Preferences for prenatal diagnosis of sickle-cell disorder: A discrete choice experiment comparing potential service users and health-care providers

Non-invasive fetal genotyping for maternal alleles with droplet digital PCR: A comparative study of analytical approaches

OBJECTIVES

To develop a flexible droplet digital PCR (ddPCR) workflow to perform non-invasive prenatal diagnosis via relative mutation dosage (RMD) for maternal pathogenic variants with a range of inheritance patterns, and to compare the accuracy of multiple analytical approaches.

METHODS

Cell free DNA (cfDNA) was tested from 124 archived maternal plasma samples: 88 cases for sickle cell disease and 36 for rare Mendelian conditions. Three analytical methods were compared: sequential probability ratio testing (SPRT), Bayesian and z-score analyses.

RESULTS

The SPRT, Bayesian and z-score analyses performed similarly well with correct prediction rates of 96%, 97% and 98%, respectively. However, there were high rates of inconclusive results for each cohort, particularly for z-score analysis which was 31% overall. Two samples were incorrectly classified by all three analytical methods; a false negative result predicted for a fetus affected with sickle cell disease and a false positive result predicting the presence of an X-linked IDS variant in an unaffected fetus.

CONCLUSIONS

ddPCR can be applied to RMD for diverse conditions and inheritance patterns, but all methods carry a small risk of erroneous results. Further evaluation is required both to reduce the rate of inconclusive results and explore discordant results in more detail.

The perception of parents with a child with sickle cell disease in Ghana towards prenatal diagnosis

Sickle cell disease is a global health concern. In the UK and USA, where the condition is common, prenatal testing is a routine aspect of antenatal care and offered on the basis of informed reproductive choice. Notwithstanding considerable advances in testing technologies, prenatal diagnosis for sickle cell disease is not common in Africa. There is a particular lack of research examining parental perceptions about the acceptability of antenatal screening. This qualitative paper explores the perceptions of parents, who had lived experiences of caring for a child with SCD, towards prenatal testing for sickle cell in Ghana. A purposive sample of 27 parents (four fathers and 23 mothers) was recruited via a sickle cell clinic in Accra, Ghana. Material was collected using semi-structured interview, using a topic guide that explored parental views on prenatal testing, along with factors influencing decision making about antenatal care. The findings shown that parents believed the decision to accept testing should be negotiated between both parents rather than the extended family. The decision to accept testing did not mean that parents would use the information to terminate the pregnancy of a child with SCD. They mentioned that they were more likely to use the test result to prepare themselves for the birth of their child. Parents accepted, however, that choice was important and that some parents may wish to terminate the pregnancy, given the impact of SCD on a person's quality of life. Parents lack awareness about prenatal testing because the procedure was not part of antenatal services in Ghana. However, the majority would accept testing should the process be available and affordable. The paper suggests that policy needs to establish and promote sickle cell prenatal testing/prenatal diagnosis and awareness among at-risk populations, bearing in mind the cost implication of the technology, equal access to healthcare, and the importance of informed reproductive decision making, which connects to the parents' experience of testing/screening.

Reproductive decision-making by women with X-linked hypohidrotic ectodermal dysplasia

BACKGROUND

In X-linked hypohidrotic ectodermal dysplasia (XLHED), ectodysplasin A1 (EDA1) deficiency results in malformation of hair, teeth, and sweat glands. Lack of sweating which can cause life-threatening hyperthermia is amenable to intrauterine therapy with recombinant EDA1.

OBJECTIVES

This study aimed at evaluating reproductive decision-making by women with XLHED and at clarifying the potential impact of a prenatal treatment option.

METHODS

In a retrospective cross-sectional analysis, a 75-item questionnaire filled in by 50 women with XLHED (age 19-49 years) was assessed.

RESULTS

16 women (32%) prevented pregnancies because of the risk to pass on XLHED, 15 considered assisted reproduction for the same reason. Twelve women had a history of miscarriage, stillbirth or abortion, three women reported on previous abortion of affected fetuses. When imagining to be pregnant, all except one showed interest in prenatal diagnosis of XLHED and in the possibility of treatment before birth. In 13 out of 50 women (26%), XLHED if detected prenatally would have impact on the continuation of pregnancy. Among 35 mothers of at least one affected child, XLHED had rarely been diagnosed during the first pregnancy (17%) but regularly during subsequent pregnancies (77%). Becoming aware of the condition before birth had caused a moral conflict for 50% of these women. Subjects with an affected child less frequently considered assisted reproduction to prevent XLHED (p<0.05). In more than 66% of the women who reported an effect of XLHED on family planning, a prenatal treatment option for this disease would influence their decision-making.

CONCLUSIONS

Many pregnant XLHED carriers who seek prenatal diagnosis experience moral conflicts. A prenatal treatment option would have strong impact on reproductive decisions, underlining the importance of adequate professional counselling.

Implementation science in maternity care: a scoping review

BACKGROUND

Despite wide recognition that clinical care should be informed by the best available evidence, this does not always occur. Despite a myriad of theories, models and frameworks to promote evidence-based population health, there is still a long way to go, particularly in maternity care. The aim of this study is to appraise the scientific study of methods to promote the systematic uptake of evidence-based interventions in maternity care. This is achieved by clarifying if and how implementation science theories, models, and frameworks are used.

METHODS

To map relevant literature, a scoping review was conducted of articles published between January 2005 and December 2019, guided by Peters and colleagues' (2015) approach. Specifically, the following academic databases were systematically searched to identify publications that presented findings on implementation science or the implementation process (rather than just the intervention effect): Business Source Complete; CINAHL Plus with Full Text; Health Business Elite; Health Source: Nursing/Academic Edition; Medline; PsycARTICLES; PsycINFO; and PubMed. Information about each study was extracted using a purposely designed data extraction form.

RESULTS

Of the 1181 publications identified, 158 were included in this review. Most of these reported on factors that enabled implementation, including knowledge, training, service provider motivation, effective multilevel coordination, leadership and effective communication-yet there was limited expressed use of a theory, model or framework to guide implementation. Of the 158 publications, 144 solely reported on factors that helped and/or hindered implementation, while only 14 reported the use of a theory, model and/or framework. When a theory, model or framework was used, it typically guided data analysis or, to a lesser extent, the development of data collection tools-rather than for instance, the design of the study.

CONCLUSION

Given that models and frameworks can help to describe phenomenon, and theories can help to both describe and explain it, evidence-based maternity care might be promoted via the greater expressed use of these to ultimately inform implementation science. Specifically, advancing evidence-based maternity care, worldwide, will require the academic community to make greater explicit and judicious use of theories, models, and frameworks.

REGISTRATION

Registered with the Joanna Briggs Institute (registration number not provided).

A novel non-invasive prenatal sickle cell disease test for all at-risk pregnancies

Sickle cell disease (SCD) is the most common genetic haematological disorder. The availability of non-invasive prenatal diagnosis (NIPD) is predicted to increase uptake of prenatal diagnosis for SCD, as it has no perceived procedure-related miscarriage risk. We report the development of a targeted massively parallel sequencing (MPS) assay for the NIPD of fetal SCD using fetal cell-free (cf)DNA from maternal plasma, with no requirement for paternal or proband samples. In all, 64 plasma samples from pregnant women were analysed: 42 from SCD carriers, 15 from women with homozygous (Hb SS) SCD and seven from women with compound heterozygous (Hb SC) SCD. Our assay incorporated a relative mutation dosage assay for maternal carriers and a wild type allele detection assay for affected women (Hb SS/Hb SC). Selective analysis of only smaller cfDNA fragments and modifications to DNA fragment hybridisation capture improved diagnostic accuracy. Clinical sensitivity was 100% and clinical specificity was 100%. One sample with a fetal fraction of <4% was correctly called as 'unaffected', but with a discordant genotype (Hb AA rather than Hb AS). Six samples gave inconclusive results, of which two had a fetal fraction of <4%. This study demonstrates that NIPD for SCD is approaching clinical utility.

Designing Unforced Choice Experiments to Inform Health Care Decision Making: Implications of Using Opt-Out, Neither, or Status Quo Alternatives in Discrete Choice Experiments

Background. Discrete choice experiments (DCEs) are increasingly used in the health care context to inform on patient preferences for health care services. In order for such experiments to provide useful and policy-relevant information, it is vital that the design includes those options that the respondent faces in the real-life situation. Whether to include opt-out, neither, or status quo alternatives has, however, received little attention in the DCE literature. We aim to investigate whether the use of different unforced choice formats affects DCE results in different settings: 1) opt-out versus neither in a health care market where there is no status quo and 2) including status quo in addition to opt-out in a health care market with a status quo. Design. A DCE on Dutch citizens’ preferences for personal health records served as our case, and 3189 respondents were allocated to the different unforced choice formats. We used mixed logit error component models to estimate preferences. Results. We found that the use of different unforced choice formats affects marginal utilities and welfare estimates and hence the conclusions that will be drawn from the DCE to inform health care decision making. Conclusions. To avoid biased estimates, we recommend that researchers are hesitant to use the neither option and consider including a status quo in addition to opt-out in settings where a status quo exists.

Preferences for aspects of antenatal and newborn screening: a systematic review

BACKGROUND

Many countries offer screening programmes to unborn and newborn babies (antenatal and newborn screening) to identify those at risk of certain conditions to aid earlier diagnosis and treatment. Technological advances have stimulated the development of screening programmes to include more conditions, subsequently changing the information required and potential benefit-risk trade-offs driving participation. Quantifying preferences for screening programmes can provide programme commissioners with data to understand potential demand, the drivers of this demand, information provision required to support the programmes and the extent to which preferences differ in a population. This study aimed to identify published studies eliciting preferences for antenatal and newborn screening programmes and provide an overview of key methods and findings.

METHODS

A systematic search of electronic databases for key terms identified eligible studies (discrete choice experiments (DCEs) or best-worst scaling (BWS) studies related to antenatal/newborn testing/screening published between 1990 and October 2018). Data were systematically extracted, tabulated and summarised in a narrative review.

RESULTS

A total of 19 studies using a DCE or BWS to elicit preferences for antenatal (n = 15; 79%) and newborn screening (n = 4; 21%) programmes were identified. Most of the studies were conducted in Europe (n = 12; 63%) but there were some examples from North America (n = 2; 11%) and Australia (n = 2; 11%). Attributes most commonly included were accuracy of screening (n = 15; 79%) and when screening occurred (n = 13; 68%). Other commonly occurring attributes included information content (n = 11; 58%) and risk of miscarriage (n = 10; 53%). Pregnant women (n = 11; 58%) and healthcare professionals (n = 11; 58%) were the most common study samples. Ten studies (53%) compared preferences across different respondents. Two studies (11%) made comparisons between countries. The most popular analytical model was a standard conditional logit model (n = 11; 58%) and one study investigated preference heterogeneity with latent class analysis.

CONCLUSION

There is an existing literature identifying stated preferences for antenatal and newborn screening but the incorporation of more sophisticated design and analytical methods to investigate preference heterogeneity could extend the relevance of the findings to inform commissioning of new screening programmes.

Preferences for prenatal diagnosis of sickle-cell disorder: A discrete choice experiment comparing potential service users and health-care providers

Background

Non‐invasive prenatal diagnosis (NIPD) for sickle‐cell disorder (SCD) is moving closer to implementation and studies considering stakeholder preferences are required to underpin strategies for offering NIPD in clinical practice.

Objective

Determine service user and provider preferences for key attributes of prenatal diagnostic tests for SCD and examine views on NIPD.

Method

A questionnaire that includes a discrete choice experiment was used to determine the preferences of service users and providers for prenatal tests that varied across three attributes: accuracy, time of test and risk of miscarriage.

Results

Adults who were carriers of SCD or affected with the condition (N=67) were recruited from haemoglobinopathy clinics at two maternity units. Health professionals, predominately midwives, who offer antenatal care (N=62) were recruited from one maternity unit. No miscarriage risk was a key driver of decision making for both service users and providers. Service providers placed greater emphasis on accuracy than service users. Current uptake of invasive tests was 63%, whilst predicted uptake of NIPD was 93.8%. Many service users (55.4%) and providers (52.5%) think pressure to have prenatal testing will increase when NIPD for SCD becomes available.

Conclusions

There are clear differences between service users and health professionals’ preferences for prenatal tests for sickle‐cell disorder. The safety of NIPD is welcomed by parents and uptake is likely to be high. To promote informed choice, pretest counselling should be balanced and not exclusively focused on test safety. Counselling strategies that are sensitive to feelings of pressure to test will be essential.