Medicine (RMH) - Research Publications
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ItemComparisons of direct and indirect utilities in adult epilepsy populations: A systematic review(WILEY, 2019-12)OBJECTIVE: Epilepsy is common and carries substantial morbidity, and therefore identifying cost-effective health interventions is essential. Cost-utility analysis is a widely used method for such analyses. For this, health conditions are rated in terms of utilities, which provide a standardized score to reflect quality of life. Utilities are obtained either indirectly using quality of life questionnaires, or directly from patients or the general population. We sought to describe instruments used to estimate utilities in epilepsy populations, and how results differ according to methods used. METHODS: We undertook a systematic review of studies comparing at least two instruments for obtaining utilities in epilepsy populations. MEDLINE, Embase, ScienceDirect, Cochrane Library, Google Scholar, and gray literature were searched from inception to June 2019. Mean utilities were recorded and compared for each method. RESULTS: Of the 38 unique records initially identified, eight studies met inclusion criteria. Utilities were highest for direct "tradeoff" methods, obtained via instruments including standard gamble (0.93) and time tradeoff (0.92), compared to indirect methods, obtained via instruments including EuroQoL five-dimensional form (range = 0.72-0.86) and Health Utilities Index Mark 3 (range = 0.52-0.71). Visual analog scale (VAS), a direct "nontradeoff" instrument, provided equal or lower utilities (range = 68.0-79.8) compared to indirect instruments. SIGNIFICANCE: Direct methods, with the important exception of VAS, may provide higher utilities than indirect methods. More studies are needed to identify the most appropriate utility instruments for epilepsy populations, and to investigate whether there is variation between utilities for different types of epilepsy and other patient- and disease-specific factors.
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ItemDiabetes Prevention and Treatment Strategies: Are we doing enough?(AMER DIABETES ASSOC, 2013-09)OBJECTIVE: Effective interventions to prevent, delay, or remit diabetes are currently available. However, their impact on the prevalence of diabetes at the population level is unknown. This study aimed to estimate the impact of a range of diabetes interventions on the population prevalence of diabetes for Australian adults between 2010 and 2025. RESEARCH DESIGN AND METHODS: We used the Australian Diabetes Projection Model to estimate the impact of a population-wide strategy, high-risk prevention, surgical diabetes treatment, and a combination strategy on the future population prevalence of diabetes and to estimate the number of diabetes cases that could be potentially prevented in the year 2025. RESULTS: We estimate that a population-wide strategy would reduce the number of diabetes cases by 60,000-85,000 in 2025 from an estimated 2 million cases under the status quo scenario. A high-risk prevention strategy would result in 106,000 to 150,000 fewer cases of diabetes in 2025, and surgically induced weight loss would result in 3,000-6,000 fewer cases. No single intervention, or combination of interventions, reversed the increasing trend in diabetes prevalence over the next 15 years. CONCLUSIONS: To reverse upward trends in diabetes prevalence in future years, it is essential that current approaches to diabetes prevention and treatment are optimized and implemented and that alternative approaches to reduce the prevalence of diabetes at a population level are developed.
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ItemCost-Effectiveness of Eplerenone Compared to Usual Care in Patients With Chronic Heart Failure and NYHA Class II Symptoms, an Australian Perspective(LIPPINCOTT WILLIAMS & WILKINS, 2016-05)The objective of this study was to determine the cost-effectiveness of eplerenone compared with usual care in patients with chronic heart failure and New York Heart Association (NYHA) Class II symptoms.A Markov model was constructed with 5 health states to reflect NYHA symptom status (Classes I-IV) and death. All subjects began in the "Class II" health state and then moved to other symptom health states or died. Subjects could also be hospitalized for HF in any cycle. Transition probabilities were derived from the Eplerenone in Mild Patients Hospitalization And Survival Study in Heart Failure (EMPHASIS-HF) study. Decision analysis was applied to compare an Eplerenone Group with a Usual Care Group (UCG). In the UCG, 47.3% of subjects in Class II and 93.7% of subjects in Classes III and IV were assumed to be taking spironolactone (as per published data). In the Eplerenone Group, all subjects in Classes II, III, and IV were assumed to be taking eplerenone. The efficacy of spironolactone was assumed to be the same as eplerenone. Cost and utility data were derived from published sources. A discount rate of 5.0% was applied to future costs and benefits. The outcome of interest was incremental cost-effectiveness ratio (ICER) (cost per year of live saved (YoLS) and quality-adjusted life years (QALY) gained).Over 10 years the model predicted that for each patient compared with usual care, eplerenone would lead to 0.26 YoLS (discounted) and 0.19 QALYs gained (discounted), at a net cost of AUD $6961 (discounted). These equate to ICERs of AUD 28,001 per YoLS and AUD 37,452 per QALY gained. Sensitivity analyses indicated a 99.0% likelihood of eplerenone being cost-effective compared with usual care at a willingness to pay threshold of AUD 50,000 per QALY gained.From an Australian healthcare perspective, the addition of eplerenone in management of patients with chronic heart failure and NYHA Class II symptoms represents a cost-effective strategy compared with usual care.
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ItemCost Effectiveness of Eplerenone in Patients with Chronic Heart Failure(ADIS INT LTD, 2014-06)BACKGROUND: Chronic heart failure (CHF) remains an important cause of morbidity and mortality worldwide. Currently, there are no cost-effectiveness studies of eplerenone use in patients with New York Heart Association (NYHA) class II CHF. OBJECTIVE: We sought to evaluate the cost effectiveness of eplerenone compared with placebo in patients with chronic systolic heart failure and NYHA class II symptoms. METHODS AND RESULTS: A 10-year Markov model with yearly cycles was constructed to evaluate the cost effectiveness of eplerenone compared with placebo, based on data from the EMPHASIS-HF (Eplerenone in Mild Patients Hospitalization And Survival Study in Heart Failure) study. The model classified subjects into two health states: 'Alive with CHF' and 'Dead'. Information about the cost of disease was derived from Australian Refined Diagnosis-Related Groups (AR-DRG) data. The cost of eplerenone was taken from the Australian Pharmaceutical Benefit Scheme. Utility data were derived from published sources, and a 5 % annual discount rate was applied to future costs and benefits. Over 10 years, and compared with placebo, the model predicted that eplerenone would lead to a saving of 0.5 life-years (discounted) and 0.4 quality-adjusted life-years (QALYs) per person. The net cost was (in Australian dollars [$A]) $A6,117 (discounted) per person. These equated to incremental cost-effectiveness ratios of $A12,024 per life-year saved and $A16,700 per QALY saved. Sensitivity analyses indicated that these results were robust. CONCLUSION: Eplerenone may represent a cost-effective strategy for preventing morbidity and mortality among patients with chronic systolic heart failure and NYHA class II symptoms.
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ItemNo Preview AvailableComparison of Health-Related Quality of Life, Work Status, and Health Care Utilization and Costs According to Hip and Knee Joint Disease Severity: A National Australian Study(OXFORD UNIV PRESS INC, 2013-07)BACKGROUND: No population-based studies have investigated how the impact of hip and knee joint disease may vary with increasing severity. OBJECTIVE: The purpose of this study was to evaluate health-related quality of life (HRQoL), work status, and health service utilization and costs according to severity of hip and knee joint disease. DESIGN: A national cross-sectional survey was conducted. METHODS: Five thousand individuals were randomly selected from the Australian electoral roll and invited to complete a questionnaire to screen for doctor-diagnosed hip arthritis, hip osteoarthritis (OA), knee arthritis, and knee OA. Severity was classified by means of Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores (range=0-100): <7=asymptomatic, 7-38=mild-moderate, and ≥39=severe. Health-related quality of life was evaluated by means of the Assessment of Quality of Life (AQoL) instrument (range=-0.04 to 1.00; scored worst-best). Self-reported data on work status and health service utilization were collected, with health care costs estimated with the use of government data. RESULTS: Data were available for 1,157 participants, with 237 (20%) reporting hip or knee joint disease. Of these, 16% (n=37) were classified as asymptomatic, 51% (n=120) as mild-moderate, and 27% (n=64) as severe. The severe group reported very low HRQoL (adjusted mean AQoL=0.43, 95% confidence interval [95% CI]=0.38-0.47) compared with the mild-moderate group (adjusted mean AQoL=0.72, 95% CI=0.69-0.75) and the asymptomatic group (adjusted mean AQoL=0.80, 95% CI=0.74-0.86). Compared with the asymptomatic group, the severe group was >3 times less likely to undertake paid work (adjusted odds ratio=0.28, 95% CI=0.09-0.88) and >4 times less likely to undertake unpaid work (adjusted odds ratio=0.24, 95% CI=0.10-0.62). Although physical therapy services were used infrequently, primary and specialist care utilization and costs were highest for the severe group. LIMITATIONS: Other costs (including physical therapy consultations) were unavailable. CONCLUSIONS: A clear pattern of worsening HRQoL, reduced work participation, and higher medical care utilization was seen with increasing severity of joint disease.
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ItemPerformance of the Assessment of Quality of Life Measure in People With Hip and Knee Joint Disease and Implications for Research and Clinical Use(WILEY, 2014-03)OBJECTIVE: To comprehensively evaluate the performance of the Assessment of Quality of Life (AQoL) instrument for measuring health-related quality of life (HRQOL) in people with hip and knee joint disease (arthritis or osteoarthritis). METHODS: Data from 237 individuals were available for analysis from a national cross-sectional, population-based study of hip and knee joint disease in Australia. AQoL-4D data were evaluated using Rasch analysis. A range of measurement properties was explored, including model and item fit, threshold ordering, differential item functioning, and targeting. RESULTS: Good overall fit of the AQoL with the Rasch model was demonstrated across a range of tests, supporting internal validity. Only 1 item (relating to hearing) showed evidence of misfit. Most AQoL items showed logical sequencing of response option categories, with threshold disordering evident for only 2 of the 12 items (items 4 and 9). Minor issues with potential clinical and research implications include limited options for reporting pain and some evidence of measurement bias between demographic subgroups (including age and sex). Participants' HRQOL was generally better than that represented by the AQoL items (mean ± SD for person abilities -2.15 ± 1.39, mean ± SD for item difficulties 0.00 ± 0.67), indicating ceiling effects that could impact the instrument's ability to detect HRQOL improvement in population-based studies. CONCLUSION: The AQoL is a competent tool for assessing HRQOL in people with hip and knee joint disease, although researchers and clinicians should consider the caveats identified when selecting appropriate HRQOL measures for future outcome assessment involving this patient group.
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ItemOverview of methods for comparing the efficacies of drugs in the absence of head-to-head clinical trial data(WILEY, 2014-01)In most therapeutic areas, multiple drug options are increasingly becoming available, but there is often a lack of evidence from head-to-head clinical trials that allows for direct comparison of the efficacy and/or safety of one drug vs. another. This review provides an introduction to, and overview of, common methods used for comparing drugs in the absence of head-to-head clinical trial evidence. Naïve direct comparisons are in most instances inappropriate and should only be used for exploratory purposes and when no other options are possible. Adjusted indirect comparisons are currently the most commonly accepted method and use links through one or more common comparators. Mixed treatment comparisons (MTCs) use Bayesian statistical models to incorporate all available data for a drug, even data that are not relevant to the comparator drug. MTCs reduce uncertainty but have not yet been widely accepted by researchers, nor drug regulatory and reimbursement authorities. All indirect analyses are based on the same underlying assumption as meta-analyses, namely that the study populations in the trials being compared are similar.
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ItemUsing WOMAC Index scores and personal characteristics to estimate Assessment of Quality of Life utility scores in people with hip and knee joint disease(SPRINGER, 2014-10)PURPOSE: To determine whether Assessment of Quality of Life (AQoL) utility scores can be reliably estimated from Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores in people with hip and knee joint disease (arthritis or osteoarthritis). METHODS: WOMAC and AQoL data were analysed from 219 people recruited for a national population-based study. Generalised linear models were used to estimate AQoL utility scores based on WOMAC total and subscale scores and personal characteristics. Goodness of fit was assessed for each model, and plots of prediction errors versus actual AQoL utility scores were used to gauge bias. RESULTS: Each model closely predicted the average AQoL utility score for the overall sample (actual mean AQoL 0.64, range of predicted means 0.63-0.64; actual median AQoL 0.71, range of predicted medians 0.68-0.69). No clear preferred model was identified, and overall, the models predicted 40-46% of the variance in AQoL utility scores. The WOMAC function subscale model performed similarly to the total score model. The models functioned best at the mid-range of AQoL scores, with greater bias observed for extreme scores. Inaccuracies in individual-level estimates and low/high health-related quality of life (HRQoL) subgroup estimates were evident. CONCLUSION: Reliable overall group-level estimates were produced, supporting the application of these techniques at a population level. Using WOMAC scores to predict individual AQoL utility scores is not recommended, and the models may produce inaccurate estimates in studies targeting patients with low/high HRQoL. Where pain and stiffness data are unavailable, the WOMAC function subscale can be used to generate a reasonable utility estimate.