Browsing by Author "Matchar, DB"
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Item Open Access Chapter 6: assessing applicability of medical test studies in systematic reviews.(Journal of general internal medicine, 2012-06) Hartmann, KE; Matchar, DB; Chang, SUse of medical tests should be guided by research evidence about the accuracy and utility of those tests in clinical care settings. Systematic reviews of the literature about medical tests must address applicability to real-world decision-making. Challenges for reviews include: (1) lack of clarity in key questions about the intended applicability of the review, (2) numerous studies in many populations and settings, (3) publications that provide too little information to assess applicability, (4) secular trends in prevalence and the spectrum of the condition for which the test is done, and (5) changes in the technology of the test itself. We describe principles for crafting reviews that meet these challenges and capture the key elements from the literature necessary to understand applicability.Item Open Access Estimating costs and benefits of stroke management: A population-based simulation model(Journal of the Operational Research Society, 2020-01-01) Bayer, S; Eom, K; Sivapragasam, N; Silva, DAD; Choon, G; Koh, H; Tan, KB; Ansah, JP; Matchar, DBThe paper demonstrates how a system dynamics approach can support strategic planning of health care services and can in particular help to balance cost-effectiveness considerations with budget impact considerations when assessing a comprehensive package of stroke care interventions in Singapore. A population-level system dynamics model is used to investigate 12 intervention scenarios based on six stroke interventions (a public information campaign, thrombolysis, endovascular therapy, acute stroke unit (ASU), out-of-hospital rehabilitation, and secondary prevention). Primary outcomes included cumulative discounted costs and quality-adjusted life years (QALYs) gained, as well as cumulative net monetary benefit by 2030. All intervention scenarios result in an increase in net monetary benefit by 2030; much of these gains were realized through improved post-acute care. Findings highlight the importance of coordination of care, and affirms the economic value of current stroke interventions.Item Open Access Executive summary: heart disease and stroke statistics-2015 update: a report from the american heart association.(Circulation, 2015-01) Mozaffarian, D; Benjamin, EJ; Go, AS; Arnett, DK; Blaha, MJ; Cushman, M; de Ferranti, S; Després, JP; Fullerton, HJ; Howard, VJ; Huffman, MD; Judd, SE; Kissela, BM; Lackland, DT; Lichtman, JH; Lisabeth, LD; Liu, S; Mackey, RH; Matchar, DB; McGuire, DK; Mohler, ER; Moy, CS; Muntner, P; Mussolino, ME; Nasir, K; Neumar, RW; Nichol, G; Palaniappan, L; Pandey, DK; Reeves, MJ; Rodriguez, CJ; Sorlie, PD; Stein, J; Towfighi, A; Turan, TN; Virani, SS; Willey, JZ; Woo, D; Yeh, RW; Turner, MBEach year, the American Heart Association (AHA), in conjunction with the Centers for Disease Control and Prevention, the National Institutes of Health, and other government agencies, brings together the most up-to-date statistics related to heart disease, stroke, and other cardiovascular and metabolic diseases and presents them in its Heart Disease and Stroke Statistical Update. The Statistical Update represents a critical resource for the lay public, policy makers, media professionals, clinicians, healthcare administrators, researchers, and others seeking the best available data on these conditions. Together, cardiovascular disease (CVD) and stroke produce immense health and economic burdens in the United States and globally. The Statistical Update brings together in a single document up-to-date information on the core health behaviors and health factors that define cardiovascular health; a range of major clinical disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, and peripheral arterial disease); and the associated outcomes (including quality of care, procedures, and economic costs). Since 2009, the annual versions of the Statistical Update have been cited >20 000 times in the literature. In 2014 alone, the various Statistical Updates were cited >5700 times. Each annual version of the Statistical Update undergoes major revisions to include the newest nationally representative data, add additional relevant published scientific findings, remove older information, add new sections or chapters, and increase the number of ways to access and use the assembled information. This year-long process, which begins as soon as the previous Statistical Update is published, is performed by the AHA Statistics Committee faculty volunteers and staff. For example, this year's edition includes a new chapter on cardiac arrest, new data on the monitoring and benefits of cardiovascular health in the population, additional information in many chapters on the global CVD and stroke burden, and further new focus on evidence-based approaches to changing behaviors, implementation strategies, and implications of the AHA's 2020 Impact Goals. Below are a few highlights from this year's Update.Item Open Access Geographic variation and trends in carotid imaging among medicare beneficiaries, 2001 to 2006.(Circulation. Cardiovascular quality and outcomes, 2010-11) Curtis, LH; Greiner, MA; Patel, MR; Duncan, PW; Schulman, KA; Matchar, DBBackground
Diagnostic imaging among Medicare beneficiaries is an important contributor to rising health care costs. We examined temporal trends and geographic variation in the use of carotid ultrasound, carotid magnetic resonance angiography (MRA), and carotid x-ray angiography.Methods and results
Analysis of a 5% national sample of claims from the Centers for Medicare and Medicaid Services for 1999 through 2006. Patients were 65 years or older and underwent carotid ultrasound, carotid MRA, carotid x-ray angiography, or a carotid intervention. The main outcome measures were annual age-adjusted rates of carotid imaging and interventions and factors associated with the use of carotid imaging. Rates of imaging increased by 27%, from 98.2 per 1000 person-years in 2001 to 124.3 per 1000 in 2006. Rates of carotid ultrasound increased by 23%, and rates of MRA increased by 66%. Carotid intervention rates decreased from 3.6 per 1000 person-years in 2001 to 3.1 per 1000 person-years in 2006. In 2006, rates of carotid ultrasound were lowest in the New England, Mountain, and West North Central regions and highest in the Middle Atlantic and South Atlantic regions. Regional differences persisted after adjustment for patient demographic characteristics, history of vascular disease and other comorbid conditions, and study year.Conclusions
From 2001 through 2006, there was substantial growth and variation in the use of carotid imaging, including a marked increase in the use of MRA, and a decrease in the overall rate of carotid intervention.Item Open Access Geographic variation in carotid revascularization among Medicare beneficiaries, 2003-2006.(Archives of internal medicine, 2010-07) Patel, MR; Greiner, MA; DiMartino, LD; Schulman, KA; Duncan, PW; Matchar, DB; Curtis, LHBackground
Little is known about patterns in the use of carotid revascularization since a 2004 Medicare national coverage decision supporting carotid artery stenting. We examined geographic variation in and predictors of carotid endarterectomy and carotid stenting.Methods
Analysis of claims from the Centers for Medicare & Medicaid Services from January 1, 2003, through December 31, 2006. Patients were 65 years or older and had undergone carotid endarterectomy or carotid stenting. The main outcome measures were annual age-adjusted rates of carotid endarterectomy and carotid stenting, factors associated with the use of carotid revascularization, and mortality rate at 30 days and 1 year.Results
The rate of endarterectomy decreased from 3.2 per 1000 person-years in 2003 to 2.6 per 1000 person-years in 2006. After adjustment for demographic and clinical characteristics, there was significant geographic variation in the odds of carotid revascularization, with the East North Central region having the greatest odds of endarterectomy (odds ratio, 1.60; 95% confidence interval, 1.55-1.65) and stenting (1.61; 1.46-1.78) compared with New England. Prior endarterectomy (odds ratio, 3.06; 95% confidence interval, 2.65-3.53) and coronary artery disease (2.12; 2.03-2.21) were strong predictors of carotid stenting. In 2005, mortality was 1.2% at 30 days and 6.8% at 1 year for endarterectomy and 2.3% at 30 days and 10.3% at 1 year for stenting.Conclusions
Significant geographic variation exists for carotid endarterectomy and carotid stenting. Prior endarterectomy and coronary disease were associated with greater odds of carotid stenting.Item Open Access Impact of the COVID-19 pandemic on a tertiary care public hospital in Singapore: resources and economic costs.(The Journal of hospital infection, 2021-12-11) Cai, Y; Kwek, S; Tang, SSL; Saffari, SE; Lum, E; Yoon, S; Ansah, JP; Matchar, DB; Kwa, AL; Ang, KA; Thumboo, J; Ong, MEH; Graves, NBackground
The COVID-19 pandemic has prompted hospitals to respond with stringent measures. Accurate estimates of costs and resources used in outbreaks can guide evaluations of responses. We report on the financial expenditure associated with COVID-19, the bed-days used for COVID-19 patients and hospital services displaced due to COVID-19 in a Singapore tertiary hospital.Methods
We conducted a retrospective cost analysis from January to December 2020 in the largest public hospital in Singapore. Costs were estimated from the hospital perspective. We examined financial expenditures made in direct response to COVID-19; hospital admissions data related to COVID-19 inpatients; and the number of outpatient and emergency department visits, non-emergency surgeries, inpatient days in 2020, compared with preceding years of 2018 and 2019. Bayesian time-series was used to estimate the magnitude of displaced services.Results
USD $41.96 million was incurred in the hospital for COVID-19-related expenses. Facilities set-up and capital assets accounted for 51.6% of the expenditure; patient-care supplies comprised 35.1%. Of the 19,611 inpatients tested for COVID-19 in 2020, 727 (3.7%) had COVID-19. The total inpatient- and intensive care unit (ICU)-days for COVID-19 patients in 2020 were 8009 and 8 days, respectively. A decline in all hospital services was observed from February following a raised disease outbreak alert level; most services quickly resumed when the lockdown was lifted in June.Conclusion
COVID-19 led to an increase in healthcare expenses and a displacement in hospital services. Our findings are useful for informing economic evaluations of COVID-19 response and provide some information about the expected costs of future outbreaks.Item Open Access Mapping the Dynamic Complexity of Chronic Disease Care in Singapore: Using Group Model Building in Knowledge Elicitation(Systems Research and Behavioral Science, 2018-11-01) Ansah, JP; Matchar, DB; Koh, V; Schoenenberger, LThis study describes a group model building exercise that aims to develop a deeper understanding of the dynamic complexity of chronic disease care delivery within a primary care setting in Singapore, leveraging on the insights of stakeholders with personal and institutional knowledge of the health care system. A group model building exercise, which included 50 stakeholders, was used to develop the qualitative model. The qualitative model helped to bring a feedback perspective to understanding the dynamic complexity of chronic disease care delivery. The feedback perspective helped in identifying the systemic issues within chronic disease care delivery, which has the potential to inform system-wide interventions and policies to improve health. Enhancing chronic care in Singapore will require an enhancement of both the capacity and capability of the primary care sector. © 2018 John Wiley & Sons, Ltd.Item Open Access Modeling manpower requirement for a changing population health needs: The case of ophthalmic nurses and allied health ophthalmic professionals(Health Policy and Technology, 2019-09-01) Ansah, JP; Koh, V; De Korne, D; Jayabaskar, T; Matchar, DB; Quek, DBackground: Prevalence of chronic eye conditions has been shown to increase with age. As the global population continues to age rapidly, the demand for eye care services is expected to increase significantly in the near future, requiring effective health workforce planning in order to provide for the needs of the population. The aim of this paper is to synthesize data from a variety of sources to develop a simulation model based on the systems modelling methodology of system dynamics that links population health needs to workforce requirements to generate evidence-based projections for ophthalmic nurses, and allied health ophthalmic professionals in Singapore. Methods: A system dynamics simulation model was developed with active engagement of key stakeholders—such as ophthalmologists, senior nurses, healthcare planners and managers, and senior technicians—to verify the model structure and assumptions. The model project the future requirement of ophthalmic nurses, technicians and patient service assistants. Results: The number of Singaporeans with eye diseases is projected to more than double by 2040. As a result, the demand for eye care services and eye care workforce is expected to increase significantly under all the plausible scenarios. The increase in eye disease burden is due mainly to population aging—given that the prevalence of eye disease increases with age. Conclusion: This research provides a future demand outlook for ophthalmic nurses, technicians and patient service assistants in Singapore and has implications for recruitment and training of ophthalmic nurses and allied health professionals in Singapore.Item Open Access Modeling to inform long-term care policy and planning for an aging society(2017-01-01) Ansah, JP; Koh, V; Qureshi, MA; Matchar, DBDemographic changes such as increasing longevity, declining family sizes, and increasing female participation in the labor market have implications for long-term care (LTC) planning for the elderly. As the population in both developed and developing world ages, the prevalence of health conditions such as chronic diseases and disabilities increases. Consequently, the proportion of elderly adults who require assistance with their daily activities rises. Further, the potential decrease in family members available as caregivers implies an increase in the demand for alternative LTC arrangements. Planning of LTC services is fraught with dynamic complexities. Various issues, such as projecting future need, cost, capacity, and quality of care and caregivers—formal and informal—can influence the effectiveness and efficiency of LTC services. The trends outlined point to the need for a comprehensive LTC planning that accounts for all these dynamics changes. This chapter aims to demonstrate the use of simulation modeling as a communication tool that allows for the LTC complexity to be reduced to its essential elements to inform policy for an aging society. The forms of simulation techniques used in the planning of LTC policy and services and real-world applications across different institutional contexts are discussed. Of particular focus is the application of the system dynamics methodology in LTC planning. Three LTC projects using system dynamics methodology are presented. Specifically, these LTC projects comprise the methodological process in the projection of the number of disabled elderly in Singapore accounting for changing educational attainment, the impact of various LTC policies on informal eldercare hours and labor force participation of informal caregivers, and the impact of LTC capacity expansion policies on acute care.Item Open Access PCV26 Lifetime Cost-Effectiveness Analysis of Ticagrelor in Patients With Acute Coronary Syndromes Based on the Plato Trial: A Singapore Health Care Perspective(Value in Health, 2012-11) Chin, CT; Mellström, C; Chua, TS; Matchar, DBItem Open Access Pre-discharge prognostic factors of physical function among older adults with hip fracture surgery: a systematic review.(Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA, 2019-05) Lim, KK; Matchar, DB; Chong, JL; Yeo, W; Howe, TS; Koh, JSBIntroduction
To identify, organize, and assess the evidence level of pre-discharge prognostic factors of physical function beyond discharge after hip fracture surgery.Methods
We performed a systematic search of four databases (PubMed, Embase, CINAHL, PsycINFO) for longitudinal studies of prognostic factors of physical function at ≥ 1 month among older adults ≥ 50 years old with surgically treated hip fracture, complemented with hand-searching. Two reviewers independently screened papers for inclusion and assessed the quality of all the included papers using the Quality in Prognosis Studies (QUIPS) tool. We assigned the evidence level for each prognostic factor based on consistency in findings and study quality.Results
From 98 papers that met our inclusion criteria, we identified 107 pre-discharge prognostic factors and organized them into the following seven categories: demographic, physical, cognitive, psychosocial, socioeconomic, injury-related, and process of care. Potentially modifiable factors with strong or moderate evidence of an association included total length of stay, physical function at discharge, and grip strength. Factors with strong or moderate evidence of no association included gender, fracture type, and time to surgery. Factors with limited, conflicting, or inconclusive evidence included body-mass index, psychological resilience, depression, and anxiety.Conclusions
Our findings highlight potentially modifiable prognostic factors that could be targeted and non-modifiable prognostic factors that could be used to identify patients who may benefit from more intensive intervention or to advise patients on their expectations on recovery. Examining the efficacies of existing interventions targeting these prognostic factors would inform future studies and whether any of such interventions could be incorporated into clinical practice.Item Open Access Projecting the Number of Elderly with Cognitive Impairment in China Using a Multi-State Dynamic Population Model(System Dynamics Review, 2017-04-01) Ansah, JP; Koh, V; Chiu, CT; Chei, CL; Zeng, Y; Yin, ZX; Shi, XM; Matchar, DBChina is aging rapidly, and the number of Chinese elderly with dementia is expected to rise. This paper projects, up to year 2060, the number of Chinese elderly within four distinct cognitive states. A multi-state population model was developed using system dynamics and parametrized with age–gender-specific transition rates (between intact, mild, moderate and severe cognitive impairment and death) estimated from two waves (2012 and 2014) of a community-based cohort of elderly in China aged ≥65 years (N = 1824). Probabilistic sensitivity analysis and the bootstrap method was used to obtain the 95% confidence interval of the transition rates. The number of elderly with any degree of cognitive impairment increases; with severe cognitive impairment increasing the most, at 698%. Among elderly with cognitive impairment, the proportion of very old elderly (age ≥ 80) is expected to rise from 53% to 78% by 2060. This will affect the demand for social and health services China. Copyright © 2017 System Dynamics Society.Item Open Access Serum cholesterol levels within the high normal range are associated with better cognitive performance among Chinese elderly(Journal of Nutrition, Health and Aging, 2016-03-01) Lv, Y-B; Yin, ZX; Chei, C-L; Brasher, MS; Zhang, J; Kraus, VB; Qian, F; Shi, X-M; Matchar, DB; Zeng, Y© 2016, Serdi and Springer-Verlag France.Objectives: The association between cognitive function and cholesterol levels is poorly understood and inconsistent results exist among the elderly. The purpose of this study is to investigate the association of cholesterol level with cognitive performance among Chinese elderly. Design: A cross-sectional study was implemented in 2012 and data were analyzed using generalized additive models, linear regression models and logistic regression models. Setting: Community-based setting in eight longevity areas in China. Subjects: A total of 2000 elderly aged 65 years and over (mean 85.8±12.0 years) participated in this study. Measurements: Total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) concentration were determined and cognitive impairment was defined as Mini-Mental State Examination (MMSE) score≤23. Results: There was a significant positive linear association between TC, TG, LDL-C, HDL-C and MMSE score in linear regression models. Each 1 mmol/L increase in TC, TG, LDL-C and HDL-C corresponded to a decreased risk of cognitive impairment in logistic regression models. Compared with the lowest tertile, the highest tertile of TC, LDL-C and HDL-C had a lower risk of cognitive impairment. The adjusted odds ratios and 95% CI were 0.73(0.62–0.84) for TC, 0.81(0.70–0.94) for LDL-C and 0.81(0.70–0.94) for HDL-C. There was no gender difference in the protective effects of high TC and LDL-C levels on cognitive impairment. However, for high HDL-C levels the effect was only observed in women. High TC, LDL-C and HDL-C levels were associated with lower risk of cognitive impairment in the oldest old (aged 80 and older), but not in the younger elderly (aged 65 to 79 years). Conclusions: These findings suggest that cholesterol levels within the high normal range are associated with better cognitive performance in Chinese elderly, specifically in the oldest old. With further validation, low cholesterol may serve a clinical indicator of risk for cognitive impairment in the elderly.Item Open Access Serum cholesterol levels within the high normal range are associated with better cognitive performance among Chinese elderly(Journal of Nutrition, Health and Aging, 2016-03-01) Lv, YB; Yin, ZX; Chei, CL; Brasher, MS; Zhang, J; Kraus, VB; Qian, F; Shi, X; Matchar, DB; Zeng, YObjectives: The association between cognitive function and cholesterol levels is poorly understood and inconsistent results exist among the elderly. The purpose of this study is to investigate the association of cholesterol level with cognitive performance among Chinese elderly. Design: A cross-sectional study was implemented in 2012 and data were analyzed using generalized additive models, linear regression models and logistic regression models. Setting: Community-based setting in eight longevity areas in China. Subjects: A total of 2000 elderly aged 65 years and over (mean 85.8±12.0 years) participated in this study. Measurements: Total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) concentration were determined and cognitive impairment was defined as Mini-Mental State Examination (MMSE) score≤23. Results: There was a significant positive linear association between TC, TG, LDL-C, HDL-C and MMSE score in linear regression models. Each 1 mmol/L increase in TC, TG, LDL-C and HDL-C corresponded to a decreased risk of cognitive impairment in logistic regression models. Compared with the lowest tertile, the highest tertile of TC, LDL-C and HDL-C had a lower risk of cognitive impairment. The adjusted odds ratios and 95% CI were 0.73(0.62–0.84) for TC, 0.81(0.70–0.94) for LDL-C and 0.81(0.70–0.94) for HDL-C. There was no gender difference in the protective effects of high TC and LDL-C levels on cognitive impairment. However, for high HDL-C levels the effect was only observed in women. High TC, LDL-C and HDL-C levels were associated with lower risk of cognitive impairment in the oldest old (aged 80 and older), but not in the younger elderly (aged 65 to 79 years). Conclusions: These findings suggest that cholesterol levels within the high normal range are associated with better cognitive performance in Chinese elderly, specifically in the oldest old. With further validation, low cholesterol may serve a clinical indicator of risk for cognitive impairment in the elderly.Item Open Access The impact of population dynamics and foreign labour policy on dependency: the case of Singapore(Journal of Population Research, 2015-06-15) Ansah, JP; Riley, CM; Thompson, JP; Matchar, DBUnderstanding population dynamics is crucial to understanding current and future health care needs and designing systems to meet those needs. In this paper, we provide a methodological approach to investigate population dynamics in a system dynamics model configurable to initialise in dynamic equilibrium or disequilibrium. We then use the model to investigate how the current measured population compares to a population of the same size in equilibrium, and how a dependency ratio will change over time under different scenarios. We apply our approach to Singapore, which, like many other countries, has a rapidly increasing proportion of elderly in the population.Item Open Access The role of primary care in the dynamics of a health system(Proceedings of Singapore Healthcare, 2018-06-01) Matchar, DB; Car, J; Koh, GCHItem Open Access Using Cost-Effectiveness Analysis in Mixed Methods Research: An Evaluation of an Integrated Care Program for Frequently Hospitalized Older Adults in Singapore(Journal of Mixed Methods Research, 2020-04-01) Penkunas, MJ; Matchar, DB; Wong, CH; Liu, C; Chan, AWMTraditional evaluation techniques are often not suitable for studying health interventions operating in real-world settings, particularly when interventions operate through complex causal pathways. We describe a mixed methods design for evaluating an integrated home care and social support service targeting mature and older adults (55+ years) in Singapore. Here, nurses and community health workers visit patients’ homes to address health and social needs while facilitating linkages to community-based services and providing caregiver support. Our mixed methods evaluation plan is composed of three components: quantitative comparison of hospital-based service utilization, cost-effectiveness analysis, and qualitative investigation into the experiences of patients, caregivers, and individuals who declined services. This article contributes a description of how cost-effectiveness analysis adds value when incorporated into mixed methods studies.Item Open Access Viewing the Role of Alternate Care Service Pathways in the Emergency Care System through a Causal Loop Diagram Lens(Systems) Kumar, A; Liu, Z; Ansah, JP; Ng, YY; Leong, BSH; Matchar, DB; Ong, MEH; Siddiqui, FJGlobally, Emergency Care Systems (ECS) are a critical resource that needs to be used judiciously as demand can easily exceed supply capacity. Sub-optimal ECS use contributes to Emergency Department (ED) crowding; this adversely affects ECS as well as system-wide service performance. Alternate Care Service Pathways (ACSPs) are innovations intended to mitigate ED crowding by re-routing less-urgent cases to sites of care other than the ED. As in other countries, policymakers in Singapore need to respond to increasing ED utilization and are evaluating the introduction of ACSPs. However, developing ACSPs is costly, entails tinkering with established critical services, and runs the risk of unintended adverse consequences. Through a Causal Loop Diagram (CLD) developed in four stages, we present a view of the current Singapore ECS and the intended role of ACSPs in relieving its stress. This exercise suggests that to be successful ACSPs must change the prevailing mental model of the ED as a “one-stop shop” but should focus on integrating with primary care. The discussions stimulated by the development, critiquing, and revision of the CLD highlighted the importance of accounting for the reservations of stakeholders for changes. The CLD has enhanced shared understanding and will be used to guide quantitative simulation modeling to promote informed policy.