Systems, design and value-for-money in the NHS: mission impossible?

NHS organisations are being challenged to transform themselves sustainably in the face of increasing demands, but they have little room for error. To manage trade-offs and risks precisely, they must integrate two very different streams of expertise: systems approaches to service design and implementation, and economic evaluation of the type pioneered by the National Institute of Health and Care Excellence (NICE) for pharmaceuticals and interventions. Neither approach is fully embedded in NHS service transformation, while the combination as an integrated discipline is still some way away. We share three examples to show how design methods may be deployed within a value-for-money framework to plan operationally and in terms of clinical outcomes. They are real cases briefl y described and the unreferenced ones are anonymised. They have been selected by one of the authors (TY) during his sabbatical research because each illustrates a commonly observed challenge. To meet these challenges, we argue that the health economics cost / quality-adjusted life year (QALY) framework promulgated by NICE provides an under-appreciated lens for thinking about trade-offs and we highlight some systems tools which have also been underutilised in this context

Cost-Effectiveness of HIV Screening in STD Clinics, Emergency Departments, and Inpatient Units: A Model-Based Analysis

Identifying and treating persons with human immunodeficiency virus (HIV) infection early in their disease stage is considered an effective means of reducing the impact of the disease. We compared the cost-effectiveness of HIV screening in three settings, sexually transmitted disease (STD) clinics serving men who have sex with men, hospital emergency departments (EDs), settings where patients are likely to be diagnosed early, and inpatient diagnosis based on clinical manifestations.We developed the Progression and Transmission of HIV/AIDS model, a health state transition model that tracks index patients and their infected partners from HIV infection to death. We used program characteristics for each setting to compare the incremental cost per quality-adjusted life year gained from early versus late diagnosis and treatment. We ran the model for 10,000 index patients for each setting, examining alternative scenarios, excluding and including transmission to partners, and assuming HAART was initiated at a CD4 count of either 350 or 500 cells/µL. Screening in STD clinics and EDs was cost-effective compared with diagnosing inpatients, even when including only the benefits to the index patients. Screening patients in STD clinics, who have less-advanced disease, was cost-effective compared with ED screening when treatment with HAART was initiated at a CD4 count of 500 cells/µL. When the benefits of reduced transmission to partners from early diagnosis were included, screening in settings with less-advanced disease stages was cost-saving compared with screening later in the course of infection. The study was limited by a small number of observations on CD4 count at diagnosis and by including transmission only to first generation partners of the index patients.HIV prevention efforts can be advanced by screening in settings where patients present with less-advanced stages of HIV infection and by initiating treatment with HAART earlier in the course of infection

Cost-Effectiveness of Male Circumcision for HIV Prevention in a South African Setting

BACKGROUND: Consistent with observational studies, a randomized controlled intervention trial of adult male circumcision (MC) conducted in the general population in Orange Farm (OF) (Gauteng Province, South Africa) demonstrated a protective effect against HIV acquisition of 60%. The objective of this study is to present the first cost-effectiveness analysis of the use of MC as an intervention to reduce the spread of HIV in sub-Saharan Africa. METHODS AND FINDINGS: Cost-effectiveness was modeled for 1,000 MCs done within a general adult male population. Intervention costs included performing MC and treatment of adverse events. HIV prevalence was estimated from published estimates and incidence among susceptible subjects calculated assuming a steady-state epidemic. Effectiveness was defined as the number of HIV infections averted (HIA), which was estimated by dynamically projecting over 20 years the reduction in HIV incidence observed in the OF trial, including secondary transmission to women. Net savings were calculated with adjustment for the averted lifetime duration cost of HIV treatment. Sensitivity analyses examined the effects of input uncertainty and program coverage. All results were discounted to the present at 3% per year. For Gauteng Province, assuming full coverage of the MC intervention, with a 2005 adult male prevalence of 25.6%, 1,000 circumcisions would avert an estimated 308 (80% CI 189–428) infections over 20 years. The cost is $181 (80$117–$306) per HIA, and net savings are$2.4 million (80% CI $1.3 million to$3.6 million). Cost-effectiveness is sensitive to the costs of MC and of averted HIV treatment, the protective effect of MC, and HIV prevalence. With an HIV prevalence of 8.4%, the cost per HIA is $551 (80$344–$1,071) and net savings are$753,000 (80% CI $0.3 million to$1.2 million). Cost-effectiveness improves by less than 10% when MC intervention coverage is 50% of full coverage. CONCLUSIONS: In settings in sub-Saharan Africa with high or moderate HIV prevalence among the general population, adult MC is likely to be a cost-effective HIV prevention strategy, even when it has a low coverage. MC generates large net savings after adjustment for averted HIV medical costs

WHO 2010 Guidelines for Prevention of Mother-to-Child HIV Transmission in Zimbabwe: Modeling Clinical Outcomes in Infants and Mothers

The Zimbabwean national prevention of mother-to-child HIV transmission (PMTCT) program provided primarily single-dose nevirapine (sdNVP) from 2002-2009 and is currently replacing sdNVP with more effective antiretroviral (ARV) regimens.Published HIV and PMTCT models, with local trial and programmatic data, were used to simulate a cohort of HIV-infected, pregnant/breastfeeding women in Zimbabwe (mean age 24.0 years, mean CD4 451 cells/µL). We compared five PMTCT regimens at a fixed level of PMTCT medication uptake: 1) no antenatal ARVs (comparator); 2) sdNVP; 3) WHO 2010 guidelines using "Option A" (zidovudine during pregnancy/infant NVP during breastfeeding for women without advanced HIV disease; lifelong 3-drug antiretroviral therapy (ART) for women with advanced disease); 4) WHO "Option B" (ART during pregnancy/breastfeeding without advanced disease; lifelong ART with advanced disease); and 5) "Option B+:" lifelong ART for all pregnant/breastfeeding, HIV-infected women. Pediatric (4-6 week and 18-month infection risk, 2-year survival) and maternal (2- and 5-year survival, life expectancy from delivery) outcomes were projected.Eighteen-month pediatric infection risks ranged from 25.8% (no antenatal ARVs) to 10.9% (Options B/B+). Although maternal short-term outcomes (2- and 5-year survival) varied only slightly by regimen, maternal life expectancy was reduced after receipt of sdNVP (13.8 years) or Option B (13.9 years) compared to no antenatal ARVs (14.0 years), Option A (14.0 years), or Option B+ (14.5 years).Replacement of sdNVP with currently recommended regimens for PMTCT (WHO Options A, B, or B+) is necessary to reduce infant HIV infection risk in Zimbabwe. The planned transition to Option A may also improve both pediatric and maternal outcomes

ASSESSING THE VALUE OF MODELING AND SIMULATION IN HEALTH CARE: AN EXAMPLE BASED ON INCREASING ACCESS TO STROKE TREATMENT

The use of modelling and simulation (M&S) to design, operate and troubleshoot care delivery processes has not been the subject of economic evaluation, so we undertake such an analysis of a modelling exercise to design better delivery: in this case, stroke care. First, the financial impact is assessed, followed by a cost-effectiveness analysis in which the clinical impact is also assessed. Because it is not usually possible to obtain all the costs of modelling, probabilistic sensitivity and threshold analyses are used to explore the uncertainties in the absence of complete information. Threshold analysis is then applied to calculate the upper bound cost and the level of service improvement that would be needed for M&S to represent good value for money

Microbial risk models designed to inform water treatment policy decisions.

Chemical risk assessments often focus on measuring exposure as if individuals were subject only to exogenous environmental sources of risk. They also presume that the infection outcomes are independent. For infectious diseases, exposure might not only depend on exogenous sources of microbes, but also on the infection status of other individuals in the population. For example, waterborne agents such as Cryptosporidium parvum and Escherichia coli : O157:H7 might be transmitted from contaminated water to humans through drinking water, from interpersonal contact, or from infected individuals to the environment and back to other susceptible individuals. These multiple pathways and the dependency of exposure on the prevalence of infection in a population suggest that epidemiological models are required to complement standard risk assessments in order to quantify the risk of infection. This dissertation presents models of infection transmission systems that are being developed for the U.S. Environmental Protection Agency as part of a project to quantify the risk of microbial infection. The first part of the dissertation presents de terministic infection transmission models for both homogeneous and heterogeneous populations. The models include infection transmission routes from direct exposure to contamination and from both secondary transmissions (human-human and human-environment-human loops). They are designed to help inform water treatment system decisions. This work shows that the best policy depends on the values of model parameters, including the secondary transmission rate, probability of infection, rate of contamination by exogenous environmental sources and the HIV prevalence. Here it is shown that assessments of water treatment benefits can be misleading if secondary transmission is not properly included in the risk assessment. In addition, a threshold parameter that says whether or not a waterborne infection can remain endemic in a population is derived. The second part of the dissertation develops analogous stochastic infection transmission models including all transmission routes presented in the deterministic models. Since some key secondary transmission parameters influencing water treatment policy are typically unknown, methods to infer these parameters are proposed. We use Bayesian methods and approximations to stationary distributions of prevalence. Data from both simulations and New York City, indicate that otherwise unobservable parameters can be inferred with these techniques. Most importantly, secondary transmission parameters can be inferred from endemic data, without the outbreak data needed by some other approaches. We also simulate the stochastic infection transmissions in a heterogeneous population and study effects of contact patterns on the endemic prevalence. Mixing patterns are shown to affect endemic levels, and indicate areas for further research.Ph.D.Applied SciencesBiological SciencesEngineering, Sanitary and MunicipalHealth and Environmental SciencesMicrobiologyOperations researchPublic healthUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/123286/2/3068970.pd

Evaluating the financial impact of modeling and simulation in healthcare: Proposed framework with a case study

Modeling and simulation have been widely used in health economics and health technology assessment for estimating long-term costs and benefits of health interventions. However, the implementation of simulation in the organizational planning of healthcare delivery is still limited and has not yet received the same level of engagement as it has in other industries. The purpose of this paper is to propose an analytic framework to quantify the value of modeling and simulation, so that the benefits can be evaluated more objectively by the healthcare stakeholders and can be compared across a broad range of health innovations. The application of the framework is illustrated in a case study of acute care for Ischemic stroke. Although the value of modeling and simulation can be measured in various forms, depending on the perspectives of stakeholders, this paper initially focuses on the financial value and takes the perspective of administrators who need to plan and manage health-care budgets

Inferring Infection Transmission Parameters That Influence Water Treatment Decisions

One charge of the United States Environmental Protection Agency is to study the risk of infection for microbial agents that can be disseminated through drinking water systems, and to recommend water treatment policy to counter that risk. Recently proposed dynamical system models quantify indirect risks due to secondary transmission, in addition to primary infection risk from the water supply considered by standard assessments. Unfortunately, key parameters that influence water treatment policy are unknown, in part because of lack of data and effective inference methods. This paper develops inference methods for those parameters by using stochastic process models to better incorporate infection dynamics into the inference process. Our use of endemic data provides an alternative to waiting for, identifying, and measuring an outbreak. Data both from simulations and from New York City illustrate the approach.Stochastic Infection Modeling, Water Treatment Policy, Public Health Policy, Bayesian Inference, Risk Dynamics