Stability results of a mathematical model for the control of HIV/AIDS with the use of male and female condoms in heterosexual populations

A compartmentalized deterministic mathematical model for the dynamics of HIV/AIDS under the use of male and female condoms has been formulated and studied qualitatively. Disease-free equilibria of the sub-models have been found to be locally and asymptotically stable. Stability results revealed threshold values for the proportions of susceptible and infected subpopulations that must use condom in order to achieve control, and possibly, eradication of HIV/AIDS in heterosexual populations. Condom use rate for the susceptible subpopulations has been found to be bounded above by the population’s birth rate, while that of the infected subpopulations is bounded below by a given threshold.KEYWORDS: Locally and asymptotically stable, disease-free equilibrium, HIVAIDS contro

SmartHIV Manager: a web-based computer simulation system for better management of HIV services

© Journal of Public Health and Emergency. All rights reserved. This work is licensed under CC-BY-NC_ND 4.0 (https://creativecommons.org/licenses/by-nc-nd/4.0/)Background: Life-changing developments enabled people living with HIV/AIDS (human immunodeficiency virus/acquired immunodeficiency syndrome) to live a relatively normal life like the general population. However, there is not any user-friendly platform that enables key decision-makers to assess scenarios for improvement. Therefore, the objective of this study is to demonstrate the potentials of a web-based simulation system for effective and efficient management of HIV services. Methods: SmartHIV Manager is a web-based interactive planning platform for management of HIV services. Discrete event simulation technique is used to capture real-life HIV patients through HIV care continuum and all the resources needed. Patient flow information from HIV caregivers in three HIV treatment centres in Kenya and Nigeria was tested and validated. A total of 93 input parameters were established in the HIV pathway of care. Dashboards, which are fed by the simulation outcomes, were prepared to assess the impact of several interventions. The dashboard components include graphs and tables on service demand and utilization, preventive strategies, UNAIDS (the joint United Nations programme on HIV/AIDS) 90-90-90 goals, human resource management, budgeting and financial planning. Results: The usefulness and functionalities of the system is demonstrated on capacity planning in prevention programmes and UNAIDS 90-90-90 target. We ran scenarios based on increasing prevention measures and increasing the number of people on treatment to reach UNAIDS 90-90-90 target for a service in Nigeria. More cases are expected to be averted, where naïve patients reduced due to prevention measures. As the service struggled to achieve UNAIDS target, necessary outputs were generated, in the form of required resources to reach the target by 2025 and assessed the overall impact on service outcomes. Conclusions: A novel simulation powered technology is developed for effective HIV/AIDS management and control. This would give a robust patient care which can be properly evaluated and predicted in interventional implementation for appropriate policy directions.Peer reviewe

Can discrete event simulation be of use in modelling major depression?

BACKGROUND: Depression is among the major contributors to worldwide disease burden and adequate modelling requires a framework designed to depict real world disease progression as well as its economic implications as closely as possible. OBJECTIVES: In light of the specific characteristics associated with depression (multiple episodes at varying intervals, impact of disease history on course of illness, sociodemographic factors), our aim was to clarify to what extent "Discrete Event Simulation" (DES) models provide methodological benefits in depicting disease evolution. METHODS: We conducted a comprehensive review of published Markov models in depression and identified potential limits to their methodology. A model based on DES principles was developed to investigate the benefits and drawbacks of this simulation method compared with Markov modelling techniques. RESULTS: The major drawback to Markov models is that they may not be suitable to tracking patients' disease history properly, unless the analyst defines multiple health states, which may lead to intractable situations. They are also too rigid to take into consideration multiple patient-specific sociodemographic characteristics in a single model. To do so would also require defining multiple health states which would render the analysis entirely too complex. We show that DES resolve these weaknesses and that its flexibility allow patients with differing attributes to move from one event to another in sequential order while simultaneously taking into account important risk factors such as age, gender, disease history and patients attitude towards treatment, together with any disease-related events (adverse events, suicide attempt etc.). CONCLUSION: DES modelling appears to be an accurate, flexible and comprehensive means of depicting disease progression compared with conventional simulation methodologies. Its use in analysing recurrent and chronic diseases appears particularly useful compared with Markov processes

Multiobjective Optimization in Health Care Management. A metaheuristic and simulation approach.

This paper describes a methodology which combines elements of statistics, probability, mathematical programming, simulation, multiobjective optimization and metaheuristics, to analyze management problems in a health care context. We apply this approach to a staffing problem in a primary care center, taking into account both cost and service quality criteria. We illustrate our approach with a case study

A simulation-based decision support tool for informing the management of patients with Parkinson’s disease

This is an Accepted Manuscript of an article published by Taylor & Francis Group in International Journal of Production Research, on 9 April 2015, available online via: http://dx.doi.org/10.1080/00207543.2015.1029647We describe a decision support toolkit that was developed with the aim of assisting those responsible with the management and treatment of Parkinson’s disease (PD) in the UK. Having created a baseline model and established its face validity, the toolkit captures the complexity of PD services at a sufficient level and operates within a user friendly environment, that is, an interface was built to allow users to specify their own local PD service and input their own estimates or data of service demands and capacities. The main strength of this decision support tool is the adoption of a team approach to studying the system, involving six PD specialist nurses across the country, ensuring that variety of views and suggestions are taken as well as systems modelling and simulations. The tool enables key decision makers to estimate the likely impact of changes, such as increased use of community services on activity, cost, staffing levels, skill-mix, and utilisation of resources. Such previously unobtainable quantitative information can be used to support business cases for changes in the increased use of community services and its impact on clinical outcomes (disease progression), nurse visits and costing.Peer reviewedFinal Accepted Versio

Patient Pathway Modelling Using Discrete Event Simulation to Improve the Management of COPD

This is an Accepted Manuscript version of 'Usame Yakutcan, Eren Demir, John R. Hurst & Paul C. Taylor (2020) Patient pathway modelling using discrete event simulation to improve the management of COPD, Journal of the Operational Research Society, DOI: 10.1080/01605682.2020.1854626'. It is deposited under the terms of the Creative Commons Attribution-NonCommercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited.” Publisher Copyright: © Operational Research Society 2020.The number of people affected by chronic obstructive pulmonary disease (COPD) is increasing and the hospital readmission rate is remarkably high. Therefore, healthcare professionals and managers have financial and workforce-related pressures. A decision support toolkit (DST) for improving the management and efficiency of COPD care is needed to respond to the needs of patients now and in the future. In collaboration with the COPD team of a hospital and community service in London, we conceptualised the pathway for COPD patients and developed a discrete event simulation model (DES) incorporating the dynamics of patient readmissions. A DES model or operational model at this scale has never been previously developed, despite many studies using other modelling and simulation techniques in COPD. Our model is the first of its kind to include COPD readmissions as well as assessing the quantifiable impact of re-designing COPD services. We demonstrate the impact of post-exacerbation pulmonary rehabilitation (PEPR) policy and observe that PEPR would be cost-effective with improvements in quality-adjusted life years (QALYs), reduction in emergency readmissions and occupied bed days. The DST improves the understanding of the impact of scenarios (activities, resources, financial implications etc.) for key decision makers and supports commissioners in implementing the interventions.Peer reviewedFinal Accepted Versio

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

A healthcare space planning simulation model for Accident and Emergency (A&E)

The National Health Service (NHS) in the United Kingdom provides a range service for its population including primary care and hospital services. The impact of the 2008 economic and financial crises prompted a tightening of public budgets including health. Over the next few years, and most likely beyond, the NHS is planning for unprecedented levels of efficiency saving in the order of £ billions. With little doubt, the NHS will need to review its way of working will need to do more with less. Simulation is an established technique with applications in many industries including healthcare. Potentially, there are huge opportunities for simulation use to make further inroads in the field of healthcare. Despite the potential, arguably, simulation has failed to make a significant impact in health. Some evidence has tended to suggest that within health there has been poor adaption along with poor linkage to real-world problems, as perceived by healthcare stakeholders. The aim of this thesis is to develop a model to help address real-world healthcare issues as recognised by healthcare stakeholders. In doing so, this thesis will focus on a couple of real-world problems, namely: What space is needed to meet service demand, when is it needed and what will it cost? What space do we have, how can it be used to meet service demand and at what cost? The developed simulation space demand model will demonstrate its value modelling dynamic systems over static models. The developed models will also show its value highlighting space demand issues by groups of patients, by time of day. Real, readily available data (arrival and length of stay, by patient group) would drive the model inputs, supporting ease of use and clarity for healthcare stakeholders. The model was modular by design to support rapid reconfiguration. Dynamically modelled space information allows service managers and Healthcare Planners to better manage and organise their space in a flexible way to meet service requirements. This work will also describe how space demand can linked with building notes to determine Schedules of Accommodation which can be used to cost floor space and consequent building or refurbishment costs. Furthermore, this information could be used to drive business plans and to develop operational cost pertaining to the floor area. This body of work debates using function-to-space ratios and attaching facilities management cost. Our findings suggest great variance in function-to-space ratios. Our findings also suggest that moving to median or lower quartile function-to-space ratios could potentially save hospitals £ millions in facilities management costs. This thesis will reflect on the level of modelling taking place in the healthcare industry by non-academic healthcare modellers, sometimes collectively known as Healthcare Planners, the Healthcare Planning role in space planning and their links with healthcare stakeholders. This reflection will also consider whether healthcare stakeholders perceive a great need for academic healthcare modelling, if they believe their modelling needs are met by Healthcare Planners. A central theme of this thesis is that academic modelling and Healthcare Planning have great synergy and that bringing together Healthcare Planners’ industry knowledge and stakeholder relationships with academic know-how, can make a significant contribution to the healthcare simulation modelling arena

Approaching parallel computing to simulating population dynamics in demography

Agent-based modelling and simulation is a promising methodology that can be applied in the study of population dynamics. The main advantage of this technique is that it allows representing the particularities of the individuals that are modeled along with the interactions that take place among them and their environment. Hence, classical numerical simulation approaches are less adequate for reproducing complex dynamics. Nowadays, there is a rise of interest on using distributed computing to perform large-scale simulation of social systems. However, the inherent complexity of this type of applications is challenging and requires the study of possible solutions from the parallel computing perspective (e.g., how to deal with fine grain or irregular workload). In this paper, we discuss the particularities of simulating populating dynamics by using parallel discrete event simulation methodologies. To illustrate our approach, we present a possible solution to make transparent the use of parallel simulation for modeling demographic systems: Yades tool. In Yades, modelers can easily define models that describe different demographic processes with a web user interface and transparently run them on any computer architecture environment thanks to its demographic simulation library and code generator. Therefore, transparency is provided by by two means: the provision of a web user interface where modelers and policy makers can specify their agent-based models with the tools they are familiar with, and the automatic generation of the simulation code that can be executed in any platform (cluster or supercomputer). A study is conducted to evaluate the performance of our solution in a High Performance Computing environment. The main benefit of this outline is that our findings can be generalized to problems with similar characteristics to our demographic simulation model

Use of Discrete-Event Simulation to Evaluate Strategies for the Prevention of Mother-to-Child Transmission of HIV in Developing Countries

HIV/AIDS affects over 40 million people worldwide, and more than 70% of these people live in Africa. Mother-to-child transmission of HIV accounts for over 90% of all HIV infections in children under the age of 15 years. However, implementing HIV prevention policies in Africa is extremely difficult because of the poor medical and socio-economic infrastructure. In this paper, we present a discrete-event simulation model that evaluates the relative benefits of two potentially affordable interventions aimed at preventing mother-to-child transmission of HIV, namely anti-retroviral treatment at childbirth and/or bottlefeeding strategies. The model uses rural Tanzanian data and compares different treatment policies. Our results demonstrate that strategic guidelines about breastfeeding are highly dependent on the assumed increase in infant mortality due to bottlefeeding, the efficacy of anti-retroviral treatment at childbirth, and the maternal health stage. The cost of averted infections, though low by Western standards, may represent significant obstacles to policy implementation in developing countries