Economic evaluation using decision analytical modelling : design, conduct, analysis, and reporting

Economic evaluations are increasingly conducted alongside randomised controlled trials, providing researchers with individual patient data to estimate cost effectiveness. However, randomised trials do not always provide a sufficient basis for economic evaluations used to inform regulatory and reimbursement decisions. For example, a single trial might not compare all the available options, provide evidence on all relevant inputs, or be conducted over a long enough time to capture differences in economic outcomes (or even measure those outcomes). In addition, reliance on a single trial may mean ignoring evidence from other trials, meta-analyses, and observational studies. Under these circumstances, decision analytical modelling provides an alternative framework for economic evaluation. Decision analytical modelling compares the expected costs and consequences of decision options by synthesising information from multiple sources and applying mathematical techniques, usually with computer software. The aim is to provide decision makers with the best available evidence to reach a decision—for example, should a new drug be adopted? Following on from our article on trial based economic evaluations, we outline issues relating to the design, conduct, analysis, and reporting of economic evaluations using decision analytical modelling

Child death in high-income countries

Although high income countries have made substantial progress towards reducing child mortality over recent decades, rates vary markedly between and within countries, and modifiable factors continue to be identified in many deaths. A series of three articles in The Lancet has described the epidemiology of child mortality and a standardised approach to child death reviews in high income countries. Patterns of child mortality at different ages are delineated into five broad categories: perinatal, congenital, acquired natural, external, and unexplained; while contributory factors are described across four broad domains: factors intrinsic to the child, the physical environment, the social environment, and service delivery. This commentary attempts to draw on the conclusions of these three articles and make practical recommendations on strategies in three key areas with perhaps the greatest potential to further reduce child mortality in high income countries: perinatal conditions, particularly preterm birth; acquired natural conditions, such as sepsis or acute respiratory problems; and external causes, including road traffic fatalities

Epidemiological trends and risk factors for tobacco, alcohol and drug use among adolescents in Scotland, 2002–13

Background This study estimates trends in prevalence, and patterns, of individual and multiple substance use between 2002 and 2013 amongst adolescents in Scotland. Methods The study uses data from 134 387 participants of the biennial national ‘Scottish Schools Adolescent Lifestyle and Substance Use Survey’ on smoking, alcohol and illicit drug use. Current regular use and current heavy use of smoking, alcohol, illicit drugs and multiple substances was measured. Time trends in the prevalence of each outcome were estimated using univariate and multivariate logistic regression. Results Regular smoking, alcohol, illicit drug and multiple substance use declined significantly amongst adolescents in Scotland. However, multivariate analyses that focussed upon high-risk levels of these behaviours revealed an upward linear trend in heavy alcohol (OR = 1.06; 95% CI: 1.04, 1.07) and heavy illicit drug (OR = 1.04; 95% CI: 1.00, 1.08) use (P < 0.05). Non-white pupils were more likely to be involved in individual and multiple substance use than ethnically white British pupils. In comparison to pupils from the least deprived socioeconomic quintile, pupils from the most deprived quintile had increased odds of 1.41 (95% CI: 1.02, 1.97; P < 0.05) and 1.62 (95% CI: 1.14, 2.29; P < 0.05) of being regular and heavy multiple substance users, respectively. Conclusions Further effort is required to tackle heavy alcohol and heavy illicit drug use amongst adolescents in Scotland. Prevention strategies should be informed by the risk profiles of substance misusers and evidence around the clinical and cost-effectiveness of preventive interventions

Examining QALY's : analysing the use of quality adjusted life years in the allocation of health care resources

This thesis examines the use quality adjusted life years (QALY'S) in the allocation of health care resources. It is divided into three broad sections. The first section discusses how health status measurement techniques can be used to derive the utility values incorporated into QALY'S. The second section uses one health status measurement instrument, the Rosser-Kind Classification of Illness States, to estimate the QALY'S gained by patients who have undergone hip and knee joint replacement surgery. It is shown that the Rosser-Kind Classification of Illness States is as effective in measuring the health-related quality of life of these patients as more detailed questionnaires. In addition, it is found that further research is required before any generalisations concerning the acceptability of retrospective data can be made. A third important result is that there are significant improvements in health- related quality of life following both types of surgery, with the highest Rosser- Kind rating scores achieved after the first year following knee replacement surgery and after the second year following hip replacement surgery. The third section of the thesis performs an extensive sensitivity analysis on the widely-quoted cost utility estimates for seven medical procedures, calculated by Gudex (1986). The estimates are shown to be sensitive to Gudex's conversion of health outcome data into the Rosser-Kind Classification, her assumptions concerning the survival period / life expectancy following each of the medical procedures and the selected discount rate. A more in depth analysis is then performed on the cost utility estimate for one of the seven procedures, ceftazidime treatment of cystic fibrosis. It is demonstrated that the health outcome and cost assumptions underlying the cost utility estimate for this procedure are not supported by the medical literature. Finally, the thesis raises a number of issues for discussion

Self-reported health and socio-economic inequalities in England, 1996–2009 : repeated national cross-sectional study

Tackling social inequalities in health has been a priority for recent UK governments. We used repeated national cross-sectional data for 155,311 participants (aged ≥16 years) in the Health Survey of England to examine trends in socio-economic inequalities in self-reported health over a recent period of sustained policy focus by successive UK governments aimed at tackling social inequalities in health. Socio-economic related inequalities in self-reported health were estimated using the Registrar General's occupational classification (1996–2009), and for sensitivity analyses, the National Statistics Socio-Economic Classification (NS-SEC; 2001–2011). Multi-level regression was used to evaluate time trends in General Health Questionnaire (GHQ-12) scores and bad or very bad self-assessed health (SAH), as well as EQ-5D utility scores. The study found that the probability of reporting GHQ-12 scores ≥4 and ≥ 1 was higher in those from lower social classes, and decreased for all social classes between 1997 and 2009. For SAH, the probability of reporting bad or very bad health remained relatively constant for social class I (professional) [0.028 (95%CI: 0.026, 0.029) in 1996 compared to 0.028 (95%CI: 0.024, 0.032) in 2009], but increased in lower social classes, with the greatest increase observed amongst those in social class V (unskilled manual) [0.089 (95%CI: 0.085, 0.093) in 1996 compared to 0.155 (95%CI: 0.141, 0.168) in 2009]. EQ-5D utility scores were lower for those in lower social classes, but remained comparable across survey years. In sensitivity analyses using the NS-SEC, health outcomes improved from 2001 to 2011, with no evidence of widening socio-economic inequalities. Our findings suggest that socio-economic inequalities have persisted, with evidence of widening for some adverse self-reported health outcomes

The economic consequences of preterm birth : a systematic review of the recent (2009-2017) literature

Abstract Background Despite extensive knowledge on the functional, neurodevelopmental, behavioural and educational sequelae of preterm birth, relatively little is known about its economic consequences. Objective To systematically review evidence around the economic consequences of preterm birth for the health services, for other sectors of the economy, for families and carers, and more broadly for society. Methods Updating previous reviews, systematic searches of Medline, EconLit, Web of Science, the Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, Embase and Scopus were performed using broad search terms, covering the literature from 1 January 2009 to 28 June 2017. Studies reporting economic consequences, published in the English language and conducted in a developed country were included. Economic consequences are presented in a descriptive manner according to study time horizon, cost category and differential denominators (live births or survivors). Results Of 4384 unique articles retrieved, 43 articles met the inclusion criteria. Of these, 27 reported resource use or cost estimates associated with the initial period of hospitalisation, while 26 reported resource use or costs incurred following the initial hospital discharge, 10 of which also reported resource use or costs associated with the initial period of hospitalisation. Only two studies reported resource use or costs incurred throughout the childhood years. Initial hospitalisation costs varied between $576 972 (range$111 152–$576 972) per infant born at 24 weeks’ gestation and$930 (range $930–$7114) per infant born at term (US$, 2015 prices). The review also revealed a consistent inverse association between gestational age at birth and economic costs regardless of date of publication, country of publication, underpinning study design, follow-up period, age of assessment or costing approach, and a paucity of evidence on non-healthcare costs. Several categories of economic costs, such as additional costs borne by families as a result of modifications to their everyday activities, are largely overlooked by this body of literature. Moreover, the number and coverage of economic assessments have not increased in comparison with previous review periods. Conclusion Evidence identified by this review can be used to inform clinical and budgetary service planning and act as data inputs into future economic evaluations of preventive or treatment interventions. Future research should focus particularly on valuing the economic consequences of preterm birth in adulthood

Cost effectiveness of HPV Vaccination : a systematic review of modelling approaches

Background A large number of economic evaluations have been published that assess alternative possible human papillomavirus (HPV) vaccination strategies. Understanding differences in the modelling methodologies used in these studies is important to assess the accuracy, comparability and generalisability of their results. Objectives The aim of this review was to identify published economic models of HPV vaccination programmes and understand how characteristics of these studies vary by geographical area, date of publication and the policy question being addressed. Methods We performed literature searches in MEDLINE, Embase, Econlit, The Health Economic Evaluations Database (HEED) and The National Health Service Economic Evaluation Database (NHS EED). From the 1189 unique studies retrieved, 65 studies were included for data extraction based on a priori eligibility criteria. Two authors independently reviewed these articles to determine eligibility for the final review. Data were extracted from the selected studies, focussing on six key structural or methodological themes covering different aspects of the model(s) used that may influence cost-effectiveness results. Results More recently published studies tend to model a larger number of HPV strains, and include a larger number of HPV-associated diseases. Studies published in Europe and North America also tend to include a larger number of diseases and are more likely to incorporate the impact of herd immunity and to use more realistic assumptions around vaccine efficacy and coverage. Studies based on previous models often do not include sufficiently robust justifications as to the applicability of the adapted model to the new context. Conclusions The considerable between-study heterogeneity in economic evaluations of HPV vaccination programmes makes comparisons between studies difficult, as observed differences in cost effectiveness may be driven by differences in methodology as well as by variations in funding and delivery models and estimates of model parameters. Studies should consistently report not only all simplifying assumptions made but also the estimated impact of these assumptions on the cost-effectiveness results

Psychometric properties of Patient Reported Outcome Measures (PROMs) in patients diagnosed with Acute Respiratory Distress Syndrome (ARDS)

Background The aim of this study was to assess the psychometric properties of the EQ-5D-3 L, the SF-12 v2 and its preference based derivative the SF-6D, and the St Georges Respiratory Questionnaire (SGRQ), in patients diagnosed with Acute Respiratory Distress Syndrome (ARDS). Methods Data from the Oscillation in ARDS (OSCAR) randomised unblinded clinical trial of 795 patients diagnosed with ARDS provided the foundation of this secondary psychometric analysis. The three source patient reported outcome measures (PROMs) (EQ-5D-3 L, SF-12 and SGRQ) were collected at both 6 and 12 months post randomisation. All measures were tested for acceptability, reliability, internal consistency, validity and responsiveness. Data from responders at 6 months was used to test for acceptability, reliability, known groups validity and internal responsiveness. Data from patients who responded at both 6 and 12 months was used to test for convergent validity and external responsiveness. Results Rates of response at both 6 and 12 months post randomisation were 89.88 % for the EQ-5D-3 L, 77.38 % for the SF-6D, 71.43 % for both the physical and mental components of the SF-12 and 38.10 % for the SGRQ. All measures had a Cronbach’s Alpha statistic higher than 0.7. For known group’s validity, there was no difference in mean summary or utility scores between known groups for all PROMs with minimal effect sizes. All three source measures showed strong convergent and discriminant validity. There was consistent evidence that the SF-6D is an empirically valid and efficient alternative to the EQ-5D-3 L. The EQ-5D-3 L and SGRQ were more responsive compared to the SF-12 and SF-6D with the EQ-5D-3 L generating greater effect sizes than the SGRQ. Conclusion The PROMs explored in this study displayed varying psychometric properties in the context of ARDS. Further research should focus on shortening the SGRQ whilst still maintaining its psychometric properties and mapping between the SGRQ and preference-based measures for future application within economic evaluations of respiratory focused interventions. The selection ofa preferred PROM for evaluative studies within the ARDS context should ultimately depend on the relative importance placed on individual psychometric properties and the importance placed on generation of health utilities for economic evaluation purposes

A computational model for path loss in wireless sensor networks in orchard environments.

A computational model for radio wave propagation through tree orchards is presented. Trees are modeled as collections of branches, geometrically approximated by cylinders, whose dimensions are determined on the basis of measurements in a cherry orchard. Tree canopies are modeled as dielectric spheres of appropriate size. A single row of trees was modeled by creating copies of a representative tree model positioned on top of a rectangular, lossy dielectric slab that simulated the ground. The complete scattering model, including soil and trees, enhanced by periodicity conditions corresponding to the array, was characterized via a commercial computational software tool for simulating the wave propagation by means of the Finite Element Method. The attenuation of the simulated signal was compared to measurements taken in the cherry orchard, using two ZigBee receiver-transmitter modules. Near the top of the tree canopies (at 3 m), the predicted attenuation was close to the measured one-just slightly underestimated. However, at 1.5 m the solver underestimated the measured attenuation significantly, especially when leaves were present and, as distances grew longer. This suggests that the effects of scattering from neighboring tree rows need to be incorporated into the model. However, complex geometries result in ill conditioned linear systems that affect the solver's convergence