Amniocentesis results: investigation of anxiety. The ARIA trial

Comprehensive review of statistical methods for analysing patient-reported outcomes (PROs) used as primary outcomes in randomised controlled trials (RCTs) published by the UK's Health Technology Assessment (HTA) journal (1997-2020)

OBJECTIVES

To identify how frequently patient-reported outcomes (PROs) are used as primary and/or secondary outcomes in randomised controlled trials (RCTs) and to summarise what statistical methods are used for the analysis of PROs.

DESIGN

Comprehensive review.

SETTING

RCTs funded and published by the United Kingdom's (UK) National Institute for Health Research (NIHR) Health Technology Assessment (HTA) Programme.

DATA SOURCES AND ELIGIBILITY

HTA reports of RCTs published between January 1997 and December 2020 were reviewed.

DATA EXTRACTION

Information relating to PRO use and analysis methods was extracted.

PRIMARY AND SECONDARY OUTCOME MEASURES

The frequency of using PROs as primary and/or secondary outcomes; statistical methods that were used for the analysis of PROs as primary outcomes.

RESULTS

In this review, 37.6% (114/303) of trials used PROs as primary outcomes, and 82.8% (251/303) of trials used PROs as secondary outcomes from 303 NIHR HTA reports of RCTs. In the 114 RCTs where the PRO was the primary outcome, the most used PRO was the Short-Form 36 (8/114); the most popular methods for multivariable analysis were linear mixed model (45/114), linear regression (29/114) and analysis of covariance (13/114); logistic regression was applied for binary and ordinal outcomes in 14/114 trials; and the repeated measures analysis was used in 39/114 trials.

CONCLUSION

The majority of trials used PROs as primary and/or secondary outcomes. Conventional methods such as linear regression are widely used, despite the potential violation of their assumptions. In recent years, there is an increasing trend of using complex models (eg, with mixed effects). Statistical methods developed to address these violations when analysing PROs, such as beta-binomial regression, are not routinely used in practice. Future research will focus on evaluating available statistical methods for the analysis of PROs.

Models and applications for measuring the impact of health research: update of a systematic review for the Health Technology Assessment programme

BACKGROUND

This report reviews approaches and tools for measuring the impact of research programmes, building on, and extending, a 2007 review.

OBJECTIVES

(1) To identify the range of theoretical models and empirical approaches for measuring the impact of health research programmes; (2) to develop a taxonomy of models and approaches; (3) to summarise the evidence on the application and use of these models; and (4) to evaluate the different options for the Health Technology Assessment (HTA) programme.

DATA SOURCES

We searched databases including Ovid MEDLINE, EMBASE, Cumulative Index to Nursing and Allied Health Literature and The Cochrane Library from January 2005 to August 2014.

REVIEW METHODS

This narrative systematic literature review comprised an update, extension and analysis/discussion. We systematically searched eight databases, supplemented by personal knowledge, in August 2014 through to March 2015.

RESULTS

The literature on impact assessment has much expanded. The Payback Framework, with adaptations, remains the most widely used approach. It draws on different philosophical traditions, enhancing an underlying logic model with an interpretative case study element and attention to context. Besides the logic model, other ideal type approaches included constructionist, realist, critical and performative. Most models in practice drew pragmatically on elements of several ideal types. Monetisation of impact, an increasingly popular approach, shows a high return from research but relies heavily on assumptions about the extent to which health gains depend on research. Despite usually requiring systematic reviews before funding trials, the HTA programme does not routinely examine the impact of those trials on subsequent systematic reviews. The York/Patient-Centered Outcomes Research Institute and the Grading of Recommendations Assessment, Development and Evaluation toolkits provide ways of assessing such impact, but need to be evaluated. The literature, as reviewed here, provides very few instances of a randomised trial playing a major role in stopping the use of a new technology. The few trials funded by the HTA programme that may have played such a role were outliers.

DISCUSSION

The findings of this review support the continued use of the Payback Framework by the HTA programme. Changes in the structure of the NHS, the development of NHS England and changes in the National Institute for Health and Care Excellence's remit pose new challenges for identifying and meeting current and future research needs. Future assessments of the impact of the HTA programme will have to take account of wider changes, especially as the Research Excellence Framework (REF), which assesses the quality of universities' research, seems likely to continue to rely on case studies to measure impact. The HTA programme should consider how the format and selection of case studies might be improved to aid more systematic assessment. The selection of case studies, such as in the REF, but also more generally, tends to be biased towards high-impact rather than low-impact stories. Experience for other industries indicate that much can be learnt from the latter. The adoption of researchfish^® (researchfish Ltd, Cambridge, UK) by most major UK research funders has implications for future assessments of impact. Although the routine capture of indexed research publications has merit, the degree to which researchfish will succeed in collecting other, non-indexed outputs and activities remains to be established.

LIMITATIONS

There were limitations in how far we could address challenges that faced us as we extended the focus beyond that of the 2007 review, and well beyond a narrow focus just on the HTA programme.

CONCLUSIONS

Research funders can benefit from continuing to monitor and evaluate the impacts of the studies they fund. They should also review the contribution of case studies and expand work on linking trials to meta-analyses and to guidelines.

FUNDING

The National Institute for Health Research HTA programme.

Amniocentesis and chorionic villus sampling for prenatal diagnosis

BACKGROUND

During pregnancy, fetal cells suitable for genetic testing can be obtained from amniotic fluid by amniocentesis (AC), placental tissue by chorionic villus sampling (CVS), or fetal blood. A major disadvantage of second trimester amniocentesis is that the results are available relatively late in pregnancy (after 16 weeks' gestation). Earlier alternatives are chorionic villus sampling (CVS) and early amniocentesis, which can be performed in the first trimester of pregnancy.

OBJECTIVES

The objective of this review was to compare the safety and accuracy of all types of AC (i.e. early and late) and CVS (e.g. transabdominal, transcervical) for prenatal diagnosis.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (3 March 2017), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP; 3 March 2017), and reference lists of retrieved studies.

SELECTION CRITERIA

All randomised trials comparing AC and CVS by either transabdominal or transcervical route.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. The quality of the evidence was assessed using the GRADE approach.

MAIN RESULTS

We included a total of 16 randomised studies, with a total of 33,555 women, 14 of which were deemed to be at low risk of bias. The number of women included in the trials ranged from 223 to 4606.Studies were categorized into six comparisons: 1. second trimester AC versus control; 2. early versus second trimester AC; 3. CVS versus second trimester AC; 4. CVS methods; 5. Early AC versus CVS; and 6. AC with or without ultrasound.One study compared second trimester AC with no AC (control) in a low risk population (women = 4606). Background pregnancy loss was around 2%. Second trimester AC compared to no testing increased total pregnancy loss by another 1%. The confidence intervals (CI) around this excess risk were relatively large (3.2% versus 2.3 %, average risk ratio (RR) 1.41, 95% CI 0.99 to 2.00; moderate-quality evidence). In the same study, spontaneous miscarriages were also higher (2.1% versus 1.3%; average RR 1.60, 95% CI 1.02 to 2.52; high-quality evidence). The number of congenital anomalies was similar in both groups (2.0% versus 2.2%, average RR 0.93, 95% CI 0.62 to 1.39; moderate-quality evidence).One study (women = 4334) found that early amniocentesis was not a safe early alternative compared to second trimester amniocentesis because of increased total pregnancy losses (7.6% versus 5.9%; average RR 1.29, 95% CI 1.03 to 1.61; high-quality evidence), spontaneous miscarriages (3.6% versus 2.5%, average RR 1.41, 95% CI 1.00 to 1.98; moderate-quality evidence), and a higher incidence of congential anomalies, including talipes (4.7% versus 2.7%; average RR 1.73, 95% CI 1.26 to 2.38; high-quality evidence).When pregnancy loss after CVS was compared with second trimester AC, there was a clinically significant heterogeneity in the size and direction of the effect depending on the technique used (transabdominal or transcervical), therefore, the results were not pooled. Only one study compared transabdominal CVS with second trimester AC (women = 2234). They found no clear difference between the two procedures in the total pregnancy loss (6.3% versus 7%; average RR 0.90, 95% CI 0.66 to 1.23, low-quality evidence), spontaneous miscarriages (3.0% versus 3.9%; average RR 0.77, 95% CI 0.49 to 1.21; low-quality evidence), and perinatal deaths (0.7% versus 0.6%; average RR 1.18, 95% CI 0.40 to 3.51; low-quality evidence). Transcervical CVS may carry a higher risk of pregnancy loss (14.5% versus 11.5%; average RR 1.40, 95% CI 1.09 to 1.81), but the results were quite heterogeneous.Five studies compared transabdominal and transcervical CVS (women = 7978). There were no clear differences between the two methods in pregnancy losses (average RR 1.16, 95% CI 0.81 to 1.65; very low-quality evidence), spontaneous miscarriages (average RR 1.68, 95% CI 0.79 to 3.58; very low-quality evidence), or anomalies (average RR 0.68, 95% CI 0.41 to 1.12; low-quality evidence). We downgraded the quality of the evidence to low due to heterogeneity between studies. Transcervical CVS may be more technically demanding than transabdominal CVS, with more failures to obtain sample (2.0% versus 1.1%; average RR 1.79, 95% CI 1.13 to 2.82, moderate-quality evidence).Overall, we found low-quality evidence for outcomes when early amniocentesis was compared to transabdominal CVS. Spontaneous miscarriage was the only outcome supported by moderate-quality evidence, resulting in more miscarriages after early AC compared with transabdominal CVS (2.3% versus 1.3%; average RR 1.73, 95% CI 1.15 to 2.60). There were no clear differences in pregnancy losses (average RR 1.15, 95% CI 0.86 to 1.54; low-quality evidence), or anomalies (average RR 1.14, 95% CI 0.57 to 2.30; very low-quality evidence).We found one study that examined AC with or without ultrasound, which evaluated a type of ultrasound-assisted procedure that is now considered obsolete.

AUTHORS' CONCLUSIONS

Second trimester amniocentesis increased the risk of pregnancy loss, but it was not possible to quantify this increase precisely from only one study, carried out more than 30 years ago.Early amniocentesis was not as safe as second trimester amniocentesis, illustrated by increased pregnancy loss and congenital anomalies (talipes). Transcervical chorionic villus sampling compared with second trimester amniocentesis may be associated with a higher risk of pregnancy loss, but results were quite heterogeneous.Diagnostic accuracy of different methods could not be assessed adequately because of incomplete karyotype data in most studies.

High Levels of Sample-to-Sample Variation Confound Data Analysis for Non-Invasive Prenatal Screening of Fetal Microdeletions

Our goal was to test the hypothesis that inter-individual genomic copy number variation in control samples is a confounding factor in the non-invasive prenatal detection of fetal microdeletions via the sequence-based analysis of maternal plasma DNA. The database of genomic variants (DGV) was used to determine the “Genomic Variants Frequency” (GVF) for each 50kb region in the human genome. Whole genome sequencing of fifteen karyotypically normal maternal plasma and six CVS DNA controls samples was performed. The coefficient of variation of relative read counts (cv.RTC) for these samples was determined for each 50kb region. Maternal plasma from two pregnancies affected with a chromosome 5p microdeletion was also sequenced, and analyzed using the GCREM algorithm. We found strong correlation between high variance in read counts and GVF amongst controls. Consequently we were unable to confirm the presence of the microdeletion via sequencing of maternal plasma samples obtained from two sequential affected pregnancies. Caution should be exercised when performing NIPT for microdeletions. It is vital to develop our understanding of the factors that impact the sensitivity and specificity of these approaches. In particular, benign copy number variation amongst controls is a major confounder, and their effects should be corrected bioinformatically.

Recent advances of genomic testing in perinatal medicine

Rapid progress in genomic medicine in recent years has made it possible to diagnose subtle genetic abnormalities in a clinical setting on routine basis. This has allowed for detailed genotype-phenotype correlations and the identification of the genetic basis of many congenital anomalies. In addition to the availability of chromosomal microarray analysis, exome and whole-genome sequencing on pre- and postnatal samples of cell-free DNA has revolutionized the field of prenatal diagnosis. Incorporation of these technologies in perinatal pathology is bound to play a major role in coming years. In this communication, we briefly present the current experience with use of classical chromosome analysis, fluorescence in situ hybridization, and microarray testing, development of whole-genome analysis by next-generation sequencing technology, offer a detailed review of the history and current status of non-invasive prenatal testing using cell-free DNA, and discuss the advents of these new genomic technologies in perinatal medicine.

Antenatal telephone support intervention with and without uterine artery Doppler screening for low risk nulliparous women: a randomised controlled trial

BACKGROUND

The number of routine antenatal visits provided to low risk nulliparous women has been reduced in the UK, acknowledging this change in care may result in women being less satisfied with their care and having poorer psychosocial outcomes. The primary aim of the study was to investigate whether the provision of proactive telephone support intervention (TSI) with and without uterine artery Doppler screening (UADS) would reduce the total number of antenatal visits required. A secondary aim was to investigate whether the interventions affected psychological outcomes.

METHODS

A three-arm randomised controlled trial involving 840 low risk nulliparous women was conducted at a large maternity unit in North East England. All women received antenatal care in line with current UK guidance. Women in the TSI group (T) received calls from a midwife at 28, 33 and 36 weeks and women in the telephone and Doppler group (T + D) received the TSI and additional UADS at 20 weeks' gestation. The main outcome measure was the total number of scheduled and unscheduled antenatal visits received after 20 weeks' gestation.

RESULTS

The median number of unscheduled (n = 2.0), scheduled visits (n = 7.0) and mean number of total visits (n = 8.8) were similar in the three groups. The majority (67%) of additional antenatal visits were made to a Maternity Assessment Unit because of commonly occurring pregnancy complications. Additional TSI+/-UADS was not associated with differences in clinical outcomes, levels of anxiety, social support or satisfaction with care. There were challenges to the successful delivery of the telephone support intervention; 59% of women were contacted at 29 and 33 weeks gestation reducing to 52% of women at 37 weeks.

CONCLUSIONS

Provision of additional telephone support (with or without UADS) in low risk nulliparous women did not reduce the number of unscheduled antenatal visits or reduce anxiety. This study provides a useful insight into the reasons why this client group attend for unscheduled visits.

TRIAL REGISTRATION

ISRCTN62354584.

High resolution non-invasive detection of a fetal microdeletion using the GCREM algorithm

BACKGROUND/OBJECTIVE

The non-invasive prenatal detection of fetal microdeletions becomes increasingly challenging as the size of the mutation decreases, with current practical lower limits in the range of a few megabases. Our goals were to explore the lower limits of microdeletion size detection via non-invasive prenatal tests using Minimally Invasive Karyotyping (MINK) and introduce/evaluate a novel statistical approach we recently developed called the GC Content Random Effect Model (GCREM).

METHODS

Maternal plasma was obtained from a pregnancy affected by a 4.2-Mb fetal microdeletion and three normal controls. Plasma DNA was subjected to capture an 8-Mb sequence spanning the breakpoint region and sequence. Data were analyzed with our published method, MINK, and a new method called GCREM.

RESULTS

The 8-Mb capture segment was divided into either 38 or 76 non-overlapping regions of 200 and 100 Kb, respectively. At 200 Kb resolution, using GCREM (but not MINK), we obtained significant adjusted p-values for all 20 regions overlapping the deleted sequence, and non-significant p-values for all 18 reference regions. At 100 Kb resolution, GCREM identified significant adjusted p-values for all but one 100-Kb region located inside the deleted region.

CONCLUSION

Targeted sequencing and GCREM analysis may enable cost effective detection of fetal microdeletions and microduplications at high resolution.

Discovery of epigenetic biomarkers for the noninvasive diagnosis of fetal disease

OBJECTIVES

The primary goal of this study was to identify CpG sites in the human genome that are differentially methylated in DNA obtained from chorionic villus sampling (CVS) samples and gestational age-matched maternal blood cell (MBC) samples.

METHODS

We used the HumanMethylation27 DNA Analysis BeadChip to characterize DNA methylation in samples of CVS and MBC. We then selected a subset of differentially methylated CpG sites on chromsome 13 and subjected them to analysis by mass spectrometry using the Epityper platform.

RESULTS

We identified 718 tissue-specific differentially methylated regions (DMRs) between MBC and CVS; 563 of these were hypermethylated in MBC and hypomethylated in CVS, whereas 155 sites were hypomethylated in MBC and hypermethylated in CVS. Further analysis of 13 DMRs on chromosome 13 by Epityper confirmed the microarray data and provided us with additional data about the methylation patterns of surrounding CpG sites.

CONCLUSIONS

Analysis of the resulting data identified a large number of cytosine-guanine dinucleotides that are potential biomarkers for the selective amplification of fetal DNA from maternal plasma and the subsequent noninvasive detection of trisomy 13.

Different communication strategies for disclosing results of diagnostic prenatal testing

BACKGROUND

Any screening program aiming to reassure pregnant women that their unborn baby is healthy will cause anxiety while waiting for the test results.

OBJECTIVES

1) To determine if revealing amniocentesis or chorionic villous sampling (CVS) results on a fixed date alters maternal anxiety during the waiting period, compared with a policy of revealing the result "when available" (i.e. variable date). 2) To evaluate whether issuing early results from a rapid molecular test alters maternal anxiety during the waiting period. 3) To evaluate whether different methods of communication (telephone, fax, email, face to face) have any impact on the parents' satisfaction and anxiety levels.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 August 2010).

SELECTION CRITERIA

All published and unpublished randomised trials, in which methods of issuing prenatal test results are compared.

DATA COLLECTION AND ANALYSIS

Two review authors (Faris Mujezinovic and Zarko Alfirevic) assessed eligibility and trial quality and performed data extraction.

MAIN RESULTS

Two studies (involving 286 women) from amniocentesis (but none from CVS) compared the impact of communicating results of rapid testing with waiting for definitive karyotype. Unfortunately, it was not possible to perform pooled analysis because one study reported only median (interquartile range) data, presumably because the data were not normally distributed.One study reported a statistically significant reduction in the average anxiety during the waiting period for women who had had a rapid test compared with those who had not (mean difference (MD) -2.30, 95% confidence intervals (CI) -3.08 to - 1.52). The other study compared median (interquartile range) for the trait- and state-anxiety scores and found no difference between the two groups.

AUTHORS' CONCLUSIONS

We found no conclusive evidence that, while waiting for the full karyotype following amniocentesis, issuing results from a rapid analysis reduces maternal anxiety. The limited evidence from the two trials included in this review does not help resolve the dilemma about whether full karyotyping should be abandoned in favour of limited rapid testing for women undergoing Down's syndrome screening. This choice will rest on clinical arguments and cost-effectiveness rather than impact on anxiety.There is also no evidence to support the view that issuing amniocentesis results as soon as they are available is more user friendly than using a pre-defined fixed date. Studies evaluating the effect of different strategies for disclosing results on women anxiety for CVS are needed.

Anxiety levels in women undergoing prenatal maternal serum screening for Down syndrome: the effect of a fast reporting system by mobile phone short-message service

OBJECTIVE

To study the effect of fast reporting by mobile phone short-message service (SMS) on anxiety levels in women undergoing prenatal biochemical screening for Down syndrome.

METHOD

From January 2005 to December 2006, 2782 women undergoing prenatal biochemical serum screening were randomized into fast reporting by SMS (group A) or without mobile phone reporting (group B). Anxiety levels were measured with the Spielberger State-Trait Anxiety Inventory (STAI) before prenatal screen testing, before the appointed clinic (when the SMS report had already been given to group A), and 3 days after the appointed clinic (when the full screening report had been given to groups A and B).

RESULTS

For screen-negative women, anxiety scores did not differ between groups before prenatal screen testing and 3 days after the appointed clinic. The state-anxiety scores measured on the second occasion had declined significantly in group A. The state-anxiety scores in both groups increased over the 3-week period after being informed of positive screen results. The trait- and state-anxiety scores at all points did not differ between the two groups of screen-positive women.

CONCLUSIONS

The provision of a routine reporting system plus additional SMS report revealed some overall benefits in reducing anxiety among women with screen-negative result.

Amniocentesis and chorionic villus sampling for prenatal diagnosis

BACKGROUND

A major disadvantage of second trimester amniocentesis is that the result is usually available only after 18 weeks' gestation. Chorionic villus sampling (CVS) and early amniocentesis can be done between 9 and 14 weeks and offer an earlier alternative.

OBJECTIVES

The objective was to assess comparative safety and accuracy of second trimester amniocentesis, early amniocentesis, transcervical and transabdominal CVS.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register (March 2003) and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 1, 2002).

SELECTION CRITERIA

All randomised trials comparing amniocentesis and CVS.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed eligibility and trial quality and performed data extraction. We analysed the data using RevMan software.

MAIN RESULTS

A total of 14 randomised studies have been included. In a low risk population with a background pregnancy loss of around 2%, a second trimester amniocentesis will increase this risk by another 1%. This difference did not reach statistical significance, but the increase in spontaneous miscarriages following second trimester amniocentesis compared with controls (no amniocentesis) did (2.1% versus 1.3%; relative risk (RR) 1.02 to 2.52). Early amniocentesis is not a safe early alternative to second trimester amniocentesis because of increased pregnancy loss (7.6% versus 5.9%; RR 1.29, 95% CI 1.03 to 1.61) and higher incidence of talipes compared to CVS (1.8% versus 0.2%; RR 6.43, 95% CI 1.68 to 24.64).Compared with second trimester amniocentesis, transcervical CVS carries a significantly higher risk of pregnancy loss (14.5% versus 11%; RR 1.40, 95% CI 1.09 to 1.81) and spontaneous miscarriage (12.9% versus 9.4%; RR 1.50, 95% CI 1.07 to 2.11). One study compared transabdominal CVS with second trimester amniocentesis and found no significant difference in the total pregnancy loss between the two procedures (6.3% versus 7%). Transcervical CVS is more technically demanding than transabdominal CVS with more failures to obtain sample and more multiple insertions.

REVIEWER'S CONCLUSIONS

Second trimester amniocentesis is safer than transcervical CVS and early amniocentesis. If earlier diagnosis is required, transabdominal CVS is preferable to early amniocentesis or transcervical CVS. In circumstances where transabdominal CVS may be technically difficult the preferred options are transcervical CVS in the first trimester or second trimester amniocentesis.