Recent economic evaluations of antenatal screening: a systematic review and critique

An economic analysis of chromosome testing in couples with children who have structural chromosome abnormalities

Background

Structural chromosome abnormalities can cause significant negative reproductive outcomes as they typically result in morbidity and mortality of newborns. The prevalence of structural chromosomal abnormalities in live births is at least 0.05%, of which many of them have parental origins. It is uncommon to predict structural chromosome abnormalities at birth in the first child but it is possible to prevent repeated abnormalities through screening and diagnostic programmes. This study will provide an economic analysis of the prenatal detection of these abnormalities.

Methods

A cost-benefit analysis using a decision analytic model was employed to compare the status quo (doing nothing) with two interventional strategies. The first strategy (Strategy I) is preconceptional screening plus amniocentesis, and the second strategy (Strategy II) is amniocentesis alone. The monetary values in Thai baht (THB) were adjusted to international dollars (I$) using purchasing power parity (PPP) (I$1 = THB 17.60 for the year 2013). The robustness of the results was tested by applying a probabilistic sensitivity analysis.

Results

Both diagnostic strategies can reduce approximately 10.7–11.1 births with abnormal chromosomes per 1,000 diagnosed couples. The benefit cost ratios were 1.62 for Strategy I and 1.24 for Strategy II. Net present values per 1,000 diagnoses in couples were I$464,000 for Strategy I and I$267,000 for Strategy II. The probabilistic sensitivity analysis suggested that the cost-benefit analysis was sufficiently robust, confirming that both strategies provided higher benefits than costs.

Conclusions

Since the benefits of both diagnostic strategies exceeded their costs, both strategies are economical–with Strategy I being more economically attractive. Strategy I is superior to Strategy II because it decreases the risk of normal children potentially dying from the amniocentesis process.

Development of a Health Screening Package Under the Universal Health Coverage: The Role of Health Technology Assessment

This study reports the systematic development of a population-based health screening package for all Thai people under the universal health coverage (UHC). To determine major disease areas and health problems for which health screening could mitigate health burden, a consultation process was conducted in a systematic, participatory, and evidence-based manner that involved 41 stakeholders in a half-day workshop. Twelve diseases/health problems were identified during the discussion. Subsequently, health technology assessments, including systematic review and meta-analysis of health benefits as well as economic evaluations and budget impact analyses of corresponding population-based screening interventions, were completed. The results led to advice against elements of current clinical practice, such as annual chest X-rays and particular blood tests (e.g. kidney function test), and indicated that the introduction of certain new population-based health screening programs, such as for chronic hepatitis B, would provide substantial health and economic benefits to the Thais. The final results were presented to a wide group of stakeholders, including decision-makers at the Ministry of Public Health and the public health insurance schemes, to verify and validate the findings and policy recommendations. The package has been endorsed by the Thai UHC Benefit Package Committee for implementation in fiscal year 2016.

Methodological reviews of economic evaluations in health care: what do they target?

INTRODUCTION AND OBJECTIVES

An increasing number of published studies of economic evaluations of health technologies have been reviewed and summarized with different purposes, among them to facilitate decision-making processes. These reviews have covered different aspects of economic evaluations, using a variety of methodological approaches. The aim of this study is to analyze the methodological characteristics of the reviews of economic evaluations in health care, published during the period 1990-2010, to identify their main features and the potential missing elements. This may help to develop a common procedure for elaborating these kinds of reviews.

METHODS

We performed systematic searches in electronic databases (Scopus, Medline and PubMed) of methodological reviews published in English, period 1990-2010. We selected the articles whose main purpose was to review and assess the methodology applied in the economic evaluation studies. We classified the data according to the study objectives, period of the review, number of reviewed studies, methodological and non-methodological items assessed, medical specialty, type of disease and technology, databases used for the review and their main conclusions. We performed a descriptive statistical analysis and checked how generalizability issues were considered in the reviews.

RESULTS

We identified 76 methodological reviews, 42 published in the period 1990-2001 and 34 during 2002-2010. The items assessed most frequently (by 70% of the reviews) were perspective, type of economic study, uncertainty and discounting. The reviews also described the type of intervention and disease, funding sources, country in which the evaluation took place, type of journal and author's characteristics. Regarding the intertemporal comparison, higher frequencies were found in the second period for two key methodological items: the source of effectiveness data and the models used in the studies. However, the generalizability issues that apparently are creating a growing interest in the economic evaluation literature did not receive as much attention in the reviews of the second period. The remaining items showed similar frequencies in both periods.

CONCLUSIONS

Increasingly more reviews of economic evaluation studies aim to analyze the application of methodological principles, and offer summaries of papers classified by either diseases or health technologies. These reviews are useful for finding literature trends, aims of studies and possible deficiencies in the implementation of methods of specific health interventions. As no significant methodological improvement was clearly detected in the two periods analyzed, it would be convenient to pay more attention to the methodological aspects of the reviews.

Systematic review and quality assessment of cost-effectiveness analysis of pharmaceutical therapies for advanced colorectal cancer

OBJECTIVE

To systematically review and assess the quality of cost-effectiveness analyses (CEAs) of pharmaceutical therapies for metastatic colorectal cancer (mCRC).

DATA SOURCES

The MEDLINE, EMBASE, Cochrane, and EconLit databases were searched for the Medical Subject Headings or text key words quality-adjusted, QALY, life-year gained (LYG), and cost-effectiveness (January 1, 1999-December 31, 2009).

STUDY SELECTION

Original CEAs of mCRC pharmacotherapy published in English were included. CEAs that measured health effects in units other than quality-adjusted life years or LYG and letters to the editor, case reports, posters, and editorials were excluded.

DATA EXTRACTION

Each article was independently assessed by 2 trained reviewers according to a quality checklist created by the Panel on Cost-Effectiveness in Health and Medicine.

RESULTS

Twenty-four CEA studies pertaining to pharmaceutical therapies for mCRC were identified. All studies showed a wide variation in methodologic approaches, which resulted in a different range of incremental cost-effectiveness ratios reported for each regimen. We found common methodologic flaws in a significant number of CEA studies, including lack of clear description for critique of data quality; lack of method for adjusting costs for inflation and methods for obtaining expert judgment; no results of model validation; wide differences in the types of perspective, time horizon, study design, cost categories, and effect outcomes; and no quality assessment of data (cost and effectiveness) for the interventions evaluation.

CONCLUSIONS

This study has shown a wide variation in the methodology and quality of cost-effectiveness analysis for mCRC. Improving quality and harmonization of CEA for cancer treatment is needed. Further study is suggested to assess the quality of CEA methodology outside the mCRC disease state.

Screening for Chlamydia trachomatis: a systematic review of the economic evaluations and modelling

OBJECTIVE

To review systematically and critically, evidence used to derive estimates of costs and cost effectiveness of chlamydia screening.

METHODS

Systematic review. A search of 11 electronic bibliographic databases from the earliest date available to August 2004 using keywords including chlamydia, pelvic inflammatory disease, economic evaluation, and cost. We included studies of chlamydia screening in males and/or females over 14 years, including studies of diagnostic tests, contact tracing, and treatment as part of a screening programme. Outcomes included cases of chlamydia identified and major outcomes averted. We assessed methodological quality and the modelling approach used.

RESULTS

Of 713 identified papers we included 57 formal economic evaluations and two cost studies. Most studies found chlamydia screening to be cost effective, partner notification to be an effective adjunct, and testing with nucleic acid amplification tests, and treatment with azithromycin to be cost effective. Methodological problems limited the validity of these findings: most studies used static models that are inappropriate for infectious diseases; restricted outcomes were used as a basis for policy recommendations; and high estimates of the probability of chlamydia associated complications might have overestimated cost effectiveness. Two high quality dynamic modelling studies found opportunistic screening to be cost effective but poor reporting or uncertainty about complication rates make interpretation difficult.

CONCLUSION

The inappropriate use of static models to study interventions to prevent a communicable disease means that uncertainty remains about whether chlamydia screening programmes are cost effective or not. The results of this review can be used by health service managers in the allocation of resources, and health economists and other researchers who are considering further research in this area.

Ultrasound diagnostic schema for the determination of increased risk for chromosomal fetal aneuploidies in the first half of pregnancy

The aim of the study was to develop an early ultrasound diagnostic schema for the determination of increased risk for fetal chromosomal aneuploidies. The study was conducted on a population of 1318 pregnant women divided into 2 groups: 1255 women with the normal course of pregnancy and 63 women with diagnosed fetal abnormalities. There were 34 cases of chromosomal abnormalities (trisomy 21, 18, 13; triploidy; unbalanced inversion 9; deletion 16) and 29 cases of structural malformations. The estimation of the range of normal values was performed for the nuchal translucency (NT) measurement between 11 and 13 weeks and the nasal bone length (NB) measurement between 12 and 20 week. The results obtained in the collective set of normal pregnancies constituted the basis for the calculation of the range of normal values. The measurements of NB and NT showed a linear value increase with the pregnancy course. The following test characteristics (correlation to CRL) were recorded: NB - sensitivity 60%, specificity 98%, positive predictive value (PPV+) 43%, negative predictive value (NPV-) 98.9%. For the assumption that the test outcome means the presence or absence of the nasal bone in the ultrasound scan the sensitivity was 40%, but specificity 100%; NT - sensitivity 63.6%, specificity 98.2%, PPV+ 38.9%, NPV - 98.2%; NT + NB - presents similar characteristic to the NB or NT alone - sensitivity 55.6%, specificity 98.6%, PPV+ 50%, NPV - 98.9%. The following test characteristics for chromosomal aberration markers (correlation to BPD) were observed: NB - sensitivity 68.4%, specificity 97.4%, PPV+ 56.5%, NPV - 98.4%; NT - sensitivity 73.9%, specificity 97.9%, PPV+ 54.8%, NPV- 99.2%; NT + NB - sensitivity 94.7%, specificity 98.9%, PPV+ 90%, NPV - 99.7%, respectively. The "genetic sonogram" protocol for the structural defect detection was analysed: sensitivity was 80%, specificity 100%, PPV+ 100%, NPV - 99.7%. It is concluded that the new biometric parameter--nasal bone length (NB) and the corrected one--nuchal translucency thickness (NT) are useful markers for fetal abnormalities, especially for chromosomal aberrations. High predictive values of the diagnostic schema for the detection of aneuploidies and structural defects indicate that its application in correlation with the biparietal diameter (BPD) is highly recommended. The proposed schema is an effective algorithm for prenatal diagnostics characterised by high prognostic values. The possible introduction of the schema could result in a decrease of the invasive procedure rates, which could minimise the rate of miscarriages as a complication of amniocenteses.

Misconstructions in health economics applied to the evaluation of prenatal screening

The application of economic evaluation to prenatal screening has led to ethical debates about the joint risks of rationing and eugenics. These debates have chosen the wrong target, as economic evaluations espouse the hypotheses and value judgment of their commissioners. This paper explores the difficulties in interpreting and using the results of economic evaluations. The first set of difficulties concerns the diversity in end points and the lack of an aggregate end point to reflect a generally desirable outcome. Another set results from the wider societal implications of economic evaluations and the implicit value judgments. Misunderstandings of the methods used for the economic evaluation of prenatal screening result from the lack of clearly stated objectives from policy makers.

Preference-based approaches to measuring the benefits of perinatal care

Studies that measure benefits of health care interventions in natural or physical units cannot incorporate the several health changes that might occur within a single measure, and they overlook individuals' preferences for those health changes. This paper discusses and critically appraises the application of preference-based approaches to the measurement of the benefits of perinatal care that have developed out of economic theory. These include quality adjusted life year (QALY)-based approaches, monetary-based approaches, and discrete choice experiments. QALY-based approaches use scaling techniques, such as the rating scale, standard gamble approach, and time trade-off approach, or multi-attribute utility measures, to measure the health-related quality of life weights of health states. Monetary-based approaches include the revealed preference approach, which involves observing decisions that individuals actually make concerning health risks, and the willingness-to-pay approach, which provides a framework for investigating individuals' willingness to pay for benefits of health care interventions. Discrete choice experiments describe health care interventions in terms of their attributes, and elicit preferences for scenarios that combine different levels of those attributes. Empirical examples are used to illustrate each preference-based approach to benefit measurement, and several methodological issues raised by the application of these approaches to the perinatal context are discussed. Particular attention is given to identifying the relevant attributes to incorporate into the measurement instrument, appropriate respondents for the measurement exercise, potential sources of bias in description and valuation processes, and the practicality, reliability, and validity of alternative measurement approaches. The paper's conclusion is that researchers should be explicit and rigorous in their application of preference-based approaches to benefit measurement in the context of perinatal care.

Risky professional boundaries

This paper examines the role of various boundaries in giving both professional groups and individuals a sense of identity that provides both with status and legitimacy. Close attention is paid to the boundaries between personal and professional identities and values. Sociologists working with a discursive approach argue that professional identity and status are achieved through the rhetorical presentation of certain values and responsibilities as personal, and therefore outside the boundaries of professional practice. This paper takes this argument forward, by arguing that in particular contexts, certain kinds of values are consciously articulated as personal and incorporated into the defence of professional legitimacy. Bringing personal claims inside professional boundaries is further evidence of the fluid and negotiated quality of the boundary between personal and professional values and notions of self. The paper consists of a discussion of the construction of professional boundaries, professional involvement in risk, issues raised by antenatal screening and analysis of a study of a group of professionals involved in antenatal screening. The paper explores the circumstances within which even senior professional groups and individuals look to representations of the personal self as a defence against critiques of their professional practice. Where the risks that professionals generate and interpret are medically ambiguous and socially contentious the abstract professional and medical framework is insufficient and other rhetorical values become resources in securing the professional role.

Methodological limitations of economic evaluations of antenatal screening

A review of recent economic studies of antenatal screening reveals widespread violation of accepted economic evaluation methodology. In particular, the costs and benefits of antenatal screening are often misclassified and conflated, and the non-resource effects of averted costs are often excluded from the evaluation process. The result is a widespread violation of the explicit and systematic approaches taken by economic analysts more generally, and conclusions that may be described as misleading. This letter calls for economic analysts to be consistent in their application of economic evaluation methodology to antenatal screening programmes.