A Systematic Review of Discrete Choice Experiments and Conjoint Analysis on Genetic Testing

Approaches to Incorporation of Preferences into Health Economic Models of Genomic Medicine: A Critical Interpretive Synthesis and Conceptual Framework

INTRODUCTION

Genomic medicine has features that make it preference sensitive and amenable to model-based health economic evaluation. Preferences of patients, caregivers, and clinicians related to the uptake and delivery of genomic medicine technologies and services that are not captured in health state utility weights can affect the intervention's cost-effectiveness and budget impact. However, there is currently no established or agreed-on approach for integrating preference information into economic evaluations. The objective of this study was to explore approaches for incorporating preferences into model-based economic evaluations of genomic medicine and to develop a conceptual framework to consider preferences in health economic models.

METHODS

We conducted a critical interpretive synthesis of published literature guided by the following question: how have preferences been incorporated into model-based economic evaluations of genomic medicine interventions? We integrated findings from the literature and expert opinion to develop a conceptual framework of ways in which preferences influence economic value in the context of genomic medicine.

RESULTS

Our synthesis included 14 articles. Revealed and stated preference data were used to estimate choice probabilities and to value outcomes. Our conceptual framework situates preference data in the context of health system, patient, clinician, and family characteristics. Preference data were sourced from clinicians, patients and families impacted by a condition or intervention, and the general public. Evaluations employed various types of models, including discrete event simulation, microsimulation, Markov, and decision tree models.

CONCLUSION

When evaluating the broad benefits and costs of implementing new interventions, sufficiently accounting for preferences in the form of model inputs and valuation of outcomes in economic evaluations is important to avoid biased implementation decisions. Incorporation of preference data may improve alignment between predicted and real-world uptake and more accurately estimate welfare impacts, and this study provides critical insights to support researchers who seek to incorporate preference information into model-based health economic evaluations.

Public Preferences for Genetic and Genomic Risk-Informed Chronic Disease Screening and Early Detection: A Systematic Review of Discrete Choice Experiments

PURPOSE

Genetic and genomic testing can provide valuable information on individuals' risk of chronic diseases, presenting an opportunity for risk-tailored disease screening to improve early detection and health outcomes. The acceptability, uptake and effectiveness of such programmes is dependent on public preferences for the programme features. This study aims to conduct a systematic review of discrete choice experiments assessing preferences for genetic/genomic risk-tailored chronic disease screening.

METHODS

PubMed, Embase, EconLit and Cochrane Library were searched in October 2023 for discrete choice experiment studies assessing preferences for genetic or genomic risk-tailored chronic disease screening. Eligible studies were double screened, extracted and synthesised through descriptive statistics and content analysis of themes. Bias was assessed using an existing quality checklist.

RESULTS

Twelve studies were included. Most studies focused on cancer screening (n = 10) and explored preferences for testing of rare, high-risk variants (n = 10), largely within a targeted population (e.g. subgroups with family history of disease). Two studies explored preferences for the use of polygenic risk scores (PRS) at a population level. Twenty-six programme attributes were identified, with most significantly impacting preferences. Survival, test accuracy and screening impact were most frequently reported as most important. Depending on the clinical context and programme attributes and levels, estimated uptake of hypothetical programmes varied from no participation to almost full participation (97%).

CONCLUSION

The uptake of potential programmes would strongly depend on specific programme features and the disease context. In particular, careful communication of potential survival benefits and likely genetic/genomic test accuracy might encourage uptake of genetic and genomic risk-tailored disease screening programmes. As the majority of the literature focused on high-risk variants and cancer screening, further research is required to understand preferences specific to PRS testing at a population level and targeted genomic testing for different disease contexts.

Preferences for genetic testing among populations underrepresented in genomic research: a systematic review

Equitable implementation of genomic medicine requires understanding preferences of diverse populations. Stated preference methods, such as discrete choice experiments (DCEs) and conjoint analyses, allow empirical evaluation of whether and how preferences for aspects of genomic medicine tests and services differ according to demographic characteristics. We aimed to understand the extent to which stated preference research in genomic medicine includes respondents that are population representative and evidence regarding preference heterogeneity by race and ethnicity. We conducted a systematic review of the stated preference literature in genomic medicine. We searched Web of Science, CINAHL, PsycINFO, PubMed, Embase, Cochrane Library, and SCOPUS for articles published from February 2021 to November 2023, extending a previously published systematic review. We extracted information on whether demographic characteristics of respondents were reported, whether investigators tested for preference heterogeneity based on race and ethnicity, and whether preference heterogeneity by race and ethnicity was identified. We identified 138 newly published records in addition to the 38 articles included in the original review. In total, we included 18 articles that reported participants' race or ethnicity. Eight articles explicitly analyzed preferences by race and ethnicity, and preference heterogeneity was identified in two. Stated preference research in genomic medicine often does not include population representative samples, and preference heterogeneity is not frequently analyzed according to race and ethnicity. Improving the representativeness of respondent populations, which allows for better understanding of whether and how preferences may differ by population subgroups, is important to guide policy and implementation decisions in genomic medicine.

Societal Preferences for Subsidizing Treatments Targeting Patients With Advanced Illness: A Discrete Choice Experiment

OBJECTIVES

Cost-effectiveness analyses are increasingly used to inform subvention decisions for moderately life extending treatments but apply several simplifying assumptions that may be inconsistent with public preferences. Contrary to standard assumptions, we hypothesize that societal willingness to allocate public funding toward these treatments is (1) diminishing for incremental improvements in survival and quality of life (QoL) and (2) greater for subvention policies that exclude the oldest old (>80 years).

METHODS

We tested these hypotheses using a web-based discrete choice experiment (n = 425) in Singapore. In each of 5 questions, respondents were shown 2 hypothetical treatments targeting patients with an expected prognosis of 2 months at very poor QoL and asked which treatment they wanted the government to subsidize, if any. Treatments were defined by 4 attributes: cost to the government, age of beneficiaries, expected gain in survival (2-12 months), and QoL (poor, fair, and good).

RESULTS

Latent class models were used to analyze results. Results revealed 2 classes. In the majority class (69.7% of sample), respondents value incremental gains in survival and QoL at a diminishing rate. Their willingness to allocate public funding estimates (Singapore dollars 16 825-91 027 per patient per month) were much higher than traditional cost-effectiveness thresholds. In the second class, respondents were unwilling to subsidize treatments offering less than 2 months of life extension or poor QoL. Neither class preferred subvention policies that exclude the oldest old.

CONCLUSIONS

These findings suggest that the Singapore government should consider cost-effectiveness thresholds that rise with increases in life extension. Age-based restrictions should not be imposed.

Preferences for Genetic Testing to Predict the Risk of Developing Hereditary Cancer: A Systematic Review of Discrete Choice Experiments

BACKGROUND

Understanding service user preferences is key to effective health care decision making and efficient resource allocation. It is of particular importance in the management of high-risk patients in whom predictive genetic testing can alter health outcomes.

PURPOSE

This review aims to identify the relative importance and willingness to pay for attributes of genetic testing in hereditary cancer syndromes.

DATA SOURCES

Searches were conducted in Medline, Embase, PsycINFO, HMIC, Web of Science, and EconLit using discrete choice experiment (DCE) terms combined with terms related to hereditary cancer syndromes, malignancy synonyms, and genetic testing.

STUDY SELECTION

Following independent screening by 3 reviewers, 7 studies fulfilled the inclusion criteria, being a DCE investigating patient or public preferences related to predictive genetic testing for hereditary cancer syndromes.

DATA EXTRACTION

Extracted data included study and respondent characteristics, DCE attributes and levels, methods of data analysis and interpretation, and key study findings.

DATA SYNTHESIS

Studies covered colorectal, breast, and ovarian cancer syndromes. Results were summarized in a narrative synthesis and the quality assessed using the Lancsar and Louviere framework.

LIMITATIONS

This review focuses only on DCE design and testing for hereditary cancer syndromes rather than other complex diseases. Challenges also arose from heterogeneity in attributes and levels.

CONCLUSIONS

Test effectiveness and detection rates were consistently important to respondents and thus should be prioritized by policy makers. Accuracy, cost, and wait time, while also important, showed variation between studies, although overall reduction in cost may improve uptake. Patients and the public would be willing to pay for improved detection and clinician over insurance provider involvement. Future studies should seek to contextualize findings by considering the impact of sociodemographic characteristics, health system coverage, and insurance policies on preferences.

HIGHLIGHTS

Test effectiveness and detection rates are consistently important to respondents in genetic testing for hereditary cancer syndromes.Reducing the cost of genetic testing for hereditary cancer syndromes may improve uptake.Individuals are most willing to pay for a test that improves detection rates, identifies multiple cancers, and for which results are shared with a doctor rather than with an insurance provider.

Eliciting parental preferences and values for the return of additional findings from genomic sequencing

Health economic evidence is needed to inform the design of high-value and cost-effective processes for returning genomic results from analyses for additional findings (AF). This study reports the results of a discrete-choice experiment designed to elicit preferences for the process of returning AF results from the perspective of parents of children with rare conditions and to estimate the value placed on AF analysis. Overall, 94 parents recruited within the Australian Genomics and Melbourne Genomics programmes participated in the survey, providing preferences in a total of 1128 choice scenarios. Statistically significant preferences were identified for the opportunity to change the choices made about AF; receiving positive AF in person from a genetic counsellor; timely access to a medical specialist and high-quality online resources; receiving automatic updates through a secure online portal if new information becomes available; and lower costs. For AF uptake rates ranging between 50-95%, the mean per person value from AF analysis was estimated at AU$450-$1700 (US$300-$1140). The findings enable the design of a value-maximising process of analysis for AF in rare-disease genomic sequencing.

Assessing the utility of measurement methods applied in economic evaluations of pharmacogenomics applications

An increasing number of economic evaluations are published annually investigating the economic effectiveness of pharmacogenomic (PGx) testing. This work was designed to provide a comprehensive summary of the available utility methods used in cost-effectiveness/cost-utility analysis studies of PGx interventions. A comprehensive review was conducted to identify economic analysis studies using a utility valuation method for PGx testing. A total of 82 studies met the inclusion criteria. A majority of studies were from the USA and used the EuroQol-5D questionnaire, as the utility valuation method. Cardiovascular disorders was the most studied therapeutic area while discrete-choice studies mainly focused on patients' willingness to undergo PGx testing. Future research in applying other methodologies in PGx economic evaluation studies would improve the current research environment and provide better results.

Role Preferences in Medical Decision Making: Relevance and Implications for Health Preference Research

Health preference research (HPR) is being increasingly conducted to better understand patient preferences for medical decisions. However, patients vary in their desire to play an active role in medical decisions. Until now, few studies have considered patients' preferred roles in decision making. In this opinion paper, we advocate for HPR researchers to assess and account for role preferences in their studies, to increase the relevance of their work for medical and shared decision making. We provide recommendations on how role preferences can be elicited and integrated with health preferences: (1) in formative research prior to a health preference study that aims to inform medical decisions or decision makers, (2a) in the development of health preference instruments, for instance by incorporating a role preference instrument and (2b) by clarifying the respondent's role in the decision prior to the preference elicitation task or by including role preferences as an attribute in the task itself, and (3) in statistical analysis by including random parameters or latent classes to raise awareness of heterogeneity in role preferences and how it relates to health preferences. Finally, we suggest redefining the decision process as a model that integrates the role and health preferences of the different parties that are involved. We believe that the field of HPR would benefit from learning more about the extent to which role preferences relate to health preferences, within the context of medical and shared decision making.

Multilevel barriers and facilitators to widespread use of preconception carrier screening in the United States

PURPOSE

Although preconception reproductive genetic carrier screening (RGCS) is preferred to screening during pregnancy, population-wide preconception screening is not routinely performed in the United States. We explored the multilevel barriers to the widespread adoption of preconception RGCS in the United States via key informant interviews.

METHODS

Semi-structured virtual video interviews were conducted with 29 informants with a breadth of professional expertise between May and October 2022. Data collection and qualitative analyses were guided by the Consolidated Framework for Implementation Research and socioecological model. Analysis focused on identifying barriers to delivering preconception RGCS at and across different levels of health care and exploring potential facilitators of preconception RGCS delivery.

RESULTS

Barriers to preconception RGCS were identified at the levels of test characteristics, patients and couples, clinicians and care teams, and the external health care and policy environments. Across the different levels of care delivery, 3 themes of barriers emerged: (1) fragmentation and inconsistencies hinder care delivery, (2) gaps in knowledge, misconceptions, and uncertainties about RGCS are pervasive, and (3) expanding preconception RGCS in the diverse US population presents unique implementation challenges. Potential solutions were detailed by informants.

CONCLUSION

Identifying individual and thematic barriers to preconception RGCS delivery may help to define strategies to alleviate obstacles.

Preferences for Palliative and End-of-Life Care: A Systematic Review of Discrete Choice Experiments

OBJECTIVES

Understanding what matters most to patients and their caregivers is fundamental to delivering high-quality care. This systematic review aimed to characterize and appraise the evidence from discrete choice experiments eliciting preferences for palliative care.

METHODS

A systematic literature search was undertaken for publications up until August 2022. Data were synthesized narratively. Thematic analysis was applied to categorize attributes into groups. Attribute development, frequency, and relative importance were analyzed. Subgroup analyses were conducted to compare outcomes between patient and proxy respondents.

RESULTS

Seventeen studies spanning 11 countries were included; 59% of studies solely considered preferences for patients with cancer. A range of respondent groups were represented including patients (76%) and proxies (caregivers [35%], health providers [12%], and the public [18%]). A total of 117 individual attributes were extracted and thematically grouped into 8 broad categories and 21 subcategories. Clinical outcomes including quality of life, length of life, and pain control were the most frequently reported attributes, whereas attributes relating to psychosocial components were largely absent. Both patients and proxy respondents prioritized pain control over additional survival time. Nevertheless, there were differences between respondent cohorts in the emphasis on other attributes such as access to care, timely information, and low risk of adverse effects (prioritized by patients), as opposed to cost, quality, and delivery of care (prioritized by proxies).

CONCLUSIONS

Our review underscores the vital role of pain control in palliative care; in addition, it shed light on the complexity and relative strength of preferences for various aspects of care from multiple perspectives, which is useful in developing personalized, patient-centered models of care for individuals nearing the end of life.

Preferences for Rehabilitation in Persons with a History of Stroke: A Discrete Choice Experiment

Objective

To investigate the preferences of persons with a history of stroke for various attributes of rehabilitation using a discrete choice experiment (DCE).

Design

Cross-sectional study.

Setting

A web-based survey.

Participants

A total of 600 adults with a history of stroke who were not asked whether or not they had participated in previous rehabilitation.

Intervention

None.

Main Outcome Measures

Preference weights by attribute ie, treatment time (30 minutes, one hour, one and a half hours), treatment content (walking exercises, activities of daily living; ADL exercises), priority treatment of paralyzed limbs (upper extremity, lower upper extremity), treatment location (hospital visit, home visit), therapist gender, and out-of-pocket costs for stroke rehabilitation using discrete choice experiment.

Results

The most common self-reported diagnosis was cerebral infarction (408 patients, 68%). The mean age was 62.0 ± 9.8 years, and 515 (85.8%) were male. Of the five attributes, excluding out-of-pocket costs, the highest relative importance score was treatment location (0.331), followed by treatment time (0.304). Among the rehabilitation programs, the statistically significant coefficients calculated were one hour of therapy (0.173, 95% CI = 0.088-0.258), hospital visits (0.241, 95% CI = 0.180-0.303), and female therapists (0.186, 95% CI = 0.125-0. 247). No significant differences were obtained regarding the treatment contents or the paralyzed limb to be treated.

Conclusion

A discrete choice experiment revealed that persons with a history of stroke prefer a one-hour hospital rehabilitation program with a female therapist, with cost being a major consideration for rehabilitation. The results of this study may provide useful information for rehabilitation professionals.

Key drivers of family-level utility of pediatric genomic sequencing: a qualitative analysis to support preference research

Given that pediatric genomic sequencing (GS) may have implications for the health and well-being of both the child and family, a clearer understanding of the key drivers of the utility of GS from the family perspective is needed. The purpose of this study is to explore what is important to caregivers of pediatric patients regarding clinical GS, with a focus on family-level considerations. We conducted semi-structured interviews with caregivers (n = 41) of pediatric patients who had been recommended for or completed GS that explored the scope of factors caregivers considered when deciding whether to pursue GS for their child. We analyzed the qualitative data in multiple rounds of coding using thematic analysis. Caregivers raised important family-level considerations, in addition to those specifically for their child, which included wanting the best chance at good quality of life for the family, the ability to learn about family health, the impact on the caregiver's well-being, privacy concerns among family members, and the cost of testing to the family. We developed a framework of key drivers of utility consisting of four domains that influenced caregivers' decision making: underlying values, perceived benefits, perceived risks, and other pragmatic considerations regarding GS. These findings can inform measurement approaches that better capture the utility of pediatric GS for families and improve assessments of the value of clinical GS.

Preferences for pharmacogenomic testing in polypharmacy patients: a discrete choice experiment

Aim: To elicit preferences for pharmacogenomic (PGx) testing in polypharmacy patients. Materials & methods: A face-to-face discrete choice experiment survey was designed and administered to adult polypharmacy patients recruited at a local retail pharmacy in Albuquerque (NM, USA). Results: A total of 128 eligible polypharmacy patients completed the discrete choice experiment survey and significantly preferred a PGx test with lower cost, better confidentiality and higher certainty of identifying best medication/dose and side effects and one that can be used to advocate for their treatment needs (all p < 0.01). Conclusion: This is the first study eliciting preferences for PGx testing among polypharmacy patients. The study found most polypharmacy patients were willing to take a PGx test and their preferences were mostly influenced by test cost.

Clinical Decision-Making for Appendectomy in Kosovo: A Conjoint Analysis

Objective: The objective was to investigate the association of clinical attributes with decision making for performing appendectomy and making preoperative preparations for appendectomy. Method: A conjoint analysis with 17 clinical scenarios was executed with surgeons employed at public hospitals in Kosovo. Setting: The study was conducted at two public hospitals in Kosovo that have benefited from quality-improvement interventions. Participants: The participants included 22 surgeons. Outcome measures: The primary outcome was the overall effect of clinical attributes on the decision to perform appendectomy and make the preoperative preparations for appendectomy. Results: In the regression analyses, several attributes demonstrated statistically significant effects on the clinical decision to perform appendectomy and on the practice of preoperative preparation. Conclusions: We found that several factors influenced the decision to perform appendectomy and the practices for preoperative preparation. Nevertheless, the small sample size limited our efforts to interpret the results. These findings could assist Kosovo in the design and implementation of future similar studies and in fostering quality improvement measures that address clinical decision making and the lack of process standardization in the delivery of surgical care.

The Value of Genomic Testing: A Contingent Valuation Across Six Child- and Adult-Onset Genetic Conditions

OBJECTIVES

The aim of this study was to elicit the willingness-to-pay (WTP) for genomic testing, using contingent valuation, among people with lived experience of genetic conditions in Australia.

METHODS

Parents of children with suspected mitochondrial disorders, epileptic encephalopathy, leukodystrophy, or malformations of cortical development completed a dynamic triple-bounded dichotomous choice (DC) contingent valuation. Adult patients or parents of children with suspected genetic kidney disease or complex neurological and neurodegenerative conditions completed a payment card (PC) contingent valuation. DC data were analyzed using a multilevel interval regression and a multilevel probit model. PC data were analyzed using a Heckman selection model.

RESULTS

In total, 360 individuals participated in the contingent valuation (CV), with 141 (39%) and 219 (61%) completing the DC and PC questions, respectively. The mean WTP for genomic testing was estimated at AU$2830 (95% confidence interval [CI] 2236-3424) based on the DC data and AU$1914 (95% CI 1532-2296) based on the PC data. The mean WTP across the six cohorts ranged from AU$1879 (genetic kidney disease) to AU$4554 (leukodystrophy).

CONCLUSIONS

Genomic testing is highly valued by people experiencing rare genetic conditions. Our findings can inform cost-benefit analyses and the prioritization of genomics into mainstream clinical care. While our WTP estimates for adult-onset genetic conditions aligned with estimates derived from discrete choice experiments (DCEs), for childhood-onset conditions our estimates were significantly lower. Research is urgently required to directly compare, and critically evaluate, the performance of CV and DCE methods.