How should costs and cost-effectiveness be considered in prenatal genetic testing?

Universal Tetanus-Diphtheria-Pertussis Vaccination During Pregnancy: A Cost-Effectiveness Analysis

OBJECTIVE

To assess the cost effectiveness of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccination in pregnant patients in the United States.

METHODS

A decision-analytic model in TreeAge was developed to compare universal Tdap vaccination in pregnancy with no Tdap vaccination in pregnancy using a theoretical cohort of 3.66 million pregnant individuals, the approximate number of deliveries per year in the United States. Outcomes included infant pertussis infections, infant hospitalizations, infant encephalopathy cases, infant deaths, and maternal pertussis infections. All probabilities and costs were derived from the literature. Utilities were applied to discounted life expectancies at a rate of 3% to generate quality-adjusted life-years (QALYs). A strategy was considered cost effective if it had an incremental cost-effectiveness ratio of less than $100,000 per QALY. Univariable and multivariable sensitivity analyses were performed to assess the robustness of the model to changes in the baseline assumptions.

RESULTS

With a baseline assumption of vaccine cost at $47.75, Tdap vaccination was cost effective at $7,601 per QALY. The vaccination strategy was associated with a decrease of 22 infant deaths, 11 infant encephalopathy cases, 2,018 infant hospitalizations, 6,164 infant pertussis infections, and 8,585 maternal pertussis infections, with an increase of 19,489 QALYs. In sensitivity analyses, the strategy was cost effective until the incidence of maternal pertussis became lower than 1.6 cases per 10,000 individuals, the cost of the Tdap vaccine was greater than $540, or previous pertussis immunity was present in more than 92.1% of pregnant individuals.

CONCLUSION

In a theoretical U.S. cohort of 3.66 million pregnant individuals, Tdap vaccination during pregnancy is cost effective and reduces infant morbidity and mortality compared with no vaccination during pregnancy. These findings are especially relevant given that approximately half of individuals are not vaccinated during pregnancy and recent data have shown that postpartum maternal vaccination and cocooning strategies are ineffective. Public health strategies to encourage greater uptake of Tdap vaccination should be used to reduce the morbidity and mortality of pertussis infection.

Patient attitudes toward prenatal diagnostic testing during antenatal care in an urban population

OBJECTIVE

Investigate factors that influence the decision to accept or decline diagnostic testing for pregnant women referred for genetic counseling.

METHODS

Cross sectional anonymous survey of pregnant women undergoing genetic counseling at a tertiary care referral center. Subjects' perceived risk of procedure related loss and fetal chromosomal problem were obtained via survey where patients rated risk from 0 (no risk) to 10 (highest risk).

RESULTS

There were no differences in sociodemographic factors between women undergoing a diagnostic procedure compared to those not undergoing a procedure. As the perceived risk for having a baby with genetic problem increased by one point, the estimated odds of having the diagnostic procedure increased by 43% controlling for the perceived risk of procedure related loss (p < .0001). Similarly, as the perceived risk of miscarriage increased by one point, the odds of having the diagnostic procedure decreased by 40%, controlling for the perceived risk of having a baby with a genetic problem (p < .0001). The main reason women cited for not undergoing a procedure was fear of procedure related loss.

CONCLUSIONS

Pregnant women that decline diagnostic testing have a higher perceived risk of procedure related loss and lower perceived risk of fetal chromosomal abnormality than those who accept.

Non-invasive cell-free fetal DNA testing for aneuploidy: multicenter study of 31 515 singleton pregnancies in southeastern China

OBJECTIVE

To analyze the non-invasive prenatal testing (NIPT) for aneuploidy results of 31 515 singleton pregnancies in Fujian province, southeastern China, and assess its performance in low-, moderate- and high-risk pregnancies.

METHODS

Women were categorized into groups according to whether their risk for fetal abnormality was low, moderate or high. Cell-free plasma DNA extracted from peripheral blood samples was subjected to low-coverage whole-genome sequencing. Standard Z-score analysis of the mapped sequencing reads was used to identify fetal aneuploidy, including the three main trisomies (T21, T18 and T13) and sex chromosome aneuploidy (SCA). NIPT-positive results were confirmed by amniocentesis and karyotyping. The performance of NIPT for detection of T21, T18, T13 and SCA was assessed by calculating the sensitivity and specificity.

RESULTS

The rate of chromosomal abnormality detected by NIPT in the study population was 1.38%. A higher rate of chromosomal abnormality was found in the high-risk group (1.57%) compared to the moderate-risk (1.05%) and low-risk (1.18%) groups (P < 0.05). Sensitivity and specificity, respectively, were 98.96% (95/96) and 99.94% (31 274/31 292) for detection of T21, 100% (25/25) and 99.96% (31 352/31 363) for T18, 100% (7/7) and 99.97% (31 373/31 381) for T13 and 100% (61/61) and 99.74% (31 245/31 327) for SCA. Positive predictive values were high for T21 (84.07%) and T18 (69.44%) and moderate for T13 (46.67%) and SCA (42.66%).

CONCLUSION

Our findings support the application of NIPT for reliable and accurate testing of the general population of reproductive-age women for clinically significant fetal aneuploidy. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

The importance of pre- and post-test counseling for prenatal cell-free DNA screening for common fetal aneuploidies

INTRODUCTION

Prenatal cell-free DNA screening for common fetal aneuploidies has rapidly changed the paradigm of prenatal care. Despite its advantages compared to conventional screening methods, its unexpectedly rapid implementation in clinical practice has generated several ethical and medical issues and misconceptions. Aggressive commercial marketing of cell-free DNA screening and media dissemination of misleading information have added confusion. Areas covered: This review provides an extensive update and will focus on the importance of pre-and post-test counseling for prenatal cell-free DNA screening not previously discussed extensively in the available literature. Additionally, we report cell-free DNA screening implementation in the largest obstetrical tertiary unit in Finland which is one of few countries that provides all prenatal screening methods free of charge for all women and has a very high uptake of first-trimester screening. This is not a systematical review, but rather a narrative overview which includes the most relevant and recent original publications and reviews covering this issue. Expert opinion: Despite being the most accurate method for screening of common fetal aneuploidies, the knowledge and counseling should be substantially improved. Cell-free DNA screening is not a replacement for diagnostic testing and its use in prenatal testing is complex and limited.