A forensic evaluation of the National Emphysema Treatment Trial using the expected value of information approach

Caring for patients with advanced COPD: beyond the inhalers…

COPD affects millions of people worldwide. Patients with advanced COPD have a high symptom burden. Breathlessness, cough and fatigue are frequent daily symptoms. Guidelines often focus on pharmacological treatment, especially inhaler therapy, but other approaches in combination with medications offer symptomatic benefit. In this review, we take a multidisciplinary approach with contributions from pulmonary physicians, cardiothoracic surgeons and a physiotherapist. The following areas are addressed: oxygen therapy and noninvasive ventilation (NIV), dyspnoea management, surgical and bronchoscopic options, lung transplantation and palliative care. Oxygen therapy prescribed within guidelines improves mortality in patients with COPD. NIV guidelines offer only low-certainty instruction on the use of this therapy on the basis of the limited available evidence. Dyspnoea management can take place through pulmonary rehabilitation. Specific criteria aid decisions on referral for lung volume reduction treatments through surgical or bronchoscopic approaches. Lung transplantation requires precise disease severity assessment to determine which patients have the most urgent need for lung transplantation and are likely to have the longest survival. The palliative approach runs in parallel with these other treatments, focusing on symptoms and aiming to improve the quality of life of patients and their families facing the problems associated with life-threatening illness. In combination with appropriate medication and an individual approach to symptom management, patients' experiences can be optimised.

Educational aims

To understand the multidisciplinary approach to management of patients with advanced COPD.To recognise the parallel approaches to oxygen, NIV and dyspnoea management with consideration of more interventional options with lung volume reduction therapy or lung transplantation.To understand the high level of symptomatology present in advanced COPD and the relevance of palliative care alongside optimal medical management.

Lung volume reduction surgery for diffuse emphysema

BACKGROUND

Lung volume reduction surgery (LVRS) performed to treat patients with severe diffuse emphysema was reintroduced in the nineties. Lung volume reduction surgery aims to resect damaged emphysematous lung tissue, thereby increasing elastic properties of the lung. This treatment is hypothesised to improve long-term daily functioning and quality of life, although it may be costly and may be associated with risks of morbidity and mortality. Ten years have passed since the last version of this review was prepared, prompting us to perform an update.

OBJECTIVES

The objective of this review was to gather all available evidence from randomised controlled trials comparing the effectiveness of lung volume reduction surgery (LVRS) versus non-surgical standard therapy in improving health outcomes for patients with severe diffuse emphysema. Secondary objectives included determining which subgroup of patients benefit from LVRS and for which patients LVRS is contraindicated, to establish the postoperative complications of LVRS and its morbidity and mortality, to determine which surgical approaches for LVRS are most effective and to calculate the cost-effectiveness of LVRS.

SEARCH METHODS

We identified RCTs by using the Cochrane Airways Group Chronic Obstructive Pulmonary Disease (COPD) register, in addition to the online clinical trials registers. Searches are current to April 2016.

SELECTION CRITERIA

We included RCTs that studied the safety and efficacy of LVRS in participants with diffuse emphysema. We excluded studies that investigated giant or bullous emphysema.

DATA COLLECTION AND ANALYSIS

Two independent review authors assessed trials for inclusion and extracted data. When possible, we combined data from more than one study in a meta-analysis using RevMan 5 software.

MAIN RESULTS

We identified two new studies (89 participants) in this updated review. A total of 11 studies (1760 participants) met the entry criteria of the review, one of which accounted for 68% of recruited participants. The quality of evidence ranged from low to moderate owing to an unclear risk of bias across many studies, lack of blinding and low participant numbers for some outcomes. Eight of the studies compared LVRS versus standard medical care, one compared two closure techniques (stapling vs laser ablation), one looked at the effect of buttressing the staple line on the effectiveness of LVRS and one compared traditional 'resectional' LVRS with a non-resectional surgical approach. Participants completed a mandatory course of pulmonary rehabilitation/physical training before the procedure commenced. Short-term mortality was higher for LVRS (odds ratio (OR) 6.16, 95% confidence interval (CI) 3.22 to 11.79; 1489 participants; five studies; moderate-quality evidence) than for control, but long-term mortality favoured LVRS (OR 0.76, 95% CI 0.61 to 0.95; 1280 participants; two studies; moderate-quality evidence). Participants identified post hoc as being at high risk of death from surgery were those with particularly impaired lung function, poor diffusing capacity and/or homogenous emphysema. Participants with upper lobe-predominant emphysema and low baseline exercise capacity showed the most favourable outcomes related to mortality, as investigators reported no significant differences in early mortality between participants treated with LVRS and those in the control group (OR 0.87, 95% CI 0.23 to 3.29; 290 participants; one study), as well as significantly lower mortality at the end of follow-up for LVRS compared with control (OR 0.45, 95% CI 0.26 to 0.78; 290 participants; one study). Trials in this review furthermore provided evidence of low to moderate quality showing that improvements in lung function parameters other than forced expiratory volume in one second (FEV1), quality of life and exercise capacity were more likely with LVRS than with usual follow-up. Adverse events were more common with LVRS than with control, specifically the occurrence of (persistent) air leaks, pulmonary morbidity (e.g. pneumonia) and cardiovascular morbidity. Although LVRS leads to an increase in quality-adjusted life-years (QALYs), the procedure is relatively costly overall.

AUTHORS' CONCLUSIONS

Lung volume reduction surgery, an effective treatment for selected patients with severe emphysema, may lead to better health status and lung function outcomes, specifically for patients who have upper lobe-predominant emphysema with low exercise capacity, but the procedure is associated with risks of early mortality and adverse events.

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.

Value of information analysis for interventional and counterfactual Bayesian networks in forensic medical sciences

OBJECTIVES

Inspired by real-world examples from the forensic medical sciences domain, we seek to determine whether a decision about an interventional action could be subject to amendments on the basis of some incomplete information within the model, and whether it would be worthwhile for the decision maker to seek further information prior to suggesting a decision.

METHOD

The method is based on the underlying principle of Value of Information to enhance decision analysis in interventional and counterfactual Bayesian networks.

RESULTS

The method is applied to two real-world Bayesian network models (previously developed for decision support in forensic medical sciences) to examine the average gain in terms of both Value of Information (average relative gain ranging from 11.45% and 59.91%) and decision making (potential amendments in decision making ranging from 0% to 86.8%).

CONCLUSIONS

We have shown how the method becomes useful for decision makers, not only when decision making is subject to amendments on the basis of some unknown risk factors, but also when it is not. Knowing that a decision outcome is independent of one or more unknown risk factors saves us from the trouble of seeking information about the particular set of risk factors. Further, we have also extended the assessment of this implication to the counterfactual case and demonstrated how answers about interventional actions are expected to change when some unknown factors become known, and how useful this becomes in forensic medical science.

Adaptive management and the value of information: learning via intervention in epidemiology

This Research Article explores the benefits of applying Adaptive Management approaches to disease outbreaks, finding that formally integrating science and policy allows one to reduce uncertainty and improve disease management outcomes.

Optimal intervention for disease outbreaks is often impeded by severe scientific uncertainty. Adaptive management (AM), long-used in natural resource management, is a structured decision-making approach to solving dynamic problems that accounts for the value of resolving uncertainty via real-time evaluation of alternative models. We propose an AM approach to design and evaluate intervention strategies in epidemiology, using real-time surveillance to resolve model uncertainty as management proceeds, with foot-and-mouth disease (FMD) culling and measles vaccination as case studies. We use simulations of alternative intervention strategies under competing models to quantify the effect of model uncertainty on decision making, in terms of the value of information, and quantify the benefit of adaptive versus static intervention strategies. Culling decisions during the 2001 UK FMD outbreak were contentious due to uncertainty about the spatial scale of transmission. The expected benefit of resolving this uncertainty prior to a new outbreak on a UK-like landscape would be £45–£60 million relative to the strategy that minimizes livestock losses averaged over alternate transmission models. AM during the outbreak would be expected to recover up to £20.1 million of this expected benefit. AM would also recommend a more conservative initial approach (culling of infected premises and dangerous contact farms) than would a fixed strategy (which would additionally require culling of contiguous premises). For optimal targeting of measles vaccination, based on an outbreak in Malawi in 2010, AM allows better distribution of resources across the affected region; its utility depends on uncertainty about both the at-risk population and logistical capacity. When daily vaccination rates are highly constrained, the optimal initial strategy is to conduct a small, quick campaign; a reduction in expected burden of approximately 10,000 cases could result if campaign targets can be updated on the basis of the true susceptible population. Formal incorporation of a policy to update future management actions in response to information gained in the course of an outbreak can change the optimal initial response and result in significant cost savings. AM provides a framework for using multiple models to facilitate public-health decision making and an objective basis for updating management actions in response to improved scientific understanding.

If the response to a disease outbreak is poorly managed, lives may be lost and money wasted unnecessarily. Lack of knowledge about the disease dynamics, and about the effects of our control strategies on those dynamics, means that it is difficult to do the best job possible managing such epidemiological problems. Here, we present an adaptive management approach that allows researchers to use knowledge gained during an outbreak to update ongoing interventions, thereby translating scientific discovery into improved policy. We explore the implications of adaptive management for foot-and-mouth disease outbreaks in livestock and for measles vaccination strategies in humans. In these two particular cases, planning to update management actions leads to the recommendation of a less aggressive initial approach than if changes in management are not anticipated. We demonstrate expected savings of up to £20 million in terms of lower livestock losses to culling in a foot-and-mouth outbreak based on the dynamics observed in the UK in 2001. Similarly, up to 10,000 cases could have been averted in a measles outbreak like the one observed in Malawi in 2010. Adaptive management allows real-time improvement of our understanding, and hence of management efforts, with potentially significant positive financial and health benefits.

Improving early cycle economic evaluation of diagnostic technologies

The rapidly increasing range and expense of new diagnostics, compels consideration of a different, more proactive approach to health economic evaluation of diagnostic technologies. Early cycle economic evaluation is a decision analytic approach to evaluate technologies in development so as to increase the return on investment as well as patient and societal impact. This paper describes examples of 'early cycle economic evaluations' as applied to diagnostic technologies and highlights challenges in its real-time application. It shows that especially in the field of diagnostics, with rapid technological developments and a changing regulatory climate, early cycle economic evaluation can have a guiding role to improve the efficiency of the diagnostics innovation process. In the next five years the attention will move beyond the methodological and analytic challenges of early cycle economic evaluation towards the challenge of effectively applying it to improve diagnostic research and development and patient value. Future work in this area should therefore be 'strong on principles and soft on metrics', that is, the metrics that resonate most clearly with the various decision makers in this field.

"Lies, damned lies ..." and observational studies in comparative effectiveness research

A new federal initiative has allocated $1.1 billion to comparative effectiveness research, and many have emphasized the importance of including observational studies in this effort. The rationale for using observational studies to assess comparative effectiveness is based on concerns that randomized controlled trials (RCTs) are not "real world" because they enroll homogeneous patient populations, measure study outcomes that are not important to patients, use protocols that are overly complex, are conducted in specialized centers, and use study treatments that are not consistent with usual care, and that RCTs are not always feasible because of a lack of equipoise, the need to assess delayed endpoints, and concerns that they take years to complete and are expensive. This essay questions the validity of each of these proposed limitations, summarizes concerns raised about the accuracy of results generated by observational studies, provides some examples of discrepancies between results of observational studies and RCTs that pertain to pulmonary and critical care, and suggests that using observational studies for comparative effectiveness research may increase rather than decrease the cost of health care and may harm patients.

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.

Minimal modeling approaches to value of information analysis for health research

Value of information (VOI) techniques can provide estimates of the expected benefits from clinical research studies that can inform decisions about the design and priority of those studies. Most VOI studies use decision-analytic models to characterize the uncertainty of the effects of interventions on health outcomes, but the complexity of constructing such models can pose barriers to some practical applications of VOI. However, because some clinical studies can directly characterize uncertainty in health outcomes, it may sometimes be possible to perform VOI analysis with only minimal modeling. This article 1) develops a framework to define and classify minimal modeling approaches to VOI, 2) reviews existing VOI studies that apply minimal modeling approaches, and 3) illustrates and discusses the application of the minimal modeling to 2 new clinical applications to which the approach appears well suited because clinical trials with comprehensive outcomes provide preliminary estimates of the uncertainty in outcomes. The authors conclude that minimal modeling approaches to VOI can be readily applied in some instances to estimate the expected benefits of clinical research.

Lung volume reduction surgery for diffuse emphysema

BACKGROUND

Lung volume reduction surgery (LVRS) has been re-introduced for treating patients with severe diffuse emphysema. It is a procedure that aims to improve long-term daily functioning, although it is costly and may also be associated with a high risk of mortality.

OBJECTIVES

To assemble evidence from randomised controlled trials for the effectiveness of LVRS, and identify optimal surgical techniques.

SEARCH STRATEGY

Randomised controlled trials were identified using the Cochrane Airways Group Chronic Obstructive Pulmonary Disease (COPD) register. Searches are current to September 2005.

SELECTION CRITERIA

Randomised controlled trials that studied the safety and efficacy of LVRS in patients with diffuse emphysema were included. Studies were excluded if they investigated giant or bullous emphysema.

DATA COLLECTION AND ANALYSIS

Two independent review authors assessed trials for inclusion and extracted data. Where possible, data from more than one study were combined using RevMan 4.2 software.

MAIN RESULTS

Eight studies (1663 participants) met the entry criteria of the review. One study accounted for 73% of the participants recruited. Study quality was high, although blinding in studies was not possible. Ninety day mortality was significantly greater in all those who underwent LVRS (odds ratio 6.57 (95% CI 3.34 to 12.95), four studies, N = 1415). A subgroup analysis by risk status suggested that there was a subgroup of participants who were consistently at a significant risk of death, although this was only measured in one large study. The ninety day mortality data indicated that death was more likely with LVRS irrespective of risk status identified in one large study. Improvements in lung function, quality of life and exercise capacity were more likely with LVRS than with usual follow-up.

AUTHORS' CONCLUSIONS

The evidence summarised in this review is drawn from one large study, and several smaller trials. The findings from the large study indicated that in patients who survive up to three months post-surgery, there were significantly better health status and lung function outcomes in favour of surgery compared with usual medical care. Patients identified post hoc as being of high risk of death from surgery were those with particularly impaired lung function and poor diffusing capacity and/or homogenous emphysema. Further research should address the effect of this intervention on exacerbations and rate of decline in lung function and health status.