Early Economic Evaluation to Identify the Necessary Test Characteristics of a New Typhoid Test to be Cost Effective in Ghana

Headroom Analysis for Early Economic Evaluation: A Systematic Review

OBJECTIVES

The headroom analysis is an early economic evaluation that quantifies the highest price at which an intervention may still be cost effective. Currently, there is no comprehensive review on how it is applied. This study investigated the application of the headroom analysis, specifically (1) how the headroom analysis is framed (2) the analytical approach and sources of evidence used, and (3) how expert judgement is used and reported.

METHODS

A systematic search was conducted in PubMed, Embase, Web of Science, EconLit, and Google Scholar on 28 April 2022. Studies were eligible if they reported an application of the headroom analysis. Data were presented in tabular form and summarised descriptively.

RESULTS

We identified 42 relevant papers. The headroom analysis was applied to medicines (29%), diagnostic or screening tests (29%), procedures, programmes and systems (21%), medical devices (19%), and a combined test and device (2%). All studies used model-based analyses, with 40% using simple models and 60% using more comprehensive models. Thirty-three percent of the studies assumed perfect effectiveness of the health technology, while 67% adopted realistic assumptions. Ten percent of the studies calculated an effectiveness-seeking headroom instead of a cost-seeking headroom. Expert judgement was used in 71% of the studies; 23 studies (55%) used expert opinion, 6 studies (14%) used expert elicitation, and 1 study (2%) used both.

CONCLUSIONS

Because the application of the headroom analysis varies considerably, we recommend its appropriate use and clear reporting of analytical approaches, level of evidence available, and the use of expert judgement.

The cost-effectiveness of using rapid diagnostic tests for the diagnosis of typhoid fever in patients with suspected typhoid fever: a systematic review

INTRODUCTION

Despite the availability of several commercial rapid diagnostic tests (RDTs) developed to detect typhoid fever, the cost-effectiveness in resource-limited settings is unclear. This review aimed to explore the literature on typhoid economic evaluations in order to assess the cost-effectiveness of using typhoid RDTs in resource-limited settings.

AREAS COVERED

A systematic review was conducted focusing on the identification of economic evaluations of typhoid RDTs to diagnose patients with suspected typhoid fever. Two studies were identified and included for narrative synthesis. Whilst highlighting a gap in the published literature, this review shows the use of typhoid RDTs to potentially be cost-effective in resource-limited settings. Factors that appeared as significant in determining cost-effectiveness related to test characteristics (such as sensitivity, specificity, and cost) and the prevalence of typhoid fever and should factor into any future evaluations.

EXPERT OPINION

Concerted effort is needed in resource-limited settings with regard to medical device regulation to ensure that clinically effective and cost-effective typhoid RDTs are widely available and introduced into clinical practice. Typhoid modeling (with respect to typhoid testing and treatment strategies) represents an understudied area and further work is needed.

Integrating Early Economic Evaluation into Target Product Profile development for medical tests: advantages and potential applications

Target Product Profiles (TPPs) outline the characteristics that new health technologies require to address an unmet clinical need. To date, published TPPs for medical tests have focused on infectious diseases, mostly in the context of low- and middle-income countries. Recently, there have been calls for a broader use of TPPs as a mechanism to ensure that diagnostic innovation is aligned with clinical needs, yet the methodology underpinning TPP development remains suboptimal. Here, we propose that early economic evaluation (EEE) should be integrated within the TPP methodology to create a more rigorous framework for the development of "fit-for-purpose" tests. We discuss the potential benefits that EEE could bring to the core activities underpinning TPP development-scoping, drafting, consensus building, and updating-and argue that using EEE to help inform TPPs provides a more objective, evidence-based, and transparent approach to defining test specifications.

Early economic evaluation of an intervention to improve uptake of the NHS England Diabetes Prevention Programme

BACKGROUND

Despite reported increases in referral numbers, a large proportion of those with prediabetes still decline participation in the NHS England Diabetes Prevention Programme (NDPP). The aim of this study was to explore whether investment in interventions to improve uptake of the programme has the potential to be cost-effective.

METHODS

An early cost-utility analysis was conducted using a Markov model parameterized based on secondary data sources. We explored different uptake scenarios and the impact that this had on the maximum allowable intervention price based on cost-effectiveness at the UK NICE willingness to pay threshold of £20,000 (US$ 25,913). Value of information analyses were conducted to explore the potential value of further research to resolve uncertainty at each uptake level.

RESULTS

As uptake levels increase, the maximum allowable intervention price and overall expected value of removing decision uncertainty increases. For 5 percentage and 50 percentage points increase in uptake levels, the maximum allowable intervention price is £41.86 (US$ 54.23) and £418.59 (US$ 542.34) per person, and the overall expected value of removing decision uncertainty are £361,818,839 (US$ 468,786,625) and £1,468,712,316 (US$ 1,902,921,063) respectively.

CONCLUSION

There is headroom for investment in interventions that improve uptake to the NDPP, thereby allowing the programme itself to be delivered in a manner that remains cost-effective.

The Application and Implications of Novel Deterministic Sensitivity Analysis Methods

Deterministic sensitivity analyses (DSA) remain important to interpret the effect of uncertainties in individual parameters on results of cost-effectiveness analyses. Classic DSA methodologies may lead to wrong conclusions due to a lack of or misleading information regarding marginal effects, non-linearity, likelihood and correlations. In addition, tornado diagrams are misleading in some situations. Recent advances in DSA methods have the potential to provide decision makers with more reliable information regarding the effects of uncertainties in individual parameters. This practical application discusses advances to classic DSA methods and their implications. Three methods are discussed: stepwise DSA, distributional DSA and probabilistic DSA. For each method, the technical specifications, options for presenting results, and its implications for decision making are discussed. Options for visualizing DSA results in incremental cost-effectiveness ratios and in incremental net benefits are presented. The use of stepwise DSA increases interpretability of marginal effects and non-linearities in the model, which is especially relevant when arbitrary ranges are implemented. Using the probability distribution of each parameter in distributional DSA provides insight on the likelihood of model outcomes while probabilistic DSA also includes the effects of correlations between parameters.Probabilistic DSA, preferably expressed in incremental net benefit, is the most appropriate method for providing insight on the effect of uncertainty in individual parameters on the estimate of cost effectiveness. However, the opportunities provided by probabilistic DSA may not always be needed for decision making. Other DSA methods, in particular distributional DSA, can sometimes be sufficient depending on model features. Decision makers must determine to which extent they will accept and implement these new and improved DSA methodologies and adjust guidelines accordingly.