Enhanced external counterpulsation for the treatment of stable angina and heart failure: a systematic review and economic analysis

Effects of single and multiple sessions of lower body diastole-synchronized compressions using a pulsating pneumatic suit on endothelium function and metabolic parameters in patients with type 2 diabetes: two controlled cross-over studies

BACKGROUND

Endothelium function is often impaired in patients with type 2 diabetes. We hypothesized that by improving endothelial function using diastole-synchronized compressions/decompressions (DSCD) to the lower body may improve the metabolic profile. The objective of this research was to evaluate the effects of single and multiple DSCD sessions on microcirculation, endothelium function and metabolic parameters of patients with type 2 diabetes.

METHODS

Two monocentric, controlled, randomized cross-over studies (Study 1 and Study 2) were performed. In Study 1, 16 patients received one 20 min DSCD and one simulated (control) session at 2 week intervals; continuous glucose monitoring and cutaneous blood flow were recorded continuously before, during and after DSCD or Control session; other vascular assessments were performed before and after DSCD and control sessions. In Study 2, 38 patients received 60 min DSCD sessions three times/week for three months followed by a 4-6 week washout and 3 month control period (without simulated sessions); vascular, metabolic, body composition, physical activity and quality of life assessments were performed before and after 3 months.

RESULTS

Both studies showed significant, multiplex effects of DSCD sessions. In Study 1, cutaneous blood flow and endothelium function increased, and plasma and interstitial glucose levels after a standard breakfast decreased after DSCD sessions. In Study 2, cutaneous endothelium function improved, LDL-cholesterol and non-HDL cholesterol decreased, extra-cell water decreased and SF-36 Vitality score increased after 3 months of DSCD sessions.

CONCLUSIONS

Our findings support the beneficial effect of DSCD on the endothelium and show concomitant beneficial metabolic and vitality effects. Future clinical trials need to test whether DSCD use translates into a preventive measure against microvascular diabetic complications and its progression. Trial registration ClinicalTrials.gov identifiers: NCT02293135 and NCT02359461.

Numerical analysis of hemodynamic effect under different enhanced external counterpulsation (EECP) frequency for cerebrovascular disease: a simulation study

Based on the changes in phase characteristics of blood flow and pressure, enhanced external counterpulsation (EECP) reduces cardiac load and improves cerebral perfusion in patients with cerebrovascular diseases. However, increased cerebral blood flow (CBF) is associated with the rise in blood pressure and its complications. Increased EECP frequency is a valuable solution when combined with the electrical equivalent impedance characteristics of the lumped parameter model (LPM) of the human blood circulation system. Herein, to investigate the effect of different EECP frequencies on CBF perfusion, an LPM was established with cardiopulmonary circulation and eight systemic blood flow units with cerebral autoregulation module of ischemic stroke patients. Then, using differential equations, we analyzed those parameters through hemodynamic simulations in four EECP modes. With related influencing parameters remaining constant, we adjusted the pressure frequency of EECP and found that when compared to the traditional sequential EECP mode, the relative increase rate of CBF was 16.68%, 18.95%, and 21.21% from 1 to 3 Hz, respectively. This study validates the effect of improving blood prefusion with increasing EECP frequency through numerical analysis.

Medium-term Effects of Enhanced External Counterpulsation in the Structural and Functional Parameters of Blood Vessels in Patients with Coronary Artery Disease

Aim. To study the mid-term effects of enhanced external counterpulsation (EECP) in the structural and functional parameters of blood vessels, exercise tolerance and quality of life indicators in patients with verified coronary artery disease (CAD).

Material and methods. Patients (n=70) with verified stable CAD (angina pectoris class II-III) complicated by chronic heart faillure class II-III (NYHA) were included in the study. Data from 65 patients (48 to 74 years old; 45 men and 20 women) are included in the final analysis. All patients had a course of EECP (35 hours procedures with a compression pressure of 220-280 mm Hg). All patients at baseline, 3 and 6 months later had a 6 walk minute test (6WMT), an assessment of the clinical status, quality of life of patients (Minnesota Living with Heart Failure Questionnaire, SF-36). Computer nailfold video capillaroscopy, photoplethysmography with pulse wave recording and contour analysis, applanation tonometry to assess central aortic systolic pressure and radial augmentation index were performed to assess the structural and functional state of large and microcirculatory vessels.

Results. Significant improvement in exercise tolerance both after 3 and after 6 months (increase in distance in 6WMT by 44.6% after 3 months and 34.3% after 6 months, p <0.05), improved quality of life (increased overall score on the SF-36 questionnaire from 50.3±8.1 to 59.8±8.8, p<0.05), an increase in the left ventricular ejection fraction were found. Significant improvement in indicators showing the function of the endothelium of both large vessels (phase shift: from 5.6 [2.45; 7.3] to 6.8 [3.1; 8.1] m / s) and microcirculatory vessels (occlusion index: from 1.51 [1.21; 1.7] to 1.66 [1.2; 1.9]), as well as a decrease in functional disorders of the capillary bed of the skin (% of perfused capillaries, density of the capillary network in the test with reactive hyperemia) were found after 3 months. However, after 6 months, there were no significant changes in these parameters compared to the baseline value. No significant change in indicators showing structural remodeling of both large vessels and microcirculatory vessels was found.

Conclusion. The positive effect of the EECP course on the functional status (exercise tolerance) and quality of life in patients with stable coronary artery disease complicated by chronic heart faillure was found both after 3 and 6 months. Positive dynamics of the functional state of large vessels and microvasculature was found only after 3 months.

Developing a reference protocol for structured expert elicitation in health-care decision-making: a mixed-methods study

BACKGROUND

Many decisions in health care aim to maximise health, requiring judgements about interventions that may have higher health effects but potentially incur additional costs (cost-effectiveness framework). The evidence used to establish cost-effectiveness is typically uncertain and it is important that this uncertainty is characterised. In situations in which evidence is uncertain, the experience of experts is essential. The process by which the beliefs of experts can be formally collected in a quantitative manner is structured expert elicitation. There is heterogeneity in the existing methodology used in health-care decision-making. A number of guidelines are available for structured expert elicitation; however, it is not clear if any of these are appropriate for health-care decision-making.

OBJECTIVES

The overall aim was to establish a protocol for structured expert elicitation to inform health-care decision-making. The objectives are to (1) provide clarity on methods for collecting and using experts' judgements, (2) consider when alternative methodology may be required in particular contexts, (3) establish preferred approaches for elicitation on a range of parameters, (4) determine which elicitation methods allow experts to express uncertainty and (5) determine the usefulness of the reference protocol developed.

METHODS

A mixed-methods approach was used: systemic review, targeted searches, experimental work and narrative synthesis. A review of the existing guidelines for structured expert elicitation was conducted. This identified the approaches used in existing guidelines (the 'choices') and determined if dominant approaches exist. Targeted review searches were conducted for selection of experts, level of elicitation, fitting and aggregation, assessing accuracy of judgements and heuristics and biases. To sift through the available choices, a set of principles that underpin the use of structured expert elicitation in health-care decision-making was defined using evidence generated from the targeted searches, quantities to elicit experimental evidence and consideration of constraints in health-care decision-making. These principles, including fitness for purpose and reflecting individual expert uncertainty, were applied to the set of choices to establish a reference protocol. An applied evaluation of the developed reference protocol was also undertaken.

RESULTS

For many elements of structured expert elicitation, there was a lack of consistency across the existing guidelines. In almost all choices, there was a lack of empirical evidence supporting recommendations, and in some circumstances the principles are unable to provide sufficient justification for discounting particular choices. It is possible to define reference methods for health technology assessment. These include a focus on gathering experts with substantive skills, eliciting observable quantities and individual elicitation of beliefs. Additional considerations are required for decision-makers outside health technology assessment, for example at a local level, or for early technologies. Access to experts may be limited and in some circumstances group discussion may be needed to generate a distribution.

LIMITATIONS

The major limitation of the work conducted here lies not in the methods employed in the current work but in the evidence available from the wider literature relating to how appropriate particular methodological choices are.

CONCLUSIONS

The reference protocol is flexible in many choices. This may be a useful characteristic, as it is possible to apply this reference protocol across different settings. Further applied studies, which use the choices specified in this reference protocol, are required.

FUNDING

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 37. See the NIHR Journals Library website for further project information. This work was also funded by the Medical Research Council (reference MR/N028511/1).

The Use of Enhanced External Counterpulsation in the Treatment of Patients with Coronary Artery Disease

Enhanced external counterpulsation (EECP) is one of the most effective and safe non-invasive methods of treatment for patients with coronary artery disease (CAD), including complicated chronic heart failure (CHF). This method of therapeutic neoangiogenesis, used in conjunction with traditional drug therapy and myocardial revascularization, can significantly improve the quality of management of these patients.

Aim. To study the effect of the EECP course on exercise tolerance, quality of life, structural and functional parameters of blood vessels in patients with verified stable CAD complicated by CHF.

Material and methods. Patients (n=70) with verified stable CAD (angina pectoris class II-III) complicated by CHF class II-III (NYHA) were included in non-randomized uncontrolled study. Data from 67 patients (48 to 74 years old; 47 men and 20 women) were included in the final analysis. All patients had a course of EECP (35 one-hour procedures with a compression pressure of 220-280 mm Hg). All patients initially and 1.5 months after the EECP course had a 6-minute walk test (6MWT), an assessment of the clinical status, quality of life of patients (MLHFQ; Minnesota Living with Heart Failure Questionnaire). Computer nailfold video capillaroscopy, photoplethysmography with pulse wave recording and contour analysis, applanation tonometry to assess central aortic systolic pressure and radial augmentation index (RAI) were performed to assess the structural and functional state of large and microcirculatory vessels.

Results. A statistically significant improvement in exercise tolerance (increase in distance in 6MWT from 212 [189; 273] to 308 [251; 336] m), improvement in the clinical status of patients (decrease in points on the rating scale of clinical state from 6.5±1.8 to 4.4±1,2), improvement in the quality of life according to the MLHFQ questionnaire (from 51.9±6.2 to 38.6±7.1), increase in the left ventricle ejection fraction (from 41.6 [36.6;47.1] to 44.8 [39.5;50.7]%) were found. A statistically significant improvement in endothelial function indices of both large vessels (phase shift: from 5.6 [2.4;7.2] to 6.8 [3.3;8] m/s) and microcirculatory vessels (occlusion index: from 1.5 [1.2;1.7] to 1.66 [1.3;1.9]), as well as a decrease in functional disorders of nailfold capillaries (percent of perfused capillaries, capillary network density in the reactive hyperemia test) also were found. But no statistically significant changes in the structural remodeling indices of both large and microcirculatory vessels were found.

Conclusion. A positive effect of the EECP course both on the functional status with an increase in exercise tolerance and improvement in the quality of life, and on the functional state of large vessels and microvasculature was found in patients with stable CAD complicated by CHF.

Optimal Allocation of Research Funds under a Budget Constraint

Purpose. Health economic evaluations that include the expected value of sample information support implementation decisions as well as decisions about further research. However, just as decision makers must consider portfolios of implementation spending, they must also identify the optimal portfolio of research investments. Methods. Under a fixed research budget, a decision maker determines which studies to fund; additional budget allocated to one study to increase the study sample size implies less budget available to collect information to reduce decision uncertainty in other implementation decisions. We employ a budget-constrained portfolio optimization framework in which the decisions are whether to invest in a study and at what sample size. The objective is to maximize the sum of the studies' population expected net benefit of sampling (ENBS). We show how to determine the optimal research portfolio and study-specific levels of investment. We demonstrate our framework with a stylized example to illustrate solution features and a real-world application using 6 published cost-effectiveness analyses. Results. Among the studies selected for nonzero investment, the optimal sample size occurs at the point at which the marginal population ENBS divided by the marginal cost of additional sampling is the same for all studies. Compared with standard ENBS optimization without a research budget constraint, optimal budget-constrained sample sizes are typically smaller but allow more studies to be funded. Conclusions. The budget constraint for research studies directly implies that the optimal sample size for additional research is not the point at which the ENBS is maximized for individual studies. A portfolio optimization approach can yield higher total ENBS. Ultimately, there is a maximum willingness to pay for incremental information that determines optimal sample sizes.

Analisi costo-utilità di dupilumab per il trattamento della dermatite atopica grave negli adulti in Italia

Background:

Atopic dermatitis (AD) is a chronic, multifactorial, inflammatory skin disease with significant impact on patients’ quality of life.

Objective:

The objective of this analysis was to estimate the incremental cost-utility ratio (ICUR) of dupilumab, administered every other week, plus supportive care (SC), vs SC, in the Italian adult population with severe AD, for whom ciclosporin treatment is contraindicated, ineffective or not tolerated.

Methods:

Simulation of outcomes and costs was conducted using a 1-year decision tree, followed by a lifetime horizon Markov model. Clinical data were derived from a pooled analysis of two studies. The analysis was conducted adopting the Italian National Health Service (NHS) perspective. In the model, the following costs were considered: i) Drug acquisition costs; ii) Disease management costs; iii) Costs of adverse events. Robustness of findings was tested using both one-way deterministic and probabilistic sensitivity analyses.

Results:

In the base case, dupilumab plus SC was more effective than SC (+2.42 quality adjusted life years, QALYs). The total lifetime cost per patient treated with dupilumab was higher than SC (€ 137,267 and € 56,744, respectively). Dupilumab plus SC was cost-effective vs. SC, with an ICUR of € 33,263 per QALY gained. The ICUR fell in the informal range of ICUR acceptability proposed for Italy (range: € 25,000-€ 40,000 per QALY gained). Sensitivity analyses confirmed robustness and reliability of base case results.

Conclusions:

Dupilumab plus SC is a cost-effective option for the treatment of patients with severe AD in Italy, compared with SC, when NHS perspective is considered.

Refractory angina frequencies during 7 weeks treatment by enhanced external counterpulsation in coronary artery disease patients with and without diabetes

Background:

Refractory angina is a clinical diagnosis which implies to chronic pain due to coronary artery insufficiency and it is often resistant to routine cardiac treatment. The present study conducted to compare changes in refractory angina frequencies during 7 weeks treatment by enhanced external counterpulsation (EECP) in coronary artery disease (CAD) patients with and without diabetes.

Methods:

In this retrospective study, 94 CAD patients (30 diabetics vs. 64 nondiabetics) who referred to cardiac rehabilitation department of Imam Ali Hospital of Kermanshah, Iran, during January 2006–2014 were assessed. The interventional method was EECP and medical records and frequencies of self-reported chest pain were research instruments. Data were analyzed through Chi-square test, mixed repeated measures, and Bonferroni test.

Results:

Frequencies of pain in both diabetic and nondiabetic groups during 7 weeks had linear reduction, but this reduction was significant only among nondiabetic patients (P < 0.0005). Furthermore, the significant reduction in frequencies of pain among this group begins after the 5^th week.

Discussion:

Diabetes is one of the obstacles to the successful control of pain frequencies by the EECP in patients with CAD. Future studies may pay attention to the confounding role of diabetes in improving the severity of chest pain.

Value of information analysis in telehealth for chronic heart failure management

OBJECTIVES

Value of information (VOI) analysis provides information on opportunity cost of a decision in healthcare by estimating the cost of reducing parametric uncertainty and quantifying the value of generating additional evidence. This study is an application of the VOI methodology to the problem of choosing between home telemonitoring and nurse telephone support over usual care in chronic heart failure management in the Netherlands.

METHODS

The expected value of perfect information (EVPI) and the expected value of partially perfect information (EVPPI) analyses were based on an informal threshold of €20K per quality-adjusted life-year. These VOI-analyses were applied to a probabilistic Markov model comparing the 20-year costs and effects in three interventions. The EVPPI explored the value of decision uncertainty caused by the following group of parameters: treatment-specific transition probabilities between New York Heart Association (NYHA) defined disease states, utilities associated with the disease states, number of hospitalizations and ER visits, health state specific costs, and the distribution of patients per NYHA group. We performed the analysis for two population sizes in the Netherlands-patients in all NYHA classes of severity, and patients in NYHA IV class only.

RESULTS

The population EVPI for an effective population of 2,841,567 CHF patients in All NYHA classes of severity over the next 20 years is more than €4.5B, implying that further research is highly cost-effective. In the NYHA IV only analysis, for the effective population of 208,003 patients over next 20 years, the population EVPI at the same informal threshold is approx. €590M. The EVPPI analysis showed that the only relevant group of parameters that contribute to the overall decision uncertainty are transition probabilities, in both All NYHA and NYHA IV analyses.

CONCLUSIONS

Results of our VOI exercise show that the cost of uncertainty regarding the decision on reimbursement of telehealth interventions for chronic heart failure patients is high in the Netherlands, and that future research is needed, mainly on the transition probabilities.

The Impact of Cell Therapy on Cardiovascular Outcomes in Patients With Refractory Angina

RATIONALE

Cell-based therapies are a novel potential treatment for refractory angina and have been found to improve markers of angina. However, the effects on mortality and major adverse cardiac events (MACE) have not been definitively investigated.

OBJECTIVE

To investigate the efficacy and safety of stem cell treatment compared with optimal medical treatment for refractory angina by conducting an updated meta-analysis, looking at clinical outcomes.

METHODS AND RESULTS

We performed a systematic review and meta-analysis of randomized controlled trials using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. A comprehensive search was performed of PubMed, EMBASE (Excerpta Medica database), Cochrane, ClinicalTrials.gov , Google Scholar databases of randomized controlled trials, and scientific session abstracts. Studies were deemed eligible if they met the following criteria: (1) full-length publications in peer-reviewed journals; (2) evaluated cell therapy use in patients with no further revascularisation options while on optimal medical treatment; (3) patients had ongoing angina, Canadian Cardiovascular Society class II-IV; and (4) included a placebo/control arm. We calculated risk ratios for all-cause mortality, combined MACE events. We assessed heterogeneity using χ² and I² tests. We identified 1191 citations with 8 randomized controlled trials meeting inclusion criteria involving 526 patients. Outcomes pooled were MACE, mortality, and indices of angina (angina episodes, Canadian Cardiovascular Society angina class, exercise tolerance, and antianginal medications). Our analysis showed a decreased risk of both MACE (odds ratio, 0.41; CI, 0.25-0.70) and mortality (odds ratio, 0.24; 95% CI, 0.10-0.60) in cell-treated patients compared with patients on maximal medical therapy. This was supported by improvements in surrogate end points of anginal episodes, use of antianginal medications, Canadian Cardiovascular Society class, and exercise tolerance.

CONCLUSIONS

In addition to improvements in indices of angina, cell-based therapies improve cardiovascular outcomes (mortality/MACE) in patients with refractory angina. Given the premature termination of the phase III study, this supports the need for further definitive trials. Prospero Registration : URL: https://www.crd.york.ac.uk/prospero/ . Unique identifier: CRD42018084257.

New Advances in the Management of Refractory Angina Pectoris

Refractory angina is a significant clinical problem and its successful management is often extremely challenging. Defined as chronic angina-type chest pain in the presence of myocardial ischaemia that persists despite optimal medical, interventional and surgical treatment, current therapies are limited and new approaches to treatment are needed. With an ageing population and increased survival from coronary artery disease, clinicians will increasingly encounter this complex condition in routine clinical practice. Novel therapies to target myocardial ischaemia in patients with refractory angina are at the forefront of research and in this review we discuss those in clinical translation and assess the evidence behind their efficacy.

Experiences of Structured Elicitation for Model-Based Cost-Effectiveness Analyses

BACKGROUND

Empirical evidence supporting the cost-effectiveness estimates of particular health care technologies may be limited, or it may even be missing entirely. In these situations, additional information, often in the form of expert judgments, is needed to reach a decision. There are formal methods to quantify experts' beliefs, termed as structured expert elicitation (SEE), but only limited research is available in support of methodological choices. Perhaps as a consequence, the use of SEE in the context of cost-effectiveness modelling is limited.

OBJECTIVES

This article reviews applications of SEE in cost-effectiveness modelling with the aim of summarizing the basis for methodological choices made in each application and recording the difficulties and challenges reported by the authors in the design, conduct, and analyses.

METHODS

The methods used in each application were extracted along with the criteria used to support methodological and practical choices and any issues or challenges discussed in the text. Issues and challenges were extracted using an open field, and then categorised and grouped for reporting.

RESULTS

The review demonstrates considerable heterogeneity in methods used, and authors acknowledge great methodological uncertainty in justifying their choices. Specificities of the context area emerging as potentially important in determining further methodological research in elicitation are between- expert variation and its interpretation, the fact that substantive experts in the area may not be trained in quantitative subjects, that judgments are often needed on various parameter types, the need for some form of assessment of validity, and the need for more integration with behavioural research to devise relevant debiasing strategies.

CONCLUSIONS

This review of experiences of SEE highlights a number of specificities/constraints that can shape the development of guidance and target future research efforts in this area.

Clinical translation of myocardial conditioning

Rapid admission and acute interventional treatment combined with modern antithrombotic pharmacologic therapy have improved outcomes in patients with ST elevation myocardial infarction. The next major target to further advance outcomes needs to address ischemia-reperfusion injury, which may contribute significantly to the final infarct size and hence mortality and postinfarction heart failure. Mechanical conditioning strategies including local and remote ischemic pre-, per-, and postconditioning have demonstrated consistent cardioprotective capacities in experimental models of acute ischemia-reperfusion injury. Their translation to the clinical scenario has been challenging. At present, the most promising mechanical protection strategy of the heart seems to be remote ischemic conditioning, which increases myocardial salvage beyond acute reperfusion therapy. An additional aspect that has gained recent focus is the potential of extended conditioning strategies to improve physical rehabilitation not only after an acute ischemia-reperfusion event such as acute myocardial infarction and cardiac surgery but also in patients with heart failure. Experimental and preliminary clinical evidence suggests that remote ischemic conditioning may modify cardiac remodeling and additionally enhance skeletal muscle strength therapy to prevent muscle waste, known as an inherent component of a postoperative period and in heart failure. Blood flow restriction exercise and enhanced external counterpulsation may represent cardioprotective corollaries. Combined with exercise, remote ischemic conditioning or, alternatively, blood flow restriction exercise may be of aid in optimizing physical rehabilitation in populations that are not able to perform exercise practice at intensity levels required to promote optimal outcomes.

Informing Reimbursement Decisions Using Cost-Effectiveness Modelling: A Guide to the Process of Generating Elicited Priors to Capture Model Uncertainties

In informing decisions, utilising health technology assessment (HTA), expert elicitation can provide valuable information, particularly where there is a less-developed evidence-base at the point of market access. In these circumstances, formal methods to elicit expert judgements are preferred to improve the accountability and transparency of the decision-making process, help reduce bias and the use of heuristics, and also provide a structure that allows uncertainty to be expressed. Expert elicitation is the process of transforming the subjective and implicit knowledge of experts into their quantifiable expressions. The use of expert elicitation in HTA is gaining momentum, and there is particular interest in its application to diagnostics, medical devices and complex interventions such as in public health or social care. Compared with the gathering of experimental evidence, elicitation constitutes a reasonably low-cost source of evidence. Given its inherent subject nature, the potential biases in elicited evidence cannot be ignored and, due to its infancy in HTA, there is little guidance to the analyst wishing to conduct a formal elicitation exercise. This article attempts to summarise the stages of designing and conducting an expert elicitation, drawing on key literature and examples, most of which are not in HTA. In addition, we critique their applicability to HTA, given its distinguishing features. There are a number of issues that the analyst should be mindful of, in particular the need to appropriately characterise the uncertainty associated with model inputs and the fact that there are often numerous parameters required, not all of which can be defined using the same quantities. This increases the need for the elicitation task to be as straightforward as possible for the expert to complete.

How to Appropriately Extrapolate Costs and Utilities in Cost-Effectiveness Analysis

Costs and utilities are key inputs into any cost-effectiveness analysis. Their estimates are typically derived from individual patient-level data collected as part of clinical studies the follow-up duration of which is often too short to allow a robust quantification of the likely costs and benefits a technology will yield over the patient's entire lifetime. In the absence of long-term data, some form of temporal extrapolation-to project short-term evidence over a longer time horizon-is required. Temporal extrapolation inevitably involves assumptions regarding the behaviour of the quantities of interest beyond the time horizon supported by the clinical evidence. Unfortunately, the implications for decisions made on the basis of evidence derived following this practice and the degree of uncertainty surrounding the validity of any assumptions made are often not fully appreciated. The issue is compounded by the absence of methodological guidance concerning the extrapolation of non-time-to-event outcomes such as costs and utilities. This paper considers current approaches to predict long-term costs and utilities, highlights some of the challenges with the existing methods, and provides recommendations for future applications. It finds that, typically, economic evaluation models employ a simplistic approach to temporal extrapolation of costs and utilities. For instance, their parameters (e.g. mean) are typically assumed to be homogeneous with respect to both time and patients' characteristics. Furthermore, costs and utilities have often been modelled to follow the dynamics of the associated time-to-event outcomes. However, cost and utility estimates may be more nuanced, and it is important to ensure extrapolation is carried out appropriately for these parameters.

Methods to construct a step-by-step beginner's guide to decision analytic cost-effectiveness modeling

BACKGROUND

Although guidance on good research practice in health economic modeling is widely available, there is still a need for a simpler instructive resource which could guide a beginner modeler alongside modeling for the first time.

AIM

To develop a beginner's guide to be used as a handheld guide contemporaneous to the model development process.

METHODS

A systematic review of best practice guidelines was used to construct a framework of steps undertaken during the model development process. Focused methods review supplemented this framework. Consensus was obtained among a group of model developers to review and finalize the content of the preliminary beginner's guide. The final beginner's guide was used to develop cost-effectiveness models.

RESULTS

Thirty-two best practice guidelines were data extracted, synthesized, and critically evaluated to identify steps for model development, which formed a framework for the beginner's guide. Within five phases of model development, eight broad submethods were identified and 19 methodological reviews were conducted to develop the content of the draft beginner's guide. Two rounds of consensus agreement were undertaken to reach agreement on the final beginner's guide. To assess fitness for purpose (ease of use and completeness), models were developed independently and by the researcher using the beginner's guide.

CONCLUSION

A combination of systematic review, methods reviews, consensus agreement, and validation was used to construct a step-by-step beginner's guide for developing decision analytical cost-effectiveness models. The final beginner's guide is a step-by-step resource to accompany the model development process from understanding the problem to be modeled, model conceptualization, model implementation, and model checking through to reporting of the model results.

Decisions on Further Research for Predictive Biomarkers of High-Dose Alkylating Chemotherapy in Triple-Negative Breast Cancer: A Value of Information Analysis

OBJECTIVES

To inform decisions about the design and priority of further studies of emerging predictive biomarkers of high-dose alkylating chemotherapy (HDAC) in triple-negative breast cancer (TNBC) using value-of-information analysis.

METHODS

A state transition model compared treating women with TNBC with current clinical practice and four biomarker strategies to personalize HDAC: 1) BRCA1-like profile by array comparative genomic hybridization (aCGH) testing; 2) BRCA1-like profile by multiplex ligation-dependent probe amplification (MLPA) testing; 3) strategy 1 followed by X-inactive specific transcript gene (XIST) and tumor suppressor p53 binding protein (53BP1) testing; and 4) strategy 2 followed by XIST and 53BP1 testing, from a Dutch societal perspective and a 20-year time horizon. Input data came from literature and expert opinions. We assessed the expected value of partial perfect information, the expected value of sample information, and the expected net benefit of sampling for potential ancillary studies of an ongoing randomized controlled trial (RCT; NCT01057069).

RESULTS

The expected value of partial perfect information indicated that further research should be prioritized to the parameter group including "biomarkers' prevalence, positive predictive value (PPV), and treatment response rates (TRRs) in biomarker-negative patients and patients with TNBC" (€639 million), followed by utilities (€48 million), costs (€40 million), and transition probabilities (TPs) (€30 million). By setting up four ancillary studies to the ongoing RCT, data on 1) TP and MLPA prevalence, PPV, and TRR; 2) aCGH and aCGH/MLPA plus XIST and 53BP1 prevalence, PPV, and TRR; 3) utilities; and 4) costs could be simultaneously collected (optimal size = 3000).

CONCLUSIONS

Further research on predictive biomarkers for HDAC should focus on gathering data on TPs, prevalence, PPV, TRRs, utilities, and costs from the four ancillary studies to the ongoing RCT.

Management of Refractory Angina Pectoris

With improvements in survival from coronary artery disease (CAD) and an ageing population, refractory angina (RA) is becoming an increasingly common clinical problem facing clinicians in routine clinical practice. These patients experience chronic symptoms in the context of CAD, characterised by angina-type pain, which is uncontrolled despite optimal pharmacological, interventional and surgical therapy. Although mortality rates are no worse in this cohort, patients experience a significantly impaired quality of life with disproportionately high utilisation of healthcare services. It has been increasingly recognised that the needs of RA patients are multifactorial and best provided by specialist multi-disciplinary units. In this review, we consider the variety of therapies available to clinicians in the management of RA and discuss the promise of novel treatments.

Use of expert knowledge elicitation to estimate parameters in health economic decision models

OBJECTIVES

The aim of this study was to determine the prevalence and methods of expert knowledge elicitation (EKE) for specifying input parameters in health economic decision models (HEDM).

METHODS

We created two samples using the National Health System Economic Evaluations Database: (1) 100 randomly selected HEDM studies to determine prevalence of EKE and (2) sixty studies using a formal EKE process to determine methods used.

RESULTS

Fifty-seven (57 percent) of the random sample included at least one EKE-derived parameter. Of these, six (10 percent) used a formal expert process. Thirty-four studies from our second sample of sixty studies (57 percent) described at least one aspect of the process (e.g., elicitation method) with reasonable clarity. In approximately two-thirds of studies the external experts estimated parameters de novo; the remainder confirmed or modified initial estimates provided by authors, or the method was unclear. The majority of elicitations obtained point estimates only, although a few studies asked experts to estimate ranges of parameter values.

CONCLUSIONS

The use of EKE for parameter estimation is common in HEDMs, although there is room for improvement in the methods used.

Unifying Research and Reimbursement Decisions: Case Studies Demonstrating the Sequence of Assessment and Judgments Required

BACKGROUND

The key principles regarding what assessments lead to different types of guidance about the use of health technologies (Only in Research, Approval with Research, Approve, or Reject) provide an explicit and transparent framework for technology appraisal.

OBJECTIVE

We aim to demonstrate how these principles and assessments can be applied in practice through the use of a seven-point checklist of assessment.

METHODS

The value of access to a technology and the value of additional evidence are explored through the application of the checklist to the case studies of enhanced external counterpulsation for chronic stable angina and clopidogrel for the management of patients with non-ST-segment elevation acute coronary syndromes.

RESULTS

The case studies demonstrate the importance of considering 1) the expected cost-effectiveness and population net health effects; 2) the need for evidence and whether the type of research required can be conducted once a technology is approved for widespread use; 3) whether there are sources of uncertainty that cannot be resolved by research but only over time; and 4) whether there are significant (opportunity) costs that once committed by approval cannot be recovered.

CONCLUSIONS

The checklist demonstrates that cost-effectiveness is a necessary but not sufficient condition for approval. Only in Research may be appropriate when a technology is expected to be cost-effective due to significant irrecoverable costs. It is only approval that can be ruled out if a technology is not expected to be cost-effective. Lack of cost-effectiveness is not a necessary or sufficient condition for rejection.

Enhanced External Counterpulsation Is Cost-Effective in Reducing Hospital Costs in Refractory Angina Patients

BACKGROUND

Enhanced external counterpulsation (EECP) is effective in the treatment of refractory angina, a condition suffered by 1.7 million Americans. Declining cardiovascular mortality and appropriate use criteria may further increase this number.

HYPOTHESIS

EECP is hypothesized to be cost-effective in reducing hospitalizations in refractory angina patients.

METHODS

The data used in this analysis were collected in phase II of the International EECP Patient Registry (IEPR-II). Data were collected on changes in Canadian Cardiovascular Society functional class, Duke Activity Status Index, and number of hospitalizations in the 6 months prior to EECP and in the 6- and 12-month intervals following EECP. Estimates of the changes in annual cost of all-cause hospitalization before and after EECP therapy were calculated by the product of the differences in hospitalization rates in the 6-month interval before and after EECP treatment and estimated hospitalization and physician charges after subtracting the average cost of EECP.

RESULTS

Data for 1015 patients were analyzed. Hospitalization occurred in 55.2% of patients, an average of 1.7 ± 1.4 hospitalizations/patient, in the 6-month period before 35 hours of EECP; and in 24.4%, an average of 1.4 ± 1.0 hospitalizations/patient, during the 6- to 12-month period after EECP. The average hospitalization and physician charge in the US was $17,995, and the average EECP cost was $4880, yielding an annual cost savings/patient of $17,074.

CONCLUSIONS

Treatment of refractory angina patients with EECP resulted in improvement in angina and functional class accompanied by a sustained reduction in health care costs over 1 year of follow-up.

Web searching for systematic reviews: a case study of reporting standards in the UK Health Technology Assessment programme

BACKGROUND

Identifying literature for a systematic review requires searching a variety of sources. The main sources are typically bibliographic databases. Web searching using search engines and websites may be used to identify grey literature. Searches should be reported in order to ensure transparency and reproducibility. This study assesses the reporting of web searching for systematic reviews carried out by the National Institute for Health Research (NIHR) Health Technology Assessment (HTA) programme (UK). The study also makes recommendations about reporting web searching for systematic reviews in order to achieve a reasonable level of transparency and reproducibility.

METHODS

Systematic reviews were identified by searching the HTA database via the Centre for Reviews and Dissemination (CRD) website. Systematic reviews were included in the study if they made reference to searching the web using either search engines or websites. A data-extraction checklist was designed to record how web searching was reported. The checklist recorded whether a systematic review reported: the names of search engines or websites; the dates they were searched; the search terms; the results of the searches; and, in the case of websites, whether a URL was reported.

RESULTS

554 HTA reports published between January 2004 and December 2013 were identified. 300 of these reports are systematic reviews, of which 108 report web searching using either a search engine or a website. Overall, the systematic reviews assessed in the study exhibit a low standard of web search reporting. In the majority of cases, the only details reported are the names of websites (n = 54) or search engines (n = 33). A small minority (n = 6) exhibit the highest standard of web search reporting.

CONCLUSIONS

Most web search reporting in systematic reviews carried out on the UK HTA programme is not detailed enough to ensure transparency and reproducibility. Transparency of reporting could be improved by adhering to a reporting standard such as the standard detailed in the CRD systematic reviews methods guidance. Reproducibility is harder to achieve due to the frequency of changes to websites and search engines.

USE OF VALUE OF INFORMATION IN UK HEALTH TECHNOLOGY ASSESSMENTS

Objectives: The aim of this study was to identify and critically appraise the use of Value of Information (VOI) analyses undertaken as part of health technology assessment (HTA) reports in England and Wales.

Methods: A systematic review of National Institute for Health Research (NIHR) funded HTA reports published between 2004 and 2013 identified the use of VOI methods and key analytical details in terms of: (i) types of VOI methodology used; (ii) parameters and key assumptions; and (iii) conclusions drawn in terms of the need for further research.

Results: A total of 512 HTA reports were published during the relevant timeframe. Of these, 203 reported systematic review and economic modeling studies and 25 of these had used VOI method(s). Over half of the twenty-five studies (n = 13) conducted both EVPI (Expected Value of Perfect Information) and EVPPI (Expected Value of Partial Perfect Information) analyses. Eight studies conducted EVPI analysis, three studies conducted EVPI, EVPPI, and EVSI (Expected Value of Sampling Information) analyses and one study conducted EVSI analysis only. The level of detail reporting the methods used to conduct the VOI analyses varied.

Conclusions: This review has shown that the frequency of the use of VOI methods is increasing at a slower pace compared with the published volume of HTA reports. This review also suggests that analysts reporting VOI method(s) in HTA reports should aim to describe the method(s) in sufficient detail to enable and encourage decision-makers guiding research prioritization decisions to use the potentially valuable outputs from quantitative VOI analyses.

Methods to elicit probability distributions from experts: a systematic review of reported practice in health technology assessment

BACKGROUND

Elicitation is a technique that can be used to obtain probability distribution from experts about unknown quantities. We conducted a methodology review of reports where probability distributions had been elicited from experts to be used in model-based health technology assessments.

METHODS

Databases including MEDLINE, EMBASE and the CRD database were searched from inception to April 2013. Reference lists were checked and citation mapping was also used. Studies describing their approach to the elicitation of probability distributions were included. Data was abstracted on pre-defined aspects of the elicitation technique. Reports were critically appraised on their consideration of the validity, reliability and feasibility of the elicitation exercise.

RESULTS

Fourteen articles were included. Across these studies, the most marked features were heterogeneity in elicitation approach and failure to report key aspects of the elicitation method. The most frequently used approaches to elicitation were the histogram technique and the bisection method. Only three papers explicitly considered the validity, reliability and feasibility of the elicitation exercises.

CONCLUSION

Judged by the studies identified in the review, reports of expert elicitation are insufficient in detail and this impacts on the perceived usability of expert-elicited probability distributions. In this context, the wider credibility of elicitation will only be improved by better reporting and greater standardisation of approach. Until then, the advantage of eliciting probability distributions from experts may be lost.

A systematic and critical review of the evolving methods and applications of value of information in academia and practice

OBJECTIVE

This article provides a systematic and critical review of the evolving methods and applications of value of information (VOI) in academia and practice and discusses where future research needs to be directed.

METHODS

Published VOI studies were identified by conducting a computerized search on Scopus and ISI Web of Science from 1980 until December 2011 using pre-specified search terms. Only full-text papers that outlined and discussed VOI methods for medical decision making, and studies that applied VOI and explicitly discussed the results with a view to informing healthcare decision makers, were included. The included papers were divided into methodological and applied papers, based on the aim of the study.

RESULTS

A total of 118 papers were included of which 50 % (n = 59) are methodological. A rapidly accumulating literature base on VOI from 1999 onwards for methodological papers and from 2005 onwards for applied papers is observed. Expected value of sample information (EVSI) is the preferred method of VOI to inform decision making regarding specific future studies, but real-life applications of EVSI remain scarce. Methodological challenges to VOI are numerous and include the high computational demands, dealing with non-linear models and interdependency between parameters, estimations of effective time horizons and patient populations, and structural uncertainties.

CONCLUSION

VOI analysis receives increasing attention in both the methodological and the applied literature bases, but challenges to applying VOI in real-life decision making remain. For many technical and methodological challenges to VOI analytic solutions have been proposed in the literature, including leaner methods for VOI. Further research should also focus on the needs of decision makers regarding VOI.

Methods to assess cost-effectiveness and value of further research when data are sparse: negative-pressure wound therapy for severe pressure ulcers

Health care resources are scarce, and decisions have to be made about how to allocate funds. Often, these decisions are based on sparse or imperfect evidence. One such example is negative-pressure wound therapy (NPWT), which is a widely used treatment for severe pressure ulcers; however, there is currently no robust evidence that it is effective or cost-effective. This work considers the decision to adopt NPWT given a range of alternative treatments, using a decision analytic modeling approach. Literature searches were conducted to identify existing evidence on model parameters. Given the limited evidence base, a second source of evidence, beliefs elicited from experts, was used. Judgments from experts on relevant (uncertain) quantities were obtained through a formal elicitation exercise. Additionally, data derived from a pilot trial were also used to inform the model. The 3 sources of evidence were collated, and the impact of each on cost-effectiveness was evaluated. An analysis of the value of further information indicated that a randomized controlled trial may be worthwhile in reducing decision uncertainty, where from a set of alternative designs, a 3-arm trial with longer follow-up was estimated to be the most efficient. The analyses presented demonstrate how allocation decisions about medical technologies can be explicitly informed when data are sparse and how this kind of analyses can be used to guide future research prioritization, not only indicating whether further research is worthwhile but what type of research is needed and how it should be designed.

Effect of enhanced external counterpulsation on coronary slow flow and its relation with endothelial function and inflammation: a mid-term follow-up study

BACKGROUND

Although enhanced external counterpulsation (EECP) showed short-term effects in improving coronary flow in patients with coronary slow flow (CSF), whether such improvement is durable remains uncertain, and the relationships between such improvement and changes in endothelial function as well as inflammatory markers have not been elucidated.

OBJECTIVES

The aim of the present study was to investigate the effects of EECP on transthoracic coronary flow, flow-mediated dilatation (FMD), and high-sensitivity C-reactive protein (hsCRP) in patients with CSF.

METHODS

Forty-five patients with documented CSF underwent transthoracic Doppler echocardiography (TTDE) for the assessment of coronary diastolic peak flow velocity (DPFV) and coronary flow reserve (CFR), and measurements of FMD and hsCRP; they were then nonrandomly assigned to two groups. Subjects in the control group (n = 24) received only medical therapy, and those in the EECP group (n = 21) were additionally treated with the 36 one-hour sessions of EECP. After 8 weeks of medical/EECP therapy, TTDE, FMD, and hsCRP examinations were repeated, and TTDE was additionally repeated after the 6-month clinical follow-up.

RESULTS

In the EECP group, resting DPFV, hyperemic DPFV, and CFR were significantly increased shortly after therapy (p < 0.001) and the improvement was maintained up to the 6-month follow-up, whereas in the control group those variables were not statistically increased. Meanwhile, hsCRP significantly decreased and FMD increased after therapy in the EECP group (p < 0.001). In all subjects, CFR improvement was negatively correlated with hsCRP change and positively correlated with FMD increase (p < 0.001).

CONCLUSIONS

EECP may have a durable effect in improving coronary flow in patients with CSF. Such improvement is related to the favorable effects of EECP on vascular inflammation and endothelial function.

Methods to elicit experts' beliefs over uncertain quantities: application to a cost effectiveness transition model of negative pressure wound therapy for severe pressure ulceration

We can use decision models to estimate cost effectiveness, quantify uncertainty regarding the adoption decision and provide estimates of the value of further research. In many cases, the existence of only limited data with which to populate a decision model can mean that a cost-effectiveness analysis either does not proceed or may misrepresent the degree of uncertainty associated with model inputs. An example is the case of negative pressure wound therapy (NPWT) used to treat severe pressure ulceration, for which the evidence base is limited and sparse. There is, however, substantial practical experience of using this treatment and its comparators. We can capture this knowledge quantitatively to inform a cost-effectiveness model by eliciting beliefs from experts. This paper describes the design and conduct of an elicitation exercise to generate estimates of multiple uncertain model inputs and validate analytical assumptions for a decision model on the use of NPWT. In designing the exercise, the primary focus was the use of elicitation to inform decision models (multistate models), where representations of uncertain beliefs need to be probabilistically coherent. This paper demonstrates that it is feasible to collect formally elicited evidence to inform decision models.

Addressing Adoption and Research Design Decisions Simultaneously

Methods to estimate the cost-effectiveness of technologies are well developed with increasing experience of their application to inform adoption decisions in a timely way. However, the experience of using similarly explicit methods to inform the associated research decisions is less well developed despite appropriate methods being available with an increasing number of applications in health. The authors demonstrate that evaluation of both adoption and research decisions is feasible within typical time and resource constraints relevant to policy decisions, even in situations in which data are sparse and formal elicitation is required. In addition to demonstrating the application of expected value of sample information (EVSI) in these circumstances, the authors examine and carefully distinguish the impact that the research decision is expected to have on patients while enrolled in the trial, those not enrolled, and once the trial reports. In doing so, the authors are able to account for the range of opportunity cost associated with research and evaluate a number of research designs including length of follow-up and sample size. The authors also explore the implications for research design of conducting research while the technology is approved for widespread use and whether approval should be withheld until research reports. In doing so, the authors highlight the impact of irrecoverable opportunity costs when the initial costs of a technology are compensated only by later gains in health outcome.

Cost-effectiveness of enhanced external counterpulsation (EECP) for the treatment of stable angina in the United Kingdom

OBJECTIVES

The objective of this study is to assess the cost-effectiveness of enhanced external counterpulsation (EECP) compared with no treatment as additional therapy to usual care for the treatment of chronic stable angina from the perspective of the UK National Health Service.

METHODS

The study design was a systematic review of published evidence, use of expert clinical opinion, and decision analytic cost-effectiveness model. The systematic review was conducted and statistical methods used to synthesize the effectiveness evidence from randomized control trials. Formal methods were used to elicit opinion from clinical experts where no evidence was available. These provide informed "priors" on key model parameters. A decision analytic model was developed to assess the costs and health consequences associated with the primary outcome of the trials over a lifetime time horizon. The main outcome measures were costs from a health service perspective and outcomes measured as quality-adjusted life-years (QALYs).

RESULTS

The incremental cost-effectiveness ratio of EECP was 18,643 pound sterling for each additional QALY, with a probability of being cost-effective of 0.44 and 0.70 at cost-effectiveness thresholds of 20,000 pound sterling and 30,000 pound sterling per QALY gained, respectively. Results were sensitive to the duration of health-related quality of life (HRQoL) benefits from treatment.

CONCLUSIONS

The long-term maintenance of HRQoL benefits of EECP is central to the estimate of cost-effectiveness. The results from a single randomized control trial do not provide firm evidence of the clinical or cost-effectiveness of EECP in stable angina. Long-term follow-up trials assessing quality of life from EECP are required.

Health economics in drug development: efficient research to inform healthcare funding decisions

In order to decide whether a new treatment should be used in patients, a robust estimate of efficacy and toxicity is no longer sufficient. As a result of increasing healthcare costs across the globe healthcare payers and providers now seek estimates of cost-effectiveness as well. Most trials currently being designed still only consider the need for prospective efficacy and toxicity data during the development life-cycle of a new intervention. Hence the cost-effectiveness estimates are inevitably less precise than the clinical data on which they are based. Methods based on decision theory are being developed by health economists that can contribute to the design of clinical trials in such a way that they can more effectively lead to better informed drug funding decisions on the basis of cost-effectiveness in addition to clinical outcomes. There is an opportunity to apply these techniques prospectively in the design of future clinical trials. This article describes the problems encountered by those responsible for drug reimbursement decisions as a consequence of the current drug development pathway. The potential for decision theoretic methods to help overcome these problems is introduced and potential obstacles in implementation are highlighted.