Public Health & Primary Care (Theses and Dissertations)Public Health & Primary Care (Theses and Dissertations)http://hdl.handle.net/2262/972024-03-28T10:33:58Z2024-03-28T10:33:58ZStrategy Selection and Comparison in the Cost-Effectiveness Analysis of Cancer ScreeningLin, Yi-Shuhttp://hdl.handle.net/2262/1037642023-08-23T17:02:22Z2023-01-01T00:00:00ZStrategy Selection and Comparison in the Cost-Effectiveness Analysis of Cancer Screening
Lin, Yi-Shu
Cost-effectiveness analysis (CEA) is well-established in application to cancer screening programmes. CEAs of screening differ from analyses of therapeutic interventions as the choice of strategies for comparison is not limited simply by the different interventions to compare but also the intensity at which they are provided. This very much depends on modelling choices made by the analysts conducting the simulation study. Existing checklists and guidelines for the application of CEA fail to fully address important issues regarding strategy choice which are relevant for adequate incremental cost-effectiveness ratio (ICER) estimation. Applied CEA models are an important tool for assessing health and economic effects of healthcare interventions but are not best suited for illustrating methodological issues. The objectives of this thesis are to review the issue of strategy omission in the CEAs of cancer screening, to provide a simple, open-source model for the simulation of disease screening cost-effectiveness for teaching and research purposes, and to demonstrate how the omission of strategy can arise by observing the impacts of characteristics of screening schedules and parameter values on the shape and composition of the efficient frontier.
This thesis comprises three studies. The first identified the issue of strategy omission existing in the CEAs of colorectal cancer (CRC) screening. The quality assessment tool developed by this thesis identified methodological concerns around the ICER generation due to inappropriate comparisons and inadequate comparators. This study revealed that many CEAs did not consider different types, i.e., stool-based and image-based, of screening modalities available for CRC screening. Many CEAs did not consider consistent screening schedules for the same type of screening modalities. In addition, this study found around half of the CEAs reviewed reported inappropriate ICERs for decision-making. In most cases, ICERs are confused with average cost-effectiveness ratios (ACERs), which are based on the comparison to the no-screening scenario. Another common inappropriate way of reporting is a cross-tabulated table that listed all the cost-effectiveness ratios (CERs), comparing all strategies to every other strategy.
The second study described a microsimulation model expressly designed for methods demonstration in CEAs of cancer screening. This simplified model has rapid simulation time, allowing the simulation of a large range of screening strategies. This framework is highly flexible in adjusting the intensities of screening strategies. This model can be used to demonstrate the complexity of screening strategies and their cost-effectiveness. The scenario analysis of this study showed how to conduct a simple face validation via the observation of the impact of changes in parameter values on the cost and effectiveness estimates. This study also showed the relevance of considering both gross cost and effects estimates and relative outcomes net to a no screening scenario. This distinction between gross and relative outcomes is helpful in providing an intuitive understanding of how cost-effectiveness estimates vary with changes in parameter values.
The third study used the pedagogical model proposed by the second study to demonstrate examples of strategy omission. The third study presented the trajectory of strategies with common characteristics on the cost-effectiveness plane with a variation in screening start ages, stop ages, and screening intervals. This study explained the policy-relevant portion of the efficient frontier which is comprised of strategies with ICERs close to the cost-effectiveness threshold and therefore should be of greatest interest to policy makers. Moreover, this study examined the convexity of the efficient frontier and whether this varies with changes in parameter values. In contrast to the position of efficient frontiers which gives a general understanding of the cost-effectiveness of screening relative to the no-screening, the change in the convexity implies the inconsistent change in ICERs of screening strategies with different intensities. This study provides guidance on how to avoid the omission of relevant strategies when conducting CEAs of cancer screening and suggests using an iterative method when choosing strategies to simulate. This approach uses the findings from the initial simulation to inform what other strategies might be worth adding to the simulation in order to include the most relevant strategies. The findings of this study give insights into how to expand the choice of strategies closer to the efficient frontier, improving the chance of strategies being cost-effective.
Take as a whole, this thesis describes the issue of strategy omission in cancer screening CEAs in detail. It examines the issue within the published literature and within an abstracted model. Using insights from both the review and a simplified model it provides suggestions on how best to avoid the omission of relevant screening strategies. Future research can extend this thesis to establish more detailed and realistic guidance for CEAs of screening.
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2023-01-01T00:00:00ZFacilitating readiness for advance care planning in Ireland: Informing the design of an innovative intervention for middle aged and older people in the communityPilch, Monika Annahttp://hdl.handle.net/2262/1031672023-08-11T11:26:42ZFacilitating readiness for advance care planning in Ireland: Informing the design of an innovative intervention for middle aged and older people in the community
Pilch, Monika Anna
Background: Advance care planning (ACP) is a process aiming to elicit, communicate, and document
future care wishes, providing mechanisms through which individual preferences can be supported.
Poor and fragmented stakeholders’ engagement in ACP poses challenges internationally, preventing
maximisation of potential benefits. Theory-based and innovative strategies are required to facilitate
stakeholders’ engagement. Aim: The aim of this project was to generate evidence to inform the
development of an intervention for increasing stakeholders’ engagement in ACP for middle-aged and
older community-dwellers (≥ 50 years old) in Ireland. Method: This mixed-methods study achieved its
aim through three sequential studies: a hybrid mixed-research systematic review (Study 1), a
secondary analysis of longitudinal population data (Study 2), and a collective intelligence workshop
with key stakeholders (Study 3). Study 1 synthesised international evidence on the barriers and
facilitators to stakeholders’ ACP engagement and mapped the findings across the Capability,
Opportunity, and Motivation dimensions of behaviour (COM-B model). Study 2 explored ACP uptake
among community-dwellers, via secondary data analysis, and identified factors associated with ACP
engagement. Study 3 explored barriers to ACP engagement, options for overcoming those barriers,
and the end-users’ needs. Findings were integrated and mapped across the intervention options and
policy categories of the Behaviour Change Wheel. Findings: Study 1 provided a comprehensive
behavioural diagnosis in relation to factors influencing stakeholders’ engagement in ACP activities for
middle-aged and older community-dwellers, with most influencing factors falling into the categories
of opportunity (connectedness, service provision, resources, sociodemographic characteristics, and
macro-level variables) and motivation (psychological factors, metapreferences, temporality,
experience). Capability included dimensions of literacy. Study 2 showed that overall engagement in
ACP behaviours in Ireland is comparatively low, although higher at wave 6 (34.9%, n=1425) when
compared to wave 4 (26.5%, n=1159). The prevalence was higher at end-of-life (57.1%, n=169). The
most frequently reported ACP behaviours were conversations with trusted others (24% (n=1048) at
wave 4, 29.4% (n=1200) at wave 6, and 48% (n=142) at end-of-life) and the appointment of a surrogate
decision-maker (43.5%, n=128). Engagement in conversations with trusted others was positively
associated with increasing age, being female, experience of pain, making a will. It was negatively
associated with being single and perceiving religion as important. Study 3 identified and grouped
barriers to ACP into seven categories, including: Psychological; Resources and Supports; ACP Process
and Methods; ACP Literacy; Interpersonal and Interprofessional; Cultural and Societal; and Servicerelated. The options for overcoming these barriers included: Changing Perceptions of ACP and
Increasing Psychological Readiness; Developing High-Quality Resources, Support Systems, and
Infrastructure; Using Creative Methods and Strategies to Facilitate Stakeholders’ Engagement in ACP;
Increasing ACP Literacy through Education and ACP Campaigns; Facilitating Timely, Focused, and
Meaningful Interaction between Stakeholders; Promoting Cultural and Societal Transformation; and
Co-designing a Needs and Values-based Service. The systematic integration of findings (studies 1-3)
resulted in identification of five clusters of integrated findings (meta-themes), which describe the
overarching patterns of ACP engagement. It facilitated specification of the dimensions of the problem
and a possible solution. Conclusion: This is the first study to explore comprehensive, theory-based
underpinnings of ACP, the findings of which inform the key characteristics of future interventions.
Priorities for future research, practice, policy and informed efforts towards the design and coproduction of ACP intervention are discussed.
Vitamin D in the Irish Population: an analysis of prevalence and determinantsScully, Helenahttp://hdl.handle.net/2262/1027292023-05-25T17:02:46Z2023-01-01T00:00:00ZVitamin D in the Irish Population: an analysis of prevalence and determinants
Scully, Helena
Introduction: Vitamin D has an established role in bone and muscle health, with deficiency causing rickets in children, osteomalacia in adults and contributing to the development of osteoporosis. More recently it has been associated with extra-skeletal effects including inflammation, cardiovascular disease (CVD), diabetes, cognitive impairment, and respiratory conditions including asthma and COVID. Due to a northern latitude (51-55°N), and limited dietary intake, the Irish population are at risk of vitamin D deficiency. However, much is unknown about the status in the population with regard to particular groups including children, ethnic minorities, urban dwellers, and younger adults. There is also a lack of research on vitamin D testing in Ireland including indications for same and the associated costs. Furthermore, no recent studies have assessed vitamin D intake in Irish adults, and few have examined peoples understanding of vitamin Ds role in health. This PhD aims to review existing research to-date in Ireland on vitamin D, and to investigate vitamin D status and its associated determinants in an Irish population. Furthermore, it explores vitamin D retesting, with a focus on inappropriate testing and its associated costs.
Methods: A literature review of existing evidence examining vitamin D status and intake between 1990-2022 in Ireland (Republic and Northern Ireland) was undertaken. To examine vitamin D status in the Irish population, a database of patients who had 25(OH)D serum concentration assessed by Liquid Chromatography Tandem Mass Spectrometry at St James’s Hospital Dublin between 2014-2020 at the request of Primary Care physicians was generated. Statistical analysis was used to determine vitamin D status and its predictors in children (1-17 years) and adults (>18 years), including non-nationals. Vitamin D retesting and associated costs were also ascertained. Finally, a stratified sample of participants completed a questionnaire to further explore the biophysical, lifestyle and dietary determinants of vitamin D status.
Results: From the comprehensive literature review, 142 studies and 7 reports were identified. Vitamin D deficiency (<30 nmol/L) was prevalent in Ireland, in up to 32% of older adults (>50 years), 38% of adults (<50 years) and 68% of children (<18 years). Adolescents, younger adults, and ethnic minorities were at greatest risk. Dietary intake was lowest in children and pregnant women, and highest in older adults. Results of our first investigation based on data analysis of community dwelling adults (n=36,466) found 15% were vitamin D deficient (<30 nmol/L), increasing to 23% in winter. Younger adults (18-39 years), males and those living in low socioeconomic locations were most at risk. In my second study, one in four adults were found to have vitamin D levels retested, with inappropriate testing resulting in €60,000 of estimated wasted expenditure per annum to St James’s hospital. In the third study, based on an analysis of vitamin D results of 1,226 children, 23% were vitamin D deficient, with a higher prevalence in females, older children (>12 years) and those living in poorer socioeconomic areas. Finally in my fourth study, total dietary vitamin D intake, ethnicity and sun habits were found to be important predictors of vitamin D status. Awareness of vitamin D supplementation recommendations and testing indications were poor, though knowledge of its importance for bone health were well known.
Conclusion: Vitamin D deficiency is highly prevalent, with a lack of research in subgroups of the population at risk of deficiency including children, younger adults, pregnant women, and ethnic groups. We also identified that younger adults, adolescents, and those living in low socioeconomic areas were most at risk of deficiency. Despite vitamin D retesting being common, there was no research on its testing indications, with many adults having levels assessed for non-specific reasons and at considerable cost. The majority of adults were also not meeting a dietary vitamin D intake of 10 μg/day and had poor awareness of the current recommended dietary allowance. The findings suggest that public health measures to address deficiency in the Irish population are urgently required, such as systematic fortification of staple foods, and establishing targeted recommendation for vulnerable population groups. In addition, clear guidance for General Practitioners and the public on the appropriate indications for vitamin D testing is necessary to reduce inappropriate referrals and expenditure.
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2023-01-01T00:00:00ZHow Local Decision Making Works for Adaptations of Health Interventions During Scale-up: A Realist ReviewPower, Jessicahttp://hdl.handle.net/2262/1001122022-07-06T17:02:30ZHow Local Decision Making Works for Adaptations of Health Interventions During Scale-up: A Realist Review
Power, Jessica
Introduction: Scaling-up health interventions is a complex process with growing recognition of the need to make adaptations to interventions to address diverse contexts and populations encountered across multiple sites. However these adaptations remain poorly understood with little documentation of what these adaptations are in practice, along with lack of specific guidance on what actions to use to make these adaptations when scaling-up. This leaves implementers with a lack of clarity as to why adaptations may be needed across sites when scaling-up, with minimal guidance on how to undertake the challenging process of adapting health interventions. As a result this may lead to ad-hoc or reactive approaches to adaptations with potential impact on intervention fidelity and effectiveness.
This research set out to uncover (i) what adaptations are made and why, when scaling up health interventions in practice and (ii) what are the actions that can be used to achieve these adaptations when scaling-up health interventions. Furthermore, the specific action of local decision making (LDM) was explored in more detail to discover (iii) how does LDM work (i.e. by what mechanisms, and in what contexts) as an action to achieve adaptations during scale-up of health interventions across diverse contexts.
Methods: These research questions were addressed using realist review methodology. Specifically, Pawson’s five stages of realist review of: (Stage-I) clarifying the review and developing initial theory, (Stage-II) developing a search strategy, (Stage-III) screening and appraisal, (Stage-IV) data extraction and (Stage-V) data synthesis and analysis, were utilised iteratively throughout the research process. As a final stage (Stage-VI), key informant interviews with those with experience of scaling-up health interventions were conducted and used to refine the theory for how and why LDM works for adapting health interventions when scaling-up. There were three distinct phases of this research.
Phase One - A background search was completed to develop an Initial Programme Theory (IPT) framework and focus the research question. The IPT was developed through analysis of previous adaptation, fidelity and scale-up guidance and frameworks, along with the wider implementation literature.
Phase Two - A systematic search was completed to identify examples of scale-up in practice where adaptations of health intervention occurred where the actions used to achieve adaptations were reported. The databases searched were; PubMed, Cinahl, Scopus, Global Indicus Medicus, Web of Science, EMBASE, and Psycinfo. Grey literature searches were also completed in Social Care Institute for Excellence (SCIE), Grey Lit and Open Grey. Further to the database searching, the references of identified articles and the ExpandNet bibliography were also hand-searched for more case examples. Through the case examples identified in this search, (i) details on the adaptations that were made (i.e. the reasons and type) and (ii) the actions that were used for these adaptations during scale-up were identified - in fulfilment of the first two research questions - and subsequently led to further refinement of the review question. For extracting the type and reasons for adaptations FRAME guidance (1) for adaptation reporting was used. For extraction of actions the IPT framework developed in phase one was used, with the actions headings refined as the review progressed.
Phase Three - The specific action of LDM was explored. IPTs relating to LDM for adaptations to health interventions during scale-up were developed and refined. Screening of case examples for relevance and rigour took place, with additional searching to identify more documents and provide further contextual information on these case examples. Data was extracted in the form of context-mechanism-outcome configurations (CMOCs). These were synthesised for demi-regularities and programme theories were refined. In addition, further searching for relevant substantive theory and interviews with key informants with experience in scale-up were utilised to refine programme theory and aid the development of an Middle Range Theory (MRT). This led to development of programme theories and an MRT on (iii) how and why LDM works for adaptations of health interventions during scale-up across diverse contexts, in fulfilment of the third research question.
Results
Phase One – An IPT framework was developed. The research question and search strategy for the subsequent phase were developed.
Phase Two - A total of n=22 case examples reporting on actions for adaptations made during scale-up were identified as a result of the systematic search in phase two. These were primarily based in Low and Middle Income Countries (LMICs) (n=19), with the remainder in High Income Countries (HICs) (n=3). The focus of the interventions ranged from: sexual and reproductive health (n=9); HIV (n=6); maternal and child health (n=4), two of which included vaccination programmes; non-communicable diseases (NCDs) (n=2); and mental health (n=1). Adaptations were primarily reported for the reason of increasing cultural acceptability (n=15), notably often to increase cultural acceptability in the wider population and context and not just for specific minority groups within a population. Adaptations were also commonly reported for resource availability (n=14), which occurred due to resource shortages at varying levels of the system i.e. at wider socio-political, organisational or recipient levels and were often unavoidable in nature. Proactive adaptations which were embedded into the scale-up design were reported in the majority of case examples (n=18). In addition to this, reactive adaptations also occurred in a number of case studies (n=11), these adaptations, although not embedded or planned from the outset, were often reported to serve needs that were identified as the intervention scaled-up. Ad-hoc unplanned adaptations (n=2) were also reported, primarily occurring at frontline provider level with a loss to fidelity noted in these case examples. Adaptations were reported at different levels of the system for example at national level (n=5); provincial, regional or district levels (n=6); organisational levels e.g. health facility or school (n=14); for specific cohorts within a population (e.g. based on gender, religion) (n=6) and based on individual recipient needs (e.g. literacy) (n=1). Fidelity considerations of adaptations and assessments were rarely documented. Adaptations were also often poorly reported. This research reflected and made suggestions for advancement of the FRAME adaptation reporting guidance, in particular for use in LMIC settings, for example suggesting further headings to differentiate resource limitations as a reason for adaptation, and the addition of further guidance on consideration of impact of adaptation on fidelity.
The actions used when scaling-up for adaptations to health interventions were identified with a resulting eight action headings emerging: (i) identification of intervention theory, core elements, components, functions or minimum standards; (ii) providing guidance to sites on intervention theory or components, on how to implement and adapt the specific intervention and/or sharing tried and tested examples of adaptations from other sites; (iii) LDM; (iv) using an adaptive scale-up design; (v) creating peer learning opportunities; (vi) ongoing assessment of the wider political, socioeconomic, cultural and organisational context to inform adaptations; (vii) the use of data to assess progress and inform or evaluate adaptations and (viii) the use of QI methods. These actions were often used in tandem. 16 of the 22 case examples reported using LDM where autonomy was given to local stakeholders to make decisions on adaptations for local fit within their setting. This occurred at varying levels within the system for example at provincial, regional, district, community, health facility levels, by frontline providers or the recipients themselves. The review was refined at this point to focus on developing theory on how and why LDM works for adaptations of health interventions during scale-up across diverse contexts.
Phase Three - Eight programme theories and an MRT were developed from the case examples which used LDM (n=16) on how and why LDM works for adaptations to health interventions when scaling-up These theories were further refined through interviews with key informants with experience in scale-up (n=6) and use of substantive theory. Multiple contexts such as: where the intervention does not align with the social norms, values and beliefs of the wider community or the local decision maker; where there is reliance on external funding and poor understanding of the intervention components from funders; and in resource limited settings where unavoidable adaptations may occur were all identified to impact how LDM works. These circumstances may lead to lead to intra- and person-role conflict for the local decision maker. Mechanisms at the level of the local decision maker of; perception of compatibility, awareness (i.e. of intervention theory), sensemaking, problem-solving, fear of repercussions, feeling valued and respected, were all found to contribute to how LDM works. The use of complementary actions such as provision of accessible guidance and support, for example on intervention components and on how to implement and adapt the specific intervention, can support local sites. Other complementary actions such as peer learning through sharing tried and tested examples from other scale-up sites, and using a data driven approach to inform and evaluate adaptations were suggested to support LDM by reducing the time needed for adaptations in later phases and contributing to buy-in from staff and the target population for the intervention.
Conclusion: Scale-up is complex, with the additional layer of making adaptations during scale-up further adding to this complexity. This research evidenced that adaptations are occurring in practice during scale-up of health interventions and has provided some guidance to implementers on actions that can be used for undertaking these adaptations. Implementers need to examine in advance what contextual challenges may occur in their setting (for example resource shortages, cultural conservatism etc.) that may lead to future adaptations and their potential impact on fidelity. This may assist implementers in considering whether adaptations are unavoidable, and in selecting what actions to embed into the scale-up plan. LDM is a promising approach for adaptations to health interventions during scale-up, however it occurs in complex systems, within a wider cultural and socioeconomic context, with varying levels of capacity, and often in tandem with numerous other approaches. While LDM may support those who know the setting to problem solve based on local knowledge leading to beneficial adaptations within their setting, it may also place local decision makers in a position of intra and person-role conflict leading to adaptations that impact the fidelity and effectiveness of the intervention. Therefore implementers need to consider the complexity of how LDM may work across the diverse contexts they encounter during scale-up.