Applications of simulation within the healthcare context

This is a pre-print of an article published in Journal of the Operation Research Society. The definitive publisher-authenticated version Katsaliaki, K., Mustafee, N.,(2010). Applications of simulation within the healthcare context. Journal of the Operation Research Society. 62, 1431-1451 is available online at: http://www.palgrave-journals.com/jors/journal/v62/n8/full/jors201020a.htmlA large number of studies have applied simulation to a multitude of issues related to healthcare. These studies have been published over a number of unrelated publishing outlets, and this may hamper the widespread reference and use of such resources. In this paper we analyse existing research in healthcare simulation in order to categorise and synthesise it in a meaningful manner. Hence, the aim of this paper is to conduct a review of the literature pertaining to simulation research within healthcare in order to ascertain its current development. A review of approximately 250 high quality journal papers published between 1970 and 2007 on healthcare-related simulation research was conducted. The results present: a classification of the healthcare publications according to the simulation techniques they employ; the impact of published literature in healthcare simulation; a report on demonstration and implementation of the studies’ results; the sources of funding; and the software used. Healthcare planners and researchers will benefit from this study by having ready access to an indicative article collection of simulation techniques applied in healthcare problems that are clustered under meaningful headings. This study facilitates the understanding of the potential of different simulation techniques for solving diverse healthcare problems

Optimising the cost-effectiveness of risk-based screening for diabetic retinopathy

Publicly provided health screening programmes tend to offer standardised screening for a fixed eligible population. Recently, the development of risk calculation engines has introduced the potential for the stratification of screening based on individuals' risks of disease onset. This possibility raises practical, methodological, and ethical challenges. To date, no such programme has been the subject of an economic evaluation. In this thesis we present reason and basis for the allocation of screening based on individual risk. The research is conducted in the context of screening for diabetic eye disease in the UK. Diabetic retinopathy is a common complication of diabetes that can lead to blindness, substantial detriments to quality of life, and significant health care resource use. Our study is linked to a programme of research that includes a cohort study and randomised controlled trial in the city of Liverpool. We review and further develop the evidence base to inform the evaluation of a risk-based screening programme for diabetic eye disease. Specifically, we generate new evidence on the costs and health outcomes associated with the screening and treatment of diabetic retinopathy. We report on a cross-sectional study of health-related quality of life for people attending screening for diabetic retinopathy and find that people with pre-symptomatic disease tend to report poorer quality of life than people with no disease, with EQ-5D-5L index values of 0.733 on average compared with 0.787 for people with no disease. A meta-analysis of published health state utility values for diabetic eye disease shows a negative impact on health-related quality of life before progression to blindness. Our meta-regression found a utility index decrement of 0.024 for people with proliferative retinopathy. The costs of screening are low at the individual level, estimated to be £32.03 in our costing study. But the overall budget impact of changes in the frequency of screening can be significant. We analyse a large data set of hospital and community screening activity to identify key treatment pathways for diabetic eye disease. We find that these have changed in recent years, with the introduction of more expensive interventions. The evidence generated by our work is used to inform the development of a decision analytic model. The model is designed to estimate the cost-effectiveness of risk-based screening for diabetic eye disease, compared with current practice. We find that risk-based screening is likely to be more cost-effective than standardised screening programmes. Evaluating a programme that allocates screening according to individuals' levels of risk raises theoretical and ethical challenges. To this end, we develop a simple framework for individualised cost-effectiveness analysis that can be used to inform the design of a risk-based screening programme. We also explore the ethics of risk-based screening, developing the notion of screening need as distinct from treatment need. Risk-based screening is likely to be cost-effective in the context of diabetic eye disease. The evidence presented in this thesis can be used to support the evaluation of new programmes, which can be designed in order to optimise cost-effectiveness using the methods that we describe. Such an approach is consistent with equitable policy objectives

Considering the need for alternative intervention strategies for the management of diabetic policy formulation in South Africa

CITATION: Thomas, V. V., De Kock, I. H. & Bam, L. 2018. Considering the need for alternative intervention strategies for the management of diabetic policy formulation in South Africa. In SAIIE29 Proceedings, 24-26 October 2018, Spier, Stellenbosch, South Africa.The original publication is available at https://conferences.sun.ac.za/index.php/saiie29/saiie29/schedConf/presentationsENGLISH ABSTRACT: The increasing prevalence of diabetes in South Africa, alongside other non-communicable diseases, places a heavy burden on the health care system; especially when faced with the significant difference in quality of care between private and public health care, and the increased burden of disease. This paper analyses various diabetic policies already implemented in South Africa, and considers the need to investigate alternative policies and intervention strategies to manage diabetes in South Africa. Due to the complex nature and non-linear interactions which exist within the health care system, a system dynamics-based approach is suggested as a useful analysis tool to evaluate and understand the dominant factors that influence the effective management of diabetes to potentially inform more effective and efficient diabetic policy formulation.https://conferences.sun.ac.za/index.php/saiie29/saiie29/paper/view/3590Publisher's versio

Assessing the Effect of Clinical Inertia on Diabetes Outcomes: An Agent-Based Modeling Approach

Clinical inertia (CI) is the failure to intensify treatment in patients with evidence of poor glycemic control. It is a critical barrier in the effective management of type 2 diabetes and can have adverse effects, such as elevated risk of diabetes-related complications. The aims of this thesis are to study the long-term effects of CI and its interaction with population characteristics on the incidence of diabetes-related complications. An agent-based simulation has been constructed to study these effects. The base model was developed by researchers from The New York Academy of Medicine and the Icahn School of Medicine at Mount Sinai. It was then extended by adding an HbA1c update formula and treatment intensification processes, which offers a flexible avenue through which to compare diverse populations and parameters in a controlled and systematic approach. To assess the accuracy of our model, we have conducted model validation using 5 published trials and compared the rates of complication incidence. We performed 12 validation exercises, comparing simulated outcomes with published outcomes. The R-square of the overall fit was 0.9065, indicating overall good agreement between the outcomes. Thus, we concluded that the model was reliable for modeling the progression of diabetes-related complications in a population. Additionally, we performed a series of experiments to meet our aims. The results indicated that a 1-year, 3-year, and 7-year CI significantly increases the 25-year cumulative incidence of most diabetes complications when compared to the non-CI group. It also indicates that CI has greater impact on specific race and age-group populations; for example, the 65-100 age-group experienced a significantly higher percent increase in the incidence of myocardial infarction, stroke, and retinopathy in comparison to the 45-64 age-group while experiencing a 3-year CI. Additionally, it indicates that the incidence of neuropathy and nephropathy due to a 3-year CI in a Native American population is significantly less than the non-Hispanic White, African American, Hispanic, and Asian populations undergoing a 3-year CI. Our model results provide insightful information for the development of effective diabetes treatment guidelines. Future research is needed to investigate the mechanism behind the differences among different population groups

Human Stem Cells for Ophthalmology: Recent Advances in Diagnostic Image Analysis and Computational Modelling

\ua9 2023, The Author(s).Purpose of Review: To explore the advances and future research directions in image analysis and computational modelling of human stem cells (hSCs) for ophthalmological applications. Recent Findings: hSCs hold great potential in ocular regenerative medicine due to their application in cell-based therapies and in disease modelling and drug discovery using state-of-the-art 2D and 3D organoid models. However, a deeper characterisation of their complex, multi-scale properties is required to optimise their translation to clinical practice. Image analysis combined with computational modelling is a powerful tool to explore mechanisms of hSC behaviour and aid clinical diagnosis and therapy. Summary: Many computational models draw on a variety of techniques, often blending continuum and discrete approaches, and have been used to describe cell differentiation and self-organisation. Machine learning tools are having a significant impact in model development and improving image classification processes for clinical diagnosis and treatment and will be the focus of much future research

Optimising the cost-effectiveness of risk-based screening for diabetic retinopathy

Publicly provided health screening programmes tend to offer standardised screening for a fixed eligible population. Recently, the development of risk calculation engines has introduced the potential for the stratification of screening based on individuals' risks of disease onset. This possibility raises practical, methodological, and ethical challenges. To date, no such programme has been the subject of an economic evaluation. In this thesis we present reason and basis for the allocation of screening based on individual risk. The research is conducted in the context of screening for diabetic eye disease in the UK. Diabetic retinopathy is a common complication of diabetes that can lead to blindness, substantial detriments to quality of life, and significant health care resource use. Our study is linked to a programme of research that includes a cohort study and randomised controlled trial in the city of Liverpool. We review and further develop the evidence base to inform the evaluation of a risk-based screening programme for diabetic eye disease. Specifically, we generate new evidence on the costs and health outcomes associated with the screening and treatment of diabetic retinopathy. We report on a cross-sectional study of health-related quality of life for people attending screening for diabetic retinopathy and find that people with pre-symptomatic disease tend to report poorer quality of life than people with no disease, with EQ-5D-5L index values of 0.733 on average compared with 0.787 for people with no disease. A meta-analysis of published health state utility values for diabetic eye disease shows a negative impact on health-related quality of life before progression to blindness. Our meta-regression found a utility index decrement of 0.024 for people with proliferative retinopathy. The costs of screening are low at the individual level, estimated to be £32.03 in our costing study. But the overall budget impact of changes in the frequency of screening can be significant. We analyse a large data set of hospital and community screening activity to identify key treatment pathways for diabetic eye disease. We find that these have changed in recent years, with the introduction of more expensive interventions. The evidence generated by our work is used to inform the development of a decision analytic model. The model is designed to estimate the cost-effectiveness of risk-based screening for diabetic eye disease, compared with current practice. We find that risk-based screening is likely to be more cost-effective than standardised screening programmes. Evaluating a programme that allocates screening according to individuals' levels of risk raises theoretical and ethical challenges. To this end, we develop a simple framework for individualised cost-effectiveness analysis that can be used to inform the design of a risk-based screening programme. We also explore the ethics of risk-based screening, developing the notion of screening need as distinct from treatment need. Risk-based screening is likely to be cost-effective in the context of diabetic eye disease. The evidence presented in this thesis can be used to support the evaluation of new programmes, which can be designed in order to optimise cost-effectiveness using the methods that we describe. Such an approach is consistent with equitable policy objectives

Screening Intervals for Diabetic Retinopathy and Implications for Care

Purpose of Review The purpose of this study is to review the evidence that lower risk groups who could safely be screened less frequently for sight-threatening diabetic retinopathy (DR) than annually. Recent Findings Data have demonstrated that people with no DR in either eye are at a low risk of progression to sight-threatening DR over a 2-year period (event rate 4.8 per 1000 person years), irrespective of whether the screening method is one-field non-mydriatic or two-field mydriatic digital photography. Low risk has been defined as no retinopathy on two consecutive screening episodes or no retinopathy on one screening episode combined with risk factor data. Summary The risk of an extension to 2 years is less than 5 per 1000 person years in a population with a national screening programme, and the general standard of diabetes care is relatively good, whether low risk is defined as no retinopathy on two consecutive screening episodes or no retinopathy on one screening episode combined with other risk factor data. The definition used in different populations is likely to depend on the availability of data