Factors affecting the uptake of prenatal diagnosis for sickle cell disease

Assessing knowledge of sickle cell disease and health beliefs on premarital genetic screening among healthcare trainees at a tertiary institution: A cross-sectional study

Background

The uptake of sickle cell trait (SCT) test is challenged by several factors. A community of healthcare professionals educating the public to undergo screening is critical in reducing the disease burden. We investigated knowledge and attitude towards premarital SCT screening among healthcare trainee students who are the next generation of healthcare practitioners.

Methods

A cross-sectional design was employed, and quantitative data were collected from 451 female students pursuing healthcare programs at a tertiary institution in Ghana. Descriptive, bivariate, and multivariate logistic regression analysis was performed.

Results

More than half of the participants were 20-24 years (54.55%) and had good knowledge (71.18%) about sickle cell disease (SCD). Age and school or social media as sources of information were significantly associated with good knowledge about SCD. Students between the age 20-24 (adjusted odds ratio [AOR] = 2.54, confidence interval [CI] = 1.30-4.97) and knowledge (AOR = 2.19, CI = 1.41-3.39) were 3 times and 2 times more likely to have a positive perception about SCD severity. Students who have SCT (AOR = 5.16, CI = 2.46-10.82), whose source of information was family member/friends (AOR = 2.83, CI = 1.44-5.59) and social media (AOR = 4.59, CI = 2.09-10.12) were 5 times, 2 times and 5 times likely to have a positive perception about the susceptibility of SCD. Students whose source of information is school (AOR = 2.06, CI = 1.11-3.81) and who have good knowledge of SCD (AOR = 2.25, CI = 1.44-3.52) were 2 times more likely to have a positive perception about the benefits of testing. Students with SCT (AOR = 2.64, CI = 1.36-5.13) and source of information was social media (AOR = 3.01, CI = 1.36-6.64) were about 3 times more likely to have a positive perception about the barriers to testing.

Conclusion

Our data shows that high level of SCD knowledge influences positive perceptions about the severity of SCD, the benefits and relatively low barriers to SCT or SCD testing and genetic counseling. Dissemination of SCT, SCD and premarital genetic counseling education should be intensified especially in schools.

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.

The Social and Cultural Context of Coping with Sickle Cell Disease: I. A Review of Biomedical and Psychosocial Issues

Sickle cell disease (SCD) is widely conceived in the United States as a group of blood disorders that principally affect African Americans. Although pain is its principal feature, strokes, lung problems, sepsis, anxiety, depression, impaired social functioning, and maladjustment at work are frequent concomitants. This article selectively reviews biomedical and psychosocial aspects of SCD related to pain assessment, medical treatment, genetic counseling, education, and employment. The strongest support exists for claims of social deficits among adolescents and depression and work-related problems among adults. The social context of SCD, including issues related to socioeconomic status (SES), urbanicity, ethnicity, cultural values, and racial stigmatization, are important to include in empirical assessments and theoretical analyses of the effects of SCD on children and their families. The adverse psychosocial functioning often described as an effect of SCD might indeed be a consequence of these factors acting alone or in concert with the strains of SCD.

Initiation of a medical genetics service in sub-Saharan Africa: experience of prenatal diagnosis in Cameroon

BACKGROUND

Initiation of Prenatal Genetic Diagnosis (PND) has laid the foundation of the first medical genetic service in Cameroon.

METHOD

Cross-sectional descriptive study, illustrating some aspects of the genetic service using a small 24-months PND experience.

RESULTS

The service began with a medical geneticist who had to follow-up the building and equipments supplies of the diagnosis laboratory; and to personally perform genetic consultations, molecular experiments and post-results counseling. PND was indicated for sickle cell disease (SCD) in 33 cases (55%) and chromosomal anomalies in 27 cases (45%). With international collaboration, DNA analysis revealed 6 SCD-affected foetuses (20.7%); QF-PCR (N=25) and full karyotype (N=8) analysis revealed cases of trisomy 21 and trisomy 18. Following PND success, national effort granted more human and material resources to improve the service. The preliminary experience was made possible by three factors: 1) the availability of a trained Cameroonian medical geneticist 2) the availability of obstetricians trained in fetal medicine and 3) advocacy initiatives at national and international levels, which have proven invaluable for advice, training, sourcing of materials, and back-up reference diagnostic laboratory.

CONCLUSION

The practice of medical genetics, involving prenatal genetic diagnosis of sickle cell disease and chromosomal anomalies, is possible in Cameroon (sub-Saharan Africa).

Offering antenatal sickle cell and thalassaemia screening to pregnant women in primary care: a qualitative study of women's experiences and expectations of participation

OBJECTIVE

To describe the acceptability to women of being offered antenatal Sickle cell and Thalassaemia (SC&T) screening in primary and secondary care at the visit to confirm pregnancy; and to explore the implications of their views for participating in decisions about their health care.

METHODS

Qualitative semi-structured interviews were conducted with twenty-one ethnically diverse women registered at twenty-five general practices in two English inner-city Primary Care Trusts. The material was analysed thematically, using the method of constant comparison.

RESULTS

Women generally welcomed the opportunity of early diagnosis, although they expected screening to confirm they were carrying a healthy child. Women felt general practitioners did not present antenatal screening as a choice, but they did not necessarily see this as a problem. Doctors were believed to be acting out of concern for the women's well being.

CONCLUSIONS

Women were generally positive about being offered screening in primary care at the first visit to confirm pregnancy. To this extent it was acceptable to them, although this was largely informed by assumptions associated with being a 'good mother' rather than a straightforward enactment of informed choice, assumed by health-care policy. This represents the context in which women participate in decisions about their health care.

The UK control programme for the haemoglobin disorders

The haemoglobin disorders are a group of recessively inherited conditions of varying severity. In the homozygous state, alpha zero thalassaemia causes hydrops fetalis, beta thalassaemia usually causes a severe transfusion-dependent anaemia and sickle cell anaemia (HbSS), haemoglobin S/C disease, haemoglobin S/D disease and haemoglobin S/beta thalassaemia cause sickling disorders ranging from quite mild to very severe. Haemoglobin disorders are among the commonest inherited diseases in the UK. Management can be very burdensome, but produces good results in many cases. The disorders can also be prevented by a programme of carrier screening, genetic counselling and prenatal diagnosis in populations at risk. The WHO has defined a “haemoglobinopathy control programme” as an integral strategy combining optimal patient care with prevention based on community education, propective carrier diagnosis, genetic counselling and the offer of prenatal diagnosis. The services required for haemoglobin disorders in the UK have recently been reviewed in a report from the Standing Medical Advisory Committee of the Department of Health. This report focuses on genetic counselling and prenatal diagnosis for haemoglobin disorders.

GPs' opinions of their role in prenatal genetic services: a cross-sectional survey

BACKGROUND

In the UK about 4.5% of the population carry cystic fibrosis, whilst in the inner city areas an even higher proportion carry one of the haemoglobin disorders such as thalassaemia. Couples who both carry the same recessive disorder have a 1 in 4 risk of an affected child in every pregnancy.

OBJECTIVES

To assess GPs' confidence in their ability to provide initial prenatal advice for couples carrying common autosomal recessive disorders (either the cystic fibrosis or thalassaemia gene), and their opinions of different approaches for referral to prenatal diagnostic services for such at-risk couples.

METHODS

A cross-sectional postal survey of all 644 GPs in 388 general practices in Nottinghamshire. Practices were randomly allocated to receive either the cystic fibrosis or the thalassaemia scenario survey. The survey questions predominantly used six-point Likert scales to assess confidence and opinions of prenatal services.

RESULTS

The questionnaire was returned by 62% (397) of GPs. Only 23% (91) were confident in providing prenatal advice to the at-risk carrier couples. GPs were more confident about advising cystic fibrosis carriers than thalassaemia carriers (P = 0.01). The least popular approach to prenatal service provision was direct referral to prenatal services after counselling with 52% (194) scoring this as useful, whilst 60.5% (233) of GPs scored referral to the obstetric services with the prenatal diagnosis organised by the obstetrician as useful.

CONCLUSIONS

GPs perceive that they lack the confidence to provide basic prenatal genetic advice to women at risk of the commonest recessive disorders, with particularly low confidence where the couple both carry thalassaemia. A significant knowledge gap was demonstrated by the poor awareness of the importance of rapid referral to prenatal diagnostic services.

Social and ethnic inequalities in the offer and uptake of prenatal screening and diagnosis in the UK: a systematic review

OBJECTIVE

To review studies addressing the question of whether there are social inequalities in either the offer or the uptake of prenatal testing in the UK.

METHOD

Systematic review of studies assessing the offer or uptake of prenatal screening or diagnosis according to social class or ethnic origin. Electronic databases were searched using a strategy developed for a review of inequalities in access to maternity care supplemented with terms specific to prenatal testing. Further papers were identified from reference lists, citation searches and key organizations.

RESULTS

From over 600 identified papers, 41 were potentially relevant. Twenty met the inclusion criteria. The studies included covered screening and/or diagnosis for Down's syndrome, neural tube defects, haemoglobin disorders and HIV. Many studies were limited by small numbers or poor reporting of data and analysis. Six studies reported data on prenatal testing according to women's social class or educational level. None found any significant social inequalities in testing. Some studies suggested that women of South Asian origin might be up to 70% less likely to receive prenatal testing for haemoglobin disorders and Down's syndrome than White women. A small number of studies suggested that South Asian women might be less likely to be offered testing.

CONCLUSIONS

This review provides some evidence of ethnic inequalities in access to prenatal testing. Further research is required to improve our understanding of why testing may not be offered, the reasons for failure to take up testing when offered, and to identify whether there are other social inequalities in access to prenatal testing.

Reproductive decisions of parents of children with metabolic disorders

The Interaction Model of Client Health Behavior (IMCHB) served as a guide for variable selection and instrument development for telephone interviews with 230 parents of children with metabolic disorders. Sociodemographic, psycho-affective and client-professional interaction variables were examined in relation to three outcomes: (1) receptivity to future prenatal diagnosis (56% were receptive); (2) likelihood of terminating an affected pregnancy (10% would); and (3) whether or not the parent had taken measures to prevent another affected pregnancy (41% had). All three outcomes were significantly correlated with higher scores on the Parent Stress Index, lower scores on the Vineland Adaptive Behavior Scales, fewer persons in the parent's social support network, greater worry about the living child's future and greater perceived difficulty meeting the child's extra care needs. A regression model constructed to explain taking measures to prevent a future affected pregnancy illustrated the usefulness of the IMCHB in research that involves multiple interacting variables on health outcomes. Few of the parents (7.4%) reported an interaction with a genetic counsellor, highlighting the need for practitioners from multiple disciplines to be adequately educated in principles of genetics, especially the psychological and affective aspects of counselling.

Initiation of prenatal diagnosis of sickle-cell disorders in Africa

We introduced prenatal diagnosis of SCD in Nigeria in order to meet a rising demand. Our approach and experience are documented as a guide to others in countries with similar problems. A cost-recovery fee charged only to sustain the service predictably limited access to it. Ultrasound-guided transcervical (TC) or transabdominal (TA) sampling of 124 chorionic villi was done from nine weeks' gestation. All couples carried the sickle trait (AS) and 52 (51 per cent) women had previously had children with sickle-cell anaemia. 72 samples were obtained by the TA and 52 by the TC route. 7.2 per cent miscarried after CVS but the miscarriage rate was significantly higher (p=0.023) after TC CVS (13.5 per cent) than after TA CVS (2.8 per cent) and also higher in the first 62 (11.3 per cent) than after the last 62 CVS (3.2 per cent). DNA analysis of CVS indicated Hb AA in 29 (23.4 per cent), AS in 67 (54 per cent) and SS in 23 (18.5 per cent). No result was obtainable in five subjects for technical reasons. 96 per cent of the women with SS fetuses terminated the pregnancies. The need for a standby source of electricity where supply is unreliable and for providing an equitable service to all couples at risk are highlighted.

A multidisciplinary approach for improving services in primary care: randomised controlled trial of screening for haemoglobin disorders

OBJECTIVE

To investigate the feasibility of improving screening for carriers of haemoglobin disorders in general practice by using a nurse facilitator to work with primary care teams and the relevant haematology laboratories; to identify problems in communication between all those involved in delivering the service, and to implement solutions.

DESIGN

Two year, practice based randomised controlled trial.

SETTING

North London area where 29% of residents and 43% of births are in ethnic groups at risk for haemoglobin disorders.

SUBJECTS

26 of the 93 practices using the services of the area's haematology laboratory agreed to take part and were randomly divided into control and intervention practices.

MAIN OUTCOME MEASURE

Change in number of requests for screening tests for haemoglobin disorders made by control and intervention practices in baseline and intervention years.

RESULTS

The number of screening tests requested varied from 0-150 in the 93 practices in the baseline year. Study practices tended to have made a moderate number of requests (10-50) during this period. During the intervention year intervention practices made 292 more requests (99% increase) and control practices made 74 fewer requests (23% decrease; P=0.001 for difference in median change). Four practices, three of which were singlehanded, accounted for 75% of the increase. The number of requests from intervention practices, adjusted for baseline requests, was 3.2 times higher than control practices (P<0.0001).

CONCLUSION

General practitioners and practice nurses are willing to undertake a new genetic screening service (or expand an existing one) if they are persuaded that it benefits the health of a significant proportion of their practice population. They need appropriate tools (for example, information materials for carriers and groups at risk), and the laboratory must be sensitive to their needs. Preconceptional carrier screening and counselling need to be coupled with antenatal screening.

"Race", ethnicity and haemoglobin disorders

The new genetics has brought forth concerns that such developments as screening for genetic diseases will accentuate the oppression of minority ethnic groups [Bradby (1996) Genetics and racism. In The Troubled Helix: social and psychological aspects of the new human genetics, ed. T. Marteau and M. Richards, pp. 295-316. Cambridge University Press, Cambridge]. Haemoglobin disorders primarily affect minority ethnic groups in the U.K. but have been the subject of protest regarding lack of services as much as the unwelcome advent of them. This paper examines various conceptions of "race", from biological reductionism, through notions of ethnicity, racialized groups, sociological conceptions of "race", political and analytical uses of the term "Black" and so-called "new ethnicities" such as situational and plastic ethnicity in order to examine the consequences of these competing conceptions of race for a social analysis of sickle cell anaemia and beta-thalassaemia. The paper concludes that any group of people associated with the haemoglobin disorders are subject both to constraints upon their actions and opportunities for re-interpreting their social world. In conclusion it is proposed that no nomenclature classifies the phenomenon unproblematically. The notion of race as a political construct [Goldberg (1993) Racist Culture: Philosophy and the Politics of Meaning. Blackwell, Oxford] is used to suggest that attempts to construct all-embracing definitions themselves signal the potential abuses which may be attendant upon programmatic or mechanistic conceptions of the relationship between race and haemoglobin disorders.

Global epidemiology of hemoglobin disorders

Thalassemias and the hemoglobinopathies such as Hemoglobins S, C and E, are now a global problem. They have spread through migration from their native areas in the Mediterranean, Africa and Asia and are now endemic throughout Europe, the Americas and Australia. Comprehensive control programs in recent years have succeeded in limiting the numbers of new births and prolonging life in affected individuals. Such programs have been successful in a minority of countries and have little global impact. Over 300,000 infants with major syndromes are born every year and the majority die undiagnosed, untreated or under-treated. Countries may be divided into three general categories according to the services available: A. Endemic Mediterranean countries. In these long-established prevention programs have succeeded in achieving 80%-100% prevention. Specialized clinics able to provide optimum treatment. B. Areas of the developed, industrialized world where prevalence is increasing because of migration. These countries have the means to provide adequate control but have problems in reaching immigrant groups with different cultural background. C. Countries of the developing world where the provision of services is hampered by economic difficulties, other health priorities due to high infant mortality from infectious diseases, and religious/cultural constraints.

Delivering genetic screening to the community

Concern is often expressed that, in the future, screening for genetic risk will become too widespread. Haemoglobin disorders (the thalassaemias and sickle cell disorders) offer an excellent model for genetic screening, because they are common and severe. They are recessively inherited. Carriers can be detected by conventional blood tests with an accuracy of 99%, so couples at risk can be identified before they have children and offered genetic counselling and prenatal diagnosis. Carrier-screening programmes have been in place in several countries for over 20 years and now offer extensive practical experience of the problems of delivering the service equitably to entire populations. This experience suggests that the main risk is of too little rather than too much genetic screening, and of doing it badly, and demonstrates the need for a discipline of 'community genetics'. Here I propose that modern information technology has a central role in providing communities with adequate access to correct genetic information.

Prenatal screening for haemoglobin disorders

The technology has been available to detect carriers of haemoglobin disorders since the late 1960s. Prenatal diagnosis has been available since 1978. First trimester diagnosis by chorionic villus sampling and DNA analysis was introduced in 1982, and subsequent simplifications in DNA technology have made screening, counselling and prenatal diagnosis cost-effective at the community level, in countries at all levels of development. Audit of prenatal diagnosis for haemoglobin disorders in countries which have the resources and infrastructure necessary for genetic population screening (such as the UK and other European countries), has shown that the number of prenatal diagnoses actually performed fall far short of expectation. The demonstration that this reflects failures in delivering information, screening and counselling to the populations at risk, rather than rejection of prenatal diagnosis, shows the importance of placing more emphasis on the organisational and social requirements for genetic population screening. In some countries current attitudes towards abortion exclude provision of prenatal diagnosis within the health service, but in many such cases it has been set up in the private sector. It is also being introduced through combined private and charitable efforts in an increasing number of developing countries, including some with extremely limited health resources: such centres are likely to act as nuclei for emergence of genetics services in these communities. A particularly notable recent achievement is the introduction of prenatal diagnosis in Nigeria, where 1-2% of all children born suffer from sickling disorders.

Psychosocial and clinical burden of thalassaemia intermedia and its implications for prenatal diagnosis

Twenty eight patients with thalassaemia intermedia and their parents were interviewed using specifically designed questionnaires to evaluate psychosocial burden. Hospital notes were analysed for clinical burden. A wide variation was found for both patients and parents, ranging from virtually unaffected to severely affected. Normal sexual function and setting up a family were mentioned by patients and parents as being particularly important for quality of life. Over half (58%) of the patients had problems with sexual maturation and functioning, and continuous monitoring of all patients with thalassaemia intermedia by a paediatric endocrinologist is therefore strongly indicated. Most parents said, in light of their experiences, that they would opt for prenatal diagnosis and termination of affected pregnancies even if a genotype predicting the mild form of disorder were discovered.

Prenatal genetic counseling for hemoglobinopathy carriers: a comparison of primary providers of prenatal care and professional genetic counselors

Health personnel trained in medical genetics are insufficient to meet the demand for genetic services. Methods must be found to enable primary care providers to offer commonly needed genetic services themselves. In our recently reported community-wide prenatal screening program for hemoglobinopathies, 36% of women detected to have a hemoglobinopathy did not come to a tertiary center for counseling and thus may have not benefited from testing. To determine whether the efficiency of the program could be increased if counseling were provided by the prenatal care provider (obstetrician or family practitioner), we developed a pilot training program on the basis of our experience in offering such services and enlisted 68% of regional prenatal care providers to participate. The proportion of patients detected to have a hemoglobinopathy who received counseling was similar in the primary and tertiary provider groups: 59% versus 50%, respectively, for sickle trait, and 69% versus 66%, respectively, for beta-thalassemia trait. Knowledge after counseling was also similar for the primary and tertiary provider groups: 64% versus 66% (mean % correct), respectively, for sickle trait, and 79% versus 78%, respectively, for beta-thalassemia trait. However, the two provider groups significantly differed with regard to whether or not the patient had her partner tested. For sickle trait, it was 25% for the primary providers but 49% for the tertiary providers (P < .001). For beta-thalassemia trait, it was 47% for the primary providers but 78% for the tertiary providers (P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)