Towards More Nuanced Patient Management: Decomposing Readmission Risk with Survival Models

Unplanned hospital readmissions are costly and associated with poorer patient outcomes. Overall readmission rates have also come to be used as performance metrics in reimbursement in healthcare policy, further motivating hospitals to identify and manage high-risk patients. Many models predicting readmission risk have been developed to facilitate the equitable measurement of readmission rates and to support hospital decision-makers in prioritising patients for interventions. However, these models consider the overall risk of readmission and are often restricted to a single time point. This work aims to develop the use of survival models to better support hospital decision-makers in managing readmission risk. First, semi-parametric statistical and nonparametric machine learning models are applied to adult patients admitted via the emergency department at Gold Coast University Hospital (n = 46,659) and Robina Hospital (n = 23,976) in Queensland, Australia. Overall model performance is assessed based on discrimination and calibration, as measured by time-dependent concordance and D-calibration. Second, a framework based on iterative hypothesis development and model fitting is proposed for decomposing readmission risk into persistent, patient-specific baselines and transient, care-related components using a sum of exponential hazards structure. Third, criteria for patient prioritisation based on the duration and magnitude of care-related risk components are developed. The extensibility of the framework and subsequent prioritisation criteria are considered for alternative populations, such as outpatient admissions and specific diagnosis groups, and different modelling techniques. Time-to-event models have rarely been applied for readmission modelling but can provide a rich description of the evolution of readmission risk post-discharge and support more nuanced patient management decisions than simple classification models

Contribution to the development of mathematical programming tools to assist decision-making in sustainability problems

L'activitat humana està excedint la capacitat de resposta de la Terra, el que pot tenir implicacions perjudicials per al futur benestar humà i del medi ambient. Sens dubte, severs canvis estructurals seran necessaris, el que exigeix prendre solucions eficaces davant els problemes emergents de sostenibilitat. En aquest context, aquesta tesi es centra en dues transformacions clau per re-connectar el desenvolupament humà amb el progrés sostenible: la "seguretat alimentària sostenible", desacoblant la intensificació agrícola de l'ús insostenible dels recursos; i el "model energètic sostenible", donant suport al canvi cap a una economia respectuosa amb el medi ambient. El marc metodològic consisteix a abordar diferents problemes mitjançant el desenvolupament d'eines sistemàtiques de programació matemàtica amb l'objectiu de donar suport a la presa de decisions i la formulació de polítiques conduents a la consecució del desenvolupament sostenible. Aquesta tesi doctoral inclou quatre contribucions principals en forma d'eines de decisió i suport de polítiques prou flexibles com per abordar diferents casos d'estudi. En primer lloc, es proposa una eina multiobjectiu per assignar àrees de cultiu considerant simultàniament criteris productius i mediambientals. En segon lloc, es proposa un model multiperíode per determinar plans de cultiu òptims i subsidis efectius per tal de promoure pràctiques agrícoles sostenibles. En tercer lloc, es proposa una metodologia per a analitzar la sostenibilitat que permet avaluar sistemes muticriteri i proporciona potencials millores d'acord amb els principis de la sostenibilitat. En quart lloc, es proposa un nou enfocament basat en l'optimització d'accions cooperatives amb l'objectiu de promoure i enfortir la cooperació internacional en la lluita contra el canvi climàtic La informació derivada de la investigació, com la presentada en aquesta tesi, pot tenir un paper fonamental en la transició cap a una nova era en la qual l'economia, la societat i el medi ambient coexisteixin com a pilars clau del desenvolupament sostenible.La actividades humanas están excediendo la capacidad de carga de la Tierra, lo que puede potencialmente generar implicaciones perjudiciales para el futuro bienestar humano y del medio ambiente. Sin duda son necesarios profundos cambios estructurales, lo que exige tomar soluciones eficaces ante los problemas emergentes de sostenibilidad. En este contexto, esta tesis se centra en dos transformaciones clave para reconectar el desarrollo humano con el progreso sostenible: la "seguridad alimentaria sostenible", desacoplando la intensificación agrícola del uso insostenible de los recursos; y el " modelo energético sostenible", apoyando el cambio hacia una economía respetuosa con el medio ambiente. El marco metodológico consiste en abordar distintos problemas mediante el desarrollo de herramientas sistemáticas de programación matemática cuyo objetivo es apoyar la toma de decisiones y la formulación de políticas tendentes hacia la consecución del desarrollo sostenible. La tesis incluye cuatro contribuciones principales en forma de herramientas de decisión y apoyo de políticas suficientemente flexibles para abordar diferentes casos de estudio. En primer lugar, se propone una herramienta multiobjetivo para asignar áreas de cultivo considerando simultáneamente criterios productivos y medioambientales. En segundo, se propone un modelo multiperiodo para determinar planes de cultivo óptimos y subsidios efectivos con el fin de promover prácticas agrícolas sostenibles. En tercero, se propone una metodología para realizar análisis de sostenibilidad que permite evaluar sistemas muticriterio y proporciona potenciales mejoras de acuerdo con principios de sostenibilidad. En cuarto lugar, se propone un nuevo enfoque basado en la optimización de acciones cooperativas con el objetivo de promover y fortalecer la cooperación internacional en la lucha contra el cambio climático La información derivada de la investigación, como la presentada en esta tesis, puede desempeñar un papel fundamental en la transición hacia una nueva era en la que la economía, la sociedad y el medio ambiente coexistan como pilares clave del desarrollo sostenible.Impacts from human activities are exceeding the Earth’s carrying capacity, which may lead to irreversible changes posing a serious threat to future human well-being and the environment. There is no doubt that an urgent shift is needed for sustainability, which calls for effective solutions when facing ongoing and emerging sustainability challenges. Against this background, this thesis focuses on two key structural transformations needed to reconnect the human development to sustained progress: the “food security transformation”, through decoupling the intensification of agricultural production from unsustainable use of resources; and the “clean energy transformation”, supporting the transition towards a more environmentally friendly economy. Methodologically, different sustainability issues are tackled by developing systematic mathematical programming tools aiming at supporting sustainable decision and policy-making which ultimately will lead to the development of more efficient mechanisms to foster a sustainable development. This thesis includes four major contributions in the form of decision and policy- support tools which are flexible and practical enough to address different case studies towards a more sustainable agriculture and energy future. First, a multi-objective tool is proposed which allows allocating cropping areas simultaneously maximizing the production and minimizing the environmental impact on ecosystems and resources. Second, a multi-period model is proposed which allows determining optimal cropping plans and effective subsidies to promote agricultural practices beneficial to the climate and the environment. Third, a novel methodology tailored to perform sustainability assessments is proposed which allows evaluating multi-criterion systems and providing improvements targets for such systems according to sustainability principles. Fourth, an optimised cooperative approach is proposed to promote and strengthen international cooperation in the fight against climate change. Research-based work as the one proposed herein may play a major role in the transition towards a new era where the economy, society and the environment coexist as key pillars of sustainable development

Robust Multi-Objective Sustainable Reverse Supply Chain Planning: An Application in the Steel Industry

In the design of the supply chain, the use of the returned products and their recycling in the production and consumption network is called reverse logistics. The proposed model aims to optimize the flow of materials in the supply chain network (SCN), and determine the amount and location of facilities and the planning of transportation in conditions of demand uncertainty. Thus, maximizing the total profit of operation, minimizing adverse environmental effects, and maximizing customer and supplier service levels have been considered as the main objectives. Accordingly, finding symmetry (balance) among the profit of operation, the environmental effects and customer and supplier service levels is considered in this research. To deal with the uncertainty of the model, scenario-based robust planning is employed alongside a meta-heuristic algorithm (NSGA-II) to solve the model with actual data from a case study of the steel industry in Iran. The results obtained from the model, solving and validating, compared with actual data indicated that the model could optimize the objectives seamlessly and determine the amount and location of the necessary facilities for the steel industry more appropriately.This article belongs to the Special Issue Uncertain Multi-Criteria Optimization Problem

Performance analytics for regulation in retail water utilities: Guiding asset management by identifying peers and targets

This research evaluates the performance of water supply utilities operating at the retail level in Portugal concerning asset management practices. The study’s main innovative feature is identifying peers and targets to guide improvements in the sector. Reliable data collected by the regulatory authority for water and waste services in Portugal (ERSAR) are employed to design two composite indicators reflecting different dimensions of asset management: operational conditions and management systems. Based on the Data Envelopment Analysis technique, the Benefit-of-the-Doubt model is employed in robust and conditional formulations. The role of the context on utilities’ performance is also investigated. The results show that the direct management model is unfavourable concerning developing structured management systems, whilst urban environments favour managerial advancement. Rural and semi-urban environments favour “good” operational results in infrastructures. The pool of peers obtained for each utility and the quantification of targets based on the observed achievements by those peers facilitates the search for industry best practices and promotes continuous improvement. Given the high heterogeneity in asset management performance within the sector, the utility-specific target-setting approach illustrated in this paper can support a regulatory policy review for determining more realistic goals

OR in search for community

This year’s Keynote has a special format. The interest in Community OR has taken the form of a new Special Interest Group that is presently taking shape. To contribute to a better understanding of the variety of interest that is being incorporated, we have invited a number of people to present their ideas as short presentations or pitches. Below you will find an outline of what we have today. These may help to summarise the current thinking and (research) practices in Community OR. The presentations will be followed by a panel discussion. Social Innovation and Community OR Communities are the main addressees for sustainable change and improvement, at least in the European Union. There are some considerable difficulties here, as the cry for policies that are effective in delivering this change is getting stronger and communities are getting better in avoiding being addressed as stooges. At present OR explores contributions to the policy problem (see the new SIG for Social Policy). It is argued that policy should be supportive to community level activities and initiatives, rather than the reverse, if social innovation is to be promoted. Examples are presented. Organising Suppliers: Chain or commune? Economy-based supplier structures are organised under drivers that aim at the alignment of goals and the optimisation of resources available; however, this does not seem to apply to any size of business. Observations on microbusinesses suggest that they do not strive for economic drivers only. Lifestyle, family and other non-economic drivers are also part of their strategic decision making processes. Different snapshots about UK and Mexican microbusinesses are used to illustrate possibilities that supply chains and communities may provide. Community OR ideas are used as a framework for the comparison

Communities and food supply: looking at their intersection

There is an extended opinion that Food Supply Chains (FSCs) create economic value; usually by aligning different actors along the chain. However, for food microproducers, economic value is not necessarily the main driver to engage with FSCs. This opens up the discussion towards how to build FSCs with potential members that do not always recognise practical advantages in working with others. We propose explore previous research done in the area of Community Operational Research (COR) by looking microproducers not as links constituting a chain, where the weakest is removed for the benefit of the rest. We explore if there are benefits from being members from a community (Food Supply Communities, FSComs), where they identify which individual actions contribute to the collective self-construction, and vice versa. To contextualise the discussion, we use the case of a typical UK regional, county-based food marketing group which provides umbrella marketing support for specialist SMEs