Cost-effectiveness of population screening for alpha-1 antitrypsin deficiency: a decision analysis

Benefits and harms of antenatal and newborn screening programmes in health economic assessments: the VALENTIA systematic review and qualitative investigation

Background

Health economic assessments are used to determine whether the resources needed to generate net benefit from an antenatal or newborn screening programme, driven by multiple benefits and harms, are justifiable. It is not known what benefits and harms have been adopted by economic evaluations assessing these programmes and whether they omit benefits and harms considered important to relevant stakeholders.

Objectives

(1) To identify the benefits and harms adopted by health economic assessments in this area, and to assess how they have been measured and valued; (2) to identify attributes or relevance to stakeholders that ought to be considered in future economic assessments; and (3) to make recommendations about the benefits and harms that should be considered by these studies.

Design

Mixed methods combining systematic review and qualitative work.

Systematic review methods

We searched the published and grey literature from January 2000 to January 2021 using all major electronic databases. Economic evaluations of an antenatal or newborn screening programme in one or more Organisation for Economic Co-operation and Development countries were considered eligible. Reporting quality was assessed using the Consolidated Health Economic Evaluation Reporting Standards checklist. We identified benefits and harms using an integrative descriptive analysis and constructed a thematic framework.

Qualitative methods

We conducted a meta-ethnography of the existing literature on newborn screening experiences, a secondary analysis of existing individual interviews related to antenatal or newborn screening or living with screened-for conditions, and a thematic analysis of primary data collected with stakeholders about their experiences with screening.

Results

The literature searches identified 52,244 articles and reports, and 336 unique studies were included. Thematic framework resulted in seven themes: (1) diagnosis of screened for condition, (2) life-years and health status adjustments, (3) treatment, (4) long-term costs, (5) overdiagnosis, (6) pregnancy loss and (7) spillover effects on family members. Diagnosis of screened-for condition (115, 47.5%), life-years and health status adjustments (90, 37.2%) and treatment (88, 36.4%) accounted for most of the benefits and harms evaluating antenatal screening. The same themes accounted for most of the benefits and harms included in studies assessing newborn screening. Long-term costs, overdiagnosis and spillover effects tended to be ignored. The wide-reaching family implications of screening were considered important to stakeholders. We observed good overlap between the thematic framework and the qualitative evidence.

Limitations

Dual data extraction within the systematic literature review was not feasible due to the large number of studies included. It was difficult to recruit healthcare professionals in the stakeholder's interviews.

Conclusions

There is no consistency in the selection of benefits and harms used in health economic assessments in this area, suggesting that additional methods guidance is needed. Our proposed thematic framework can be used to guide the development of future health economic assessments evaluating antenatal and newborn screening programmes.

Study registration

This study is registered as PROSPERO CRD42020165236.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR127489) and is published in full in Health Technology Assessment; Vol. 28, No. 25. See the NIHR Funding and Awards website for further award information.

Benefits and harms adopted by health economic assessments evaluating antenatal and newborn screening programmes in OECD countries: A systematic review of 336 articles and reports

BACKGROUND

Health economic assessments are used to determine whether the resources needed to generate net benefit from a screening programme, driven by multiple complex benefits and harms, are justifiable. We systematically identified the benefits and harms incorporated within economic assessments evaluating antenatal and newborn screening programmes.

METHODS

For this systematic review and thematic analysis, we searched the published and grey literature from January 2000 to January 2021. Studies that included an economic evaluation of an antenatal or newborn screening programme in an OECD country were eligible. We identified benefits and harms using an integrative descriptive analysis, and illustrated a thematic framework. (Systematic review registration PROSPERO, CRD42020165236).

FINDINGS

The searches identified 52,244 articles and reports and 336 (242 antenatal and 95 newborn) were included. Eighty-six subthemes grouped into seven themes were identified: 1) diagnosis of screened for condition, 2) life years and health status adjustments, 3) treatment, 4) long-term costs, 5) overdiagnosis, 6) pregnancy loss, and 7) spillover effects on family members. Diagnosis of screened for condition (115 studies, 47.5%), life-years and health status adjustments (90 studies, 37.2%) and treatment (88 studies, 36.4%) accounted for most of the benefits and harms evaluating antenatal screening. The same themes accounted for most of the benefits and harms included in studies assessing newborn screening. Overdiagnosis and spillover effects tended to be ignored.

INTERPRETATION

Our proposed framework can be used to guide the development of future health economic assessments evaluating antenatal and newborn screening programmes, to prevent exclusion of important potential benefits and harms.

Costs and health-related quality of life in Alpha-1-Antitrypsin Deficient COPD patients

BACKGROUND

Alpha-1-Antitrypsin Deficiency (AATD) is an economically unexplored genetic disease.

METHODS

Direct and indirect costs (based on self-reported information on healthcare utilization) and health-related quality of life (HRQL, as assessed by SGRQ, CAT, and EQ-5D-3 L) were compared between 131 AATD patients (106 with, 25 without augmentation therapy (AT)) and 2,049 COPD patients without AATD participating in the COSYCONET COPD cohort. The medication costs of AT were excluded from all analyses to reveal differences associated with morbidity profiles. The association of AATD (with/without AT) with costs or HRQL was examined using generalized linear regression modelling (GLM) adjusting for age, sex, GOLD grade, BMI, smoking status, education and comorbidities.

RESULTS

Adjusted mean direct annual costs were €6,099 in AATD patients without AT, €7,117 in AATD patients with AT (excluding costs for AT), and €7,460 in COPD patients without AATD. AATD with AT was significantly associated with higher outpatient (+273%) but lower inpatient (-35%) and medication costs (-10%, disregarding AT) compared with COPD patients without AATD. There were no significant differences between groups regarding indirect costs and HRQL.

CONCLUSION

Apart from AT costs, AATD patients tended to have lower, though not significant, overall costs and similar HRQL compared to COPD patients without AATD. AT was not associated with lower costs or higher HRQL.

TRIAL REGISTRATION

NCT01245933.

Results from a large targeted screening program for alpha-1-antitrypsin deficiency: 2003 - 2015

Background

Alpha-1-antitrypsin deficiency (AATD) is an autosomal codominant inherited disease that is significantly underdiagnosed. We have previously shown that the combination of an awareness campaign with the offer of free diagnostic testing results in the detection of a relevant number of severely deficient AATD patients. The present study provides an update on the results of our targeted screening program (German AAT laboratory, University of Marburg) covering a period from August 2003 to May 2015.

Methods

Diagnostic AATD detection test kits were offered free of charge. Dried blood samples were sent to our laboratory and used for the semiquantitative measurement of the AAT-level (nephelometry) and the detection of the S- or Z-allele (PCR). Isoelectric focusing was performed when either of the initial tests was indicative for at least one mutation. Besides, we evaluated the impact of additional screening efforts and the changes of the detection rate over time, and analysed the relevance of clinical parameters in the prediction of severe AATD.

Results

Between 2003 and 2015, 18,638 testing kits were analysed. 6919 (37.12 %) carried at least one mutation. Of those, we identified 1835 patients with severe AATD (9.82 % of the total test population) including 194 individuals with rare genotypes. Test initiatives offered to an unselected population resulted in a dramatically decreased detection rate. Among clinical characteristics, a history of COPD, emphysema, and bronchiectasis were significant predictors for Pi*ZZ, whereas a history of asthma, cough and phlegm were predictors of not carrying the genotype Pi*ZZ.

Conclusion

A targeted screening program, combining measures to increase awareness with cost-free diagnostic testing, resulted in a high rate of AATD detection. The clinical data suggest that testing should be primarily offered to patients with COPD, emphysema, and/or bronchiectasis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13023-016-0453-8) contains supplementary material, which is available to authorized users.

Indications for active case searches and intravenous alpha-1 antitrypsin treatment for patients with alpha-1 antitrypsin deficiency chronic pulmonary obstructive disease: an update

The effect of hereditary alpha-1 antitrypsin (AAT) deficiency can manifest clinically in the form of chronic obstructive pulmonary disease (COPD). AAT deficiency (AATD) is defined as a serum concentration lower than 35% of the expected mean value or 50 mg/dl (determined by nephelometry). It is associated in over 95% of cases with Pi*ZZ genotypes, and much less frequently with other genotypes resulting from combinations of Z, S, rare and null alleles. A systematic qualitative review was made of 107 articles, focusing mainly on an active search for AATD in COPD patients and intravenous (iv) treatment with AAT. On the basis of this review, the consultant committee of the Spanish Registry of Patients with AATD recommends that all COPD patients be screened for AATD with the determination of AAT serum concentrations, and when these are low, the evaluation must be completed with phenotyping and, on occasions, genotyping. Patients with severe AATD COPD should receive the pharmacological and non-pharmacological treatment recommended in the COPD guidelines. There is enough evidence from large observational studies and randomized placebo-controlled clinical trials to show that the administration of iv AAT reduces mortality and slows the progression of emphysema, hence its indication in selected cases that meet the inclusion criteria stipulated in international guidelines. The administration of periodic infusions of AAT is the only specific treatment for delaying the progression of emphysema associated with AATD.

Accounting for increased non-target-disease-specific mortality in decision-analytic screening models for economic evaluation

BACKGROUND

Positive screening results are often associated not only with target-disease-specific but also with non-target-disease-specific mortality. In general, this association is due to joint risk factors. Cost-effectiveness estimates based on decision-analytic models may be biased if this association is not reflected appropriately.

OBJECTIVE

To develop a procedure for quantifying the degree of bias when an increase in non-target-disease-specific mortality is not considered.

METHODS

We developed a family of parametric functions that generate hazard ratios (HRs) of non-target-disease-specific mortality between subjects screened positive and negative, with the HR of target-disease-specific mortality serving as the input variable. To demonstrate the efficacy of this procedure, we fitted a function within the context of coronary artery disease (CAD) risk screening, based on HRs related to different risk factors extracted from published studies. Estimates were embedded into a decision-analytic model, and the impact of 'modelling increased non-target-disease-specific mortality' was assessed.

RESULTS

In 55-year-old German men, based on a risk screening with 5% positively screened subjects, and a CAD risk ratio of 6 within the first year after screening, incremental quality-adjusted life-years were 19% higher and incremental costs were 8% lower if no adjustment was made. The effect varied depending on age, gender, the explanatory power of the screening test and other factors.

CONCLUSION

Some bias can occur when an increase in non-target-disease-specific mortality is not considered when modelling the outcomes of screening tests.

A review of augmentation therapy for alpha-1 antitrypsin deficiency

INTRODUCTION

Alpha-1 antitrypsin deficiency (AATD) is a relatively common, but under-recognized condition which manifests commonly with liver cirrhosis and emphysema. Specific therapy for lung-affected individuals with AATD is augmentation therapy, which consists of intravenous infusion of purified human plasma-derived alpha-1 antitrypsin (AAT). Augmentation therapy was first approved by the United States Food and Drug Administration (FDA) in 1987 for emphysema associated with severe AATD and today, six augmentation therapy preparations, all of which derive from pooled human plasma, have received FDA approval.

AREAS COVERED

This paper reviews augmentation therapy for AATD, including the various available commercial preparations, their processing and biochemical differences, evidence regarding biochemical and clinical efficacy, patterns of clinical use, adverse effect profiles, cost-effectiveness and potential uses in conditions other than emphysema associated with AATD. Novel and emerging strategies for treating AATD are briefly discussed next, including alternative dosing and administration strategies, recombinant preparations, small molecule inhibitors of neutrophil elastase and of AAT polymerization, autophagy-enhancing drugs and gene therapy approaches.

EXPERT OPINION

We conclude with a discussion of our approach to managing patients with AATD and use of augmentation therapy.

Detection of alpha-1 antitrypsin deficiency: a review

Screening studies reveal a much larger number of individuals expected to have alpha-1 antitrypsin deficiency than is clinically recognized, with estimates that only about 2-10% of such individuals have been diagnosed. In the context that recognition of alpha-1 antitrypsin may prompt specific interventions (e.g., smoking avoidance, testing of family members, genetic counseling, and consideration of augmentation therapy), diagnosis is important, inviting much attention for efforts to identify affected individuals. Strategies to identify affected individuals include both population-based screening and targeted detection, and available studies have employed both approaches, though large-scale population-based screening is challenging. As reviewed in this paper, targeted-detection studies have generally produced a higher rate of detecting disease, and tend to be more successful with easier sampling techniques. Strategies to enhance detection in targeted studies have included awareness campaigns, easy testing techniques (such as evaluation of dried blood spots and home, confidential testing), and inclusive criteria for testing which span the full spectrum of clinical manifestations of alpha-1 antitrypsin deficiency.