The Use of Decision-Analytic Models in Atopic Eczema: A Systematic Review and Critical Appraisal

Cost-Effectiveness Study of Difamilast 1% for the Treatment of Atopic Dermatitis in Adult Japanese Patients

INTRODUCTION

Difamilast has proven to be an effective treatment for the treatment of atopic dermatitis (AD) in Japan, but its cost-effectiveness remains unknown. Therefore, the objective of the current study was to determine the cost-effectiveness of difamilast 1% compared with delgocitinib 0.5% in Japanese adult patients with moderate-to-severe AD and compared with placebo in Japanese adult patients with all-severity AD from a Japanese public health-care perspective.

METHODS

The analysis was conducted using a cost-effectiveness model from the Japanese public health-care perspective. This model had four health states ("clear," "mild," "moderate," and "severe") defined according to the Eczema Area and Severity Index score. The time horizon of the analysis was 1 year. Because the analysis period was short, no discount rate was applied. The proportions of patients previously estimated by the anchored matching-adjusted indirect comparison were implemented in the model. The model was further populated with data from the literature. The main model outcomes were quality-adjusted life-years (QALY), costs, and outcomes, including the incremental cost-effectiveness ratio. All prices were stated in JPY at the price level from 2018 April to 2019 March. One-way sensitivity analysis and probabilistic sensitivity analysis (PSA) were performed to assess the robustness of the results.

RESULTS

In the base case, the cost-effectiveness of difamilast 1% compared with delgocitinib 0.5% and placebo was JPY 827,054/QALY and JPY 1,518,657/QALY, respectively. The PSA showed that the cost-effectiveness of difamilast 1% compared with delgocitinib 0.5% and placebo had a 66.6% and 99.6% probability of being below the JPY 5 million/QALY threshold, respectively.

CONCLUSION

The results suggest that difamilast 1% is a more cost-effective treatment option compared with delgocitinib 0.5% in Japanese adult patients with moderate-to-severe AD and compared with placebo in adult patients with all-severity AD from a Japanese public health-care perspective.

Emollient application from birth to prevent eczema in high-risk children: the BEEP RCT

Background

Atopic eczema is a common childhood skin problem linked with asthma, food allergy and allergic rhinitis that impairs quality of life.

Objectives

To determine whether advising parents to apply daily emollients in the first year can prevent eczema and/or other atopic diseases in high-risk children.

Design

A United Kingdom, multicentre, pragmatic, two-arm, parallel-group randomised controlled prevention trial with follow-up to 5 years.

Setting

Twelve secondary and four primary care centres.

Participants

Healthy infants (at least 37 weeks' gestation) at high risk of developing eczema, screened and consented during the third trimester or post delivery.

Interventions

Infants were randomised (1 : 1) within 21 days of birth to apply emollient (Doublebase Gel®; Dermal Laboratories Ltd, Hitchin, UK or Diprobase Cream®) daily to the whole body (excluding scalp) for the first year, plus standard skin-care advice (emollient group) or standard skin-care advice only (control group). Families were not blinded to allocation.

Main outcome measures

Primary outcome was eczema diagnosis in the last year at age 2 years, as defined by the UK Working Party refinement of the Hanifin and Rajka diagnostic criteria, assessed by research nurses blinded to allocation. Secondary outcomes up to age 2 years included other eczema definitions, time to onset and severity of eczema, allergic rhinitis, wheezing, allergic sensitisation, food allergy, safety (skin infections and slippages) and cost-effectiveness.

Results

One thousand three hundred and ninety-four newborns were randomised between November 2014 and November 2016; 693 emollient and 701 control. Adherence in the emollient group was 88% (466/532), 82% (427/519) and 74% (375/506) at 3, 6 and 12 months. At 2 years, eczema was present in 139/598 (23%) in the emollient group and 150/612 (25%) in controls (adjusted relative risk 0.95, 95% confidence interval 0.78 to 1.16; p = 0.61 and adjusted risk difference -1.2%, 95% confidence interval -5.9% to 3.6%). Other eczema definitions supported the primary analysis. Food allergy (milk, egg, peanut) was present in 41/547 (7.5%) in the emollient group versus 29/568 (5.1%) in controls (adjusted relative risk 1.47, 95% confidence interval 0.93 to 2.33). Mean number of skin infections per child in the first year was 0.23 (standard deviation 0.68) in the emollient group versus 0.15 (standard deviation 0.46) in controls; adjusted incidence rate ratio 1.55, 95% confidence interval 1.15 to 2.09. The adjusted incremental cost per percentage decrease in risk of eczema at 2 years was £5337 (£7281 unadjusted). No difference between the groups in eczema or other atopic diseases was observed during follow-up to age 5 years via parental questionnaires.

Limitations

Two emollient types were used which could have had different effects. The median time for starting emollients was 11 days after birth. Some contamination occurred in the control group (< 20%). Participating families were unblinded and reported on some outcomes.

Conclusions

We found no evidence that daily emollient during the first year of life prevents eczema in high-risk children. Emollient use was associated with a higher risk of skin infections and a possible increase in food allergy. Emollient use is unlikely to be considered cost-effective in this context.

Future research

To pool similar studies in an individual patient data meta-analysis.

Trial registration

This trial is registered as ISRCTN21528841.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 12/67/12) and is published in full in Health Technology Assessment; Vol. 28, No. 29. See the NIHR Funding and Awards website for further award information.

Emollients for preventing atopic eczema: Cost-effectiveness analysis of the BEEP trial

BACKGROUND

Recent discoveries have led to the suggestion that enhancing skin barrier from birth might prevent eczema and food allergy.

OBJECTIVE

To determine the cost-effectiveness of daily all-over-body application of emollient during the first year of life for preventing atopic eczema in high-risk children at 2 years from a health service perspective. We also considered a 5-year time horizon as a sensitivity analysis.

METHODS

A within-trial economic evaluation using data on health resource use and quality of life captured as part of the BEEP trial alongside the trial data. Parents/carers of 1394 infants born to families at high risk of atopic disease were randomised 1:1 to the emollient group, which were advised to apply emollient (Doublebase Gel or Diprobase Cream) to their child at least once daily to the whole body during the first year of life or usual care. Both groups received advice on general skin care. The main economic outcomes were incremental cost-effectiveness ratio (ICER), defined as incremental cost per percentage decrease in risk of eczema in the primary cost-effectiveness analysis. Secondary analysis, undertaken as a cost-utility analysis, reports incremental cost per Quality-Adjusted Life Year (QALY) where child utility was elicited using the proxy CHU-9D at 2 years.

RESULTS

At 2 years, the adjusted incremental cost was £87.45 (95% CI -54.31, 229.27) per participant, whilst the adjusted proportion without eczema was 0.0164 (95% CI -0.0329, 0.0656). The ICER was £5337 per percentage decrease in risk of eczema. Adjusted incremental QALYs were very slightly improved in the emollient group, 0.0010 (95% CI -0.0069, 0.0089). At 5 years, adjusted incremental costs were lower for the emollient group, -£106.89 (95% CI -354.66, 140.88) and the proportion without eczema was -0.0329 (95% CI -0.0659, 0.0002). The 5-year ICER was £3201 per percentage decrease in risk of eczema. However, when inpatient costs due to wheezing were excluded, incremental costs were lower and incremental effects greater in the usual care group.

CONCLUSIONS

In line with effectiveness endpoints, advice given in the BEEP trial to apply daily emollient during infancy for eczema prevention in high-risk children does not appear cost-effective.

What are the highest yielding search strategy terms for systematic reviews in atopic dermatitis? A systematic review

The impact of search strategies on systematic reviews (SR) of atopic dermatitis (AD) is unknown. The purpose of this review was to evaluate search strategies used in SR of AD and their impact on the frequency of manuscripts identified. MEDLINE and EMBASE were searched for SR related to AD. Simulations were performed by running combinations of search terms in MEDLINE and EMBASE. Overall, 250 SR met inclusion criteria, of which 225 specified search strategies. SR using 5-6 terms (20.0% to 12.1%) or ≥ 7 (40.0% to 18.8%) terms decreased, whereas SR using 3-4 terms numerically increased (18.8% to 30.2%) and 1-2 terms remained similar (37.5% to 38.9%) from 1999-2009 to 2015-2019. The most commonly searched terms were "atopic dermatitis" (n = 166), followed by "eczema" (n = 156), "dermatitis atopic'" (n = 81), "atopic eczema" (n = 74), "neurodermatitis" (n = 59), "Besniers prurigo" (n = 29), "infantile eczema" (n = 27), and "childhood eczema" (n = 19). Simulations revealed that "eczema" and "atopic dermatitis" yielded the most hits. The number of search terms that maximized hits in MEDLINE and EMBASE was 5 and 4, respectively. Search strategies for AD were heterogeneous, with high proportions of search strategies providing few search hits. Future studies should use standardized and optimized search terms.

Models for estimating and projecting global, regional and national prevalence and disease burden of asthma: a systematic review

Background

Statistical models are increasingly being used to estimate and project the prevalence and burden of asthma. Given substantial variations in these estimates, there is a need to critically assess the properties of these models and assess their transparency and reproducibility. We aimed to critically appraise the strengths, limitations and reproducibility of existing models for estimating and projecting the global, regional and national prevalence and burden of asthma.

Methods

We undertook a systematic review, which involved searching Medline, Embase, World Health Organization Library and Information Services (WHOLIS) and Web of Science from 1980 to 2017 for modelling studies. Two reviewers independently assessed the eligibility of studies for inclusion and then assessed their strengths, limitations and reproducibility using pre-defined quality criteria. Data were descriptively and narratively synthesised.

Results

We identified 108 eligible studies, which employed a total of 51 models: 42 models were used to derive national level estimates, two models for regional estimates, four models for global and regional estimates and three models for global, regional and national estimates. Ten models were used to estimate the prevalence of asthma, 27 models estimated the burden of asthma – including, health care service utilisation, disability-adjusted life years, mortality and direct and indirect costs of asthma – and 14 models estimated both the prevalence and burden of asthma. Logistic and linear regression models were most widely used for national estimates. Different versions of the DisMod-MR- Bayesian meta-regression models and Cause Of Death Ensemble model (CODEm) were predominantly used for global, regional and national estimates. Most models suffered from a number of methodological limitations – in particular, poor reporting, insufficient quality and lack of reproducibility.

Conclusions

Whilst global, regional and national estimates of asthma prevalence and burden continue to inform health policy and investment decisions on asthma, most models used to derive these estimates lack the required reproducibility. There is a need for better-constructed models for estimating and projecting the prevalence and disease burden of asthma and a related need for better reporting of models, and making data and code available to facilitate replication.

Understanding economic evidence for the prevention and treatment of atopic eczema

BACKGROUND

Atopic eczema is an inflammatory skin condition, with a similar impact on health-related quality of life as other chronic diseases. Increasing pressures on resources within the National Health Service increase the importance of having good economic evidence to inform their allocation.

OBJECTIVES

To educate dermatologists about economic methods with reference to currently available economic evidence on eczema.

METHODS

The role of different types of economic evidence is illustrated by evidence found in a systematic literature search conducted across 12 online databases up to 22 May 2017. Primary empirical studies either reporting the results of a cost-of-illness study or evaluating the cost, utility or full economic evaluation of interventions for preventing or treating eczema were included. Two reviewers independently assessed studies for eligibility and performed data abstraction, with disagreements resolved by a third reviewer. Evidence tables of results were produced for narrative discussion. The reporting quality of economic evaluations was assessed.

RESULTS

Seventy-eight studies (described in 80 papers) were deemed eligible. Thirty-three (42%) were judged to be economic evaluations, 12 (15%) cost analyses, six (8%) utility analyses, 26 (33%) cost-of-illness studies and one a feasibility study (1%). The calcineurin inhibitors tacrolimus and pimecrolimus, as well as barrier creams, had the most economic evidence available. Partially hydrolysed infant formula was the most commonly evaluated prevention.

CONCLUSIONS

The current level of economic evidence for interventions aimed at preventing and treating eczema is limited compared with that available for clinical outcomes, suggesting that greater collaboration between clinicians and economists might be beneficial.

Barriers and Facilitators to Model Replication Within Health Economics

BACKGROUND

Model replication is important because it enables researchers to check research integrity and transparency and, potentially, to inform the model conceptualization process when developing a new or updated model.

OBJECTIVE

The aim of this study was to evaluate the replicability of published decision analytic models and to identify the barriers and facilitators to replication.

METHODS

Replication attempts of 5 published economic modeling studies were made. The replications were conducted using only publicly available information within the manuscripts and supplementary materials. The replicator attempted to reproduce the key results detailed in the paper, for example, the total cost, total outcomes, and if applicable, incremental cost-effectiveness ratio reported. Although a replication attempt was not explicitly defined as a success or failure, the replicated results were compared for percentage difference to the original results.

RESULTS

In conducting the replication attempts, common barriers and facilitators emerged. For most case studies, the replicator needed to make additional assumptions when recreating the model. This was often exacerbated by conflicting information being presented in the text and the tables. Across the case studies, the variation between original and replicated results ranged from -4.54% to 108.00% for costs and -3.81% to 0.40% for outcomes.

CONCLUSION

This study demonstrates that although models may appear to be comprehensively reported, it is often not enough to facilitate a precise replication. Further work is needed to understand how to improve model transparency and in turn increase the chances of replication, thus ensuring future usability.

An introduction to the methods of decision-analytic modelling used in economic evaluations for Dermatologists

Economic evaluations are used to identify which health treatments or preventions offer the most effective use of resources, or value for money. This is achieved by identifying, measuring and valuing the inputs and outcomes of alternative interventions. These evaluations are often conducted alongside clinical trials; however, these trials may end before the outcomes of economic interest have been observed and measured. An alternative to within trial economic evaluation is to use decision modelling, which can model the cost-effectiveness of interventions over an extended time period. This paper aims to provide an overview for clinicians of the different modelling techniques used within health economic evaluations and to introduce methods for critical appraisal. The most common modelling approaches, and their associated strengths and weaknesses, were discussed. Alongside this, practical examples specific to dermatology were given. These examples include studies where the model chosen or the methods used may not have been the most appropriate. Methods for critical appraisal were also highlighted. Common modelling approaches include Decision Trees, Markov Cohort, extensions to the Markov model (Monte Carlo Simulation) and Discrete Event Simulation models. Items of the Philips Checklist were discussed in the context of performing critical appraisal. Health economic decision models are multi-faceted and can often be complex. Full critical appraisal requires clinicians' unique knowledge, which is complementary to the knowledge of health economists.

Novel systemic therapies in atopic dermatitis: what do we need to fulfil the promise of a treatment revolution?

Patients with atopic dermatitis (AD) who do not adequately respond to topical therapy and phototherapy often need systemic immunomodulatory treatment to control their symptoms. Conventional systemic agents, such as ciclosporin, azathioprine, and methotrexate, have been used for decades, but there are concerns about their safety profile. There are now many novel systemic agents emerging through clinical trials, which may have great potential in the treatment of AD. Despite this, there are very few data comparing the performance of these drugs against each other. The purpose of this article is to review the current systemic therapies in AD and present an indirect comparison of systemic AD treatments using effectiveness and safety data from published randomised controlled trials, highlighting important remaining gaps in knowledge. Although the latest developments in systemic AD treatments are exciting and dearly needed, further work is required before the promise of a therapeutic revolution becomes reality.

Quality assessment of atopic dermatitis clinical practice guidelines in ≤ 18 years

Atopic dermatitis (AD) is a chronic inflammatory skin disease that affects the patients' quality of life greatly often from a very young age. Its worldwide incidence in children and adults varies, but it is usually among the first ten causes of dermatological consultation worldwide. There is a wide variety of treatment options for this condition including topical and systemic regimes. The decision to choose a treatment option in dermatological diseases is greatly influenced by the personal experience of each specialist, which increases variability in the selection of available therapies. Clinical practice guidelines (CPGs) not only offer recommendations supported on the available scientific evidence, but also are intended to assist in making appropriate decisions in clinical scenarios. To standardize the way in which CPGs should be developed, an instrument called AGREE II (Appraisal of Guidelines for Research and Evaluation) is used. In this study, ten clinical practice guidelines in ≤ 18 years were evaluated. Six domains (scope and purpose, stakeholder involvement, rigor of development, clarity and presentation, applicability, and editorial independence) were assessed for each guideline, by three reviewers. Most of the domains obtained high scores except in the applicability domain. It is suggested that future atopic dermatitis CPGs should emphasize in the facilitating factors and barriers that may influence the application of guideline recommendations.