ORAHS 2015

HEC Montréal, July 19 - 24, 2015



HEC Montréal, 19 July — 31 August 2015

Schedule Authors My Schedule

ThC3 Disease Modeling and Policy 2

Jul 23, 2015 01:30 PM – 03:00 PM

Location: Banque Scotia

Chaired by Alexander Rutherford

3 Presentations

  • 01:30 PM - 02:00 PM

    Compliance with National Guidelines for Stroke in Radiology

    • Izabela Komenda, presenter, Cardiff University
    • Vincent Knight, Cardiff University
    • Paul Harper, Cardiff University

    Stroke is a medical emergency, and if patient outcomes are to be improved there should be no time delays in accessing treatment. As management and prognosis of stroke are determined by aetiology, it is vital to delineate the causality of an event as soon as it is practicable. This project focuses on the application of Operational Research methodology to investigate how the Royal Gwent Hospital can comply with revised CT scanning guidelines for stroke. Such guidelines, released by the Royal College of Physicians in December 2012, recommend a 50% reduction in maximum time from hospital admission to delivery and report of a CT head scan to just 12 hours. Statistical analyses were conducted upon historical hospital data to investigate trends in CT scan request demand. The results of this investigation were used to populate a discrete event simulation model describing patient flow through the CT scanning process in SIMUL8 software. Following successful validation and verification, the model was applied to explore a number of operational modifications to the CT scanning system through a series of scenario analyses. Each of the scenarios focused upon policies in direct relation to stroke, and were proposed during observations of key processes and through discussion with radiology staff. The results of this investigation presented evidence of a number of strategies to support operational improvements in relation to revised stroke guidelines. A range of areas for further investigation were also proposed.

  • 02:00 PM - 02:30 PM

    Stroke care modelling in Singapore

    • Steffen Bayer, presenter, Duke-NUS Graduate Medical School
    • Kirsten Eom, Duke-NUS Graduate Medical School
    • Gerald Koh, National University of Singapore/National University Health System
    • Kelvin Bryan Tan, Ministry of Health Singapore
    • David Matchar, Duke-NUS Graduate Medical School

    Stroke is one of leading causes of death and the leading cause of long-term disability in Singapore as in many other countries. With the rapidly ageing population in Singapore, it is of great importance to reduce the burden of stroke on patients, their family members, as well as the health care system. In light of this, there is an urgent need to prioritize clinical interventions and pertinent policies to maximize patients’ outcomes and properly allocate the available resources.

    As a part of the effort to address this need, we have developed a system dynamics model using Singapore-specific stroke epidemiology data, clinical practice guidelines of stroke, and cost estimates of the interventions. Targeting those with history of stroke in Singapore, the model simulates the natural history of stroke within the adult Singapore population. The stroke population in the model is categorized by time since most recent stroke and functional independence (modified Rankin Scale).

    Simulating the impact of different types of interventions across the wide spectrum of stroke care (incl. dysphagia screening, DVT prophylaxis, thrombolysis, rehabilitation and secondary prevention) we identify potential approaches to reduce the risk of secondary stroke, improve patient care, and help stroke survivors in Singapore reach the best possible post-stroke outcomes at acceptable costs. Comparing levels of care and projected level of care with plausible effort we estimate the impact on cumulative quality-adjusted life years, incident strokes, and stroke fatalities over a 15-year time period.

    As the project was designed to support policy formulation and implementation as well as programme planning for stroke care in Singapore, we reflect on the usefulness of simulation modelling in informing discussions on different ways to improve the current practice at systems-level and supporting policy makers and clinicians deciding on evidence-based recommendations related to stroke care.

  • 02:30 PM - 03:00 PM

    UNAIDS 90-90-90 Targets for Reducing HIV Incidence: An Operational Analysis for Vancouver, Canada

    • Alexander Rutherford, presenter, The IRMACS Centre, Simon Fraser University
    • Lukas Ahrenberg, The IRMACS Centre, Simon Fraser University
    • Bojan Ramadanovic, The IRMACS Centre, Simon Fraser University
    • Brian Williams, South African Centre for Epidemiological Modelling and Analysis
    • Krisztina Vasarhelyi, Faculty of Heath Sciences and the IRMACS Centre, Simon Fraser University

    UNAIDS recently launched new targets for combating the HIV/AIDS epidemic that call for 90% of HIV-positive individuals to be diagnosed, 90% of them to be on treatment, and 90% of patients on treatment to be virally suppressed. UNAIDS anticipates that meeting this 90-90-90 target by 2020 will significantly reduce HIV incidence by 2030 and effectively end the epidemic. Utilising a differential equation model of the continuum of HIV testing, treatment, care, and disease transmission, we examine the epidemiological implications of implementing different operational approaches to reach the 90-90-90 targets in Vancouver, Canada.

    Our model predicts that reaching the 90-90-90 target by 2020 would reduce HIV incidence in Vancouver from 178 cases/year in 2013 to approximately 97 cases per year in 2030. HIV incidence varies only by about 3% with redistributing testing resources between targeted testing, routine testing in high prevalence settings, and routine
    testing in acute care. However, we find wide variation in costs of testing programmes that can meet the 90-90-90 target. Using budget units of $1 for a routine test, simply expanding the current testing programme to meet the 90-90-90 target would cost approximately $91,000 per year. However, through optimally re-allocating testing resources, we are able to meet the target with an annual testing budget of just $18,000. This minimal-cost programme emphasise routine testing in high prevalence settings for gay men and injection drug users.

    The model predicts that reaching the 90-90-90 targets by 2020 would reduce HIV incidence to approximately 50% of baseline by 2030. This corresponds to less than 30 cases in the injection drug user and general populations, combined. However almost 70 new infections are still expected among gay men. We further examine the feasibility of a two-dimensional family of 2020 operational targets to reduce HIV incidence by 90% in 2030.