Cost-effectiveness of prenatal screening and diagnostic strategies for Down syndrome: A microsimulation modeling analysis

Objectives

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

Methods

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

Results

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

Conclusion

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

Estimating Nationwide Prevalence of Live Births with Down Syndrome and Their Medical Expenditures in Korea

BACKGROUND

This study aimed to estimate the nationwide prevalence of live births with Down syndrome (DS) and its trends and compare the observed and model-based predicted prevalence rates. Further, we compared the direct medical expenditures among DS and non-DS patients.

METHODS

Using the health administrative data of Health Insurance Review and Assessment in Korea, we selected 2,301 children with DS who were born between 2007 and 2016 to estimate the prevalence of live births with DS, and 12,265 non-DS children who were born between 2010 and 2014 to compare the direct medical expenditures among patients.

RESULTS

The prevalence of live births with DS was 5.03 per 10,000 births in 9 years, and 13% of children with DS were medical aid recipients during the study period. The medical expenditure of children with DS was about 10-fold higher than that of non-DS children and their out-of-pocket expenditure was about twice as high.

CONCLUSION

The prevalence of live birth with DS is high in the low socioeconomic group and the healthcare costs for the children with DS are significantly higher than those for non-DS children. Therefore, health authorities should help mothers at lower socioeconomic levels to receive adequate antenatal care and consider the cost of medical care for children with DS.

Cost and efficacy comparison of prenatal recall and reflex DNA screening for trisomy 21, 18 and 13

Objective

To compare costs and efficacy of reflex and recall prenatal DNA screening for trisomy 21, 18 and 13 (affected pregnancies). In both methods women have Combined test markers measured. With recall screening, women with a high Combined test risk are recalled for counselling and offered a DNA blood test or invasive diagnostic testing. With reflex screening, a DNA analysis is automatically performed on plasma collected when blood was collected for measurement of the Combined test markers.

Methods

Published data were used to estimate, for each method, using various unit costs and risk cut-offs, the cost per woman screened, cost per affected pregnancy diagnosed, and for a given number of women screened, numbers of affected pregnancies diagnosed, unaffected pregnancies with positive results, and women with unaffected pregnancies having invasive diagnostic testing.

Results

Cost per woman screened is lower with reflex v recall screening: £37 v £38, and £11,043 v £11,178 per affected pregnancy diagnosed (DNA £250, Combined test markers risk cut-off 1 in 150). Reflex screening results in similar numbers of affected pregnancies diagnosed, with 100-fold fewer false-positives and 20-fold fewer women with unaffected pregnancies having invasive diagnostic testing.

Conclusions

Reflex DNA screening is less expensive, more cost-effective, and safer than recall screening.

The contingent use of cell-free fetal DNA for prenatal screening of trisomies 21, 18, 13 in pregnant women within a national health service: A budget impact analysis

OBJECTIVE

Non-invasive prenatal testing (NIPT) based on cell-free fetal DNA (cffDNA) is highly accurate in the detection of common fetal autosomal trisomies. Aim of this project was to investigate short-term costs and clinical outcomes of the contingent use of cffDNA for prenatal screening of trisomies 21, 18, 13 within a national health service (NHS).

METHODS

An economic analysis was developed from the perspective of the Italian NHS to compare two possible scenarios for managing pregnant women: women managed according to the Standard of Care screening (SoC) vs a cffDNA scenario, where Harmony Prenatal Test was introduced as a second line screening choice for women with an "at risk" result from SoC screening.

RESULTS

The introduction of cffDNA as a second line screening test, conditional to a risk ≥ 1:1,000 from SoC screening, showed a 3% increase in the detection of trisomies, with a 71% decrease in the number of invasive tests performed. Total short-term costs (pregnancy management until childbirth) decreased by € 19 million (from € 84.5 to 65.5 million).

CONCLUSION

The adoption of the Harmony Prenatal Test in women resulting at risk from SoC screening, implied a greater number of trisomies detection, together with a reduction of the healthcare costs.

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

BACKGROUND

Non-invasive prenatal testing (NIPT) for Down's syndrome (DS) using cell free fetal DNA in maternal blood has the potential to dramatically alter the way prenatal screening and diagnosis is delivered. Before NIPT can be implemented into routine practice, information is required on its costs and benefits. We investigated the costs and outcomes of NIPT for DS as contingent testing and as first-line testing compared with the current DS screening programme in the UK National Health Service.

METHODS

We used a pre-existing model to evaluate the costs and outcomes associated with NIPT compared with the current DS screening programme. The analysis was based on a hypothetical screening population of 10,000 pregnant women. Model inputs were taken from published sources. The main outcome measures were number of DS cases detected, number of procedure-related miscarriages and total cost.

RESULTS

At a screening risk cut-off of 1∶150 NIPT as contingent testing detects slightly fewer DS cases, has fewer procedure-related miscarriages, and costs the same as current DS screening (around UK£280,000) at a cost of £500 per NIPT. As first-line testing NIPT detects more DS cases, has fewer procedure-related miscarriages, and is more expensive than current screening at a cost of £50 per NIPT. When NIPT uptake increases, NIPT detects more DS cases with a small increase in procedure-related miscarriages and costs.

CONCLUSIONS

NIPT is currently available in the private sector in the UK at a price of £400-£900. If the NHS cost was at the lower end of this range then at a screening risk cut-off of 1∶150 NIPT as contingent testing would be cost neutral or cost saving compared with current DS screening. As first-line testing NIPT is likely to produce more favourable outcomes but at greater cost. Further research is needed to evaluate NIPT under real world conditions.

Non-invasive prenatal screening for trisomy 21: what women want and are willing to pay

OBJECTIVE

To investigate the attitude among pregnant women regarding non-invasive prenatal testing (NIPT) for detecting trisomy 21 (T21) and to quantify their willingness to pay for NIPT.

METHODS

A questionnaire was administered to pregnant women who received counselling for first-trimester screening (FTS) in two hospitals and nine midwife practices in the Netherlands.

RESULTS

A total of 147 women completed the questionnaire, yielding a response rate of 43%. If NIPT for detecting T21 were available, 81% stated they would choose to have this test, and 57% of women who elected not to undergo FTS in their current pregnancy would perform NIPT if available. Willingness to pay for NIPT was correlated with age and income, but not education level. The price that participants were willing to pay for NIPT was similar to the current price for FTS.

CONCLUSION

The pregnant women in our study had a positive attitude regarding NIPT for T21, and more than half of the women who rejected prenatal screening would receive NIPT if available.

PRACTICE IMPLICATIONS

Due to the elimination of iatrogenic miscarriage, caregivers should be aware that informed decision-making can change with respect to prenatal screening with the introduction of NIPT.

Caregivers' reported functional limitations in activities of daily living among middle-aged adults with intellectual disabilities

This study was conducted to describe the functioning of Activities of Daily Living (ADL) and to examine socio-economic effects on ADL functioning among adults with intellectual disabilities (ID) aged 45 years and older (N=480) in Taiwan. The Barthel Index (BI) was used to determine a baseline level of ADL functioning in the study participants. There are five categories of functional impairment using the following cut-off values in Taiwan: total dependence (BI score 0-20), severe (BI score 21-60), moderate (BI score 61-90), mild (BI score 91-99), and total independence (BI score 100) (Taiwan Department of Health, 2012). The results revealed that 2.3% of adults with ID were in total dependence, 11.9% were in severe dependence, 27.9% were in moderate dependence, 8.1% had a mild dependence, and 49.8% were totally independent. In the multiple linear regression model of the ADL score, we determined that educational level, comorbid Down's syndrome, and disability level are the variables able to significantly predict ADL score (R(2)=0.190) after controlling for the factors of age, marital status, and other comorbidity conditions. Those ID adults with a lower education level (primary vs. literate, β=4.780, p=0.031; intermediate vs. literate, β=6.642, p=0.030), with comorbid Down's syndrome (β=-7.135, p=0.063), and with a more severe disability condition (severe vs. mild, β=-7.650, p=0.007; profound vs. mild, β=-19.169, p<0.001) had significantly lower ADL scores. The present study highlights the need to support mobility in older adults with ID as much as possible to optimize independence in this group.

Health care in adults with Down syndrome: a longitudinal cohort study

BACKGROUND

Individuals with Down syndrome increasingly survive into adulthood, yet little is known about their healthcare patterns as adults. Our study sought to characterise patterns of health care among adults with Down syndrome based on whether they had fully transitioned to adult-oriented providers by their inception in this cohort.

METHODS

In this retrospective observational cohort study, healthcare utilisation and annualised patient charges were evaluated in patients with Down syndrome aged 18-45 years who received care in a single academic health centre from 2000 to 2008. Comparisons were made based on patients' provider mix (only adult-focused or 'mixed' child- and adult-focused providers).

RESULTS

The cohort included 205 patients with median index age = 28 years; 52% of these adult patients had incompletely transitioned to adult providers and received components of their care from child-focused providers. A higher proportion of these 'mixed' patients were seen exclusively by subspecialty providers (mixed = 81%, adult = 46%, P < 0.001), suggesting a need for higher intensity specialised services. Patients in the mixed provider group incurred higher annualised charges in analyses adjusted for age, mortality, total annualised encounters, and number of subspecialty disciplines accessed. These differences were most pronounced when stratified by whether patients were hospitalised during the study period (e.g., difference in adjusted means between mixed versus adult provider groups: $571 without hospitalisation, $19,061 with hospitalisation).

CONCLUSIONS

In this unique longitudinal cohort of over 200 adults aged 18-45 years with Down syndrome, over half demonstrated incomplete transition to adult care. Persistent use of child-focused care, often with a subspecialty emphasis, has implications for healthcare charges. Future studies must identify reasons for distinct care patterns, examine their relationship with clinical outcomes, and evaluate which provider types deliver the highest quality care for adults with Down syndrome and a wide variety of comorbidities.

Racial/ethnic differences in hospital use and cost among a statewide population of children with Down syndrome

Children with Down syndrome (DS) use hospital services more often than children without DS, but data on racial/ethnic variations are limited. This study generated population-based estimates of hospital use and cost to 3 years of age by race/ethnicity among children with DS in Massachusetts using birth certificates linked to birth defects registry and hospital discharge data from 1999 to 2004. Hospital use (≥ 1 post-birth hospitalization and median days hospitalized birth and post-birth) and reasons for hospitalization were compared across maternal race/ethnicity using relative risk (RR) and Wilcoxon rank sums tests, as appropriate. Costs were calculated in 2011 United States dollars. Greater hospital use was observed among children with DS with Hispanic vs. Non-Hispanic White (NHW) mothers (post-birth hospitalization: RR 1.4; median days hospitalized: 20.0 vs. 11.0, respectively). Children with DS and congenital heart defects of Non-Hispanic Black (NHB) mothers had significantly greater median days hospitalized than their NHW counterparts (24.0 vs. 16.0, respectively). Respiratory diagnoses were listed more often among children with Hispanic vs. NHW mothers (50.0% vs. 29.1%, respectively), and NHBs had more cardiac diagnoses (34.1% vs. 21.5%, respectively). The mean total hospital cost was nine times higher among children with DS ($40,075) than among children without DS ($4053), and total costs attributable to DS were almost $18 million. Median costs were $22,781 for Hispanics, $18,495 for NHBs, and $13,947 for NHWs. Public health interventions should address the higher rates of hospital use and hospitalizations for respiratory and cardiac diseases among racial/ethnic minority children with DS in Massachusetts.

Hospitalizations and mortality in the United States for adults with Down syndrome and congenital heart disease

Congenital heart disease (CHD) is common in patients with Down syndrome (DS), and these patients are living longer lives. The aim of this study was to describe the epidemiology of hospitalizations in adults with DS and CHD in the United States. Hospitalizations from 1998 to 2009 for adults aged 18 to 64 years with and without DS with CHD diagnoses associated with DS (atrioventricular canal defect, ventricular septal defect, tetralogy of Fallot, and patent ductus arteriosus) were analyzed using the Nationwide Inpatient Sample. Outcomes of interest were (1) in-hospital mortality, (2) common co-morbidities, (3) cardiac procedures, (4) hospital charges, and (5) length of stay. Multivariate modeling adjusted for age, gender, CHD diagnosis, and co-morbidities. There were 78,793 ± 2,653 CHD admissions, 9,088 ± 351 (11.5%) of which were associated with diagnoses of DS. The proportion of admissions associated with DS (DS/CHD) decreased from 15.2 ± 1.3% to 8.5 ± 0.9%. DS was associated with higher in-hospital mortality (odds ratio [OR] 1.8, 95% confidence interval [CI] 1.4 to 2.4), especially in women (OR 2.4, 95% CI 1.7 to 3.4). DS/CHD admissions were more commonly associated with hypothyroidism (OR 7.7, 95% CI 6.6 to 9.0), dementia (OR 82.0, 95% CI 32 to 213), heart failure (OR 2.2, 95% CI 1.9 to 2.5), pulmonary hypertension (OR 2.5, 95% CI 2.2 to 2.9), and cyanosis or secondary polycythemia (OR 4.6, 95% CI 3.8 to 5.6). Conversely, DS/CHD hospitalizations were less likely to include cardiac procedures or surgery (OR 0.3, 95% CI 0.2 to 0.4) and were associated with lower charges ($23,789 ± $1,177 vs $39,464 ± $1,371, p <0.0001) compared to non-DS/CHD admissions. In conclusion, DS/CHD hospitalizations represent a decreasing proportion of admissions for adults with CHD typical of DS; patients with DS/CHD are more likely to die during hospitalization but less likely to undergo a cardiac procedure.

Genetic testing in the European Union: does economic evaluation matter?

OBJECTIVE

We review the published economic evaluation studies applied to genetic technologies in the EU to know the main diseases addressed by these studies, the ways the studies were conducted and to assess the efficiency of these new technologies. The final aim of this review was to understand the possibilities of the economic evaluations performed up to date as a tool to contribute to decision making in this area.

METHODS

We have reviewed a set of articles found in several databases until March 2010. Literature searches were made in the following databases: PubMed; Euronheed; Centre for Reviews and Dissemination of the University of York-Health Technology Assessment, Database of Abstracts of Reviews of Effects, NHS Economic Evaluation Database; and Scopus. The algorithm was "(screening or diagnosis) and genetic and (cost or economic) and (country EU27)". We included studies if they met the following criteria: (1) a genetic technology was analysed; (2) human DNA must be tested for; (3) the analysis was a real economic evaluation or a cost study, and (4) the articles had to be related to any EU Member State.

RESULTS

We initially found 3,559 papers on genetic testing but only 92 articles of economic analysis referred to a wide range of genetic diseases matched the inclusion criteria. The most studied diseases were as follows: cystic fibrosis (12), breast and ovarian cancer (8), hereditary hemochromatosis (6), Down's syndrome (7), colorectal cancer (5), familial hypercholesterolaemia (5), prostate cancer (4), and thrombophilia (4). Genetic tests were mostly used for screening purposes, and cost-effectiveness analysis is the most common type of economic study. The analysed gene technologies are deemed to be efficient for some specific population groups and screening algorithms according to the values of their cost-effectiveness ratios that were below the commonly accepted threshold of 30,000€.

CONCLUSIONS

Economic evaluation of genetic technologies matters but the number of published studies is still rather low as to be widely used for most of the decisions in different jurisdictions across the EU. Further, the decision bodies across EU27 are fragmented and the responsibilities are located at different levels of the decision process for what it is difficult to find out whether a given decision on genetic tests was somehow supported by the economic evaluation results.

Down syndrome-associated periodontitis: a critical review of the literature

Down syndrome, or trisomy 21 (T21), was first described by John Langdon Down in 1866. Down identified the phenotypic expression of patients with circulation and coordination problems as having Down syndrome. More than a century later, Jerome Lejeune hypothesized that nondysjunction during meiosis could lead to trisomy of the 21st chromosome. The incidence of T21 is one in 800 to 1,000 live births in the United States. Generally, these patients now live to age 50 and some to age 60. As life expectancy increases, medical and social costs garner greater attention. Also, societal changes have allowed for better quality of life. Dental practitioners are challenged by the high incidence of early onset aggressive periodontal disease in T21; these patients have higher levels of periodontal pathogens and periodontitis-associated interproximal bone loss. The complex anatomy, physiology, immunology, and microbiology underscore the need for further investigation in specific areas related to dental treatment of these patients. This article is a critical review of the periodontal research concerning T21. Creating awareness enables dental professionals who have the power and knowledge to appropriately address the needs of those affected by T21.

The choice of detecting Down syndrome: does money matter?

The prenatal diagnosis of Down syndrome (amniocentesis) presents parents with a complex dilemma which requires comparing the risk of giving birth to an affected child and the risk of losing an unaffected child through amniocentesis-related miscarriage. Building on the specific features of the French Health insurance system, this paper shows that variation in the monetary costs of the diagnosis procedure may have a very significant impact on how parents solve this ethical dilemma. The French institutions make it possible to compare otherwise similar women facing very different reimbursement schemes and we find that eligibility to full reimbursement has a largely positive effect on the probability of taking an amniocentesis test. By contrast, the sole fact of being labelled 'high-risk' by the Health system seems to have, as such, only a modest effect on subsequent choices. Finally, building on available information on post-amniocentesis outcomes, we report new evidence suggesting that amniocentesis increases the risk of premature birth and low weight at birth.

Cost of hospitalization and length of stay in people with Down syndrome: evidence from a national hospital discharge claims database

The present paper aims to describe the hospitalization profiles which include medical expenses and length of stays, and to determine their possible influencing factors of hospital admission on persons with Down syndrome in Taiwan. We employed a population-based, retrospective analyses used national health insurance hospital discharge data of the year 2005 in this study. Subject inclusion criteria included residents of Taiwan, and diagnosed with Down syndrome (ICD code is 758.0; N=375). Inpatient records included personal characteristics, admissions, length of stay, and medical expenses of study subjects. The results found that Down syndrome patients used 2 hospital admissions and their annual length of stay in hospital was 22.26 days, and the mean medical cost of admissions was 143,257 NT$. The admission figures show that Down syndrome individuals used two times of hospital days and nearly three times of medical expenses comparing to the general population in Taiwan. Finally, the multiple regression models revealed that factors of age, hold a serious illness card, low income family member, frequency of hospital admission, high medical expense user were more likely to use longer inpatient days (R2=0.36). Annual inpatient expense of people with Down syndrome was significantly affected by factors of severe illness card holder, low income family member, frequency of hospital admission and longer hospital stays (R2=0.288). Based on these findings, we suggest the further study should focus on the effects of medical problems among persons with Down syndrome admitted for hospital care is needed.

Comparison of different strategies in prenatal screening for Down's syndrome: cost effectiveness analysis of computer simulation

OBJECTIVES

To assess and compare the cost effectiveness of three different strategies for prenatal screening for Down's syndrome (integrated test, sequential screening, and contingent screenings) and to determine the most useful cut-off values for risk.

DESIGN

Computer simulations to study integrated, sequential, and contingent screening strategies with various cut-offs leading to 19 potential screening algorithms.

DATA SOURCES

The computer simulation was populated with data from the Serum Urine and Ultrasound Screening Study (SURUSS), real unit costs for healthcare interventions, and a population of 110 948 pregnancies from the province of Québec for the year 2001.

MAIN OUTCOME MEASURES

Cost effectiveness ratios, incremental cost effectiveness ratios, and screening options' outcomes.

RESULTS

The contingent screening strategy dominated all other screening options: it had the best cost effectiveness ratio ($C26,833 per case of Down's syndrome) with fewer procedure related euploid miscarriages and unnecessary terminations (respectively, 6 and 16 per 100,000 pregnancies). It also outperformed serum screening at the second trimester. In terms of the incremental cost effectiveness ratio, contingent screening was still dominant: compared with screening based on maternal age alone, the savings were $C30,963 per additional birth with Down's syndrome averted. Contingent screening was the only screening strategy that offered early reassurance to the majority of women (77.81%) in first trimester and minimised costs by limiting retesting during the second trimester (21.05%). For the contingent and sequential screening strategies, the choice of cut-off value for risk in the first trimester test significantly affected the cost effectiveness ratios (respectively, from $C26,833 to $C37,260 and from $C35,215 to $C45,314 per case of Down's syndrome), the number of procedure related euploid miscarriages (from 6 to 46 and from 6 to 45 per 100,000 pregnancies), and the number of unnecessary terminations (from 16 to 26 and from 16 to 25 per 100,000 pregnancies).

CONCLUSIONS

Contingent screening, with a first trimester cut-off value for high risk of 1 in 9, is the preferred option for prenatal screening of women for pregnancies affected by Down's syndrome.

Inequalities in provision of the Disability Living Allowance for Down syndrome

OBJECTIVES

To assess factors associated with granting of the Disability Living Allowance (DLA) for Down syndrome.

DESIGN

Cross-sectional survey.

SETTING

Families with a child with Down syndrome enrolled in a community-based trial of vitamin supplementation.

PARTICIPANTS

156 children with trisomy 21 (59% male, 20% non-white) were enrolled before 7 months of age and 138 completed follow-up.

MAIN OUTCOME MEASURES

Before the child was 2 years old, we surveyed parents about applications for the DLA and socioeconomic factors, and assessed the child's development.

RESULTS

Application for the DLA was not associated with ethnicity or speaking English. Significantly fewer ethnic minority parents (OR = 0.10; 95% CI 0.03 to 0.35; 69% vs 96%, risk difference 27%) and parents with English as a second language (OR = 0.15: 95% CI 0.04 to 0.62; 67% vs 93%, risk difference 26%) were granted the DLA. Amongst those granted the DLA, ethnic minority families were significantly less likely to be granted a higher monetary award (OR = 0.19; 95% CI 0.06 to 0.55). Severity of disability, reflected by quartile of Griffiths Developmental Quotient or the presence of severe cardiac disease requiring surgery, was not associated with application, granting or level of the DLA award.

CONCLUSIONS

Although all children with Down syndrome meet some of the criteria for the DLA, only 80% were receiving this benefit. The decision to award the DLA and the monetary level of the award favoured white, English speaking parents and was not related to severity of disability. Routine monitoring of awards by ethnicity and language spoken is needed.

TRIAL REGISTRATION NUMBER

NCT00378456.

Costs of NHS maternity care for women with multiple pregnancy compared with high-risk and low-risk singleton pregnancy

OBJECTIVE

To compare antenatal and obstetric costs for multiple pregnancy versus singleton pregnancy risk groups and to identify factors driving cost differentials.

DESIGN

Observational study over 15 months (2001-02).

SETTING

Four district hospitals in southeast England.

POPULATION

Consecutive women with multiple pregnancy and singleton women with risk factors for fetal congenital heart disease (CHD) (pregestational diabetes, epilepsy, or family history of CHD) or Down syndrome, and a sample of low-risk singleton women.

METHODS

Clinical care was audited from the second trimester anomaly scan until postnatal discharge, and the resource items were costed. Multiple regression analysis determined predictors of costs.

MAIN OUTCOME MEASURES

NHS mean costs of antenatal and obstetric care for different types of pregnancy.

RESULTS

A total of 959 pregnancies were studied. Three percent of 243 women with multiple pregnancy reached 40 weeks of gestation compared with 54-55% of 163 low-risk and 322 Down syndrome risk women and 36% of 231 cardiac risk women. Antenatal costs for cardiac risk (1,153 pounds sterling) and multiple pregnancy (1,048 pounds sterling) were nearly double the costs for other two groups (P < 0.001). As 63% of multiple births were delivered by caesarean section, the obstetric cost for multiple pregnancy (3,393 pounds sterling) was 1,000 pounds sterling greater overall. Pregestational diabetes was the most influential factor driving singleton costs, resulting in similar total costs for multiple pregnancy women (4,442 pounds sterling) and for women with diabetes (4,877 pounds sterling).

CONCLUSIONS

Our analyses confirm that multiple pregnancies are substantially more costly than most singleton pregnancies. Identifying women with diabetes as equally costly is pertinent because of the findings of the Confidential Enquiry into Maternal and Child Health that standards of maternal care for diabetics often are inadequate.

Cross-trimester marker ratios in prenatal screening for Down syndrome

OBJECTIVE

To examine the performance of Integrated Down syndrome screening (first- and second-trimester measurements integrated into a single screening test) when ratios of the levels of the same serum markers measured in both these trimesters (cross-trimester ratios) are added as new screening markers.

METHODS

Using data from Serum Urine and Ultrasound Screening Study (SURUSS), second-trimester concentrations (in multiples of the median, or MoM) of pregnancy associated plasma protein A (PAPP-A), alphafetoprotein (AFP), unconjugated oestriol (uE(3)), human chorionic gonadotrophin (hCG) (free beta and total), and inhibin-A were divided by the first-trimester concentration to obtain a cross-trimester (CT) ratio for each analyte in 74 Down syndrome and 492 unaffected pregnancies. We identified CT ratios that improved screening performance and then, using Monte Carlo simulations, estimated the efficacy and cost effectiveness of adding them to the Integrated and serum Integrated tests.

RESULTS

All the median CT ratios differed significantly between Down syndrome and unaffected pregnancies. Setting the Integrated test to achieve a 90% detection rate, the false-positive rate (FPR) was 0.7% with CT ratios for PAPP-A, uE(3), inhibin-A, and total hCG compared with 2.2% without CT ratios, a reduction of about two-thirds. Using the serum Integrated test to achieve the same 90% detection rate and the first-trimester measurements made at 11 completed weeks of pregnancy, the corresponding FPRs were 2.4 and 8.1%, a similar proportional reduction. The AFP CT ratio had little effect on screening performance. Using CT ratios did not increase the cost per Down syndrome pregnancy detected.

CONCLUSION

The addition of CT ratios to an Integrated test substantially improves the efficacy and safety of prenatal screening for Down syndrome. It is cost effective and could be usefully introduced into screening programmes.

Sequential and contingent prenatal screening for Down syndrome

OBJECTIVE

To compare the Integrated test in three policies for prenatal Down syndrome screening: Integrated screening for all women, sequential screening (first-trimester tests allowing early completion of screening for high-risk pregnancies), and Contingent screening (early completion of screening for high- and low-risk pregnancies).

DESIGN AND METHODS

Estimation of detection rates (DRs) and false-positive rates (FPRs) using Monte Carlo simulation and cost effectiveness for each method.

SETTING AND POPULATION

Down syndrome affected and unaffected pregnancies studied in the Serum Urine and Ultrasound Screening Study (SURUSS). RESULTS AND MAIN OUTCOMES: Integrated screening has the best screening performance. The performance of the other two policies approached that of Integrated screening as the first-trimester test FPR decreased. If the first-trimester FPR is set to 0.5% (risk >or= 1 in 30) with an overall DR of 90%, sequential and contingent screening yield overall FPRs of 2.25% and 2.42%, respectively, and 66% of the affected pregnancies are detected by the first-trimester test. The Integrated test on all women yields an FPR of 2.15%. With sequential screening, 99.5% of women would proceed to an Integrated test, or 30% with contingent screening if those with first-trimester test risks of <or=1 in 2000 are classified screen-negative and receive no further testing. About 20% of affected pregnancies identified in the first trimester using sequential or contingent screening would have unnecessary terminations (they would miscarry before the early second trimester). Contingent screening is the most cost-effective if there is no alphafetoprotein screening for neural tube defects, otherwise Integrated screening is more cost-effective.

CONCLUSIONS

Integrated screening for all women is the simplest, most effective, and the safest policy. Contingent screening is the most complex with the lowest screening performance. Making an earlier diagnosis with sequential and contingent screening has adverse consequences that are sufficient to discourage their use.

First trimester screening: economic implications

The implementation of new strategies for the detection of Down syndrome will have economic implications. These economic considerations must be considered before implementation, since resources are limited and health care costs in the Unites States are soaring. Economic analyses of prenatal diagnosis have unique challenges that must be considered. Most analyses include only direct medical costs, ignoring indirect and intangible costs.

The cost effectiveness of prenatal ultrasound screening for trisomy 21

Objectives: The cost-effectiveness of opportunistic nuchal translucency ultrasound screening in pregnancy was compared with alternative screening strategies for trisomy 21 in Australia.

Methods: A decision analytic model was used of various pregnancy screening strategies based on a systematic review of the literature on the effectiveness of nuchal translucency ultrasound and serum screening and costs based on current reimbursement fees. The model included the likelihood and cost of terminations after diagnostic testing and the associated risk of fetal loss. All prices are in 2001 Australian dollars.

Results: With a twenty percentage point difference in detection rate, the incremental cost for a combination of nuchal translucency and serum screening with age in the first trimester compared with maternal serum screening in the second trimester was $105,484 per extra case detected and $374,779 per live trisomy 21 birth avoided. Serum screening in the second trimester had an incremental cost per extra case detected of between $61,700 and $117,100 per extra live birth avoided when compared with no screening.

Conclusions: The cost-effectiveness of ultrasound screening for trisomy 21 would appear to be more attractive if it were done at the same time as current dating ultrasound. Any funding mechanism for screening should take this strategy into account by incorporating, as far as possible, provision of nuchal translucency screening into existing services provided in early pregnancy.

SURUSS in perspective

BACKGROUND

Until the publication of the Serum Urine and Ultrasound Screening Study (SURUSS) report, it was difficult to compare the different antenatal screening tests for Down's Syndrome because of variations in study designs. We here present the main results from SURUSS, updated to take account of recent information on nuchal translucency in Down's Syndrome pregnancies, and discuss their implications.

METHODS

SURUSS was a prospective study of 47,053 singleton pregnancies (including 101 pregnancies with Down's Syndrome) conducted in 25 maternity units. Nuchal translucency measurements were taken. Serum and urine samples collected between 9 and 13 weeks, and again between 14 and 20 weeks of pregnancy were stored. Samples from each affected pregnancy and five matched controls were tested for currently used or suggested biochemical Down's Syndrome screening markers. Pregnancies were followed up to determine the presence or absence of Down's Syndrome. For an 85% Down's Syndrome detection rate, the false-positive rate for the Integrated test (nuchal translucency and pregnancy associated plasma protein-A [PAPP-A] at 11 completed weeks of pregnancy, and alpha-fetoprotein, unconjugated oestriol [uE(3)], free beta or total human chorionic gondaotrophin (hCG) and inhibin-A in the early second trimester) was 0.9%, the Serum integrated test (without nuchal translucency) 2.7%, the Combined test (nuchal translucency with free beta-hCG and PAPP-A at 11 weeks) 4.3%, the Quadruple test (alpha-fetoprotein, uE(3), free beta or total hCG and inhibin-A) 6.2%, and nuchal translucency at 11 weeks, 15.2%. All tests included maternal age. Using the Integrated test at an 85% detection rate, there would be six diagnostic procedure-related unaffected fetal losses following amniocentesis per 100,000 women screened compared with 35 using the Combined test or 45 with the Quadruple test.

CONCLUSIONS

The Integrated test offers the most effective and safe method of screening for women who attend in the first trimester. The next best test is the Serum integrated test. The Quadruple test is the best test for women who first attend in the second trimester. There is no justification for retaining the Double (alpha-fetoprotein and hCG) or Triple (alpha-fetoprotein, uE(3), and hCG) tests, or nuchal translucency alone (with or without maternal age) in antenatal screening for Down's Syndrome.

Improving population health or the population itself? Health technology assessment and our genetic future

The province of British Columbia (BC), Canada is developing its first population-wide prenatal genetic screening program, known as triple-marker screening (TMS). TMS, initiated with a simple blood test, is most commonly used to screen for fetuses with the chromosomal abnormality known as Down syndrome or neural tube disorders. Women testing TMS-positive are offered diagnostic amniocentesis and, if the diagnosis is confirmed, selective second-trimester abortion. The project described in this study was initiated to address the broad range of issues arising from this testing technology and provides an example of the new type of health technology assessment (HTA) contribution emerging (and likely to become increasing necessary) in health policy development. With the advent of prenatal genetic screening programs, would-be parents gain the promise of identifying target conditions and, hence, the option of selective abortion of affected fetuses. There is considerable awareness that these developments pose challenges in every dimension (ethical, political, economic, and clinical) of the health-care environment. In the effort to construct an appropriate prenatal screening policy, therefore, administrators have understandably sought guidance from within the field of HTA. The report authors concluded that, within the restricted path open to it, the role of government is relatively clear. It has the responsibility to maintain equal access to prenatal testing, as to any other health service. It should also require maintenance of medical standards and evaluation of program performance. At the same time, policy-makers need actively to support those individuals born with disabilities and their families.

Genetic sonography: an option for women of advanced maternal age with negative triple-marker maternal serum screening results

OBJECTIVE

To determine whether offering genetic sonography to patients 35 years of age and older with negative maternal serum triple-marker screening results will result in an increase in the detection rate of trisomy 21.

METHODS

The detection rate of trisomy 21 was determined in women 35 years of age and older whose pregnancies were managed according to the following 3 policies: policy I, universal amniocentesis; policy II, maternal serum triple-marker screening followed by amniocentesis only in high-risk women (risk >1:190); and policy III, genetic sonography in women with negative maternal serum screening results (policy II). Policy III included the offering of genetic amniocentesis to patients with abnormal genetic sonographic findings. The rate of acceptance of genetic amniocentesis was modeled, as was the sensitivity (50%-90%) and false-positive rate (5%-25%) of genetic sonography.

RESULTS

The number of fetuses expected to have trisomy 21 was 784. For patients evaluated under policy II, 86.3% of fetuses with trisomy 21 were detected. On the basis of the detection rate for trisomy 21 of policy II, the addition of fetuses with trisomy 21 identified under policy III was significantly (P < .01) increased (93.2% to 98.6%) for genetic sonographic sensitivities ranging between 50% and 90%.

CONCLUSIONS

A policy of offering genetic sonography followed by amniocentesis to patients 35 years of age and older who originally had triple-marker maternal serum screening findings that were negative for the diagnosis of trisomy 21 results in a higher overall detection rate of trisomy 21.

Is genetic ultrasound cost-effective?

During the past 10 years, investigators have reported studies examining the potential of second-trimester genetic sonography to identify fetuses at risk for trisomy 21. The consensus among most investigators is that genetic sonography offers an alternative to universal amniocentesis in high-risk women and lowers the loss rate of normal fetuses subjected to amniocentesis because of risk factors associated with advanced maternal age or abnormal maternal-serum screening. Although there is now consensus that genetic sonography may be a useful screening tool, there has been a paucity of data regarding its cost-effectiveness. In this review, 3 studies are examined and cost-effectiveness of genetic sonography evaluated. The first study compared genetic sonography and universal amniocentesis and found that genetic sonography was cost-effective if the sensitivity is 75% or higher, resulted in a savings to the healthcare system of 9%, and decreased the loss rate of normal fetuses following amniocentesis by 87%. The second study examined the use of genetic sonography in women less than 35 years of age who underwent maternal-serum triple-marker serum screening. Women who were screen negative but who were classified as moderate risk for trisomy 21 (risk 1:191 to 1:1,000) were offered genetic sonography. Amniocentesis was offered only if the genetic sonogram was abnormal. The study demonstrated that the use of genetic sonography in this group of patients increased the detection rate of trisomy 21, was cost effective, and was a safe procedure. The third study examined the use of genetic sonography in women 35 years of age and older who declined amniocentesis following second-trimester genetic counseling. Genetic sonography was offered to this group of patients followed by amniocentesis if an abnormal ultrasound finding was present. The data were analyzed for various acceptance rates of amniocentesis by the patient when informed of the ultrasound findings. Examination of the data demonstrated this approach increased the detection rate of trisomy 21, was cost-effective, and was a safe procedure. In conclusion, genetic sonography when applied in the above clinical settings is cost-effective, results in a higher detection rate of trisomy 21, and is safe procedure.

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

OBJECTIVE

The purpose of this study was to compare the cost-effectiveness of combined first-trimester screening for fetal Down syndrome with second-trimester maternal serum triple screening.

STUDY DESIGN

A first-trimester screening approach that used nuchal translucency measurement and maternal serum screening was evaluated against second-trimester maternal serum triple screening in a hypothetic population. Screening sensitivities and screen-positive rates were 91% and 5% for the first-trimester approach and 70% and 7.5% for the second-trimester approach, respectively. The costs of fetal Down syndrome, live-born Down syndrome cost, and total costs (screening plus live-born costs) were calculated for each screening program.

RESULTS

First-trimester screening was associated with lower screening and live-born Down syndrome costs versus second-trimester serum screening. Total Down syndrome screening costs were 29.1% lower with first-trimester screening.

CONCLUSION

In this hypothetic model, combined first-trimester screening for fetal Down syndrome was more cost-effective than universal second-trimester triple serum screening.

Parental responsibility and the morality of selective abortion

It is now a common opinion in Western countries that a child's impairment would probably place an unexpected burden on her parents, a burden that the parents have not committed themselves to dealing with. Therefore, selective abortion is in general a morally justified option for the parents. I argue that this view is based on biased information about the quality of life of individuals with impairments and their families. Also, a conscious decision to procreate should bring about conscious assent to assuming obligations as a parent. This implies a duty of caring for any kind of child. Consequently, if the child's condition is not such that it would make its life not worth living, and if the parents live in an environment where they are not able to provide their child and themselves an adequate well-being, they do not have a morally sufficient reason to terminate the pregnancy on the grounds of fetal abnormality.

Genetic sonography: a cost-effective method for evaluating women 35 years and older who decline genetic amniocentesis

OBJECTIVE

To determine whether offering genetic sonography to patients who decline invasive testing can increase the detection rate of trisomy 21 and is cost-effective.

METHODS

The detection rate of trisomy 21, the number of pregnancy losses after amniocentesis, and the cost of detecting a single fetus with trisomy 21 were determined in women 35 years and older managed according to the following 3 policies: (1) universal amniocentesis, (2) genetic counseling for maternal age-associated risks for trisomy 21 followed by amniocentesis in patients who elected it, and (3) genetic counseling followed by genetic sonography in patients who originally declined genetic amniocentesis.

RESULT

From a population of 40,143 women 35 years and older, the expected number of trisomy 21 fetuses was 349. After genetic counseling, 32% of patients declined invasive testing, resulting in detection of 70% of fetuses with trisomy 21. For universal amniocentesis, the cost to detect 1 fetus with trisomy 21 was $138,036. For the 32% who declined invasive testing after genetic counseling and underwent genetic sonography, the cost to detect a single fetus with trisomy 21 was a function of sensitivity and the screen-positive rate. For screen-positive rates between 5% and 25%, genetic sonography resulted in a cost savings between 14.3% and 18.8% when compared with universal invasive testing and resulted in a considerable increase in detection of fetuses with trisomy 21 (77% to 97%).

CONCLUSIONS

A policy of offering genetic sonography followed by amniocentesis to patients 35 years and older who originally decline invasive testing for the diagnosis of trisomy 21 is cost-effective and results in a higher overall detection rate for trisomy 21 without an increased risk of pregnancy loss.

Down's syndrome: cost, quality and value of life

Routine prenatal screening is based on the assumption that it is reasonable for prospective parents to choose to prevent a life with Down's syndrome. This paper questions whether Down's syndrome necessarily involves the costs, limitations and suffering which are assumed in the prenatal literature, and examines the lack of evidence about the value and quality of life with Down's syndrome. Tensions between the aims of prenatal screening policies to support women's personal choices, prevent distress, and reduce the suffering and costs of disability, versus the inadvertent effects of screening which can undermine these aims, are considered. Strengths and weaknesses in medically and socially based models of research about disability, and their validity and reliability are reviewed. From exploratory qualitative research with 40 adults who have congenital conditions which are tested for prenatally, interviews with five adults with Down's syndrome are reported. Interviewees discuss their relationships, education and employment, leisure interests, hopes, aspects of themselves and of society they would like to change, and their views on prenatal screening. They show how some people with Down's syndrome live creative, rewarding and fairly independent lives, and are not inevitably non-contributing dependents. Like the other 35 interviewees, they illustrate the importance of social supports, and their problems with excluding attitudes and barriers. Much more social research with people who have congenital conditions is required, if prenatal screening policies and counselling are to be evidence based.

Recent economic evaluations of antenatal screening: a systematic review and critique

A systematic review of recent economic evaluations of antenatal screening was conducted. Relevant studies were identified from a number of sources including computerised databases, bibliographies of economic evaluations, and searches of unpublished manuscripts. Each study identified by the literature searches was categorised on the basis of its title and abstract. Studies considered relevant to the systematic review were obtained from libraries. The methodology, results, and policy implications of studies categorised as economic evaluations upon full review were documented. A total of 566 studies were identified by the literature searches, 41 of which were categorised as economic evaluations upon full review. The economic evaluations covered a range of antenatal screening practices, aimed mainly at the prevention of infectious diseases and fetal anomalies. The review highlighted the poor methodological quality of the bulk of economic evaluations of antenatal screening. The study design, data collection methods, and analysis and interpretation of results frequently violated methodological guidelines adopted by health economists. The review also highlighted the narrow definition of benefits adopted by this body of literature, with most studies reporting outcomes in terms of cases detected, cases of particular disorders prevented or, most often, costs averted. The conclusions arrived at differed by area of antenatal screening. There appeared to be clear economic arguments in favour of some forms of antenatal screening, for example, triple test screening for Down's syndrome. Other economic evaluations pertained to specific locations, which suggests that the results may not necessarily be generalizable to different settings. For all areas of antenatal screening, an updating of published economic evaluations may be required to account for evolving economic, epidemiological, and clinical effectiveness evidence.

Cost and effectiveness of the California triple marker prenatal screening program

PURPOSE

To report the utilization of services offered and pregnancy outcomes for a unique statewide prenatal triple marker screening program and to present a cost-benefit analysis. A state population of 32 million with considerable ethnic and age distribution and with a wide variety of delivery systems providing prenatal care was considered. The entire pregnant population who appeared for care before 20 weeks gestation, approximately one-half million per year during the years of 1995 to 1997, was included in the study.

METHODS

Mandatory offering of serum testing, using alpha-fetoprotein from 1986 to 1995, and the addition of human chorionic gonadotropin and unconjugated estriol in 1995, with systematic follow-up of serum screen positives with ultrasound and amniocentesis. This study collected and analyzed the program data and reports of outcomes and collected similar information from the birth defects registry.

RESULTS

Triple marker serum screening was accepted by 67.4% of the women eligible and yielded an initial positive rate of 7.3%. More than 90% of the initially screen positive pregnancies were seen at a prenatal diagnostic center. After correction of gestational age, 71.3% had amniocentesis. The overall amniocentesis rate among women screened was 2.6%. The Program's detection rate was predicted to be 85% for neural tube defects, and, based on Monte Carlo modeling, was theoretically calculated to be 62% for Down syndrome. In practice, detection rates were 75% for neural tube defects and 41% for Down syndrome due to lower than expected amniocentesis acceptance rate. Nevertheless, at a 5% discount rate, the screening program was cost beneficial at a ratio of 2.69:1. The cost per case detected was $35,365 and per case prevented was $110,741.

CONCLUSION

It is possible to implement a cost-effective population-based screening in compliance with quality standards in a diverse ethnic population with a variety of health-care providers. Triple marker screening in the second trimester is a cost beneficial program even if utilization of all services is less than ideal.

Down syndrome clinic in a semi-rural setting

We established a multidisciplinary clinic for Down syndrome patients and their families. Over a 20-month period, we saw 49 patients for a total of 79 patient visits. We were able to address health care, psychosocial, educational, and financial issues for these individuals with a diverse team of professionals and parent advocates. Some of these issues would probably not be identified during routine health care. The success of the clinic demonstrates the ability to establish such a venture in a semi-rural, nonacademic medical center setting.

Economic evaluation of prenatal screening for Down syndrome in the U.S.A

Maternal serum screening for Down syndrome involves biochemical tests such as alpha-fetoprotein (alpha FP), human chorionic gonadotrophin (hCG) and unconjugated oestriol (uE3), either alone or in combination, that have variable detection and false-positive rates. Choosing a screening protocol requires a trade-off between a desired detection rate and an acceptable false-positive rate. Selecting a screening protocol that maximizes the net benefit to society provides one approach. We have developed a general formula for calculating the per case net social benefit of a screening test and have applied it to United States data. The maximum net benefit associated with each of the various screening options currently available is estimated and the model is further applied to determine the conditions under which the addition of a new marker to an existing protocol can be justified. For each test, or combination of tests, optimal net benefits occur at different detection and false-positive rates. Net benefits are strongly and positively dependent on maternal age; high net benefits are associated with older patients and low, or even negative, net benefits with younger patients. Also, net benefits are affected by the term risk cut-off rate. For triple testing, the 1:351 Down syndrome term risk cut-off appears to provide a higher net benefit than that obtained with 1:250 or 1:300. The optimization of societal net benefit provides a powerful approach to evaluating screening strategies, but the policies used must also consider individuals' freedom in decision making at each step of the prenatal diagnosis pathway.

Choosing options for ultrasound screening in pregnancy and comparing cost effectiveness: a decision analysis approach

OBJECTIVE

To compare the cost effectiveness of different programmes of routine antenatal ultrasound screening to detect four key fetal anomalies: serious cardiac anomalies, spina bifida, Down's syndrome and lethal anomalies, using existing evidence.

DESIGN

Decision analysis was used based on the best data currently available, including expert opinion from the Royal College of Obstetricians and Gynaecologists, Working Party and secondary data from the literature, to predict the likely outcomes in terms of malformations detected by each screening programme.

SETTING

Results applicable in clinics, hospitals or GP practices delivering antenatal screening.

MAIN OUTCOME MEASURE

The number of cases with a 'target' malformation correctly detected antenatally.

RESULTS

There was substantial overlap between the cost ranges of each screening programme demonstrating considerable uncertainty about the relative economic efficiency of alternative programmes for ultrasound screening. The cheapest, but not the most effective, screening programme consisted of one second trimester ultrasound scan. The cost per target anomaly detected (cost effectiveness) for this programme was in the range 5,000 pound silver-109,000, pound silver but in any 1000 women it will also fail to detect between 3.6 and 4.7 target anomalies.

CONCLUSIONS

The range of uncertainty in the costs did not allow selection of any one programme as a clear choice for NHS purchasers. The results suggested that the overall allocation of resources for routine ultrasound screening in the UK is not currently economically efficient, but that certain scenarios for ultrasound screening are potentially within the range of cost effectiveness reached by other, possibly competing, screening programmes. The model highlighted the weakness of available evidence and demonstrated the need for more information both about current practice and costs.

The value of screening for Down's syndrome in a socioeconomically deprived area with a high ethnic population

OBJECTIVE

To assess the utility of biochemical antenatal screening for Down's syndrome in a socioeconomically deprived area with a high proportion of Asian women from the Indian Subcontinent.

DESIGN

Audit of Down's syndrome biochemical screening service over a four-year period.

SETTING

Teaching hospital and community antenatal clinic in inner city Birmingham.

POPULATION

Women booked between October 1992 and December 1996.

METHODS

Blood for screening was collected between 14 and 21 weeks gestation, alpha-fetoprotein and intact human chorionic gonadotrophin were measured in serum and the risk of Down's syndrome was calculated.

MAIN OUTCOME MEASURES

Uptakes of screening and amniocentesis, screen positive rate, odds of being affected given a positive result, miscarriages associated with amniocentesis offered following a high risk result, detection rate, number of Down's cases prevented and a cost analysis. Outcome measures were compared between Asians and Caucasians.

RESULTS

Overall 11,974 women (71%) accepted serum screening. The screen positive rate was 8.3% in Asians and 5.0% in Caucasians. The uptake of amniocentesis in women following a high risk result was 54% overall (35% Asian, 67% Caucasian). Nineteen cases of Down's syndrome were identified, of which 13 occurred in women who opted for biochemical screening. The detection rate of the biochemical screening programme was 85% (11/13). Of these 11 cases, six (none of whom were Asian) elected to have an amniocentesis, of whom four thereafter had a termination.

CONCLUSION

In this study the public health benefits of screening for Down's syndrome in a socioeconomically deprived area with a high Asian population, were small.

An economic evaluation of first-trimester genetic sonography for prenatal detection of Down syndrome

OBJECTIVE

To determine 1) the diagnostic accuracy requirements of first-trimester genetic sonography from the cost-benefit point of view and 2) the economic impact of first-trimester genetic sonography for the United States on the basis of the accuracy of previously published studies.

METHODS

A cost-benefit equation was developed on the basis of the hypothesis that the cost of chorionic villus sampling (CVS) in pregnant women with advanced maternal age (at least 35 years old) should be at least equal to the cost of genetic sonography with CVS used only for those with abnormal ultrasound results. The components of the equation included the diagnostic accuracy of genetic ultrasound (sensitivity and specificity for detecting Down syndrome), the costs of the CVS package and genetic ultrasound, and the lifetime cost of Down syndrome cases.

RESULTS

First-trimester genetic sonography was found to be beneficial if the overall sensitivity for detecting Down syndrome was greater than 70%, and even then, the cost-benefit ratio depended on the corresponding false-positive rate. The required minimum ultrasound sensitivity varied according to the maternal age-specific prevalence of Down syndrome and ranged between 40% (for women 35 years old) to 96% (for women 44 years old). Of eight published cohorts using nuchal translucency thickness for genetic sonography, five had accuracies of genetic ultrasound compatible with net benefits.

CONCLUSION

The benefits of first-trimester genetic sonography depend on its diagnostic accuracy. First-trimester genetic sonography has the potential for annual savings of 22 million dollars in the United States.

Marginal costs and benefits

Decision makers are interested in measuring the costs and benefits of various interventions, and sometimes they are presented with the average costs and benefits of alternative interventions and asked to compare these. Usually a newer intervention is being compared with an existing one, and the most appropriate comparison is not of average costs (and benefits) but of the extra--or marginal--costs (and benefits) of the new intervention. Reanalysis of the cost effectiveness ratio of biochemical screening of all women for Down's syndrome compared with age based screening shows that the marginal cost effectiveness of biochemical screening is 47,786 pounds, compared with an average cost effectiveness of 37,591 pounds. It may sometimes be difficult or costly to calculate marginal costs and benefits, but this should be done whenever possible.

[The triple test scenario for Styria. With data of the Styria Abnormalities Register]

OBJECTIVE

The aim of the study was to clarify by a cost-effectiveness analysis, if a triple-marker screening for trisomy 21 (triple test) should be established in Austria.

METHODS

The published triple-test results of the last years were combined with the data of the Styrian Malformation Register covering the years 1985-1992. The cost-effectiveness analysis was based on total costs of prenatal diagnosis, costs per fetus diagnosed as affected, the number of affected fetuses detected, and the number of procedure-related losses.

RESULTS

If low costs are given priority, the triple test should be offered to women 35 years of age or older. If a high detection rate is given top priority, the test should be offered to all pregnant women.

CONCLUSION

The results suggest that the present policy of maternal age screening in Austria should be replaced by maternal serum screening.

[Evaluation of the value of triple diagnosis in prenatal medicine]

The evaluation for every new method of early diagnostics is the criterion of quality of previous methods. The Triple diagnostics in the prenatal medicine however does not fulfill the criterion of standard for example for early diagnostics in gynecological oncology. Particularly, the precision in laboratories cannot be safely assumed so that false positive as well as false negative results are possible. The consequences of this method of early diagnostics are uncertainty for patients and physicians and of high expenditure for both.