely confirmed by classical karyotyping. Only six karyotype findings were not identified by Prenatal-BoBs, all of them due to the known limitations of the technique. In summary, the BACs-on-Beads technology was an accurate, robust, and efficient method for the rapid diagnosis of common aneuploidies and microdeletion syndromes in prenatal samples.

Cost-effectiveness and accuracy of prenatal Down syndrome screening strategies: should the combined test continue to be widely used?

OBJECTIVE

We analyzed the cost-effectiveness (CE) and performances of commonly used prenatal Down syndrome (DS) screening strategies.

STUDY DESIGN

We performed computer simulations to compare 8 screening options by applying empirical data from Serum, Urine, and Ultrasound Screening Study trials on the population of 110,948 pregnancies. Screening strategies outcomes, CE ratios, and incremental CE ratios were measured.

RESULTS

The most CE DS screening strategy was the contingent screening method (CE ratio of Can$26,833 per DS case). Its incremental CE ratio compared to the second-most CE strategy (serum integrated screening) was Can$3815 per DS birth detected. Among the procedures respecting guidelines, our results identified the combined test as the screening strategy with the highest CE ratio (Can$47,358) and the highest number of procedure-related euploid miscarriages (n = 71).

CONCLUSION

In regard to CE, contingent screening is the best choice. The combined test, which is the most popular screening strategy, shows many limitations.

First-trimester Down syndrome screening in women younger than 35 years old and cost-effectiveness analysis in Taiwan population

OBJECTIVES

Outcome of the first-trimester Down syndrome screening in younger population was less reported before. We present the outcome of this screening in Taiwanese women younger than 35 years old. We also test whether or not the first-trimester Down syndrome screening of women <35 years of age and women >35 years old routinely receiving amniocentesis is cost-effective compared with all pregnant women screened with this test in the setting of increased maternal age.

METHODS

From 1999 to 2007, the first-trimester Down syndrome screening including nuchal thickness, pregnancy-associated plasma protein A and free beta-hCG are provided to 10 811 singleton women <35 years of age with the cut-off of 1/270. A cost-effectiveness analysis of young women receiving this screening and older women undergo amniocentesis versus all women undergo this screening was performed in Taiwan population from 1987 to 2006, in which advanced age pregnancies increased from 2.8% to 11.6% of total pregnancies.

RESULTS

Detection rates of trisomy 21, trisomy 18, Turner syndrome and other chromosome anormalies in women <35 years of age are 87.5% (14/16), 50% (2/4), 80% (8/10) and 63% (12/19), respectively, with a false-positive rate of 5.5% (590/10 811). As advanced age pregnancies reached 11.6%, the average cost per one case averted for all women screened ranged from $77 204 to $98 421, while the cost ranged from $99 647 to $116 433 for only women <35 years of age receiving this screening.

CONCLUSIONS

In an aging population, the first-trimester Down syndrome screening should be implemented for all pregnant women when it is available.

First- and Second-Trimester Evaluation of Risk for Down Syndrome

OBJECTIVE

To investigate the differences in costs and outcomes of Down syndrome screening using data from the First and Second Trimester Evaluation of Risk (FASTER) Trial.

METHODS

Seven possible screening options for Down syndrome were compared: 1) Triple Screen-maternal serum alpha fetoprotein, estriol, and hCG; 2) Quad-maternal serum alpha fetoprotein, estriol, hCG, and Inhibin A; 3) Combined First-nuchal translucency, pregnancy-associated plasma protein A (PAPP-A), free beta-hCG; 4) Integrated-nuchal translucency, PAPP-A, plus Quad; 5) Serum Integrated-PAPP-A, plus Quad; 6) Stepwise Sequential-Combined First plus Quad with results given after each test; and 7) Contingent Sequential-Combined First and only those with risk between 1:30 and 1:1,500 have Quad screen. The detection rates for each option were used given a 5% false-positive rate except for Contingent Sequential with a 4.3% false-positive rate. Outcomes included societal costs of each screening regimen (screening tests, amniocentesis, management of complications, and cost of care of Down syndrome live births), Down syndrome fetuses identified and born, the associated quality-adjusted life years, and the incremental cost-utility ratio.

RESULTS

Based on the screening results derived from the 38,033 women evaluated in the FASTER trial, the Contingent Sequential screen dominated (lower costs with better outcomes) all other screens. For example, the Contingent Sequential cost 32.3 million dollars whereas the other screens ranged from 32.8 to 37.5 million dollars. The Sequential strategy led to the identification of the most Down syndrome fetuses of all of the screens, but at a higher cost per Down syndrome case diagnosed ($719,675 compared with $690,427) as compared with the Contingent Sequential. Because of the lower overall false-positive rate leading to fewer procedure-related miscarriages, the Contingent Sequential resulted in the highest quality-adjusted life years as well. The Contingent Sequential remained the most cost-effective option throughout sensitivity analysis of inputs, including amniocentesis rate after positive screen, rate of therapeutic abortion after Down syndrome diagnosis, and rate of procedure-related miscarriages.

CONCLUSION

Analysis of this actual data from the FASTER Trial demonstrates that the Contingent Sequential test is the most cost-effective. This information can help shape future policy regarding Down syndrome screening.

Misconstructions in health economics applied to the evaluation of prenatal screening

The application of economic evaluation to prenatal screening has led to ethical debates about the joint risks of rationing and eugenics. These debates have chosen the wrong target, as economic evaluations espouse the hypotheses and value judgment of their commissioners. This paper explores the difficulties in interpreting and using the results of economic evaluations. The first set of difficulties concerns the diversity in end points and the lack of an aggregate end point to reflect a generally desirable outcome. Another set results from the wider societal implications of economic evaluations and the implicit value judgments. Misunderstandings of the methods used for the economic evaluation of prenatal screening result from the lack of clearly stated objectives from policy makers.

Cost-effectiveness model for first-trimester versus second-trimester ultrasound screening for down syndrome

PURPOSE

To develop a cost-effectiveness analysis model from the perspective of Medicare reimbursement to evaluate the costs and potential risks involved in performing second-trimester genetic sonography following the first-trimester sonographic measurement of nuchal translucency and serology for Down syndrome screening.

METHODS

Three clinical screening algorithms were constructed that detailed the diagnostic evaluation of the target population by using first-trimester or second-trimester ultrasound and appropriate serologies or first-trimester and second-trimester screening in combination. The cost analysis was then created by using a computer spreadsheet program by applying Medicare reimbursement, the prevalence of Down syndrome, and reported sensitivities of first-trimester and second-trimester ultrasound and analytes for Down syndrome for each clinical algorithm. Medicare Current Procedural Terminology codes, total relative value units, and payments for first-trimester and second-trimester ultrasound, chorionic villous sampling, amniocentesis, and serum analytes were obtained from the Medicare Part B Washington 2002 Provider Disclosure Report.

RESULTS

At any given prevalence of Down syndrome, first-trimester screening is always slightly less expensive to society than the other two models for both total cost and cost to diagnose each case of Down syndrome. Even if second-trimester screening were 100% sensitive, the sensitivity of first-trimester screening would have to fall below 55% for model 2 to be cheaper than model 1. Combining both first-trimester and second-trimester screening was substantially more expensive than models 1 or 2. More iatrogenic fetal deaths occur with combined screening than with either first or second trimester screening alone.

CONCLUSIONS

Screening using first-trimester ultrasound and serologic markers to screen for Down syndrome is always slightly less expensive to society than second-trimester serologic and ultrasound screening. However, there is a significantly increased risk for iatrogenic fetal death if second-trimester genetic sonography is performed following normal first-trimester screening using currently accepted risk ratios. Patients should be counseled appropriately with this information, because an individual's circumstances will affect that person's perception of risk and subsequently affect his or her decision making.

First trimester prenatal diagnosis

PURPOSE OF REVIEW

The recent developments in first trimester sonography promise to greatly enhance our diagnostic capabilities for detection of aneuploidies. Collateral benefits of nuchal translucency measurements include the prediction of non-chromosomal adverse outcomes. These advances will fundamentally change clinical practices. All obstetricians must therefore have a working knowledge of the expanding literature in this field.

RECENT FINDINGS

The review covers developments in nuchal translucency based first trimester detection of chromosomal anomalies and discusses the recent literature on the use of fetal nasal bone measurements to further improve diagnostic accuracy. Emerging data on the relationship between nuchal fluid measurement and the risk of cardiac anomaly will also be presented.

SUMMARY

It is likely that the emphasis in obstetric clinical care will shift substantially towards the first trimester. With the enhanced diagnostic capabilities, greater research emphasis will inevitably need to be placed on the first trimester treatment of fetal disorders.

Advances in preconception genetic counseling

Preconception counseling offers couples contemplating pregnancy the opportunity to identify and reduce potential pregnancy risks, plan care for known risks, and establish early prenatal care. The goal of preconception counseling is to promote physically and emotionally healthy parents in an attempt to ensure optimal prenatal, intrapartum, and postpartum maternal and fetal health. The advantages of addressing these issues prior to conception include the opportunity of giving recurrence or occurrence risk information for informed decision regarding pregnancy, the accessibility of more reproductive options such as preimplantation genetic diagnosis, and the opportunity to make lifestyle, medical, and behavior alterations for optimal maternal and fetal outcome. This article will discuss advances and updates in preconception genetic counseling including risk assessment and potential intervention for concerns identified through evaluation of family history, ethnicity, maternal age, medical and obstetric history, and associated psychosocial and nursing implications. Significant advances have emerged in the areas of cystic fibrosis carrier screening, first trimester screening, preimplantation genetic diagnosis, and detection and treatment of maternal thrombophilia.