Bridging the gap between methods research and the needs of policy makers: A review of the research priorities of the National Institute for Health and Clinical Excellence

Objectives: The aim of this study was to establish a list of priority topics for methods research to support decision making at the National Institute for Health and Clinical Excellence (NICE). Methods: Potential priorities for methods research topics were identified through a focused literature review, interviews, an email survey, a workshop and a Web-based feedback exercise. Participants were members of the NICE secretariat and its advisory bodies, representatives from academia, industry, and other organizations working closely with NICE. The Web exercise was open to anyone to complete but publicized among the above groups. Results: A list of potential topics was collated. Priorities for further research differed according to the type of respondent and the extent to which they work directly with NICE. Priorities emerging from the group closest to NICE included: methodology for indirect and mixed treatment comparisons; synthesis of qualitative evidence; research relating to the use of quality-adjusted life-years (QALYs) in decision making; methods and empirical research for establishing the cost-effectiveness threshold; and determining how data on the uncertainty of effectiveness and cost-effectiveness data should be taken into account in the decision-making process. Priorities emerging from the broadest group of respondents (through the Web exercise) included: methods for extrapolating beyond evidence observed in trials, methods for capturing benefits not included in the QALY and methods to assess when technologies should be recommended in the context of further evidence gathering. Conclusions: Consideration needs to be given to the needs of those who use the outputs of research for decision making when determining priorities for future methods research.NIHR Medical Research Council

Simulation optimisation to inform economic evaluations of sequential therapies for chronic conditions: a case study in Rheumatoid Arthritis

This thesis investigates the problem of treatment sequencing within health economic evaluations. For some chronic conditions, sequences of treatments can be used. When there are a lot of alternative treatments, then the number of possible sequences becomes very large. When undertaking an economic evaluation, it may not be feasible to estimate the costs and benefits of every alternative treatment sequence. The objective of the thesis is to test the feasibility of simulation optimisation methods to find an optimal or set of near-optimal sequences of disease modifying treatments for rheumatoid arthritis in an economic evaluation framework. A large number of economic evaluations have been undertaken to estimate the costs and benefits associated with different treatments for rheumatoid arthritis. Many of these have not considered the downstream sequence of treatments provided, and no published study has considered identifying the best, or optimal, treatment sequence. The published evidence is therefore of limited applicability if the objective is to maximise patient benefit while constrained by a finite budget. It is plausible that decision-makers have developed sub-optimal guidance for rheumatoid arthritis, and this could extend to other chronic conditions. A simulation model can provide an expectation of the population mean costs and benefits for alternative treatment sequences. These models are routinely used to inform health economic evaluations. However, they can be computationally expensive to run, and therefore the evaluation of potentially millions of treatment sequences is not feasible. However, simulation optimisation methods exist to identify a good solution from a simulation model within a feasible period of time. Using these methods within an economic evaluation of treatment sequences has not previously been investigated. In this thesis I highlight the importance of the treatment sequencing problem, review and assess relevant simulation optimisation methods, and implement a simulated annealing algorithm to explore its feasibility and appropriateness. From the implementation case study within rheumatoid arthritis, simulation optimisation via simulated annealing appears to be a feasible method to identify a set of good treatment sequences. However, the method requires a significant amount of time to implement and execute, which may limit its appropriateness for health resource allocation decision making. Further research is required to investigate the generalisability of the method, and further consideration regarding its use in a decision-making context is important

In vitro culture of embryonic mouse intestinal epithelium: cell differentiation and introduction of reporter genes

BACKGROUND: Study of the normal development of the intestinal epithelium has been hampered by a lack of suitable model systems, in particular ones that enable the introduction of exogenous genes. Production of such a system would advance our understanding of normal epithelial development and help to shed light on the pathogenesis of intestinal neoplasia. The criteria for a reliable culture system include the ability to perform real time observations and manipulations in vitro, the preparation of wholemounts for immunostaining and the potential for introducing genes. RESULTS: The new culture system involves growing mouse embryo intestinal explants on fibronectin-coated coverslips in basal Eagle's medium+20% fetal bovine serum. Initially the cultures maintain expression of the intestinal transcription factor Cdx2 together with columnar epithelial (cytokeratin 8) and mesenchymal (smooth muscle actin) markers. Over a few days of culture, differentiation markers appear characteristic of absorptive epithelium (sucrase-isomaltase), goblet cells (Periodic Acid Schiff positive), enteroendocrine cells (chromogranin A) and Paneth cells (lysozyme). Three different approaches were tested to express genes in the developing cultures: transfection, electroporation and adenoviral infection. All could introduce genes into the mesenchyme, but only to a small extent into the epithelium. However the efficiency of adenovirus infection can be greatly improved by a limited enzyme digestion, which makes accessible the lateral faces of cells bearing the Coxsackie and Adenovirus Receptor. This enables reliable delivery of genes into epithelial cells. CONCLUSION: We describe a new in vitro culture system for the small intestine of the mouse embryo that recapitulates its normal development. The system both provides a model for studying normal development of the intestinal epithelium and also allows for the manipulation of gene expression. The explants can be cultured for up to two weeks, they form the full repertoire of intestinal epithelial cell types (enterocytes, goblet cells, Paneth cells and enteroendocrine cells) and the method for gene introduction into the epithelium is efficient and reliable

Experimental Conversion of Liver to Pancreas

AbstractBackground: The liver and the pancreas arise from adjacent regions of endoderm in embryonic development. Pdx1 is a key transcription factor that is essential for the development of the pancreas and is not expressed in the liver. The aim of this study was to determine whether a gene overexpression protocol based on Pdx1 would be able to cause conversion of liver to pancreas.Results: We show that a modified form of Pdx1, carrying the VP16 transcriptional activation domain, can cause conversion of liver to pancreas, both in vivo and in vitro. Transgenic Xenopus tadpoles carrying the construct TTR-Xlhbox8-VP16:Elas-GFP were prepared. Xlhbox8 is the Xenopus homolog of Pdx1, the TTR (transthyretin) promoter directs expression to the liver, and the GFP is under the control of an elastase promoter and provides a real-time visible marker of pancreatic differentiation. In the transgenic tadpoles, part or all of the liver is converted to pancreas, containing both exocrine and endocrine cells, while liver differentiation products are lost from the regions converted to pancreas. The timing of events is such that the liver is differentiating by the time Xlhbox8-VP16 is expressed, so we consider this a transdifferentiation event rather than a reprogramming of embryonic development. Furthermore, this same construct will bring about transdifferentiation of human hepatocytes in culture, with formation of both exocrine and endocrine cells.Conclusions: We consider that the conversion of liver to pancreas could be the basis of a new type of therapy for insulin-dependent diabetes. Although expression of the transgene is transient, once the ectopic pancreas is established, it persists thereafter

Health state utility values for diabetic retinopathy: protocol for a systematic review and meta-analysis

Background People with diabetic retinopathy tend to have lower levels of health-related quality of life than individuals with no retinopathy. Strategies for screening and treatment have been shown to be cost-effective. In order to reduce the bias in cost-effectiveness estimates, systematic reviews of health state utility values (HSUVs) are crucial for health technology assessment and the development of decision analytic models. A review and synthesis of HSUVs for the different stages of disease progression in diabetic retinopathy has not previously been conducted. Methods/Design We will conduct a systematic review of the available literature that reports HSUVs for people with diabetic retinopathy, in correspondence with current stage of disease progression and/or visual acuity. We will search Medline, EMBASE, Web of Science, Cost-Effectiveness Analysis Registry, Centre for Reviews and Dissemination Database, and EconLit to identify relevant English-language articles. Data will subsequently be synthesized using linear mixed effects modeling meta-regression. Additionally, reported disease severity classifications will be mapped to a four-level grading scale for diabetic retinopathy. Discussion The systematic review and meta-analysis will provide important evidence for future model-based economic evaluations of technologies for diabetic retinopathy. The meta-regression will enable the estimation of utility values at different disease stages for patients with particular characteristics and will also highlight where the design of the study and HSUV instrument have influenced the reported utility values. We believe this protocol to be the first of its kind to be published

Consensus Decision Models for Biologics in Rheumatoid and Psoriatic Arthritis: Recommendations of a Multidisciplinary Working Party.

INTRODUCTION: Biologic therapies are efficacious but costly. A number of health economic models have been developed to determine the most cost-effective way of using them in the treatment pathway. These models have produced conflicting results, driven by differences in assumptions, model structure, and data, which undermine the credibility of funding decisions based on modeling studies. A Consensus Working Party met to discuss recommendations and approaches for future models of biologic therapies. METHODS: Our working party consisted of clinical specialists, modelers, and policy makers. Two 1-day meetings were held for members to arrive at consensus positions on model structure, assumptions, and appropriate data sources. These views were guided by clinical aspects of rheumatoid and psoriatic arthritis and the principles of evidence-based medicine. Where opinions differed, we sought to identify a research agenda that would generate the evidence needed to reach consensus. RESULTS: We gained consensus in four areas of model development: initial response to treatment; long-term disease progression; lifetime costs and benefits; and model structure. Consensus was also achieved on some key parameters such as choices of outcome measures, methods for extrapolation beyond trial data, and treatment switching. A research agenda to support further consensus was also identified. CONCLUSION: Consensus guidance that fully reflects current evidence and clinical understanding was gained successfully. In addition, research needs have been identified. Such guidance can be updated as evidence develops and policy questions change and need not be prescriptive as long as deviations from consensus are clearly explained and justified. FUNDING: Arthritis Research UK and the UK Medical Research Council Network of Hubs for Trials Methodology Research

Health Economic Modelling of Treatment Sequences for Rheumatoid Arthritis: A Systematic Review

The objective of the work reported in this paper was to critically assess how sequential disease-modifying anti-rheumatic drugs (DMARDs) have been modelled in the context of economic evaluation of the use of DMARDs for treatment of rheumatoid arthritis (RA). A secondary purpose was to identify the methodological challenges of modelling sequential therapies. Systematic searches of 10 databases were undertaken in February 2013. Studies were included if they were in the English language and a full comparative economic evaluation was reported. They were appraised by use of the Drummond checklist (Appendix to this paper). Data extracted included economic evaluation data, data relating to sequential treatment, and data on the modelling methods used. Fifty-seven studies were identified, with 25 (44 %) modelling a sequence of treatments. Forty-three (75 %) were cost–utility analyses. Eleven (19 %) were UK studies and 11 (19 %) were US. The remainder were mainly European (26 (46 %)). A distinction was made between studies of recent-onset RA (14 (25 %)) and those of established RA (42 (74 %)). One study (1 %) was unclear. Individual-level models were more likely to meet the Drummond criteria and evaluate sequences. No study identified an optimum sequence of multiple treatments given a set of treatment options. The level of reporting of the methods and evidence used to assess the effect of downstream treatments in the sequence was generally poor. When lifelong models and downstream treatment sequences were considered, evidence gaps were identified. The review discovered that methods have not been consistently applied, leading to varied estimates of cost-effectiveness. Treatment sequences have not been fully considered and modelled, potentially resulting in inaccurate estimates of cost-effectiveness

Simulating the effect of climatic variations on the long-term performance of different agroforestry systems within field trials using virtual experiments

Agroforestry systems can reduce some of the adverse effects of climate change in agriculture by e.g. serving as a windbreak or shade provider to protect crops or grazing livestock and supporting beneficial species for pest control. The prediction of the long-term performance of different agroforestry options is however difficult to obtain through field quantify experiments due to the length of time trees grow for experiments. Numerical modelling can contribute to a better understanding of a system’s performance, since the effect of different climatic alterations can be tested using virtual experiments for different periods of time. Within the Horizon 2020 AGROMIX project, we are analysing the long-term performance of eight different agroforestry trials (Figure 1), using different modelling approaches. The trials are spread over three biogeographic regions (Mediterranean, Continental, and Atlantic) and are of varying age (4 to 33 years). In total, six silvoarable and five silvopastoral farming systems are maintained at the eight field trials. Through the use of different numerical models the effect of changes in temperature and precipitation patterns or the occurrence of extreme events such as droughts or late spring frost on the different agroforestry systems will be predicted. Additionally, experimental data on crop performance as well as animal behaviour and welfare, in particular under heat stress, are being obtained and will potentially be included in the model predictions. This poster aims to give an overview on the field trials and the numerical modelling approaches that are being applied to predict long-term system performance