The economics of routine antenatal anti-D prophylaxis for pregnant women who are rhesus negative

Cost-effectiveness of noninvasive fetal RhD blood group genotyping in nonalloimmunized and alloimmunized pregnancies

BACKGROUND

We sought to determine the cost-effectiveness of noninvasive fetal RhD blood group genotyping in nonalloimmunized and alloimmunized pregnancies in Canada.

STUDY DESIGN AND METHODS

We developed two probabilistic state-transition (Markov) microsimulation models to compare fetal genotyping followed by targeted management versus usual care (i.e., universal Rh immunoglobulin [RhIG] prophylaxis in nonalloimmunized RhD-negative pregnancies, or universal intensive monitoring in alloimmunized pregnancies). The reference case considered a healthcare payer perspective and a 10-year time horizon. Sensitivity analysis examined assumptions related to test cost, paternal screening, subsequent pregnancies, other alloantibodies (e.g., K, Rh c/C/E), societal perspective, and lifetime horizon.

RESULTS

Fetal genotyping in nonalloimmunized pregnancies (at per-sample test cost of C$247/US$311) was associated with a slightly higher probability of maternal alloimmunization (22 vs. 21 per 10,000) and a reduced number of RhIG injections (1.427 vs. 1.795) than usual care. It was more expensive (C$154/US$194, 95% Credible Interval [CrI]: C$139/US$175-C$169/US$213) and had little impact on QALYs (0.0007, 95%CrI: -0.01-0.01). These results were sensitive to the test cost (threshold achieved at C$88/US$111), and inclusion of paternal screening. Fetal genotyping in alloimmunized pregnancies (at test cost of C$328/US$413) was less expensive (-C$6280/US$7903, 95% CrI: -C$6325/US$7959 to -C$6229/US$7838) and more effective (0.19 QALYs, 95% CrI 0.17-0.20) than usual care. These cost savings remained robust in sensitivity analyses.

DISCUSSION

Noninvasive fetal RhD genotyping saves resources and represents good value for the management of alloimmunized pregnancies. If the cost of genotyping is substantially decreased, the targeted intervention can become a viable option for nonalloimmunized pregnancies.

Noninvasive Fetal RhD Blood Group Genotyping: A Systematic Review of Economic Evaluations

OBJECTIVE

Noninvasive fetal rhesus D (RhD) blood group genotyping may prevent unnecessary use of anti-D immunoglobulin (RhIG) in non-alloimmunized RhD-negative pregnancies and can guide management of alloimmunized pregnancies. We conducted a systematic review of the economic literature to determine the cost-effectiveness of this intervention over usual care.

DATA SOURCES

Systematic literature searches of bibliographic databases (Ovid MEDLINE, Embase, and Cochrane) until February 26, 2019, and auto-alerts until October 30, 2020, and of grey literature sources were performed to retrieve all English-language studies.

STUDY SELECTION

We included studies done in serologically confirmed non-alloimmunized or alloimmunized RhD-negative pregnancies, comparing costs and effectiveness of the intervention versus usual care.

DATA EXTRACTION AND SYNTHESIS

Two reviewers extracted data from the eligible studies and assessed their methodological quality (risk of bias) using the Quality of Health Economic Studies (QHES) and Drummond tools. We narratively synthesized findings. Our review included 8 economic studies that evaluated non-invasive fetal RhD genotyping followed by targeted RhIG prophylaxis in non-alloimmunized pregnancies. Five studies further considered a subsequent alloimmunized pregnancy. The cost-effectiveness of the intervention versus usual care (e.g., universal RhIG or prophylaxis conditional on results of paternal testing) for non-alloiummunized pregnancies was inconsistent. Two studies indicated greater benefits and lower costs for the intervention, and another 2 suggested a trade-off. In 4 studies, the intervention was less effective and costlier than alternatives. Three studies were determined to be of high quality by both tools. Two of these studies favoured the intervention, and one assessed benefits in quality-adjusted life-years. No study clearly examined the cost-effectiveness of repetitive use of fetal genotyping in multiple non-alloimmunized or alloimmunized pregnancies. The cost of genotyping was the most influential parameter.

CONCLUSION

The cost-effectiveness of noninvasive fetal RhD genotyping for non-alloimmunized pregnancies varies between studies. Potential savings from targeted management of alloimmunized pregnancies requires further research.

Time points and risk factors for RhD immunizations after the implementation of targeted routine antenatal anti-D prophylaxis: A retrospective nationwide cohort study

INTRODUCTION

Targeted routine antenatal anti-D prophylaxis was introduced to the national prophylaxis program in Finland in late 2013. The aim of this study was to assess the incidence, time-points, and risk factors for Rhesus D immunization after the implementation of routine antenatal anti-D prophylaxis, in all women in Finland with antenatal anti-D antibodies detected in 2014-2017.

MATERIAL AND METHODS

In a nationwide population-based retrospective cohort study, the incidence, time-points, and risk factors of anti-D immunizations were analyzed. Information on antenatal screening was obtained from the Finnish Red Cross Blood Service database, and obstetric data from hospital records and the Finnish Medical Birth Register.

RESULTS

The study included a total of 228 women (197 with complete data for all pregnancies). After the implementation of routine antenatal anti-D prophylaxis, the prevalence of pregnancies with anti-D antibodies decreased from 1.52% in 2014 to 0.88% in 2017, and the corresponding incidence of new immunizations decreased from 0.33% to 0.10%. Time-points for detection of new anti-D antibodies before and after 2014 were the first screening sample at 8-12 weeks of gestation in 52% versus 19%, the second sample at 24-26 weeks in 20% versus 50%, and the third screening at 36 weeks in 28% versus 32%.

CONCLUSIONS

The incidence of new anti-D immunizations decreased as expected after the implementation of routine antenatal anti-D prophylaxis. True failures are rare and they mainly occur when the prophylaxis is not given appropriately, suggesting a need for constant education of healthcare professionals on the subject.

A case report of haemolytic disease of the foetus and newborn caused by Alloantibody D and Jka in a Rhesus D negative Nigerian woman: Justification for the implementation of universal access to prophylaxis and evidenced-based best practices

A case report of a 38 years old ABO group A and Rhesus D negative multiparous, gravidae 8 and para 2, Nigerian woman who had a case of premarital miscarriage and who was not offered anti-D prophylaxis as part of her management. Lady went on to develop alloantibody D and Jka. Lady has had 7 further pregnancies post the miscarriage. The first child who is B Rhesus D positive is the only surviving child. The surviving child was delivered severely jaundiced and needed management post-delivery for haemolytic disease of the foetus and newborn (HDFN). Lady has had a history of a stillbirth. She was given a non-clinically indicated anti-D prophylaxis during the second pregnancy despite having been previously sensitized. The second baby died 3 months after delivery from complications of HDFN. She had had a further history of 5 miscarriages. She has had challenge with conception since 2010. Alloantibody testing confirms the presence alloantibody D and anti-Jka. Finding from this is a clear case of sub-optimal laboratory, obstetric and neonatal care offered particularly to pregnant women who are Rh D negative and those with alloantibodies in Nigeria. The Nigerian government will need to implement evidenced-based best practices; determination of alloantibody status of pregnant women during their first antenatal visit; provision of facilities for alloantibody identification, titration, quantification and feto maternal haemorrhage testing (FMH); implementation of a policy on universal access to anti-D prophylaxis for pregnant Rh D negative women who are not previously sensitized; provision of facilities required for the optimal intrauterine management of HDFN (foetal genotype testing, intrauterine transfusion, doppler ultrasound to diagnose anaemia inutero and provision of donor blood that meet the minimum requirements for intrauterine transfusion); determination of Rh D status of women who require a termination of pregnancy and provision of prophylactic anti-D for those found Rh D negative within 72 hours of procedure and the optimization of the knowledge of Medical Laboratory Scientist, Obstetricians, Neonatologist, Pharmacist and Traditional Birth Attendants in a bid to reduce the residual number of women who become sensitized and the number of preventable deaths of babies with HDFN.

Recommendations Regarding Practical DEL Typing Strategies for Serologically D-Negative Asian Donors

Background

DEL, the weakest D variant, is mistyped as D-negative by routine serological assays. Transfusion of red blood cells expressing the DEL phenotype has the potential to elicit anti-D alloimmunization in D-negative recipients. The goal of this study was to recommend DEL typing strategies for serologically D-negative Asian donors.

Methods

RhCE phenotyping and the adsorption-elution test were performed on 674 serologically D-negative samples. RHD genotyping using real-time polymerase chain reaction and melting curve analysis were also undertaken to identify DEL alleles. Costs and turnaround time of RhCE phenotyping, the adsorption-elution test, and RHD genotyping were estimated.

Results

Sensitivity and specificity of the adsorption-elution test for serologically D-negative samples were 94.9% (93/98) and 91.5% (527/576), respectively. C+ phenotypes were detected in all 98 samples with DEL alleles. Despite comparable costs, RHD genotyping was more accurate and rapid than the adsorption-elution test.

Conclusions

Two practical DEL typing strategies using RhCE phenotyping as an initial screening method were recommended for serologically D-negative Asian donors. Compared with DEL typing using RHD genotyping, serological DEL typing using adsorption-elution test is predicted to increase the incidence of anti-D alloimmunization and decrease the D-negative donor pool without having any cost-competitiveness but can be used in laboratories where molecular methods are not applicable.

High-throughput non-invasive prenatal testing for fetal rhesus D status in RhD-negative women not known to be sensitised to the RhD antigen: a systematic review and economic evaluation

BACKGROUND

High-throughput non-invasive prenatal testing (NIPT) for fetal rhesus (D antigen) (RhD) status could avoid unnecessary treatment with routine anti-D immunoglobulin for RhD-negative women carrying a RhD-negative fetus, although this may lead to an increased risk of RhD sensitisations.

OBJECTIVES

To systematically review the evidence on the diagnostic accuracy, clinical effectiveness and implementation of high-throughput NIPT and to develop a cost-effectiveness model.

METHODS

We searched MEDLINE and other databases, from inception to February 2016, for studies of high-throughput NIPT free-cell fetal deoxyribonucleic acid (DNA) tests of maternal plasma to determine fetal RhD status in RhD-negative pregnant women who were not known to be sensitised to the RhD antigen. Study quality was assessed with the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) and A Cochrane Risk of Bias Assessment Tool: for Non-Randomised Studies of Interventions (ACROBAT-NRSI). Summary estimates of false-positive rates (FPRs) and false-negative rates (FNRs) were calculated using bivariate models. Clinical effectiveness evidence was used to conduct a simulation study. We developed a de novo probabilistic decision tree-based cohort model that considered four alternative ways in which the results of NIPT could guide the use of anti-D immunoglobulin antenatally and post partum. Sensitivity analyses (SAs) were conducted to address key uncertainties and model assumptions.

RESULTS

Eight studies were included in the diagnostic accuracy review, seven studies were included in the clinical effectiveness review and 12 studies were included in the review of implementation. Meta-analyses included women mostly at or post 11 weeks' gestation. The pooled FNR (women at risk of sensitisation) was 0.34% [95% confidence interval (CI) 0.15% to 0.76%] and the pooled FPR (women needlessly receiving anti-D) was 3.86% (95% CI 2.54% to 5.82%). SAs did not materially alter the overall results. Data on clinical outcomes, including sensitisation rates, were limited. Our simulation suggests that NIPT could substantially reduce unnecessary use of antenatal anti-D with only a small increase in the risk of sensitisation. All large implementation studies suggested that large-scale implementation of high-throughput NIPT was feasible. Seven cost-effectiveness studies were included in the review, which found that the potential for the use of NIPT to produce cost savings was dependent on the cost of the test. Our de novo model suggested that high-throughput NIPT is likely to be cost saving compared with the current practice of providing routine antenatal anti-D prophylaxis to all women who are RhD negative. The extent of the cost saving appeared to be sufficient to outweigh the small increase in sensitisations. However, the magnitude of the cost saving is highly sensitive to the cost of NIPT itself.

LIMITATIONS

There was very limited evidence relating to the clinical effectiveness of high-throughput NIPT, with no evidence on potential adverse effects. The generalisability of the findings to non-white women and multiple pregnancies is unclear.

CONCLUSIONS

High-throughput NIPT is sufficiently accurate to detect fetal RhD status in RhD-negative women from 11 weeks' gestation and would considerably reduce unnecessary treatment with routine anti-D immunoglobulin, potentially resulting in cost savings of between £485,000 and £671,000 per 100,000 pregnancies if the cost of implementing NIPT is in line with that reflected in this evaluation.

FUTURE WORK

Further research on the diagnostic accuracy of NIPT in non-white women is needed.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42015029497.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Rhesus disease: a global prevention strategy

After nearly five decades of effective prophylaxis in high-income countries, the incidence of rhesus haemolytic disease (also known as haemolytic disease of the fetus and newborn) has substantially decreased, and as a result, clinical experience of the disease among health-care providers is insufficient. By contrast, a worldwide study found that rhesus haemolytic disease continues to be a public health problem in low-income and middle-income countries, affecting annually in more than 150 000 children, and causing thousands of stillbirths, neonatal deaths, and cases of hyperbilirubinaemia with its sequelae (kernicterus and bilirubin-induced neurological dysfunction). Solutions to this problem will require the combined and integrated effort of physicians and other health-care workers, international agencies, manufacturers of the prophylactic agent (rhesus immunoglobulin), health policy makers, and governments of low-income and middle-income countries.

Rh(O)D immune globulin products for prevention of alloimmunization during pregnancy

PURPOSE

The pharmacologic properties of Rhesus (Rh) immune globulin (RhIG) and clinical data on its effectiveness in preventing Rh-antigen alloimmunization in pregnant women are reviewed.

SUMMARY

RhIG is a human plasma derivative that targets red blood cells (RBCs) positive for Rh(O) antigen (also called D antigen). In the United States and other countries, the widespread use of RhIG has markedly reduced the occurrence of hemolytic disease of the fetus and newborn (HDFN), a devastating condition caused by D-antigen sensitization of a pregnant woman via exposure to fetal RBCs (usually during detachment of the placenta in labor) that results in a maternal immune response leading to severe hemolysis in the fetus. Routine administration of RhIG at 26-30 weeks' gestation and again within 72 hours of delivery has been shown to be highly effective in preventing maternal Rh alloimmunization, with very low rates of D-antigen sensitization (in the range of 0-2.2%) reported in multiple studies of at-risk women. The four RhIG products currently available in the United States have common clinical indications but differ in certain attributes. Pharmacists can play an important role in guiding other clinicians on the rationale for the use of RhIG, important differences between products, and appropriate timing of RhIG therapy.

CONCLUSION

Routine administration of RhIG to women at risk for Rh alloimmunization is clinically effective and has made HDFN a rare clinical event. The available RhIG products are not the same and should be carefully reviewed to ensure that they are administered safely.

Cost-analysis of the WHO Essential Medicines List in A Resource-Limited Setting: Experience from A District Hospital in India

The World Health Organization (WHO) has been publishing the essential medicines list (EML) since 1977. The EML includes the most efficacious, safe and cost-effective drugs for the most relevant public health conditions worldwide. The WHO performs a cost-effectiveness analysis within each therapeutic group, but very little is known about which therapeutic groups are costliest for hospitals that adopt the WHO EML concept. In this study, we have described the annual consumption of medicines in a district hospital in India, that limited the list of available drugs according to the WHO EML concept. Only 21 drugs constituted 50% of the hospital spending. Anti-infective medicines accounted for 41% of drug spending, especially antiretrovirals which were used to treat HIV infection. Among other therapeutic groups, insulin had the highest impact on the hospital budget. We identified medicines used in perinatal care, which included anti-D immunoglobulin and lung surfactants, that were used rarely, but bore a relatively high cost burden. The results of this study indicate that, in district that adopt the WHO EML, antiretrovirals and antibiotics were the top therapeutic groups for the drug hospital budgets.

Public health and prevention in Europe: is it cost-effective?

Objectives

In the public debate surrounding public health and prevention, it is sometimes assumed that preventive interventions are by definition cost-effective. This paper aims to explore whether preventive pharmaceutical interventions are more cost-effective than a curative approach to diseases.

Methods

A descriptive study identified European economic evaluations in the Tufts Medical Center Cost-Effectiveness Analysis Registry between 2000 and 2007. Data were extracted on publication year, target population, intervention, patient sample, disease, prevention stage and incremental cost-utility ratio of each economic evaluation. Preventive interventions were defined as measures preventing disease onset. Curative interventions related to measures identifying patients with risk factors or preclinical disease or interventions limiting disability after harm has occurred. Results were expressed in terms of costs (valued in Euros at 2008 prices) per quality-adjusted life year. The association between incremental cost-utility ratios and prevention stage was examined by means of the Mann–Whitney U test.

Key findings

The analysis included 231 studies that reported information about 608 incremental cost-effectiveness ratios. Preventive interventions included interventions that were more effective and less expensive than comparators (41% of incremental cost-effectiveness ratios), and interventions that improved outcomes and increased costs (59%). Both preventive and curative interventions covered the full range of cost-effectiveness results. However, preventive interventions had a significantly lower median ratio of €6255 per quality-adjusted life year and were thus more cost-effective than curative interventions (€12 917 per quality-adjusted life year) (P=0.002).

Conclusions

Although the cost-effectiveness of preventive interventions varies substantially, preventive interventions tended to be more cost-effective than curative interventions.

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.

Relevance of new recommendations on routine antenatal prevention of rhesus immunization: an appraisal based on a retrospective analysis of all cases observed in two French administrative areas of 3 million inhabitants

OBJECTIVE

To assess the potential impact of new guidelines recommending routine antenatal prophylaxis at 28 weeks of pregnancy on incidence, consequences and cost of rhesus immunization.

STUDY DESIGN

All rhesus immunizations of 224,500 ongoing pregnancies in two neighbouring administrative areas in France between 2000 and 2006 were enrolled in this retrospective study. To determine the aetiology of immunization and to specify when sensitization occurred, we searched sensitizing events between the last negative and the first positive red-cell antibody test results. Perinatal consequences and costing were also analyzed.

RESULTS

From 138 rhesus negative women bearing anti-D antibodies, none had received routine prophylaxis at 28 weeks. 37% were primary immunizations and 63% were reactivating former immunization. 63% sensitizations occurred after unprovoked foetal-maternal haemorrhage, mostly after 28 weeks (54%). Twenty-five (18.1%) sensitizations resulted from inappropriate management of existing prophylaxis. Immigrants with previously acquired antibodies accounted for 10% of cases. There was no foetal demise and none born before 28 weeks among our 140 babies. Only 25% required intensive care, mostly those born to mothers reactivating immunization, with an overall good perinatal outcome. Systematic 28-week prophylaxis would have cost about euro 2.5 million to reduce overall cost of immunizations by euro 0.6 million.

CONCLUSIONS

The incidence of rhesus immunization in our population was low at 0.41 per thousand. Routine antenatal prophylaxis could have avoided 54% of these immunizations but expected perinatal benefits are low, as newborns with the worst issue were born to mothers with unavoidable immunizations. Therefore the cost-effectiveness of this strategy is doubtful.

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

Articles reporting the diagnostic accuracy of non-invasive prenatal diagnostic (NIPD) tests for RHD genotyping using fetal material extracted from maternal blood have been published steadily for over a decade. Health care providers in Europe have started to use this technology for management of the small number of sensitised pregnancies (ca. 220-600 per annum in the Netherlands, Germany, France and the UK). Scientists and clinicians are also advocating widespread implementation for the far larger number of non-sensitised RhD-negative pregnancies (ca. 34,000-125,000 per annum in the same countries). Large-scale, prospective trials are only now underway. Estimates of the technical performance of these tests are currently based on results from small-scale studies, together with formal meta-analysis. The issue of early assessment of test performance is one faced by many new genetic tests. As part of a wider study we have investigated the quality of reporting of diagnostic accuracy in publications and produced guidelines for future studies. A systematic search of the literature identified 27 papers which met predefined inclusion criteria. All 27 papers were, first, assessed against an international quality (STARD) checklist for reporting of diagnostic accuracy and, second, against our own in-house NIPD proforma to assess the implications of the quality of reporting specifically for the RhD NIPD test. Authors were found to generally present an optimistic view of NIPD, bearing in mind weaknesses identified in reporting and conduct of their studies and the analysis of results, as evidenced by the low STARD scores. The NIPD proforma identified that specific biases were potentially introduced through selective population sampling and/or failure to report the make-up of the population tested, omission of inconclusive results, inconsistencies in the handling of repeat results on a sample, and lack of adequate controls. These factors would inevitably affect the validity of diagnostic accuracy as reported in individual publications, as well as any subsequent meta-analyses. Together, published reports to date may provide a biased picture of the actual potential of NIPD testing for fetal RHD genotyping. Generalisation of the available evidence on diagnostic accuracy, especially to large-scale implementation of NIPD testing of non-sensitised women, will also require that decision makers consider further aspects such as test reliability and cost of routine testing in clinical practice. It is recommended that all studies of diagnostic accuracy of NIPD tests adhere to the STARD quality checklist in order to improve reporting, thereby, minimising bias and increasing the comparability of studies. Researchers should also consider specific shortcomings for NIPD and avoid selective participant sampling; report population characteristics; report handling of replicate sampling as well as their failure rates; and include controls for genotypes tested in the study. Furthermore, meta-analyses should consider the quality, as well as the sample size, of NIPD studies in their analysis. Larger trials, required to produce results that are valid and meaningful for clinical practice, must also adhere to these reporting standards.