The Sheffield Type 1 Diabetes Policy Model is a patient-level simulation model of type 1 diabetes... more The Sheffield Type 1 Diabetes Policy Model is a patient-level simulation model of type 1 diabetes and its associated complications, which was developed as part of the National Institute for Health Research Dose Adjustment for Normal Eating (DAFNE) research programme. The aim of this paper is to describe the conceptual modelling, model implementation, and model validation phases of the Sheffield Type 1 Diabetes Model development process. The model is highly flexible and has broad potential application to evaluate DAFNE, other diabetes structured education programmes, and other interventions for type 1 diabetes.
Numerous studies examine simulation modelling in healthcare. These studies present a bewildering ... more Numerous studies examine simulation modelling in healthcare. These studies present a bewildering array of simulation techniques and applications, making it challenging to characterise the literature. The aim of this paper is to provide an overview of the level of activity of simulation modelling in healthcare and the key themes. We performed an umbrella review of systematic literature reviews of simulation modelling in healthcare. Searches were conducted of academic databases (JSTOR, Scopus, PubMed, IEEE, SAGE, ACM, Wiley Online Library, ScienceDirect) and grey literature sources, enhanced by citation searches. The articles were included if they performed a systematic review of simulation modelling techniques in healthcare. After quality assessment of all included articles, data were extracted on numbers of studies included in each review, types of applications, techniques used for simulation modelling, data sources and simulation software. The search strategy yielded a total of 117...
Partial expected value of perfect information (EVPI) calculations can quantify the value of learn... more Partial expected value of perfect information (EVPI) calculations can quantify the value of learning about particular subsets of uncertain parameters in decision models. Published case studies have used different computational approaches. This article examines the computation of partial EVPI estimates via Monte Carlo sampling algorithms. The mathematical definition shows 2 nested expectations, which must be evaluated separately because of the need to compute a maximum between them. A generalized Monte Carlo sampling algorithm uses nested simulation with an outer loop to sample parameters of interest and, conditional upon these, an inner loop to sample remaining uncertain parameters. Alternative computation methods and shortcut algorithms are discussed and mathematical conditions for their use considered. Maxima of Monte Carlo estimates of expectations are biased upward, and the authors show that the use of small samples results in biased EVPI estimates. Three case studies illustrate...
Background . Numerous guidelines have been published defining good practice for the conduct of ec... more Background . Numerous guidelines have been published defining good practice for the conduct of economic evaluations in general and model-based evaluations in particular. The extent to which guidelines are accepted is unknown, and the impact of deviations from good practice is not generally recorded. The authors identified 4 specific issues in applied studies that may affect the accuracy and comparability of different evaluations. Methods . A descriptive analysis of 4 modeling issues (inclusion of incident cases over a model time horizon, appropriate time horizon, parsimonious model structure, and the handling of age-specific subgroups) is presented. A case study model is analyzed to illustrate the quantitative impact of 3 of the issues. Results . In the case study model, alternative specifications of the modeling framework are shown to alter the estimated cost-effectiveness by large percentages. The combined effect of including incident cases and reduced follow-up yielded the highes...
Background. This study reports incremental cost-utility of sibutramine compared to diet and lifes... more Background. This study reports incremental cost-utility of sibutramine compared to diet and lifestyle advice for the treatment of obesity. Method. The model estimates the costs and quality of life benefits associated with weight loss itself and the reduced incidence of coronary heart disease (CHD) and diabetes in the “healthy obese.” The key source of effectiveness data is 2 randomized controlled trials over 12 months. Utility gain per kilogram lost is analyzed using Short Form–36 data from sibutramine trials. The impact on CHD is estimated using the Framingham risk equation, which relates age/sex/body mass index to risk of heart disease. The reduced incidence of diabetes due to weight loss is estimated from published literature. A life tables approach was used to calculate the cost per quality-adjusted life year (QALY) of 1 year’s treatment with sibutramine compared to diet and lifestyle advice. Results. The incremental cost per QALY of sibutramine is £4780. Sensitivity analyses sh...
Page 1. Decision Modeling to Inform Decision Making: Seeing the Wood for the Trees Jonathan Karno... more Page 1. Decision Modeling to Inform Decision Making: Seeing the Wood for the Trees Jonathan Karnon, PhD, Alan Brennan, PhD, Ron Akehurst, Hon MFPHM Goldman and Gaspoz1 recently responded to an article2 that queried ...
The Sheffield Type 1 Diabetes Policy Model is a patient-level simulation model of type 1 diabetes... more The Sheffield Type 1 Diabetes Policy Model is a patient-level simulation model of type 1 diabetes and its associated complications, which was developed as part of the National Institute for Health Research Dose Adjustment for Normal Eating (DAFNE) research programme. The aim of this paper is to describe the conceptual modelling, model implementation, and model validation phases of the Sheffield Type 1 Diabetes Model development process. The model is highly flexible and has broad potential application to evaluate DAFNE, other diabetes structured education programmes, and other interventions for type 1 diabetes.
Numerous studies examine simulation modelling in healthcare. These studies present a bewildering ... more Numerous studies examine simulation modelling in healthcare. These studies present a bewildering array of simulation techniques and applications, making it challenging to characterise the literature. The aim of this paper is to provide an overview of the level of activity of simulation modelling in healthcare and the key themes. We performed an umbrella review of systematic literature reviews of simulation modelling in healthcare. Searches were conducted of academic databases (JSTOR, Scopus, PubMed, IEEE, SAGE, ACM, Wiley Online Library, ScienceDirect) and grey literature sources, enhanced by citation searches. The articles were included if they performed a systematic review of simulation modelling techniques in healthcare. After quality assessment of all included articles, data were extracted on numbers of studies included in each review, types of applications, techniques used for simulation modelling, data sources and simulation software. The search strategy yielded a total of 117...
Partial expected value of perfect information (EVPI) calculations can quantify the value of learn... more Partial expected value of perfect information (EVPI) calculations can quantify the value of learning about particular subsets of uncertain parameters in decision models. Published case studies have used different computational approaches. This article examines the computation of partial EVPI estimates via Monte Carlo sampling algorithms. The mathematical definition shows 2 nested expectations, which must be evaluated separately because of the need to compute a maximum between them. A generalized Monte Carlo sampling algorithm uses nested simulation with an outer loop to sample parameters of interest and, conditional upon these, an inner loop to sample remaining uncertain parameters. Alternative computation methods and shortcut algorithms are discussed and mathematical conditions for their use considered. Maxima of Monte Carlo estimates of expectations are biased upward, and the authors show that the use of small samples results in biased EVPI estimates. Three case studies illustrate...
Background . Numerous guidelines have been published defining good practice for the conduct of ec... more Background . Numerous guidelines have been published defining good practice for the conduct of economic evaluations in general and model-based evaluations in particular. The extent to which guidelines are accepted is unknown, and the impact of deviations from good practice is not generally recorded. The authors identified 4 specific issues in applied studies that may affect the accuracy and comparability of different evaluations. Methods . A descriptive analysis of 4 modeling issues (inclusion of incident cases over a model time horizon, appropriate time horizon, parsimonious model structure, and the handling of age-specific subgroups) is presented. A case study model is analyzed to illustrate the quantitative impact of 3 of the issues. Results . In the case study model, alternative specifications of the modeling framework are shown to alter the estimated cost-effectiveness by large percentages. The combined effect of including incident cases and reduced follow-up yielded the highes...
Background. This study reports incremental cost-utility of sibutramine compared to diet and lifes... more Background. This study reports incremental cost-utility of sibutramine compared to diet and lifestyle advice for the treatment of obesity. Method. The model estimates the costs and quality of life benefits associated with weight loss itself and the reduced incidence of coronary heart disease (CHD) and diabetes in the “healthy obese.” The key source of effectiveness data is 2 randomized controlled trials over 12 months. Utility gain per kilogram lost is analyzed using Short Form–36 data from sibutramine trials. The impact on CHD is estimated using the Framingham risk equation, which relates age/sex/body mass index to risk of heart disease. The reduced incidence of diabetes due to weight loss is estimated from published literature. A life tables approach was used to calculate the cost per quality-adjusted life year (QALY) of 1 year’s treatment with sibutramine compared to diet and lifestyle advice. Results. The incremental cost per QALY of sibutramine is £4780. Sensitivity analyses sh...
Page 1. Decision Modeling to Inform Decision Making: Seeing the Wood for the Trees Jonathan Karno... more Page 1. Decision Modeling to Inform Decision Making: Seeing the Wood for the Trees Jonathan Karnon, PhD, Alan Brennan, PhD, Ron Akehurst, Hon MFPHM Goldman and Gaspoz1 recently responded to an article2 that queried ...
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