The use of probabilistic decision models in technology assessment : the case of total hip replacement

Cost effectiveness of a novel swallowing and respiratory sensation assessment and a modelled intervention to reduce acute exacerbations of COPD

Swallowing impairment observed in ~ 20% of people with Chronic Obstructive Pulmonary Disease (COPD) may increase the risk of aspiration pneumonia and acute exacerbations. We designed a decision analytic model to assess the cost-effectiveness of the Swallowing and Respiratory Sensation Assessment (SwaRSA) tests and swallowing rehabilitation to reduce COPD exacerbations. We believe that swallowing rehabilitation to improve coordination of swallowing and breathing may reduce exacerbations in people with COPD.From the Australia health system perspective, we assessed the cost effectiveness of four tests relative to standard of care, or no testing, over a time horizon of one year. The SwaRSA tests assessed relative to a standard of care arm of no testing: included the Eating Assessment Tool (EAT-10) score, Swallowing Capacity of Liquids, Tongue Strength Assessment, and Respiratory Sensation Assessment, in people with moderate to severe COPD. Outcome measures were COPD exacerbations per year, which were converted into quality adjusted life years (QALYs). Model inputs including costs, test sensitivities and specificities, COPD exacerbation risks, and exacerbation-related utilities were derived from published sources. Our assumptions on the costs, recovery, and risk reduction are based on the available data on pulmonary rehabilitation in COPD.Relative to no-SwaRSA, three individual testing strategies were found to be cost-effective at incremental cost effectiveness ratio per QALY ranging from $27,000 to $37,000 AUD assuming a willingness to pay of $50,000 AUD. The EAT-10 and the tongue strength were the two dominant options on the cost-effectiveness frontier. Model results were robust to variations in one-way and probabilistic sensitivity analyses.In COPD, SwaRSA modelling suggests that self-assessment with the EAT-10 and subsequent intervention is highly cost-effective relative to no-SwaRSA.

Inebilizumab for neuromyelitis optica spectrum disorders in Italy: a budget impact model

BACKGROUND

The Italian National Health Service (INHS) has recently reimbursed the monoclonal antibody inebilizumab as a second line monotherapy after rituximab (RTX) use for neuromyelitis optica spectrum disorders (NMOSD) patients ≥ 18 years anti-aquaporin 4 antibody-immunoglobulin G positive, who experienced a relapse in the last year or cannot receive RTX, if incident patients. Other INHS-reimbursed drugs for NMOSD treatment are satralizumab, eculizumab and, off-label, besides RTX, ocrelizumab, tocilizumab, and immunosuppressants.

RESEARCH DESIGN AND METHODS

A 3-year (2023-2025) prevalence-based budget impact model following the INHS viewpoint compared the costs and the NMOSD attacks without (1st scenario) and with inebilizumab (2nd scenario). The epidemiology of NMOSD, and the INHS-funded healthcare resources (drugs and their administration; specialist visits; hospitalizations due to drug-related adverse events and NMOSD attacks) were obtained from the literature. One-way, threshold value and scenario sensitivity analyses investigated the robustness of the baseline findings.

RESULTS

During 2023-2025 inebilizumab saves the INHS €8,373,125.13 (1st scenario: €176,770,028.63; 2nd scenario: €168,396,903.50) and 12.74 NMOSD attacks (1st scenario: 213.94; 2nd scenario: 201.19). Sensitivity analyses confirmed the robustness of the baseline results.

CONCLUSION

Inebilizumab reduces the INHS expenditure for NMOSD drugs. Future research should explore the cost-effectiveness of inebilizumab vs other NMOSD-targeting drugs in Italy.

Extensions of Health Economic Evaluations in R for Microsoft Excel Users: A Tutorial for Incorporating Heterogeneity and Conducting Value of Information Analyses

Advanced health economic analysis techniques currently performed in Microsoft Excel, such as incorporating heterogeneity, time-dependent transitions and a value of information analysis, can be easily transferred to R. Often the outputs of survival analyses (such as Weibull regression models) will estimate the impacts of correlated patient characteristics on patient outcomes, and are utilised directly as inputs for health economic decision models. This tutorial provides a step-by-step guide of how to conduct such analyses with a Markov model developed in R, and offers a comparison with established analyses performed in Microsoft Excel. This is done through the conversion of a previously published Microsoft Excel case study of a hip replacement surgery cost-effectiveness model. We hope that this paper can act as a facilitator in switching decision models from Microsoft Excel to R for complex health economic analyses, providing open-access code and data, suitable for future adaptation.

Understanding no-show behaviour for cervical cancer screening appointments among hard-to-reach women in Bogotá, Colombia: A mixed-methods approach

The global burden of cervical cancer remains a concern and higher early mortality rates are associated with poverty and limited health education. However, screening programs continue to face implementation challenges, especially in developing country contexts. In this study, we use a mixed-methods approach to understand the reasons for no-show behaviour for cervical cancer screening appointments among hard-to-reach low-income women in Bogotá, Colombia. In the quantitative phase, individual attendance probabilities are predicted using administrative records from an outreach program (N = 23384) using both LASSO regression and Random Forest methods. In the qualitative phase, semi-structured interviews are analysed to understand patient perspectives (N = 60). Both inductive and deductive coding are used to identify first-order categories and content analysis is facilitated using the Framework method. Quantitative analysis shows that younger patients and those living in zones of poverty are more likely to miss their appointments. Likewise, appointments scheduled on Saturdays, during the school vacation periods or with lead times longer than 10 days have higher no-show risk. Qualitative data shows that patients find it hard to navigate the service delivery process, face barriers accessing the health system and hold negative beliefs about cervical cytology.

Cost-Effectiveness Analysis Combining Medical and Mental Health Services for Older Adults with HIV in New York City

Older adults with the human immunodeficiency virus or HIV (OAWH), people 50 years and older, are aging with the disease and experience low quality of life. Mental health disorders trigger and worsen health inequalities with larger impacts on the quality of life of OAWH. This paper evaluated two rival health interventions using a standard decision-analytic model and quantified the cost per quality-adjusted life-years (QALY) to understand the differential in cost and effectiveness of an additional unit of perfect health. HIV medical care was compared with a combined strategy that includes both HIV medical and behavioral care. Primary data from a convenience sample (n=139) collected in New York City and outcomes for healthy older adults from the literature were used in this study. The incremental cost-effectiveness ratio (ICER) evaluating the economic cost and health benefits of the new intervention was $36,166 per QALY, which is less than the willingness to pay ($75,000). The ICER for Hispanics was $35,325 and for White/Caucasians was $40,499. Integrated medical plus behavioral care is cost-effective and improves quality of life among OAWH. Given the high rates of mental health disorders along with an underutilization of behavioral care among OAWH, timely and effective mental health programs are paramount to increase quality of life.

Artificial neural network metamodel for sensitivity analysis in a total hip replacement health economic model

Objectives: Metamodels have been used to approximate complex simulations and have many applications with sensitivity analysis, optimization, etc. However, their use in health economics is very limited. Application of artificial neural network (ANN) with a health economic model has never been investigated. The study intends to introduce ANN as a metamodeling method to conduct sensitivity analysis in a total hip replacement decision analytical model and compare its performance with two other counterparts. Methods: First, a nonlinear factor screening method was adopted to screen out unimportant factors from the simulation. Second, an ANN was developed using the important variables to approximate the simulation. Performance of the ANN metamodel was then compared with its Gaussian Process (GP) and multiple linear regression (MLR) counterparts. Results: Out of 31, the factor screening method identified 12 important variables from the simulation. ANN metamodels showed best predictive capabilities in terms of performance measures (mean squared error of prediction, MSEP and mean absolute percentage deviation, MAPD) used for predicting both costs and quality-adjusted life years (QALYs) for two prostheses. Conclusion: The study provides a methodological development in sensitivity analysis and demonstrates that an ANN metamodel is a potential approximation method for computationally expensive health economic simulations.

Comparison of the flexible parametric survival model and Cox model in estimating Markov transition probabilities using real-world data

BACKGROUND AND OBJECTIVE

Markov micro-simulation models are being increasingly used in health economic evaluations. An important feature of the Markov micro-simulation model is its ability to consider transition probabilities of heterogeneous subgroups with different risk profiles. A survival analysis is generally performed to accurately estimate the transition probabilities associated with the risk profiles. This study aimed to apply a flexible parametric survival model (FPSM) to estimate individual transition probabilities.

MATERIALS AND METHODS

The data were obtained from a cohort study investigating ischemic stroke outcomes in Western China. In total, 585 subjects were included in the analysis. To explore the goodness of fit of the FPSM, we compared the estimated hazard ratios and baseline cumulative hazards, both of which are necessary to the calculate individual transition probabilities, and the Markov micro-simulation models constructed using the FPSM and Cox model to determine the validity of the two Markov micro-simulation models and cost-effectiveness results.

RESULTS

The flexible parametric proportional hazards model produced hazard ratio and baseline cumulative hazard estimates that were similar to those obtained using the Cox proportional hazards model. The simulated cumulative incidence of recurrent ischemic stroke and 5-years cost-effectiveness of Incremental cost-effectiveness Ratios (ICERs) were also similar using the two approaches. A discrepancy in the results was evident between the 5-years cost-effectiveness and the 10-years cost-effectiveness of ICERs, which were approximately 0.9 million (China Yuan) and 0.5 million (China Yuan), respectively.

CONCLUSIONS

The flexible parametric survival model represents a good approach for estimating individual transition probabilities for a Markov micro-simulation model.

Development of a Procedure for the Government Provision of Bone-Anchored Prosthesis Using Osseointegration in Australia

BACKGROUND

Governmental organizations are facing challenges in adjusting procedures providing equitable assistance to consumers with amputation choosing newly available osseointegrated fixations for bone-anchored prostheses (BAPs) over socket-suspended prostheses.

OBJECTIVES

The aims of this study were to (1) present a procedure focusing on tasks, documents and costs of prosthetic care, and (2) share observed obstacles and facilitators to implementation.

METHODS

This research aimed at developing a governmental procedure for the provision of BAPs was designed as an action research study. A total of 18 individuals with transfemoral amputation solely funded by a Queensland State organization were considered.

RESULTS

The procedure, developed between January 2011 and June 2015, included seven processes involving fixed expenses during treatment and five processes regulating ongoing prosthetic care expenses. Prosthetic care required 22 h of labor, corresponding to AUD$3300 per patient, during rehabilitation. Prosthetists spend 64 and 36% of their time focusing on prosthetic care and other activities, respectively. The procedure required adjustments related to the scope of practice of prosthetists, funding of prosthetic limbs during rehabilitation, and allocation of microprocessor-controlled prosthetic knees. Approximately 41% (7) and 59% (10) of obstacles were within (e.g. streamlining systematic processes, sustaining evaluation of this complex procedure) or outside (e.g. early and consistent consultations of stakeholders, lack of a definitive rehabilitation program) governmental control, respectively, and approximately 89% (17) of the facilitators were within governmental control (e.g. adapting existing processes).

CONCLUSION

This study provides a working plan to stakeholders developing and implementing policies around the care of individuals choosing osseointegration for BAPs.

Lower limb arthroplasty: can we produce a tool to predict outcome and failure, and is it cost-effective? An epidemiological study

Background

Although hip and knee arthroplasties are considered to be common elective cost-effective operations, up to one-quarter of patients are not satisfied with the operation. A number of risk factors for implant failure are known, but little is known about the predictors of patient-reported outcomes.

Objectives

(1) Describe current and future needs for lower limb arthroplasties in the UK; (2) describe important risk factors for poor surgery outcomes and combine them to produce predictive tools (for hip and knee separately) for poor outcomes; (3) produce a Markov model to enable a detailed health economic analysis of hip/knee arthroplasty, and for implementing the predictive tool; and (4) test the practicality of the prediction tools in a pragmatic prospective cohort of lower limb arthroplasty.

Design

The programme was arranged into four work packages. The first three work packages used the data from large existing data sets such as Clinical Practice Research Datalink, Hospital Episode Statistics and the National Joint Registry. Work package 4 established a pragmatic cohort of lower limb arthroplasty to test the practicality of the predictive tools developed within the programme.

Results

The estimated number of total knee replacements (TKRs) and total hip replacements (THRs) performed in the UK in 2015 was 85,019 and 72,418, respectively. Between 1991 and 2006, the estimated age-standardised rates (per 100,000 person-years) for a THR increased from 60.3 to 144.6 for women and from 35.8 to 88.6 for men. The rates for TKR increased from 42.5 to 138.7 for women and from 28.7 to 99.4 for men. The strongest predictors for poor outcomes were preoperative pain/function scores, deprivation, age, mental health score and radiographic variable pattern of joint space narrowing. We found a weak association between body mass index (BMI) and outcomes; however, increased BMI did increase the risk of revision surgery (a 5-kg/m2rise in BMI increased THR revision risk by 10.4% and TKR revision risk by 7.7%). We also confirmed that osteoarthritis (OA) severity and migration pattern of the hip predicted patient-reported outcome measures. The hip predictive tool that we developed performed well, with a correctedR2of 23.1% and had good calibration, with only slight overestimation of Oxford Hip Score in the lowest decile of outcome. The knee tool developed performed less well, with a correctedR2of 20.2%; however, it had good calibration. The analysis was restricted by the relatively limited number of variables available in the extant data sets, something that could be addressed in future studies. We found that the use of bisphosphonates reduced the risk of revision knee and hip surgery by 46%. Hormone replacement therapy reduced the risk by 38%, if used for at least 6 months postoperatively. We found that an increased risk of postoperative fracture was prevented by bisphosphonate use. This result, being observational in nature, will require confirmation in a randomised controlled trial. The Markov model distinguished between outcome categories following primary and revision procedures. The resulting outcome prediction tool for THR and TKR reduced the number and proportion of unsatisfactory outcomes after the operation, saving NHS resources in the process. The highest savings per quality-adjusted life-year (QALY) forgone were reported from the oldest patient subgroups (men and women aged ≥ 80 years), with a reported incremental cost-effectiveness ratio of around £1200 saved per QALY forgone for THRs. In the prospective cohort of arthroplasty, the performance of the knee model was modest (R2 = 0.14) and that of the hip model poor (R2 = 0.04). However, the addition of the radiographic OA variable improved the performance of the hip model (R2 = 0.125 vs. 0.110) and high-sensitivity C-reactive protein improved the performance of the knee model (R2 = 0.230 vs. 0.216). These data will ideally need replication in an external cohort of a similar design. The data are not necessarily applicable to other health systems or countries.

Conclusion

The number of total hip and knee replacements will increase in the next decade. High BMI, although clinically insignificant, is associated with an increased risk of revision surgery and postoperative complications. Preoperative pain/function, the pattern of joint space narrowing, deprivation index and level of education were found to be the strongest predictors for THR. Bisphosphonates and hormone therapy proved to be beneficial for patients undergoing lower limb replacement. The addition of new predictors collected from the prospective cohort of arthroplasty slightly improved the performance of the predictive tools, suggesting that the potential improvements in both tools can be achieved using the plethora of extra variables from the validation cohort. Although currently it would not be cost-effective to implement the predictive tools in a health-care setting, we feel that the addition of extensive risk factors will improve the performances of the predictive tools as well as the Markov model, and will prove to be beneficial in terms of cost-effectiveness. Future analyses are under way and awaiting more promising provisional results.

Future work

Further research should focus on defining and predicting the most important outcome to the patient.

Funding

The National Institute for Health Research Programme Grants for Applied Research programme.

Medial compartment knee osteoarthritis: age-stratified cost-effectiveness of total knee arthroplasty, unicompartmental knee arthroplasty, and high tibial osteotomy

PURPOSE

To compare the age-based cost-effectiveness of total knee arthroplasty (TKA), unicompartmental knee arthroplasty (UKA), and high tibial osteotomy (HTO) for the treatment of medial compartment knee osteoarthritis (MCOA).

METHODS

A Markov model was used to simulate theoretical cohorts of patients 40, 50, 60, and 70 years of age undergoing primary TKA, UKA, or HTO. Costs and outcomes associated with initial and subsequent interventions were estimated by following these virtual cohorts over a 10-year period. Revision and mortality rates, costs, and functional outcome data were estimated from a systematic review of the literature. Probabilistic analysis was conducted to accommodate these parameters' inherent uncertainty, and both discrete and probabilistic sensitivity analyses were utilized to assess the robustness of the model's outputs to changes in key variables.

RESULTS

HTO was most likely to be cost-effective in cohorts under 60, and UKA most likely in those 60 and over. Probabilistic results did not indicate one intervention to be significantly more cost-effective than another. The model was exquisitely sensitive to changes in utility (functional outcome), somewhat sensitive to changes in cost, and least sensitive to changes in 10-year revision risk.

CONCLUSIONS

HTO may be the most cost-effective option when treating MCOA in younger patients, while UKA may be preferred in older patients. Functional utility is the primary driver of the cost-effectiveness of these interventions. For the clinician, this study supports HTO as a competitive treatment option in young patient populations. It also validates each one of the three interventions considered as potentially optimal, depending heavily on patient preferences and functional utility derived over time.

Has Metal-On-Metal Resurfacing Been a Cost-Effective Intervention for Health Care Providers?-A Registry Based Study

Background

Total hip replacement for end stage arthritis of the hip is currently the most common elective surgical procedure. In 2007 about 7.5% of UK implants were metal-on-metal joint resurfacing (MoM RS) procedures. Due to poor revision performance and concerns about metal debris, the use of RS had declined by 2012 to about a 1% share of UK hip procedures. This study estimated the lifetime cost-effectiveness of metal-on-metal resurfacing (RS) procedures versus commonly employed total hip replacement (THR) methods.

Methodology/Principal Findings

We performed a cost-utility analysis using a well-established multi-state semi-Markov model from an NHS and personal and social services perspective. We used individual patient data (IPD) from the National Joint Registry (NJR) for England and Wales on RS and THR surgery for osteoarthritis recorded from April 2003 to December 2012. We used flexible parametric modelling of NJR RS data to guide identification of patient subgroups and RS devices which delivered revision rates within the NICE 5% revision rate benchmark at 10 years. RS procedures overall have an estimated revision rate of 13% at 10 years, compared to <4% for most THR devices. New NICE guidance now recommends a revision rate benchmark of <5% at 10 years. 60% of RS implants in men and 2% in women were predicted to be within the revision benchmark. RS devices satisfying the 5% benchmark were unlikely to be cost-effective compared to THR at a standard UK willingness to pay of £20,000 per quality-adjusted life-year. However, the probability of cost effectiveness was sensitive to small changes in the costs of devices or in quality of life or revision rate estimates.

Conclusion/Significance

Our results imply that in most cases RS has not been a cost-effective resource and should probably not be adopted by decision makers concerned with the cost effectiveness of hip replacement, or by patients concerned about the likelihood of revision, regardless of patient age or gender.

OPTIMA prelim: a randomised feasibility study of personalised care in the treatment of women with early breast cancer

BACKGROUND

There is uncertainty about the chemotherapy sensitivity of some oestrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancers. Multiparameter assays that measure the expression of several tumour genes simultaneously have been developed to guide the use of adjuvant chemotherapy for this breast cancer subtype. The assays provide prognostic information and have been claimed to predict chemotherapy sensitivity. There is a dearth of prospective validation studies. The Optimal Personalised Treatment of early breast cancer usIng Multiparameter Analysis preliminary study (OPTIMA prelim) is the feasibility phase of a randomised controlled trial (RCT) designed to validate the use of multiparameter assay directed chemotherapy decisions in the NHS.

OBJECTIVES

OPTIMA prelim was designed to establish the acceptability to patients and clinicians of randomisation to test-driven treatment assignment compared with usual care and to select an assay for study in the main RCT.

DESIGN

Partially blinded RCT with adaptive design.

SETTING

Thirty-five UK hospitals.

PARTICIPANTS

Patients aged ≥ 40 years with surgically treated ER-positive HER2-negative primary breast cancer and with 1-9 involved axillary nodes, or, if node negative, a tumour at least 30 mm in diameter.

INTERVENTIONS

Randomisation between two treatment options. Option 1 was standard care consisting of chemotherapy followed by endocrine therapy. In option 2, an Oncotype DX(®) test (Genomic Health Inc., Redwood City, CA, USA) performed on the resected tumour was used to assign patients either to standard care [if 'recurrence score' (RS) was > 25] or to endocrine therapy alone (if RS was ≤ 25). Patients allocated chemotherapy were blind to their randomisation.

MAIN OUTCOME MEASURES

The pre-specified success criteria were recruitment of 300 patients in no longer than 2 years and, for the final 150 patients, (1) an acceptance rate of at least 40%; (2) recruitment taking no longer than 6 months; and (3) chemotherapy starting within 6 weeks of consent in at least 85% of patients.

RESULTS

Between September 2012 and 3 June 2014, 350 patients consented to join OPTIMA prelim and 313 were randomised; the final 150 patients were recruited in 6 months, of whom 92% assigned chemotherapy started treatment within 6 weeks. The acceptance rate for the 750 patients invited to participate was 47%. Twelve out of the 325 patients with data (3.7%, 95% confidence interval 1.7% to 5.8%) were deemed ineligible on central review of receptor status. Interviews with researchers and recordings of potential participant consultations made as part of the integral qualitative recruitment study provided insights into recruitment barriers and led to interventions designed to improve recruitment. Patient information was changed as the result of feedback from three patient focus groups. Additional multiparameter analysis was performed on 302 tumour samples. Although Oncotype DX, MammaPrint(®)/BluePrint(®) (Agendia Inc., Irvine, CA, USA), Prosigna(®) (NanoString Technologies Inc., Seattle, WA, USA), IHC4, IHC4 automated quantitative immunofluorescence (AQUA(®)) [NexCourse BreastTM (Genoptix Inc. Carlsbad, CA, USA)] and MammaTyper(®) (BioNTech Diagnostics GmbH, Mainz, Germany) categorised comparable numbers of tumours into low- or high-risk groups and/or equivalent molecular subtypes, there was only moderate agreement between tests at an individual tumour level (kappa ranges 0.33-0.60 and 0.39-0.55 for tests providing risks and subtypes, respectively). Health economics modelling showed the value of information to the NHS from further research into multiparameter testing is high irrespective of the test evaluated. Prosigna is currently the highest priority for further study.

CONCLUSIONS

OPTIMA prelim has achieved its aims of demonstrating that a large UK clinical trial of multiparameter assay-based selection of chemotherapy in hormone-sensitive early breast cancer is feasible. The economic analysis shows that a trial would be economically worthwhile for the NHS. Based on the outcome of the OPTIMA prelim, a large-scale RCT to evaluate the clinical effectiveness and cost-effectiveness of multiparameter assay-directed chemotherapy decisions in hormone-sensitive HER2-negative early breast would be appropriate to take place in the NHS.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN42400492.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 10. See the NIHR Journals Library website for further project information. The Government of Ontario funded research at the Ontario Institute for Cancer Research. Robert C Stein received additional support from the NIHR University College London Hospitals Biomedical Research Centre.

Cost-effectiveness analysis of online hemodiafiltration versus high-flux hemodialysis

Background

Clinical studies suggest that hemodiafiltration (HDF) may lead to better clinical outcomes than high-flux hemodialysis (HF-HD), but concerns have been raised about the cost-effectiveness of HDF versus HF-HD. Aim of this study was to investigate whether clinical benefits, in terms of longer survival and better health-related quality of life, are worth the possibly higher costs of HDF compared to HF-HD.

Methods

The analysis comprised a simulation based on the combined results of previous published studies, with the following steps: 1) estimation of the survival function of HF-HD patients from a clinical trial and of HDF patients using the risk reduction estimated in a meta-analysis; 2) simulation of the survival of the same sample of patients as if allocated to HF-HD or HDF using three-state Markov models; and 3) application of state-specific health-related quality of life coefficients and differential costs derived from the literature. Several Monte Carlo simulations were performed, including simulations for patients with different risk profiles, for example, by age (patients aged 40, 50, and 60 years), sex, and diabetic status. Scatter plots of simulations in the cost-effectiveness plane were produced, incremental cost-effectiveness ratios were estimated, and cost-effectiveness acceptability curves were computed.

Results

An incremental cost-effectiveness ratio of €6,982/quality-adjusted life years (QALY) was estimated for the baseline cohort of 50-year-old male patients. Given the commonly accepted threshold of €40,000/QALY, HDF is cost-effective. The probabilistic sensitivity analysis showed that HDF is cost-effective with a probability of ~81% at a threshold of €40,000/QALY. It is fundamental to measure the outcome also in terms of quality of life. HDF is more cost-effective for younger patients.

Conclusion

HDF can be considered cost-effective compared to HF-HD.

Bayesian Solutions for Handling Uncertainty in Survival Extrapolation

OBJECTIVE

Survival extrapolation using a single, best-fit model ignores 2 sources of model uncertainty: uncertainty in the true underlying distribution and uncertainty about the stability of the model parameters over time. Bayesian model averaging (BMA) has been used to account for the former, but it can also account for the latter. We investigated BMA using a published comparison of the Charnley and Spectron hip prostheses using the original 8-year follow-up registry data.

METHODS

A wide variety of alternative distributions were fitted. Two additional distributions were used to address uncertainty about parameter stability: optimistic and skeptical. The optimistic (skeptical) model represented the model distribution with the highest (lowest) estimated probabilities of survival but reestimated using, as prior information, the most optimistic (skeptical) parameter estimated for intermediate follow-up periods. Distributions were then averaged assuming the same posterior probabilities for the optimistic, skeptical, and noninformative models. Cost-effectiveness was compared using both the original 8-year and extended 16-year follow-up data.

RESULTS

We found that all models obtained similar revision-free years during the observed period. In contrast, there was variability over the decision time horizon. Over the observed period, we detected considerable uncertainty in the shape parameter for Spectron. After BMA, Spectron was cost-effective at a threshold of £20,000 with 93% probability, whereas the best-fit model was 100%; by contrast, with a 16-year follow-up, it was 0%.

CONCLUSIONS

This case study casts doubt on the ability of the single best-fit model selected by information criteria statistics to adequately capture model uncertainty. Under this scenario, BMA weighted by posterior probabilities better addressed model uncertainty. However, there is still value in regularly updating health economic models, even where decision uncertainty is low.

Total hip replacement and surface replacement for the treatment of pain and disability resulting from end-stage arthritis of the hip (review of technology appraisal guidance 2 and 44): systematic review and economic evaluation

BACKGROUND

Total hip replacement (THR) involves the replacement of a damaged hip joint with an artificial hip prosthesis. Resurfacing arthroplasty (RS) involves replacement of the joint surface of the femoral head with a metal surface covering.

OBJECTIVES

To undertake clinical effectiveness and cost-effectiveness analysis of different types of THR and RS for the treatment of pain and disability in people with end-stage arthritis of the hip, in particular to compare the clinical effectiveness and cost-effectiveness of (1) different types of primary THR and RS for people in whom both procedures are suitable and (2) different types of primary THR for people who are not suitable for hip RS.

DATA SOURCES

Electronic databases including MEDLINE, EMBASE, The Cochrane Library, Current Controlled Trials and UK Clinical Research Network (UKCRN) Portfolio Database were searched in December 2012, with searches limited to publications from 2008 and sample sizes of ≥ 100 participants. Reference lists and websites of manufacturers and professional organisations were also screened.

REVIEW METHODS

Systematic reviews of the literature were undertaken to appraise the clinical effectiveness and cost-effectiveness of different types of THR and RS for people with end-stage arthritis of the hip. Included randomised controlled trials (RCTs) and systematic reviews were data extracted and risk of bias and methodological quality were independently assessed by two reviewers using the Cochrane Collaboration risk of bias tool and the Assessment of Multiple Systematic Reviews (AMSTAR) tool. A Markov multistate model was developed for the economic evaluation of the technologies. Sensitivity analyses stratified by sex and controlled for age were carried out to assess the robustness of the results.

RESULTS

A total of 2469 records were screened of which 37 were included, representing 16 RCTs and eight systematic reviews. The mean post-THR Harris Hip Score measured at different follow-up times (from 6 months to 10 years) did not differ between THR groups, including between cross-linked polyethylene and traditional polyethylene cup liners (pooled mean difference 2.29, 95% confidence interval -0.88 to 5.45). Five systematic reviews reported evidence on different types of THR (cemented vs. cementless cup fixation and implant articulation materials) but these reviews were inconclusive. Eleven cost-effectiveness studies were included; four provided relevant cost and utility data for the model. Thirty registry studies were included, with no studies reporting better implant survival for RS than for all types of THR. For all analyses, mean costs for RS were higher than those for THR and mean quality-adjusted life-years (QALYs) were lower. The incremental cost-effectiveness ratio for RS was dominated by THR, that is, THR was cheaper and more effective than RS (for a lifetime horizon in the base-case analysis, the incremental cost of RS was £11,284 and the incremental QALYs were -0.0879). For all age and sex groups RS remained clearly dominated by THR. Cost-effectiveness acceptability curves showed that, for all patients, THR was almost 100% cost-effective at any willingness-to-pay level. There were age and sex differences in the populations with different types of THR and variations in revision rates (from 1.6% to 3.5% at 9 years). For the base-case analysis, for all age and sex groups and a lifetime horizon, mean costs for category E (cemented components with a polyethylene-on-ceramic articulation) were slightly lower and mean QALYs for category E were slightly higher than those for all other THR categories in both deterministic and probabilistic analyses. Hence, category E dominated the other four categories. Sensitivity analysis using an age- and sex-adjusted log-normal model demonstrated that, over a lifetime horizon and at a willingness-to-pay threshold of £20,000 per QALY, categories A and E were equally likely (50%) to be cost-effective.

LIMITATIONS

A large proportion of the included studies were inconclusive because of poor reporting, missing data, inconsistent results and/or great uncertainty in the treatment effect estimates. This warrants cautious interpretation of the findings. The evidence on complications was scarce, which may be because of the absence or rarity of these events or because of under-reporting. The poor reporting meant that it was not possible to explore contextual factors that might have influenced study results and also reduced the applicability of the findings to routine clinical practice in the UK. The scope of the review was limited to evidence published in English in 2008 or later, which could be interpreted as a weakness; however, systematic reviews would provide summary evidence for studies published before 2008.

CONCLUSIONS

Compared with THR, revision rates for RS were higher, mean costs for RS were higher and mean QALYs gained were lower; RS was dominated by THR. Similar results were obtained in the deterministic and probabilistic analyses and for all age and sex groups THR was almost 100% cost-effective at any willingness-to-pay level. Revision rates for all types of THR were low. Category A THR (cemented components with a polyethylene-on-metal articulation) was more cost-effective for older age groups. However, across all age-sex groups combined, the mean cost for category E THR (cemented components with a polyethylene-on-ceramic articulation) was slightly lower and the mean QALYs gained were slightly higher. Category E therefore dominated the other four categories. Certain types of THR appeared to confer some benefit, including larger femoral head sizes, use of a cemented cup, use of a cross-linked polyethylene cup liner and a ceramic-on-ceramic as opposed to a metal-on-polyethylene articulation. Further RCTs with long-term follow-up are needed.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013003924.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Lifetime cost effectiveness of different brands of prosthesis used for total hip arthroplasty: a study using the NJR dataset

There is little evidence on the cost effectiveness of different brands of hip prostheses. We compared lifetime cost effectiveness of frequently used brands within types of prosthesis including cemented (Exeter V40 Contemporary, Exeter V40 Duration and Exeter V40 Elite Plus Ogee), cementless (Corail Pinnacle, Accolade Trident, and Taperloc Exceed) and hybrid (Exeter V40 Trilogy, Exeter V40 Trident, and CPT Trilogy). We used data from three linked English national databases to estimate the lifetime risk of revision, quality-adjusted life years (QALYs) and cost. For women with osteoarthritis aged 70 years, the Exeter V40 Elite Plus Ogee had the lowest risk of revision (5.9% revision risk, 9.0 QALYs) and the CPT Trilogy had the highest QALYs (10.9% revision risk, 9.3 QALYs). Compared with the Corail Pinnacle (9.3% revision risk, 9.22 QALYs), the most commonly used brand, and assuming a willingness-to-pay of £20,000 per QALY gain, the CPT Trilogy is most cost effective, with an incremental net monetary benefit of £876. Differences in cost effectiveness between the hybrid CPT Trilogy and Exeter V40 Trident and the cementless Corail Pinnacle and Taperloc Exceed were small, and a cautious interpretation is required, given the limitations of the available information. However, it is unlikely that cemented brands are among the most cost effective. Similar patterns of results were observed for men and other ages. The gain in quality of life after total hip arthroplasty, rather than the risk of revision, was the main driver of cost effectiveness. Cite this article: Bone Joint J 2015;97-B:762-70.

Cost effectiveness of total hip arthroplasty in osteoarthritis

Many different designs of total hip arthroplasty (THA) with varying performance and cost are available. The identification of those which are the most cost-effective could allow significant cost-savings. We used an established Markov model to examine the cost effectiveness of five frequently used categories of THA which differed according to bearing surface and mode of fixation, using data from the National Joint Registry for England and Wales. Kaplan–Meier analyses of rates of revision for men and women were modelled with parametric distributions. Costs of devices were provided by the NHS Supply Chain and associated costs were taken from existing studies. Lifetime costs, lifetime quality-adjusted-life-years (QALYs) and the probability of a device being cost effective at a willingness to pay £20 000/QALY were included in the models.

The differences in QALYs between different categories of implant were extremely small (<  0.0039 QALYs for men or women over the patient’s lifetime) and differences in cost were also marginal (£2500 to £3000 in the same time period). As a result, the probability of any particular device being the most cost effective was very sensitive to small, plausible changes in quality of life estimates and cost.

Our results suggest that available evidence does not support recommending a particular device on cost effectiveness grounds alone. We would recommend that the choice of prosthesis should be determined by the rate of revision, local costs and the preferences of the surgeon and patient.

Cite this article: Bone Joint J 2015;97-B:449–57.

Cost-Effectiveness Uncertainty Analysis Methods: A Comparison of One-Way Sensitivity, Analysis of Covariance, and Expected Value of Partial Perfect Information

OBJECTIVES

To compare model input influence on incremental net monetary benefit (INMB) across 3 uncertainty methods: 1) 1-way sensitivity analysis; 2) probabilistic analysis of covariance (ANCOVA); and 3) expected value of partial perfect information (EVPPI).

METHODS

In a preliminary model, we used a published cost-effectiveness model and assumed £20,000 per quality-adjusted life-year (QALY) willingness-to-pay (Case 1: lower decision uncertainty) and £8000/QALY willingness-to-pay (Case 2: higher decision uncertainty). We conducted 1-way sensitivity, ANCOVA (10,000 Monte Carlo draws), and EVPPI for each model input (1000 inner and 1000 outer draws). We ranked inputs based on influence of INMB and compared input ranks across methods within case using Spearman's rank correlation. We replicated this approach in 3 follow-up models: an additional linear model, a less linear model with uncorrelated inputs, and a less linear model with correlated inputs.

RESULTS

In the preliminary model, lower and higher decision uncertainty cases had the same top 3 influential parameters across uncertainty methods. The 2 most influential inputs contributed 78% and 49% of variation in outcome based on ANCOVA for lower decision uncertainty and higher decision uncertainty cases, respectively. In the follow-up models, input rank order correlations were higher across uncertainty methods in the linear model compared with both of the less linear models.

CONCLUSIONS

Evidence across models suggests influential input rank agreement between 1-way and more advanced uncertainty analyses for relatively linear models with uncorrelated parameters but less agreement for less linear models. Although each method provides unique information, the additional resources needed to generate and communicate advanced analyses should be weighed, especially when outcome decision uncertainty is low. For less linear models or those with correlated inputs, performing and reporting deterministic and probabilistic uncertainty analyses appear prudent and conservative.

The cost-effectiveness of total joint arthroplasty: a systematic review of published literature

OBJECTIVE

To summarise the state of the literature evaluating the cost-effectiveness of elective total hip and knee arthroplasty (THA and TKA).

METHODS

We conducted a systematic review of published cost-effectiveness analyses of THA and TKA. To limit our search to high-quality published papers, we selected those papers included in the Cost-Effectiveness Analysis Registry (created by the Center for the Evaluation of Value and Risk in Health at Tufts University) and augmented the search with papers listed in PubMed. The data abstracted included incremental cost-effectiveness ratios, perspective of the analysis, time frame, sensitivity analyses conducted, and utility assessment. All cost-effectiveness ratios were converted to 2011 USD.

RESULTS

Seven studies presenting cost-effectiveness ratios for TKA and six studies for THA were included in our review. All economic evaluations of TKA were published between 2006 and 2012. By contrast, THA studies were published between 1996 and 2008. Out of the 13 studies evaluated in this review, four were from the societal perspective and eight were from the payer perspective. Five studies spanned the lifetime horizon. Of the selected studies, six used probabilistic sensitivity analysis to address uncertainty in data parameters. Both procedures have been shown to be highly cost-effective from the societal perspective over the entire lifespan.

CONCLUSION

THA and TKA have been found to be highly cost-effective in a number of high-quality studies. Further analyses are needed on the cost-effectiveness of alternative surgical options, particularly osteotomy. Future economic evaluations should address the expanding indications of THA and TKA to younger, more physically active individuals.

The "hazards" of extrapolating survival curves

BACKGROUND

It is widely recommended that health technology appraisals adopt a lifetime horizon to assess the relative costs and benefits of an intervention. However, most trials or clinical studies have relatively short follow-up periods, with the event of interest not occurring before the end of the study for many subjects. In such cases, survival analysis using parametric models can be used to extrapolate into the future.

OBJECTIVE

To assess the accuracy of survival analysis in projecting future events beyond the sample estimation period.

DESIGN

Using a previously published comparison of 2 alternative hip replacement prostheses based on 8 years of data as a case study, we extend the data set to include 8 years more data. Using the new data, the parametric assumptions of the previous study and its success in predicting the outcomes are assessed.

RESULTS

The extended data set casts doubt on the previous study's findings. The failure curves of the 2 prostheses now cross, and the proportional hazards assumption no longer holds. Extrapolations from the original data set yielded very good predictions for one prosthesis for the full 16 years but were much poorer for the other, even when the proportionality assumption was relaxed.

CONCLUSIONS

Care should be taken when extrapolating treatment benefits for new technologies early in their life cycle based on observational or randomized controlled trial data sources. This case study reveals that predictions of prosthesis failure based on a short follow-up period were inaccurate compared with those after a longer period of follow-up.

Cost-effectiveness analysis of early versus late total hip replacement in Italy

OBJECTIVE

To assess the cost-effectiveness of early primary total hip replacement (THR) for functionally independent older adult patients with osteoarthritis (OA) versus 1) nonsurgical therapy followed by THR once the patient has progressed to a functionally dependent state ("delayed THR") and 2) nonsurgical therapy alone ('medical therapy'), from the Italian National Health Service perspective.

METHODS

Individual patient data and evidence from published literature on disease progression, economic costs and THR outcomes in OA, including utilities, perioperative mortality rates, prosthesis survival, and costs of prostheses, THR, rehabilitation, follow-up, revision, and nonsurgical management, combined with population life tables, were synthesized in a Markov model of OA. The model represents the lifetime experience of a patient cohort following their treatment choice, discounting costs and benefits (quality-adjusted life-years) at 3% annually.

RESULTS

At age 65 years, the incremental cost per quality-adjusted life-year of THR over delayed THR was €987 in men and €466 in women; the figures for delayed THR versus medical therapy were €463 and €82, respectively. Among 80-year-olds, early THR is (extended) dominant. With gradual utility loss after primary THR, delaying surgery may be more appealing in women than in men in their 50s, because longer female life expectancy implies longer latter periods of low health-related quality of life (HRQOL) with early THR.

CONCLUSIONS

THR is cost-effective. Patients' HRQOL benefits forgone with delayed THR are worth more than the costs it saves to the Italian National Health Service. This analysis might help to explain women's consistently lower HRQOL by the time of primary operation.

Cemented, cementless, and hybrid prostheses for total hip replacement: cost effectiveness analysis

OBJECTIVE

To compare the cost effectiveness of the three most commonly chosen types of prosthesis for total hip replacement.

DESIGN

Lifetime cost effectiveness model with parameters estimated from individual patient data obtained from three large national databases.

SETTING

English National Health Service.

PARTICIPANTS

Adults aged 55 to 84 undergoing primary total hip replacement for osteoarthritis.

INTERVENTIONS

Total hip replacement using either cemented, cementless, or hybrid prostheses.

MAIN OUTCOME MEASURES

Cost (£), quality of life (EQ-5D-3L, where 0 represents death and 1 perfect health), quality adjusted life years (QALYs), incremental cost effectiveness ratios, and the probability that each prosthesis type is the most cost effective at alternative thresholds of willingness to pay for a QALY gain.

RESULTS

Lifetime costs were generally lowest with cemented prostheses, and postoperative quality of life and lifetime QALYs were highest with hybrid prostheses. For example, in women aged 70 mean costs were £6900 ($11 000; €8200) for cemented prostheses, £7800 for cementless prostheses, and £7500 for hybrid prostheses; mean postoperative EQ-5D scores were 0.78, 0.80, and 0.81, and the corresponding lifetime QALYs were 9.0, 9.2, and 9.3 years. The incremental cost per QALY for hybrid compared with cemented prostheses was £2500. If the threshold willingness to pay for a QALY gain exceeded £10 000, the probability that hybrid prostheses were most cost effective was about 70%. Hybrid prostheses have the highest probability of being the most cost effective in all subgroups, except in women aged 80, where cemented prostheses were most cost effective.

CONCLUSIONS

Cemented prostheses were the least costly type for total hip replacement, but for most patient groups hybrid prostheses were the most cost effective. Cementless prostheses did not provide sufficient improvement in health outcomes to justify their additional costs.

Methods for estimating subgroup effects in cost-effectiveness analyses that use observational data

Decision makers require cost-effectiveness estimates for patient subgroups. In nonrandomized studies, propensity score (PS) matching and inverse probability of treatment weighting (IPTW) can address overt selection bias, but only if they balance observed covariates between treatment groups. Genetic matching (GM) matches on the PS and individual covariates using an automated search algorithm to directly balance baseline covariates. This article compares these methods for estimating subgroup effects in cost-effectiveness analyses (CEA). The motivating case study is a CEA of a pharmaceutical intervention, drotrecogin alfa (DrotAA), for patient subgroups with severe sepsis (n = 2726). Here, GM reported better covariate balance than PS matching and IPTW. For the subgroup at a high level of baseline risk, the probability that DrotAA was cost-effective ranged from 30% (IPTW) to 90% (PS matching and GM), at a threshold of £20 000 per quality-adjusted life-year. We then compared the methods in a simulation study, in which initially the PS was correctly specified and then misspecified, for example, by ignoring the subgroup-specific treatment assignment. Relative performance was assessed as bias and root mean squared error (RMSE) in the estimated incremental net benefits. When the PS was correctly specified and inverse probability weights were stable, each method performed well; IPTW reported the lowest RMSE. When the subgroup-specific treatment assignment was ignored, PS matching and IPTW reported covariate imbalance and bias; GM reported better balance, less bias, and more precise estimates. We conclude that if the PS is correctly specified and the weights for IPTW are stable, each method can provide unbiased cost-effectiveness estimates. However, unlike IPTW and PS matching, GM is relatively robust to PS misspecification.

A cluster randomised controlled trial of the clinical and cost-effectiveness of a 'whole systems' model of self-management support for the management of long- term conditions in primary care: trial protocol

BACKGROUND

Patients with long-term conditions are increasingly the focus of quality improvement activities in health services to reduce the impact of these conditions on quality of life and to reduce the burden on care utilisation. There is significant interest in the potential for self-management support to improve health and reduce utilisation in these patient populations, but little consensus concerning the optimal model that would best provide such support. We describe the implementation and evaluation of self-management support through an evidence-based 'whole systems' model involving patient support, training for primary care teams, and service re-organisation, all integrated into routine delivery within primary care.

METHODS

The evaluation involves a large-scale, multi-site study of the implementation, effectiveness, and cost-effectiveness of this model of self-management support using a cluster randomised controlled trial in patients with three long-term conditions of diabetes, chronic obstructive pulmonary disease (COPD), and irritable bowel syndrome (IBS). The outcome measures include healthcare utilisation and quality of life. We describe the methods of the cluster randomised trial.

DISCUSSION

If the 'whole systems' model proves effective and cost-effective, it will provide decision-makers with a model for the delivery of self-management support for populations with long-term conditions that can be implemented widely to maximise 'reach' across the wider patient population.

TRIAL REGISTRATION NUMBER

ISRCTN: ISRCTN90940049.

The economic benefit of hip replacement: a 5-year follow-up of costs and outcomes in the Exeter Primary Outcomes Study

OBJECTIVES

To assess changes in quality of life and costs of patients undergoing primary total hip replacement using the Exeter prosthesis compared with a hypothetical 'no surgery' group.

DESIGN

The incremental quality of life, quality-adjusted life years (QALYs) and cost of Exeter Primary Outcomes Study patients was compared with hypothetical 'no surgery' group over 5 years. Scores from annual SF-36 assessments were converted into utility scores using an established algorithm and the QALY gains calculated from pre-operative baseline scores. Costs included implant costs and length of stay.

SETTING

Secondary care hospitals.

PARTICIPANTS

Patients receiving a primary Exeter implant enrolled in five of seven Exeter Primary Outcomes Study centres.

RESULTS

On average, patients gained around 0.8 QALYs over 5 years. Younger and male patients or those with lower body mass index and poorer Oxford Hip Scores were significantly associated with increased QALYs. Treatment costs for a primary episode of care were just over £5000 (95% CI £4588 to £5812) per patient. Compared with 'no surgery', the cost per QALY was £7182 (95% CI £6470 to £7678), and this remained stable when key cost parameters were varied. The most likely cost per QALY was between £7058 and £7220. Older patients (age 75+) cost more, mainly due to longer average hospital stays and had a higher cost per QALY, although this remained below £10 000.

CONCLUSIONS

85% of cases had a cost of <£20 000 per QALY (with 70% having a cost per QALY under £10 000) compared with no surgery. Cases would be considered cost-effective under currently accepted thresholds (£25 000-£30 000) compared with 'no surgery'. However, depending on age and severity, younger patients and more severe patients had below average cost per QALYs. These results help to confirm the long-term benefits and cost-effectiveness of total hip replacement in a wide variety of patients using well-established implant models such as the Exeter. However, further and ongoing economic appraisal of this and other models is required for comparative purposes.

Economic evaluation of genomic test-directed chemotherapy for early-stage lymph node-positive breast cancer

BACKGROUND

Multi-parameter genomic tests identify patients with early-stage breast cancer who are likely to derive little benefit from adjuvant chemotherapy. These tests can potentially spare patients the morbidity from unnecessary chemotherapy and reduce costs. However, the costs of the test must be balanced against the health benefits and cost savings produced. This economic evaluation compared genomic test-directed chemotherapy using the Oncotype DX 21-gene assay with chemotherapy for all eligible patients with lymph node-positive, estrogen receptor-positive early-stage breast cancer.

METHODS

We performed a cost-utility analysis using a state transition model to calculate expected costs and benefits over the lifetime of a cohort of women with estrogen receptor-positive lymph node-positive breast cancer from a UK perspective. Recurrence rates for Oncotype DX-selected risk groups were derived from parametric survival models fitted to data from the Southwest Oncology Group 8814 trial. The primary outcome was the incremental cost-effectiveness ratio, expressed as the cost (in 2011 GBP) per quality-adjusted life-year (QALY). Confidence in the incremental cost-effectiveness ratio was expressed as a probability of cost-effectiveness and was calculated using Monte Carlo simulation. Model parameters were varied deterministically and probabilistically in sensitivity analysis. Value of information analysis was used to rank priorities for further research.

RESULTS

The incremental cost-effectiveness ratio for Oncotype DX-directed chemotherapy using a recurrence score cutoff of 18 was £5529 (US $8852) per QALY. The probability that test-directed chemotherapy is cost-effective was 0.61 at a willingness-to-pay threshold of £30 000 per QALY. Results were sensitive to the recurrence rate, long-term anthracycline-related cardiac toxicity, quality of life, test cost, and the time horizon. The highest priority for further research identified by value of information analysis is the recurrence rate in test-selected subgroups.

CONCLUSIONS

There is substantial uncertainty regarding the cost-effectiveness of Oncotype DX-directed chemotherapy. It is particularly important that future research studies to inform cost-effectiveness-based decisions collect long-term outcome data.

Esophageal Doppler monitoring during colorectal resection offers cost-effective improvement of hemodynamic control

OBJECTIVES

Hemodynamic control can improve the outcome of surgery. Esophageal Doppler monitoring measures blood flow by ultrasound waves. This work investigates the cost-effectiveness of this procedure during colorectal resection.

METHODS

Meta-analyses of randomized controlled trials of esophageal Doppler monitoring used in colorectal resection were conducted to help determine its cost-effectiveness. An analytical decision model was used to compare the cost-effectiveness of strategies involving conventional clinical assessment with or without the measurement of central venous pressure, with or without esophageal Doppler monitoring. Avoided mortality and avoided major complications were used as measures of clinical effectiveness.

RESULTS

In the meta-analyses comparing conventional clinical assessment plus central venous pressure monitoring with or without esophageal Doppler monitoring, statistically significant differences in total and major complications favoring the use of Doppler were found. No differences were seen in mortality. The use of esophageal Doppler monitoring was associated with lower costs, mainly due to fewer complications, shorter hospital stays and shorter surgery times.

CONCLUSIONS

Although the information regarding the clinical effectiveness of esophageal Doppler monitoring in colorectal resection is limited, strategies including this form of blood flow monitoring may be cost-effective. Further comparisons of Doppler monitoring against other hemodynamic monitoring systems should be undertaken.

Can choices between alternative hip prostheses be evidence based? a review of the economic evaluation literature

Background

Total hip replacement surgery places a considerable financial burden on health services and society. Given the large number of hip prostheses available to surgeons, reliable economic evidence is crucial to inform resource allocation decisions. This review summarises published economic evidence on alternative hip prostheses to examine the potential for the literature to inform resource allocation decisions in the UK.

Methods

We searched nine medical and economics electronic databases. 3,270 studies were initially identified, 17 studies were included in the review. Studies were critically appraised using three separate guidelines.

Results

Several methodological problems were identified including a lack of observed long term prosthesis survival data, limited up-to-date and UK based evidence and exclusion of patient and societal perspectives.

Conclusions

More clinical trials including long term follow-up and economic evaluation are needed. These should compare the cost-effectiveness of different prostheses with longer-term follow-up and including a wider perspective.

Cost of routine immunization of young children against rotavirus infection with Rotarix versus RotaTeq

Using a probabilistic model of the clinical and economic burden of rotavirus gastroenteritis (RVGE), we estimated the expected impact of vaccinating a US birth cohort with Rotarix in lieu of RotaTeq. Assuming full vaccination of all children, use of Rotarix - rather than RotaTeq - was estimated to reduce the total number of RVGE events by 5% and associated costs by 8%. On an overall basis, Rotarix would reduce costs by $77.2 million (95% CI $71.5-$86.5). Similar reductions with Rotarix were estimated to occur under an assumption of incomplete immunization of children.

Methods for determining cost-benefit ratios for pharmaceuticals in Germany

The aim of this methodological paper is to summarize evidence on how to implement cost-benefit assessment according to the new German legislative framework (Competition Enhancement Act). Given the complexity of existing health policy frameworks within industrialised countries in adapting health economics in their respective regulatory scheme, no clear international scientific consensus on which health economic methods should be chosen for assessment can be determined. Nevertheless, a broad consensus on the internal properties of methods itself can be found. Based on these common international standards in methodology, this work provides a minimum catalogue of methods and criteria that meet legal and local German requirements with regard to specific factors of its health care system. Aside from categorising clearly defined standards (e.g., study forms, cost and benefit categories) the suggested catalogue specifies some intensively debated areas in Germany (e.g., the QALY, modelling, the perspective used in the assessment). After the proposition of certain methods the paper leads to a first recommendation of a detailed assessment-process itself specific for the German way in implementing cost-benefit ratios within regulatory decision making in Germany.

Analysis sans frontières: can we ever make economic evaluations generalisable across jurisdictions?

Over the last decade or so, a number of healthcare systems have used economic evaluations as a formal input into decisions about the coverage or reimbursement of new healthcare interventions. This change in the policy landscape has placed some important demands on the design and characteristics of economic evaluation and these are increasingly evident in studies being presented to decision makers. One challenge has been to make studies specific to the context in which the decision is being taken. This is because of the inevitable geographical variation in many of the parameters within an analysis. There has been a series of important contributions to the published literature in recent years on how to quantify geographical heterogeneity within economic analyses based on randomised controlled trials. However, there are good reasons for economic evaluation for decision making to be undertaken using methods of evidence synthesis and decision analytical modelling, but issues of geographical variation still need to be handled appropriately. The key requirements of economic evaluations for decision making within healthcare systems can be defined as follows: (i) a design that meets the objectives and constraints of the healthcare system; (ii) coherent and complete specification of the decision problem; (iii) inclusion of all relevant evidence; and (iv) recognition and appropriate handling of uncertainty. In satisfying these requirements, it is important to be aware of variation between jurisdictions, and this imposes some important analytical requirements on economic studies. While many agencies have produced guidelines on preferred methods for healthcare economic evaluation, these exhibit considerable variation. Some of this variation can be justified by genuine differences between systems in clinical practice, objectives and constraints, while some of the variation relates to differences of opinion about appropriate analysis given methodological uncertainty. However, some of the variation in guidance is difficult to justify and is inconsistent with the aims and objectives of the systems the analyses are seeking to inform. Decision makers and analysts need to work together to streamline and where possible harmonise guidelines on methods for economic evaluations, whilst recognising legitimate variation in the needs of different healthcare systems. Otherwise, there is the risk that scarce resources will be wasted in producing country-specific analyses in situations where these are not justified. Expected value of information analyses are also emerging as a tool that could be considered by decision makers to guide their policy on the acceptance or non-acceptance of data from other jurisdictions.

Presidential guest address: the Swedish Hip Registry: increasing the sensitivity by patient outcome data

The Swedish Hip Register was initiated in 1979. The mission of the register is to improve the outcome of THA. The hypothesis is that feedback of data stimulates participating clinics to reflect and improve. In addition to revision surgery, patient-based outcome measures and radiographic results are included to improve sensitivity. All patients who have a total hip arthroplasty answer a questionnaire preoperatively and again after 1, 6, and 10 years postoperatively. The questionnaire includes the Charnley classification, EQ-5D and visual analog scales concerning pain and overall satisfaction and is used by 31 of 81 units. Average costs for the procedure ($11,000) are obtained from a national database. The mean gain in the EQ-5D index after 1 year for 3900 patients was 0.37, giving a low cost of $3000 per quality adjusted life year. Patient satisfaction and pain amelioration generally was high. The national average 7-year survival (revision as endpoint), has improved from 93.5% (+/- 0.15) to 95.8 (+/- 0.15) between the two periods 1979 to 1991 and 1992 to 2003. National implant registers define the epidemiology of primary and revision surgery. In conjunction with individual subjective patient data and radiography they contribute to development of evidence-based THA surgery.