Parameterising User Uptake in Economic Evaluations: The role of discrete choice experiments

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.

A socially interdependent choice framework for social influences in healthcare decision-making: a study protocol

OBJECTIVES

Current choice models in healthcare (and beyond) can provide suboptimal predictions of healthcare users' decisions. One reason for such inaccuracy is that standard microeconomic theory assumes that decisions of healthcare users are made in a social vacuum. Healthcare choices, however, can in fact be (entirely) socially determined. To achieve more accurate choice predictions within healthcare and therefore better policy decisions, the social influences that affect healthcare user decision-making need to be identified and explicitly integrated into choice models. The purpose of this study is to develop a socially interdependent choice framework of healthcare user decision-making.

DESIGN

A mixed-methods approach will be used. A systematic literature review will be conducted that identifies the social influences on healthcare user decision-making. Based on the outcomes of a systematic literature review, an interview guide will be developed that assesses which, and how, social influences affect healthcare user decision-making in four different medical fields. This guide will be used during two exploratory focus groups to assess the engagement of participants and clarity of questions and probes. The refined interview guide will be used to conduct the semistructured interviews with healthcare professionals and users. These interviews will explore in detail which, and how, social influences affect healthcare user decision-making. Focus group and interview transcripts will be analysed iteratively using a constant comparative approach based on a mix of inductive and deductive coding. Based on the outcomes, a social influence independent choice framework for healthcare user decision-making will be drafted. Finally, the Delphi technique will be employed to achieve consensus about the final version of this choice framework.

ETHICS AND DISSEMINATION

This study was approved by the Erasmus School of Health Policy and Management Research Ethics Review Committee (ESHPM, Rotterdam, The Netherlands; reference ETH2122-0666).

Two into one does go: Formulation development of a multipurpose combination vaginal ring releasing dapivirine and metronidazole for prevention of HIV infection and treatment of bacterial vaginosis

Bacterial vaginosis (BV) is a common but often asymptomatic dysbiosis of the human vagina characterized by an imbalance in the normal vaginal microbiota due to loss of lactobacilli and an overgrowth of certain anaerobic bacteria. While BV itself is not a sexually transmitted infection, it is associated with an increased risk in women of various sexually acquired infections, including human immunodeficiency virus (HIV) infection. There is, therefore, a strong rationale for pursuing new multipurpose products that seek to treat or prevent BV alongside preventing HIV infection. With the dapivirine-releasing vaginal ring for HIV prevention now approved in several African countries, here we report formulation development of a next-generation ring product that releases both dapivirine (DPV) and the antibiotic drug metronidazole (MET). Following thermal analysis studies to characterize the phase behaviour of DPV-MET mixtures and rheological analysis to assess the cure characteristics of the active silicone elastomer mixes, matrix-type rings were manufactured containing 25 or 200 mg DPV in combination with 100, 250, 500, 1000 or 2000 mg MET. The results for drug content, in vitro release, mechanical testing, and Gardnerella vaginalis time-kill experiments demonstrate the feasibility of incorporating both DPV and MET in a matrix-type ring formulation and indicate that clinically effective release rates may be possible.

A modelling framework for translating discrete choice experiment results into cost-effectiveness estimates: an application to designing tailored and scalable HIV and contraceptive services for adolescents in Gauteng, South Africa

INTRODUCTION

South African youth and adolescents face a high burden of (Sexually Transmitted Infections) STIs, HIV and unintended pregnancies, but uptake of services remains low. To address this, tailored and scalable interventions are urgently needed. We developed a framework to fill the gap and translate the impact of facility-level attributes into a cost-effectiveness analysis for increasing HIV/contraceptive service uptake in adolescents using a discrete choice experiment (DCE).

METHODS

We used a DCE (n = 805) conducted in Gauteng, South Africa, which found that staff attitude, confidentiality, Wi-Fi, subsidized food, afternoon hours and youth-only services were preferred attributes of health services. Based on this, we simulated the uptake of services adapted for these preferences. We divided preferences into modifiable attributes that could readily be adapted (e.g. Wi-Fi), and challenging to modify (more nuanced attributes that are more challenging to cost and evaluate): staff attitude and estimated the incremental change in the uptake of services using adapted services. Costs for modifiable preferences were estimated using data from two clinics in South Africa (2019 US$). We determined the incremental cost-effectiveness ratio (ICER) for additional adolescents using services of 15 intervention combinations, and report the results of interventions on the cost-effectiveness frontier.

RESULTS

Greatest projected impact on uptake was from friendly and confidential services, both of which were considered challenging to modify (18.5% 95% CI: 13.0%-24.0%; 8.4% 95% CI: 3.0%-14.0%, respectively). Modifiable factors on their own resulted in only small increases in expected uptake. (Food: 2.3% 95% CI: 4.0%-9.00%; Wi-Fi: 3.0% 95% CI: -4.0% to 10.0%; Youth-only services: 0.3% 95% CI: -6.0% to 7.0%; Afternoon services: 0.8% 95% CI: -6.0% to 7.0%). The order of interventions on the cost-effectiveness frontier are Wi-Fi and youth-only services (ICER US$7.01-US$9.78 per additional adolescent utilizing HIV and contraceptive services), Wi-Fi, youth-only services and food (ICER US$9.32-US$10.45), followed by Wi-Fi, youth-only services and extended afternoon hours (ICER US$14.46-US$43.63).

CONCLUSIONS

Combining DCE results and costing analyses within a modelling framework provides an innovative way to inform decisions on effective resource utilization. Modifiable preferences, such as Wi-Fi provision, youth-only services and subsidized food, have the potential to cost-effectively increase the proportion of adolescents accessing HIV and contraceptive services.

Feasibility and acceptability of integrating hepatitis B care into routine HIV services: a qualitative study among health care providers and patients in West Nile region, Uganda

BACKGROUND

Despite facing a dual burden of HBV and HIV, Africa lacks experience in offering integrated care for HIV and HBV. To contextualize individual and group-level feasibility and acceptability of an integrated HIV/HBV care model, we explored perspectives of health care providers and care recipients on feasibility and acceptability of integration.

METHODS

In two regional hospitals of West Nile region, we performed a demonstration project to assess feasibility and acceptability of merging the care of HBV-monoinfected patients with existing HIV care system. Using interviews with health care providers as key informants, and 6 focus groups discussions with 3 groups of patients, we explored feasibility [(i)whether integration is perceived to fit within the existing healthcare infrastructure, (ii) perceived ease of implementation of HIV/HBV integrated care, and (iii) perceived sustainability of integration] and acceptability [whether the HIV/HBV care model is perceived as (i) suitable, (ii) satisfying and attractive (iii) there is perceived demand, need and intention to recommend its use]. We audio-recorded the interviews and data was analysed using framework analysis.

RESULTS

The following themes emerged from the data (i) integrating HBV into HIV care is perceived to be feasible, fit and beneficial, after making requisite adjustments (ii) integration is acceptable due to the need for both free treatment and anticipated collaboration between HIV and HBV clients in terms of peer-support (iii) there are concerns about the likely rise in stigma and the lack of community awareness about integrated care.

CONCLUSION

The integrated HIV/HBV care model is feasible and acceptable among both providers and recipients. Necessary adjustments to the existing care system, including training, for community sensitization on the reasons and significance of integration are required.

Patient Preferences for Longer or More Frequent In-Center Hemodialysis Regimens: A Multicenter Discrete Choice Study

RATIONALE & OBJECTIVE

Longer and more frequent hemodialysis sessions are associated with both benefits and harms. However, their relative importance to patients and how they influence acceptability for patients have not been quantified.

STUDY DESIGN

Discrete-choice experiment in which a scenario followed by 12 treatment choice sets were presented to patients in conjunction with varying information about the clinical impact of the treatments offered.

SETTING & PARTICIPANTS

Patients with kidney failure treated with maintenance dialysis for≥1 year in 5 UK kidney centers.

PREDICTORS

Length and frequency of hemodialysis sessions and their prior reported associations with survival, quality of life, need for fluid restriction, hospitalization, and vascular access complications.

OUTCOME

Selection of longer (4.5 hours) or more frequent (4 sessions per week) hemodialysis regimens versus remaining on 3 sessions per week with session lengths of 4 hours.

ANALYTICAL APPROACH

Multinomial mixed effects logistic regression estimating the relative influence of different levels of the predictors on the selection of longer and more frequent dialysis, controlling for patient demographic characteristics.

RESULTS

Among 183 prevalent in-center hemodialysis patients (mean age of 63.7 years, mean dialysis vintage of 4.7 years), 38.3% (70 of 183) always chose to remain on regimens of 3 sessions per week with session duration of 4 hours. Depicted associations of increasing survival and quality of life, reduced need for fluid restriction, and avoiding additional access complications were all significantly associated with choosing longer or more frequent treatment regimens. Younger age, fatigue, previous experience of vascular access complications, absence of heart failure, and shorter travel time to dialysis centers were associated with preference for 4 sessions per week. Patients expressed willingness to trade up to 2 years of life to avoid regimens of 4 sessions per week or access complications. After applying estimated treatment benefits and harms from existing literature, the fully adjusted model revealed that 27.1% would choose longer regimens delivered 3 times per week and 34.3% would choose 4 hours 4 times per week. Analogous estimates for younger fatigued patients living near their unit were 23.5% and 62.5%, respectively.

LIMITATIONS

Estimates were based on stated preferences rather than observed behaviors. Predicted acceptance of regimens was derived from data on treatment benefits and harms largely sourced from observational studies.

CONCLUSIONS

Predicted acceptance of longer and more frequent hemodialysis regimens substantially exceeds their use in current clinical practice. These findings underscore the need for robust data on clinical effectiveness of these more intensive regimens and more extensive consideration of patient choice in the selection of dialysis regimens.

Understanding Uptake of Digital Health Products: Methodology Tutorial for a Discrete Choice Experiment Using the Bayesian Efficient Design

Understanding the preferences of potential users of digital health products is beneficial for digital health policy and planning. Stated preference methods could help elicit individuals' preferences in the absence of observational data. A discrete choice experiment (DCE) is a commonly used stated preference method-a quantitative methodology that argues that individuals make trade-offs when engaging in a decision by choosing an alternative of a product or a service that offers the greatest utility, or benefit. This methodology is widely used in health economics in situations in which revealed preferences are difficult to collect but is much less used in the field of digital health. This paper outlines the stages involved in developing a DCE. As a case study, it uses the application of a DCE to reveal preferences in targeting the uptake of smoking cessation apps. It describes the establishment of attributes, the construction of choice tasks of 2 or more alternatives, and the development of the experimental design. This tutorial offers a guide for researchers with no prior knowledge of this research technique.

How to integrate evidence from patient preference studies into health technology assessment: a critical review and recommendations

Health technology assessment (HTA) agencies vary in their use of quantitative patient preference data (PP) and the extent to which they have formalized this use in their guidelines. Based on the authors' knowledge of the literature, we identified six different PP "use cases" that integrate PP into HTA in five different ways: through endpoint selection, clinical benefit rating, predicting uptake, input into economic evaluation, and a means to weight all HTA criteria. Five types of insight are distinguished across the use cases: understanding what matters to patients, predicting patient choices, estimating the utility generated by treatment benefits, estimating the willingness to pay for treatment benefits, and informing distributional considerations. Summarizing the literature on these use cases, we recommend circumstances in which PP can add value to HTA and the further research and guidance that is required to support the integration of PP in HTA. Where HTA places more emphasis on clinical outcomes, novel endpoints are available; or where there are already many treatment options, PP can add value by helping decision makers to understand what matters to patients. Where uptake is uncertain, PP can be used to estimate uptake probability. Where indication-specific utility functions are required or where existing utility measures fail to capture the value of treatments, PP can be used to generate or supplement existing utility estimates. Where patients are paying out of pocket, PP can be used to estimate willingness to pay.

Cost-Effectiveness of HIV Pre-exposure Prophylaxis Among Heterosexual Men in South Africa: A Cost-Utility Modeling Analysis

INTRODUCTION

Heterosexual men are not considered a key population in the HIV response and are mostly absent from pre-exposure prophylaxis (PrEP) studies to date. Yet, South African men face considerable HIV risk. We estimate the incremental cost-effectiveness of providing oral PrEP, injectable PrEP, or a combination of both to heterosexual South African men to assess whether providing PrEP would efficiently use resources.

METHODS

Epidemiological and costing models estimated the one-year costs and outcomes associated with PrEP use in 3 scenarios. PrEP uptake was estimated for younger (aged 18-24) and older (aged 25-49) men using a discrete choice experiment. Scenarios were compared with a baseline scenario of male condom use, while a health system perspective was used to estimate discounted lifetime costs averted per HIV infection. PrEP benefit was estimated in disability-adjusted life years (DALYs) averted. Uncertainty around the estimated incremental cost-effectiveness ratios (ICERs) was assessed using deterministic and probabilistic sensitivity analyses.

RESULTS

No PrEP intervention scenarios were cost-effective for both age groups at a willingness-to-pay threshold of $1175/DALY averted. The lowest ICER ($2873/DALY averted) was for the provision of oral PrEP to older men, although probability of cost-effectiveness was just 0.26%. Results found that ICERs were sensitive to HIV incidence and antiretroviral coverage.

CONCLUSIONS

This study estimates that providing PrEP to heterosexual South African men is not cost-effective at current cost-effectiveness thresholds. Given the ICERs' sensitivity to several variables, alongside the heterogeneity of HIV infection among South African men, PrEP may be cost-effective for older men with high incidence and other subgroups based on locality and race. We recommend further investigation to better identify and target these groups.

Measuring commissioners' willingness-to-pay for community based childhood obesity prevention programmes using a discrete choice experiment

BACKGROUND

In the UK, rates of childhood obesity remain high. Community based programmes for child obesity prevention are available to be commissioned by local authorities. However, there is a lack of evidence regarding how programmes are commissioned and which attributes of programmes are valued most by commissioners. The aim of this study was to determine the factors that decision-makers prioritise when commissioning programmes that target childhood obesity prevention.

METHODS

An online discrete choice experiment (DCE) was used to survey commissioners and decision makers in the UK to assess their willingness-to-pay for childhood obesity programmes.

RESULTS

A total of 64 commissioners and other decision makers completed the DCE. The impact of programmes on behavioural outcomes was prioritised, with participants willing to pay an extra £16,600/year if average daily fruit and vegetable intake increased for each child by one additional portion. Participants also prioritised programmes that had greater number of parents fully completing them, and were willing to pay an extra £4810/year for every additional parent completing a programme. The number of parents enrolling in a programme (holding the number completing fixed) and hours of staff time required did not significantly influence choices.

CONCLUSIONS

Emphasis on high programme completion rates and success increasing children's fruit and vegetable intake has potential to increase commissioning of community based obesity prevention programmes.

HIV prevention is not all about HIV - using a discrete choice experiment among women to model how the uptake and effectiveness of HIV prevention products may also rely on pregnancy and STI protection

INTRODUCTION

In sub-Saharan Africa, considerable HIV-burden exists among women. Anti-retroviral (ARV) based prevention products could decrease this burden, and their uptake could be increased if they also protect against pregnancy and sexually transmitted infections (STI).

METHODS

A discrete choice experiment (DCE) was undertaken in South Africa (2015) through a household survey of adult females (n = 158) and adolescent girls (n = 204) who self-reported HIV-negative status. The DCE was used to project the uptake (percentage using product) of oral pre-exposure prophylaxis (PrEP), vaginal rings, and injectable long-lasting ARV agents among these women, and how uptake could depend on whether these products protect against pregnancy or STI acquisition. Uptake estimates were used to model how each product could decrease a women's HIV acquisition risk.

RESULTS

In adolescent women, there will be limited uptake (< 6% for any product) and impact (< 4% decrease in HIV acquisition risk) of new products unless they provide pregnancy protection, which could quadruple use and impact. Adult women have weaker preference for pregnancy protection, with moderate use (< 17% for each) and impact (< 14 percentage point decrease) if they only provide HIV protection. All women had highest preference for injectable ARVs, with oral PrEP having high preference if injectable ARVs are not available. Adult women will use the ring, but adolescent women will not. Importantly, even with three additional prevention products, all providing pregnancy and STI protection, > 14% of women will remain unprotected and > 31% of the baseline acquisition risk will remain.

CONCLUSIONS

Incorporating multiple prevention components into new ARV-based prevention products may increase their uptake and impact among women.

Incorporating discrete choice experiments into policy decisions: Case of designing public long-term care insurance

Discrete choice experiments (DCEs) have been widely used to elicit preferences in the health economics field but recent reviews found that DCE results are rarely incorporated into health policy decisions. We conjecture that one reason is most health policy practitioners only focus on estimating marginal willingness to pay, the measure that is not directly applicable for policy-related questions. We show that when designing a new program, translating preference information into the demand for packages and benefits of alternative schemes (the choices made available) can make the DCE results more policy relevant. This concept is illustrated using data collected to evaluate the benefits of introducing a public long-term care insurance program to a middle-income country, Thailand. The stratified sample consisted of 2019 households from all regions, and the interview took place between October and December 2017. We find that preferences are very heterogeneous, implying that no one-size-fits-all solution exists. The estimates from the preferred model are then used to calculate benefits and losses (based on the consumer surplus measure) for plausible implementation scenarios such as different universal schemes, multiple-tier schemes, and schemes in which premium are subsidized for low-income households.

Are Healthcare Choices Predictable? The Impact of Discrete Choice Experiment Designs and Models

BACKGROUND

Lack of evidence about the external validity of discrete choice experiments (DCEs) is one of the barriers that inhibit greater use of DCEs in healthcare decision making.

OBJECTIVES

To determine whether the number of alternatives in a DCE choice task should reflect the actual decision context, and how complex the choice model needs to be to be able to predict real-world healthcare choices.

METHODS

Six DCEs were used, which varied in (1) medical condition (involving choices for influenza vaccination or colorectal cancer screening) and (2) the number of alternatives per choice task. For each medical condition, 1200 respondents were randomized to one of the DCE formats. The data were analyzed in a systematic way using random-utility-maximization choice processes.

RESULTS

Irrespective of the number of alternatives per choice task, the choice for influenza vaccination and colorectal cancer screening was correctly predicted by DCE at an aggregate level, if scale and preference heterogeneity were taken into account. At an individual level, 3 alternatives per choice task and the use of a heteroskedastic error component model plus observed preference heterogeneity seemed to be most promising (correctly predicting >93% of choices).

CONCLUSIONS

Our study shows that DCEs are able to predict choices-mimicking real-world decisions-if at least scale and preference heterogeneity are taken into account. Patient characteristics (eg, numeracy, decision-making style, and general attitude for and experience with the health intervention) seem to play a crucial role. Further research is needed to determine whether this result remains in other contexts.

The cost-effectiveness of multi-purpose HIV and pregnancy prevention technologies in South Africa

Introduction

A number of antiretroviral HIV prevention products are efficacious in preventing HIV infection. However, the sexual and reproductive health needs of many women extend beyond HIV prevention, and research is ongoing to develop multi‐purpose prevention technologies (MPTs) that offer dual HIV and pregnancy protection. We do not yet know if these products will be an efficient use of constrained health resources. In this paper, we estimate the cost‐effectiveness of combinations of candidate multi‐purpose prevention technologies (MPTs), in South Africa among general population women and female sex workers (FSWs).

Methods

We combined a cost model with a static model of product impact based on incidence data in South Africa to estimate the cost‐effectiveness of five candidate co‐formulated or co‐provided MPTs: oral PrEP, intravaginal ring, injectable ARV, microbicide gel and SILCS diaphragm used in concert with gel. We accounted for the preferences of end‐users by predicting uptake using a discrete choice experiment (DCE). Product availability and protection were systematically varied in five potential rollout scenarios. The impact model estimated the number of infections averted through decreased incidence due to product use over one year. The comparator for each scenario was current levels of male condom use, while a health system perspective was used to estimate discounted lifetime treatment costs averted per HIV infection. Product benefit was estimated in disability‐adjusted life years (DALYs) averted. Benefits from contraception were incorporated through adjusting the uptake of these products based on the DCE and through estimating the costs averted from avoiding unwanted pregnancies. We explore the additional impact of STI protection through increased uptake in a sensitivity analysis.

Results

At central incidence rates, all single‐ and multi‐purpose scenarios modelled were cost‐effective among FSWs and women aged 16–24, at a governmental willingness‐to‐pay threshold of $1175/DALY averted (range: $214–$810/DALY averted among non‐dominant scenarios), however, none were cost‐effective among women aged 25–49 (minimum $1706/DALY averted). The cost‐effectiveness of products improved with additional protection from pregnancy. Estimates were sensitive to variation in incidence assumptions, but robust to other parameters.

Conclusions

To the best of our knowledge, this is the first study to estimate the cost‐effectiveness of a range of potential MPTs; suggesting that MPTs will be cost‐effective among higher incidence FSWs or young women, but not among lower incidence older women. More work is needed to make attractive MPTs available to potential users who could use them effectively.

Preferences for aspects of antenatal and newborn screening: a systematic review

BACKGROUND

Many countries offer screening programmes to unborn and newborn babies (antenatal and newborn screening) to identify those at risk of certain conditions to aid earlier diagnosis and treatment. Technological advances have stimulated the development of screening programmes to include more conditions, subsequently changing the information required and potential benefit-risk trade-offs driving participation. Quantifying preferences for screening programmes can provide programme commissioners with data to understand potential demand, the drivers of this demand, information provision required to support the programmes and the extent to which preferences differ in a population. This study aimed to identify published studies eliciting preferences for antenatal and newborn screening programmes and provide an overview of key methods and findings.

METHODS

A systematic search of electronic databases for key terms identified eligible studies (discrete choice experiments (DCEs) or best-worst scaling (BWS) studies related to antenatal/newborn testing/screening published between 1990 and October 2018). Data were systematically extracted, tabulated and summarised in a narrative review.

RESULTS

A total of 19 studies using a DCE or BWS to elicit preferences for antenatal (n = 15; 79%) and newborn screening (n = 4; 21%) programmes were identified. Most of the studies were conducted in Europe (n = 12; 63%) but there were some examples from North America (n = 2; 11%) and Australia (n = 2; 11%). Attributes most commonly included were accuracy of screening (n = 15; 79%) and when screening occurred (n = 13; 68%). Other commonly occurring attributes included information content (n = 11; 58%) and risk of miscarriage (n = 10; 53%). Pregnant women (n = 11; 58%) and healthcare professionals (n = 11; 58%) were the most common study samples. Ten studies (53%) compared preferences across different respondents. Two studies (11%) made comparisons between countries. The most popular analytical model was a standard conditional logit model (n = 11; 58%) and one study investigated preference heterogeneity with latent class analysis.

CONCLUSION

There is an existing literature identifying stated preferences for antenatal and newborn screening but the incorporation of more sophisticated design and analytical methods to investigate preference heterogeneity could extend the relevance of the findings to inform commissioning of new screening programmes.

Using discrete choice experiments to inform the design of complex interventions

BACKGROUND

Complex health interventions must incorporate user preferences to maximize their potential effectiveness. Discrete choice experiments (DCEs) quantify the strength of user preferences and identify preference heterogeneity across users. We present the process of using a DCE to supplement conventional qualitative formative research in the design of a demand creation intervention for voluntary medical male circumcision (VMMC) to prevent HIV in Tanzania.

METHODS

The VMMC intervention was designed within a 3-month formative phase. In-depth interviews (n = 30) and participatory group discussions (n = 20) sought to identify broad setting-specific barriers to and facilitators of VMMC among adult men. Qualitative results informed the DCE development, identifying the role of female partners, service providers' attitudes and social stigma. A DCE among 325 men in Njombe and Tabora, Tanzania, subsequently measured preferences for modifiable VMMC service characteristics. The final VMMC demand creation intervention design drew jointly on the qualitative and DCE findings.

RESULTS

While the qualitative research informed the community mobilization intervention, the DCE guided the specific VMMC service configuration. The significant positive utilities (u) for availability of partner counselling (u = 0.43, p < 0.01) and age-separated waiting areas (u = 0.21, p < 0.05) led to the provision of community information booths for partners and provision of age-separated waiting areas. The strong disutility of female healthcare providers (u = - 0.24, p < 0.01) led to re-training all providers on client-friendliness.

CONCLUSION

This is, to our knowledge, the first study documenting how user preferences from DCEs can directly inform the design of a complex intervention. The use of DCEs as formative research may help increase user uptake and adherence to complex interventions.

Does a Patient-Directed Financial Incentive Affect Patient Choices About Controller Medicines for Asthma? A Discrete Choice Experiment and Financial Impact Analysis

BACKGROUND

In Australia, many patients who are initiated on asthma controller inhalers receive combination inhaled corticosteroid/long-acting beta₂-agonist (ICS/LABA) despite having asthma of sufficiently low severity that ICS-alone would be equally effective and less costly for the government.

METHODS

We conducted a discrete choice experiment (DCE) in a nationally representative sample of adults (n = 792) and parents of children (n = 609) with asthma. Mixed multinomial models were estimated and calibrated to reflect the estimated market shares of ICS-alone, ICS/LABA and no controller. We then simulated the impact of varying patient co-payment on demand and the financial impact on government pharmaceutical expenditure.

RESULTS

Preference for inhaler decreased with increasing costs to the patient or government, increasing chance of a repeat visit to the doctor, and if fewer symptoms were present. Adults preferred high-strength controllers, but parents preferred low-strength inhalers for children (general beneficiaries only). The DCE predicted a higher proportion choosing controller treatment (89%) compared to current levels (57%) at the current co-payment level, with proportionately higher uptake of ICS-alone and a lower average cost per patient [32.73 Australian dollars (AU$) c.f. AU$38.54]. Reducing the co-payment on ICS-alone by 50% would increase its market share to 50%, whilst completely removing the co-payment would only have a small marginal impact on market share, but increased average cost of treatment to the government to AU$41.04 per person.

CONCLUSIONS

Patient-directed financial incentives are unlikely to encourage much switching of medicines, and current levels of under-treatment are not explained by patient preferences. Interventions directed at prescribers are more likely to promote better use of asthma medicines.

How well do discrete choice experiments predict health choices? A systematic review and meta-analysis of external validity

Discrete choice experiments (DCEs) are economic tools that elicit the stated preferences of respondents. Because of their increasing importance in informing the design of health products and services, it is critical to understand the extent to which DCEs give reliable predictions outside of the experimental context. We systematically reviewed the literature of published DCE studies comparing predictions to choices made in reality; we extracted individual-level data to estimate a bivariate mixed-effects model of pooled sensitivity and specificity. Eight studies met the inclusion criteria, and six of these gave sufficient data for inclusion in a meta-analysis. Pooled sensitivity and specificity estimates were 88% (95% CI 81, 92%) and 34% (95% CI 23, 46%), respectively, and the area under the SROC curve (AUC) was 0.60 (95% CI 0.55, 0.64). Results indicate that DCEs can produce reasonable predictions of health-related behaviors. There is a great need for future research on the external validity of DCEs, particularly empirical studies assessing predicted and revealed preferences of a representative sample of participants.

Factors and situations influencing the value of patient preference studies along the medical product lifecycle: a literature review

Industry, regulators, health technology assessment (HTA) bodies, and payers are exploring the use of patient preferences in their decision-making processes. In general, experience in conducting and assessing patient preference studies is limited. Here, we performed a systematic literature search and review to identify factors and situations influencing the value of patient preference studies, as well as applications throughout the medical product lifecyle. Factors and situations identified in 113 publications related to the organization, design, and conduct of studies, and to communication and use of results. Although current use of patient preferences is limited, we identified possible applications in discovery, clinical development, marketing authorization, HTA, and postmarketing phases.

Specialty training for the retention of Malawian doctors: A cost-effectiveness analysis

Few medical schools and sustained emigration have led to low numbers of doctors in many sub-Saharan African countries. The opportunity to undertake specialty training has been shown to be particularly important in retaining doctors. Yet limited training capacity means that doctors are often sent to other countries to specialise, increasing the risk that they may not return. Expanding domestic training, however, may be constrained by the reluctance of doctors to accept training in their home country. We modelled different policy options in an example country, Malawi, to examine the cost-effectiveness of expanding specialty training to retain doctors in sub-Saharan Africa. We designed a Markov model of the physician labour market in Malawi, incorporating data from graduate tracing studies in 2006 and 2012, a 2013 discrete choice experiment on 148 Malawian doctors and 2015 cost data. A government perspective was taken with a time horizon of 40 years. Expanded specialty training in Malawi or South Africa with increasing mandatory service before training was compared against baseline conditions. The outcome measures were cost per doctor-year and cost per specialist-year spent working in the Malawian public sector. Expanding specialty training in Malawi is more cost-effective than training outside Malawi. At least two years of mandatory service would be more cost-effective, with five years adding the most value in terms of doctor-years. After 40 years of expanded specialty training in Malawi, the medical workforce would be over fifty percent larger with over six times the number of specialists compared to current trends. However, the government would need to be willing to pay at least 3.5 times more per doctor-year for a 5% increase and a third more per specialist-year for a four-fold increase. Greater returns are possible from doctors with more flexible training preferences. Sustained funding of specialty training may improve retention in sub-Saharan Africa.

Novel multipurpose pod-intravaginal ring for the prevention of HIV, HSV, and unintended pregnancy: Pharmacokinetic evaluation in a macaque model

Globally, women bear an uneven burden for sexual HIV acquisition. Results from two clinical trials evaluating intravaginal rings (IVRs) delivering the antiretroviral agent dapivirine have shown that protection from HIV infection can be achieved with this modality, but high adherence is essential. Multipurpose prevention technologies (MPTs) can potentially increase product adherence by offering protection against multiple vaginally transmitted infections and unintended pregnancy. Here we describe a coitally independent, long-acting pod-IVR MPT that could potentially prevent HIV and HSV infection as well as unintended pregnancy. The pharmacokinetics of MPT pod-IVRs delivering tenofovir alafenamide hemifumarate (TAF2) to prevent HIV, acyclovir (ACV) to prevent HSV, and etonogestrel (ENG) in combination with ethinyl estradiol (EE), FDA-approved hormonal contraceptives, were evaluated in pigtailed macaques (N = 6) over 35 days. Pod IVRs were exchanged at 14 days with the only modification being lower ENG release rates in the second IVR. Plasma progesterone was monitored weekly to determine the effect of ENG/EE on menstrual cycle. The mean in vivo release rates (mg d-1) for the two formulations over 30 days ranged as follows: TAF2 0.35-0.40; ACV 0.56-0.70; EE 0.03-0.08; ENG (high releasing) 0.63; and ENG (low releasing) 0.05. Mean peak progesterone levels were 4.4 ± 1.8 ng mL-1 prior to IVR insertion and 0.075 ± 0.064 ng mL-1 for 5 weeks after insertion, suggesting that systemic EE/ENG levels were sufficient to suppress menstruation. The TAF2 and ACV release rates and resulting vaginal tissue drug concentrations (medians: TFV, 2.4 ng mg-1; ACV, 0.2 ng mg-1) may be sufficient to protect against HIV and HSV infection, respectively. This proof of principle study demonstrates that MPT-pod IVRs could serve as a potent biomedical prevention tool to protect women's sexual and reproductive health and may increase adherence to HIV PrEP even among younger high-risk populations.

Preferences for ARV-based HIV prevention methods among men and women, adolescent girls and female sex workers in Gauteng Province, South Africa: a protocol for a discrete choice experiment

INTRODUCTION

For the past few decades, condoms have been the main method of HIV prevention. Recent advances in antiretroviral (ARV)-based prevention products have substantially changed the prevention landscape, yet little is known about how popular these products will be among potential users, or whether new methods might be used in conjunction with, or instead of, condoms. This study will use a discrete choice experiment (DCE) to (1) explore potential users' preferences regarding HIV prevention products, (2) quantify the importance of product attributes and (3) predict the uptake of products to inform estimates of their potential impact on the HIV epidemic in South Africa. We consider preferences for oral pre-exposure prophylaxis; a vaginal microbicide gel; a long-acting vaginal ring; a SILCS diaphragm used in concert with gel; and a long-acting ARV-based injectable.

METHODS AND ANALYSIS

This study will gather data from 4 populations: 200 women, 200 men, 200 adolescent girls (aged 16-17 years) and 200 female sex workers. The DCE attributes and design will be developed through a literature review, supplemented by a thematic analysis of qualitative focus group discussions. Extensive piloting will be carried out in each population through semistructured interviews. The final survey will be conducted using computer tablets via a household sample (for women, men and adolescents) and respondent-driven sampling (for female sex workers), and DCE data analysed using a range of multinomial logit models.

ETHICS AND DISSEMINATION

This study has been approved by the University of the Witwatersrand Human Research Ethics Committee and the Research Ethics Committee at the London School of Hygiene and Tropical Medicine. Findings will be presented to international conferences and peer-reviewed journals. Meetings will be held with opinion leaders in South Africa, while results will be disseminated to participants in Ekurhuleni through a public meeting or newsletter.

Incorporating Demand and Supply Constraints into Economic Evaluations in Low-Income and Middle-Income Countries

Global guidelines for new technologies are based on cost and efficacy data from a limited number of trial locations. Country-level decision makers need to consider whether cost-effectiveness analysis used to inform global guidelines are sufficient for their situation or whether to use models that adjust cost-effectiveness results taking into account setting-specific epidemiological and cost heterogeneity. However, demand and supply constraints will also impact cost-effectiveness by influencing the standard of care and the use and implementation of any new technology. These constraints may also vary substantially by setting. We present two case studies of economic evaluations of the introduction of new diagnostics for malaria and tuberculosis control. These case studies are used to analyse how the scope of economic evaluations of each technology expanded to account for and then address demand and supply constraints over time. We use these case studies to inform a conceptual framework that can be used to explore the characteristics of intervention complexity and the influence of demand and supply constraints. Finally, we describe a number of feasible steps that researchers who wish to apply our framework in cost-effectiveness analyses.