Non-invasive fetal RHD genotyping tests: a systematic review of the quality of reporting of diagnostic accuracy in published studies

Antenatal RHD screening to guide antenatal anti-D immunoprophylaxis in non-immunized D- pregnant women

In pregnancy, D- pregnant women may be at risk of becoming immunized against D when carrying a D+ fetus, which may eventually lead to hemolytic disease of the fetus and newborn. Administrating antenatal and postnatal anti-D immunoglobulin prophylaxis decreases the risk of immunization substantially. Noninvasive fetal RHD genotyping, based on testing cell-free DNA extracted from maternal plasma, offers a reliable tool to predict the fetal RhD phenotype during pregnancy. Used as a screening program, antenatal RHD screening can guide the administration of antenatal prophylaxis in non-immunized D- pregnant women so that unnecessary prophylaxis is avoided in those women who carry a D- fetus. In Europe, antenatal RHD screening programs have been running since 2009, demonstrating high test accuracies and program feasibility. In this review, an overview is provided of current state-of-the-art antenatal RHD screening, which includes discussions on the rationale for its implementation, methodology, detection strategies, and test performance. The performance of antenatal RHD screening in a routine setting is characterized by high accuracy, with a high diagnostic sensitivity of ≥99.9 percent. The result of using antenatal RHD screening is that 97-99 percent of the women who carry a D- fetus avoid unnecessary prophylaxis. As such, this activity contributes to avoiding unnecessary treatment and saves valuable anti-D immunoglobulin, which has a shortage worldwide. The main challenges for a reliable noninvasive fetal RHD genotyping assay are low cell-free DNA levels, the genetics of the Rh blood group system, and choosing an appropriate detection strategy for an admixed population. In many parts of the world, however, the main challenge is to improve the basic care for D- pregnant women.

Scoping review on interventions to improve adherence to reporting guidelines in health research

OBJECTIVES

The goal of this study is to identify, analyse and classify interventions to improve adherence to reporting guidelines in order to obtain a wide picture of how the problem of enhancing the completeness of reporting of biomedical literature has been tackled so far.

DESIGN

Scoping review.

SEARCH STRATEGY

We searched the MEDLINE, EMBASE and Cochrane Library databases and conducted a grey literature search for (1) studies evaluating interventions to improve adherence to reporting guidelines in health research and (2) other types of references describing interventions that have been performed or suggested but never evaluated. The characteristics and effect of the evaluated interventions were analysed. Moreover, we explored the rationale of the interventions identified and determined the existing gaps in research on the evaluation of interventions to improve adherence to reporting guidelines.

RESULTS

109 references containing 31 interventions (11 evaluated) were included. These were grouped into five categories: (1) training on the use of reporting guidelines, (2) improving understanding, (3) encouraging adherence, (4) checking adherence and providing feedback, and (5) involvement of experts. Additionally, we identified lack of evaluated interventions (1) on training on the use of reporting guidelines and improving their understanding, (2) at early stages of research and (3) after the final acceptance of the manuscript.

CONCLUSIONS

This scoping review identified a wide range of strategies to improve adherence to reporting guidelines that can be taken by different stakeholders. Additional research is needed to assess the effectiveness of many of these interventions.

Does the medical literature remain inadequately described despite having reporting guidelines for 21 years? - A systematic review of reviews: an update

PURPOSE

Reporting guidelines (eg, Consolidated Standards of Reporting Trials [CONSORT] statement) are intended to improve reporting standards and enhance the transparency and reproducibility of research findings. Despite accessibility of such guidelines, researchers are not required to adhere to them. Our goal was to determine the current status of reporting quality in the medical literature and examine whether adherence of reporting guidelines has improved since the inception of reporting guidelines.

MATERIALS AND METHODS

Eight reporting guidelines, such as CONSORT, Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), STrengthening the Reporting of OBservational studies in Epidemiology (STROBE), Quality of Reporting of Meta-analysis (QUOROM), STAndards for Reporting of Diagnostic accuracy (STARD), Animal Research: Reporting In Vivo Experiments (ARRIVE), Consolidated Health Economic Evaluation Reporting Standards (CHEERS), and Meta-analysis of Observational Studies in Epidemiology (MOOSE) were examined. Our inclusion criteria included reviews published between January 1996 to September 2016 which investigated the adherence to reporting guidelines in the literature that addressed clinical trials, systematic reviews, observational studies, meta-analysis, diagnostic accuracy, economic evaluations, and preclinical animal studies that were in English. All reviews were found on Web of Science, Excerpta Medical Database (EMBASE), MEDLINE, and Cumulative Index to Nursing and Allied Health Literature (CINAHL).

RESULTS

Among the general searching of 26,819 studies by using the designed searching method, 124 studies were included post screening. We found that 87.9% of the included studies reported suboptimal adherence to reporting guidelines. Factors associated with poor adherence included non-pharmacological interventions, year of publication, and trials concluding with significant results. Improved adherence was associated with better study designs such as allocation concealment, random sequence, large sample sizes, adequately powered studies, multiple authorships, and being published in journals endorsing guidelines.

CONCLUSION

We conclude that the level of adherence to reporting guidelines remains suboptimal. Endorsement of reporting guidelines by journals is important and recommended.

Noninvasive prenatal diagnosis for X-linked disease by maternal plasma sequencing in a family of Hemophilia B

OBJECTIVE

To apply a Hidden Markov Model to test Hemophilia B in a fetus by maternal plasma sequencing only employing proband and maternal haplotypes.

CASE REPORT

A family at risk for Hemophilia B was recruited in this study. We performed genetic diagnosis on the proband using our targeted capture system (containing F9 gene coding region, highly heterozygous SNPs and a 13-kb chromosome Y specific region), and revealed a causative F9 gene mutation (c.190T>C, p.Cys64Arg). Maternal plasma cell-free DNA obtained at 8 weeks of gestation was targeted-captured and sequenced using the customized system. The fetus inherited the F9 (c.190T>C, p.Cys64Arg) mutation according to the Hidden Markov Model. The mother continued the pregnancy.

CONCLUSIONS

This study is the first report of a haplotype-based approach in NIPD of Hemophilia B. With further evaluation, this method might be useful for NIPD of Hemophilia B and for other X-linked single-gene disorders.

Haplotype-based approach for noninvasive prenatal tests of Duchenne muscular dystrophy using cell-free fetal DNA in maternal plasma

PURPOSE

This study demonstrates noninvasive prenatal testing (NIPT) for Duchenne muscular dystrophy (DMD) using a newly developed haplotype-based approach.

METHODS

Eight families at risk for DMD were recruited for this study. Parental haplotypes were constructed using target-region sequencing data from the parents and the probands. Fetal haplotypes were constructed using a hidden Markov model through maternal plasma DNA sequencing. The presence of haplotypes linked to the maternal mutant alleles in males indicated affected fetuses. This method was further validated by comparing the inferred single-nucleotide polymorphism (SNP) genotypes to the direct sequencing results of fetal genomic DNA. Prenatal diagnosis was confirmed with amniocentesis, and those results were interpreted in a blinded fashion.

RESULTS

The results showed an average accuracy of 99.98% for the total inferred maternal SNPs. With a mean depth of 30× achieved in the 10-Mb target region of each sample, the noninvasive results were consistent with those of the invasive procedure.

CONCLUSION

This is the first report of NIPT for DMD and the first application of a haplotype-based approach in NIPT for X-linked diseases. With further improvements in accuracy, this haplotype-based strategy could be feasible for NIPT for DMD and even other X-linked single-gene disorders.

Noninvasive single-exon fetal RHD determination in a routine screening program in early pregnancy

OBJECTIVE

To develop a simple and robust assay suitable for fetal RHD screening in first-trimester pregnancy and to estimate the sensitivity and specificity of the test after its implementation in an unselected pregnant population.

METHODS

Pregnant women attending their first antenatal visit were included, and fetal RHD determination was performed for all women who typed RhD-negative by routine serology. DNA was extracted by an automated system and quantitative polymerase chain reaction was done by an assay based on exon 4. Reporting criteria were simple and strict.

RESULTS

Four thousand one hundred eighteen pregnancies, with a median gestational age of 10 weeks, were included. After 211 (5.1%) reanalyses, fetal RHD was reported positive in 2,401 (58.3%), negative in 1,552 (37.7%), and inconclusive in 165 (4.0%) based on the first sample. After a second sample in 147 of 165, only 14 remained inconclusive, all resulting from a weak or silent maternal RHD gene. Using blood group serology of the newborns as the gold standard, the false-negative rate was 55 of 2,297 (2.4%) and the false-positive rate was 15 of 1,355 (1.1%). After exclusion of samples obtained before gestational week 8, the false-negative rate was 23 of 2,073 (1.1%) and the false-positive rate was 14 of 1,218 (1.1%). Both sensitivity and specificity were close to 99% provided samples were not collected before gestational week 8. From gestational week 22, sensitivity was 100%.

CONCLUSION

Fetal RHD detection in early pregnancy using a single-exon assay in a routine clinical setting is feasible and accurate.

LEVEL OF EVIDENCE

I.

Relation of completeness of reporting of health research to journals' endorsement of reporting guidelines: systematic review

OBJECTIVE

To assess whether the completeness of reporting of health research is related to journals' endorsement of reporting guidelines.

DESIGN

Systematic review.

DATA SOURCES

Reporting guidelines from a published systematic review and the EQUATOR Network (October 2011). Studies assessing the completeness of reporting by using an included reporting guideline (termed "evaluations") (1990 to October 2011; addendum searches in January 2012) from searches of either Medline, Embase, and the Cochrane Methodology Register or Scopus, depending on reporting guideline name.

STUDY SELECTION

English language reporting guidelines that provided explicit guidance for reporting, described the guidance development process, and indicated use of a consensus development process were included. The CONSORT statement was excluded, as evaluations of adherence to CONSORT had previously been reviewed. English or French language evaluations of included reporting guidelines were eligible if they assessed the completeness of reporting of studies as a primary intent and those included studies enabled the comparisons of interest (that is, after versus before journal endorsement and/or endorsing versus non-endorsing journals).

DATA EXTRACTION

Potentially eligible evaluations of included guidelines were screened initially by title and abstract and then as full text reports. If eligibility was unclear, authors of evaluations were contacted; journals' websites were consulted for endorsement information where needed. The completeness of reporting of reporting guidelines was analyzed in relation to endorsement by item and, where consistent with the authors' analysis, a mean summed score.

RESULTS

101 reporting guidelines were included. Of 15,249 records retrieved from the search for evaluations, 26 evaluations that assessed completeness of reporting in relation to endorsement for nine reporting guidelines were identified. Of those, 13 evaluations assessing seven reporting guidelines (BMJ economic checklist, CONSORT for harms, PRISMA, QUOROM, STARD, STRICTA, and STROBE) could be analyzed. Reporting guideline items were assessed by few evaluations.

CONCLUSIONS

The completeness of reporting of only nine of 101 health research reporting guidelines (excluding CONSORT) has been evaluated in relation to journals' endorsement. Items from seven reporting guidelines were quantitatively analyzed, by few evaluations each. Insufficient evidence exists to determine the relation between journals' endorsement of reporting guidelines and the completeness of reporting of published health research reports. Journal editors and researchers should consider collaborative prospectively designed, controlled studies to provide more robust evidence.

SYSTEMATIC REVIEW REGISTRATION

Not registered; no known register currently accepts protocols for methodology systematic reviews.

Reporting quality of diagnostic accuracy studies: a systematic review and meta-analysis of investigations on adherence to STARD

BACKGROUND

Poor reporting of diagnostic accuracy studies impedes an objective appraisal of the clinical performance of diagnostic tests. The Standards for Reporting of Diagnostic Accuracy Studies (STARD) statement, first published in 2003, aims to improve the reporting quality of such studies.

OBJECTIVE

To investigate to which extent published diagnostic accuracy studies adhere to the 25-item STARD checklist, whether the reporting quality has improved after STARD's launch and whether there are any factors associated with adherence.

STUDY SELECTION

We performed a systematic review and searched MEDLINE, EMBASE and the Methodology Register of the Cochrane Library for studies that primarily aimed to examine the reporting quality of articles on diagnostic accuracy studies in humans by evaluating adherence to STARD. Study selection was performed in duplicate; data were extracted by one author and verified by the second author.

FINDINGS

We included 16 studies, analysing 1496 articles in total. Three studies investigated adherence in a general sample of diagnostic accuracy studies; the others did so in a specific field of research. The overall mean number of items reported varied from 9.1 to 14.3 between 13 evaluations that evaluated all 25 STARD items. Six studies quantitatively compared post-STARD with pre-STARD articles. Combining these results in a random-effects meta-analysis revealed a modest but significant increase in adherence after STARD's introduction (mean difference 1.41 items (95% CI 0.65 to 2.18)).

CONCLUSIONS

The reporting quality of diagnostic accuracy studies was consistently moderate, at least through halfway the 2000s. Our results suggest a small improvement in the years after the introduction of STARD. Adherence to STARD should be further promoted among researchers, editors and peer reviewers.

Non-invasive Prenatal Testing: Technologies, Clinical Assays and Implementation Strategies for Women's Healthcare Practitioners

The field of prenatal genetic testing has exploded with new non-invasive technologies and test options in the past several years. It is challenging for women's healthcare providers to keep up with the multitude of publications and provide patients with the most accurate and up-to-date information possible regarding prenatal testing. In this article, we examine the sequencing technologies that provide the framework for non-invasive prenatal testing (NIPT) and review the major North American NIPT clinical validation studies published in 2011 and 2012. This paper also compares and contrasts the commercially available non-invasive prenatal tests in the United States, discusses clinical implementation recommendations from professional societies and highlights considerations for genetic counseling.

Cell-free fetal nucleic acids as prenatal biomarkers

INTRODUCTION

Cell-free fetal nucleic acids in maternal plasma or serum have become important tools in the pursuance of new methods for non-invasive prenatal diagnosis, such as the determination of fetal blood groups and fetal gender. During these pioneering explorations, elevations in the concentration of these new-found biological analytes were noted in several pregnancy-related disorders, including preterm labor, pre-eclampsia and malimplantation. As these elevations appeared to occur before onset of clinical symptoms, it was proposed that such analyses might assist in screening for at-risk pregnancies. A major problem with these early studies is that they relied on the quantitation of Y-chromosome-specific gene sequences, and as such could be applied only in those cases where the fetus was male. Recent developments that might permit gender-independent analysis include epigenetic markers, as well as the analysis of cell-free placentally derived mRNA species.

AREAS COVERED

This article focuses specifically on prognostic markers, which enable at-risk pregnancies to be identified, allowing the modification of pregnancy management and in turn improvement of pregnancy outcome. The authors also provide their opinion on the progress and future challenges that lie ahead.

EXPERT OPINION

Accurate quantification of fetal nucleic acids and the specificity of these elevations for particular disorders remain controversial issues. Regarding the multifactorial etiology of some pregnancy disorders, the use of fetal nucleic acids as prenatal markers is restricted to well-defined high-risk groups.

A new fetal RHD genotyping test: costs and benefits of mass testing to target antenatal anti-D prophylaxis in England and Wales

BACKGROUND

Postnatal and antenatal anti-D prophylaxis have dramatically reduced maternal sensitisations and cases of rhesus disease in babies born to women with RhD negative blood group. Recent scientific advances mean that non-invasive prenatal diagnosis (NIPD), based on the presence of cell-free fetal DNA in maternal plasma, could be used to target prophylaxis on "at risk" pregnancies where the fetus is RhD positive. This paper provides the first assessment of cost-effectiveness of NIPD-targeted prophylaxis compared to current policies.

METHODS

We conducted an economic analysis of NIPD implementation in England and Wales. Two scenarios were considered. Scenario 1 assumed that NIPD will be only used to target antenatal prophylaxis with serology tests continuing to direct post-delivery prophylaxis. In Scenario 2, NIPD would also displace postnatal serology testing if an RhD negative fetus was identified. Costs were estimated from the provider's perspective for both scenarios together with a threshold royalty fee per test. Incremental costs were compared with clinical implications.

RESULTS

The basic cost of an NIPD in-house test is £16.25 per sample (excluding royalty fee). The two-dose antenatal prophylaxis policy recommended by NICE is estimated to cost the NHS £3.37 million each year. The estimated threshold royalty fee is £2.18 and £8.83 for Scenarios 1 and 2 respectively. At a £2.00 royalty fee, mass NIPD testing would produce no saving for Scenario 1 and £507,154 per annum for Scenario 2. Incremental cost-effectiveness analysis indicates that, at a test sensitivity of 99.7% and this royalty fee, NIPD testing in Scenario 2 will generate one additional sensitisation for every £9,190 saved. If a single-dose prophylaxis policy were implemented nationally, as recently recommended by NICE, Scenario 2 savings would fall.

CONCLUSIONS

Currently, NIPD testing to target anti-D prophylaxis is unlikely to be sufficiently cost-effective to warrant its large scale introduction in England and Wales. Only minor savings are calculated and, balanced against this, the predicted increase in maternal sensitisations may be unacceptably high. Reliability of NIPD assays still needs to be demonstrated rigorously in different ethnic minority populations. First trimester testing is unlikely to alter this picture significantly although other emerging technologies may.

Detection of fetal RhD gene from maternal blood

OBJECTIVE

Hemolytic disease of the newborn (HDN) is a clinic phenomenon which occurs during pregnancy due to the Rhesus (Rh) D alloimmunization between a Rh (-) pregnant woman, who has become sensitive to RhD antigens, and her Rh (+) fetus. As a result of the attack of maternal RhD antibodies on fetal RhD antigens, fetal anemia, HDN and fetal death may occur. % 40 of Rh (-) pregnant women carry Rh (-) fetus. However, all Rh (-) pregnant women are offered anti-D Immunoglobulin (Anti-D Ig) at 28 weeks' gestation in case of fetomaternal haemorrhage, so the pregnant women carrying Rh (-) fetus are exposed to blood products unnecessarily. Although the RhD of fetus can be detected, methods used for prenatal diagnosis recently are invasive tests and they can result in abortion in a certain percentage. The discovery of circulating cell-free fetal nucleic acids in maternal plasma has opened up new possibilities for non invasive prenatal diagnosis. The aim of this study was to detect prenatal RhD by analysing the presence of the RhD gene of fetal DNA in maternal blood.

MATERIAL AND METHODS

Total free DNA was isolated from the blood of 19 Rh (-) pregnant women, who had RhD alloimmunization with their husbands, in the 11-14 th week of their pregnancy. The existence of a gene in isolated DNA was investigated with TaqMan prob and "Real-time PCR" method by using primers belonging to exon 7 of RhD gene.

RESULTS

Using a quantitative real-time PCR assay, the presence of RhD gene sequences was evaluated in the serum of patients at the onset of pregnancy. We have analyzed 19 Rh (-) pregnant women. Twelve of them were Rh (-) and the rest of them were 7 Rh (+). After birth the baby's blood groups were concordant with our results.

CONCLUSION

The results obtained by RhD primer were analysed. The possibility of detection of fetal RhD gene in maternal blood contributed to noninvasive prenatal diagnosis.