Challenges encountered in the economic evaluation of medical devices

This thesis concerns the linking together of the challenges encountered in the economic evaluation of medical devices and credible ways of performing economic evaluation in such a scenario. Although the standard methods of estimating cost-effectiveness have gained widespread acceptance, there are concerns around the methods for conducting economic evaluation in the health technology assessment of devices. Currently, the lack of appropriate comparators and evidence generation (i.e. quantity and quality of the clinical and economic evidence) have been identified as the main challenges

Setting benchmark revision rates for total hip replacement: analysis of registry evidence

Objective - To compare 10 year revision rates for frequently used types of primary total hip replacement to inform setting of a new benchmark rate in England and Wales that will be of international relevance. Design - Retrospective cohort study. Setting - National Joint Registry. Participants - 239 000 patient records. Main outcome measures - Revision rates for five frequently used types of total hip replacement that differed according to bearing surface and fixation mode, encompassing 62% of all primary total hip replacements in the National Joint Registry for England and Wales. Revision rates were compared using Kaplan-Meier and competing risks analyses, and five and 10 year rates were estimated using well fitting parametric models. Results - Estimated revision rates at 10 years were 4% or below for four of the five types of total hip replacement investigated. Rates differed little according to Kaplan-Meier or competing risks analysis, but differences between prosthesis types were more substantial. Cemented prostheses with ceramic-on-polyethylene bearing surfaces had the lowest revision rates (1.88-2.11% at 10 years depending on the method used), and cementless prostheses with ceramic-on-ceramic bearing surfaces had the highest revision rates (3.93-4.33%). Men were more likely to receive revision of total hip replacement than were women, and this difference was statistically significant for four of the five prosthesis types. Conclusions - Ten year revision rate estimates were all less than 5%, and in some instances considerably less. The results suggest that the current revision rate benchmark should be at least halved from 10% to less than 5% at 10 years. This has implications for benchmarks internationally

The Community In-reach Rehabilitation and Care Transition (CIRACT) clinical and cost-effectiveness randomisation controlled trial in older people admitted to hospital as an acute medical emergency

Objective: To compare the clinical and cost-effectiveness of a Community In-reach Rehabilitation and Care Transition (CIRACT) service with the traditional hospital-based rehabilitation (THB-Rehab) service. Design: Pragmatic randomised controlled trial with an integral health economic study. Settings: Large UK teaching hospital, with community follow-up. Subjects: Frail older people aged 70 years and older admitted to hospital as an acute medical emergency. Measurements: Primary outcome: hospital length of stay; secondary outcomes: readmission, day 91-super spell bed days, functional ability, co-morbidity and health-related quality of life; cost-effectiveness analysis. Results: A total of 250 participants were randomised. There was no significant difference in length of stay between the CIRACT and THB-Rehab service (median 8 versus 9 days; geometric mean 7.8 versus 8.7 days, mean ratio 0.90, 95% confidence interval (CI) 0.74–1.10). Of the participants who were discharged from hospital, 17% and 13% were readmitted within 28 days from the CIRACT and THB-Rehab services, respectively (risk difference 3.8%, 95% CI −5.8% to 13.4%). There were no other significant differences in any of the other secondary outcomes between the two groups. The mean costs (including NHS and personal social service) of the CIRACT and THB-Rehab service were £3,744 and £3,603, respectively (mean cost difference £144; 95% CI −1,645 to 1,934). Conclusion: The CIRACT service does not reduce major hospital length of stay nor reduce short-term readmission rates, compared to the standard THB-Rehab service; however, a modest (<2.3 days) effect cannot be excluded. Further studies are necessary powered with larger sample sizes and cluster randomisation. Trial registration: ISRCTN 94393315, 25th April 201

Analysis of influence of the relative weir height of rectangular broad-crested weir on discharge coefficient

Diplomová práce pojednává o vlivu relativní výšky přelivu pravoúhlého průřezu se širokou korunou na součinitel průtoku. Na základě měření úrovně hladiny před přelivem při různých průtocích i výškách přelivu P, byly stanoveny hodnoty součinitele průtoku v závislosti na h/P. Tyto hodnoty byly porovnány s výsledky měření a vztahy, jež jsou uvedeny v odborné literatuře. V závěru práce byly vyvozeny nové vztahy, kterých lze pro výpočet součinitele průtoku vztaženého k přepadové výšce využít.This diploma thesis dealt with the influence of relative weir height of rectangular broad-crested weir on discharge coefficient. Based on the level measurement in front of weir for different heights of the weir P and discharges were determined values of discharge coefficient according h/P. These values were compared with the results of measurements and relationships, which are mentioned in the professional literature. In conclusion were derived new relationships that can be used to calculate the discharge coefficient relative to the overflow head.

Cost-effectiveness of left ventricular assist devices (LVADs) for patients with advanced heart failure : analysis of the British NHS Bridge to Transplant (BTT) program

Background: A previous cost-effectiveness analysis showed that bridge to transplant (BTT) with early design left ventricular assist devices (LVADs) for advanced heart failure was more expensive than medical management while appearing less beneficial. Older LVADs were pulsatile, but current second and third generation LVADs are continuous flow pumps. This study aimed to estimate comparative cost-effectiveness of BTT with durable implantable continuous flow LVADs compared to medical management in the British NHS. Methods and results: A semi-Markov multi-state economic model was built using NHS costs data and patient data in the British NHS Blood and Transplant Database (BTDB). Quality-adjusted life years (QALYs) and incremental costs per QALY were calculated for patients receiving LVADs compared to those receiving inotrope supported medical management. LVADs cost £80,569 ($127,887) at 2011 prices and delivered greater benefit than medical management. The estimated probabilistic incremental cost-effectiveness ratio (ICER) was £53,527 ($84,963)/QALY (95%CI: £31,802–£94,853; $50,479–$150,560) (over a lifetime horizon). Estimates were sensitive to choice of comparator population, relative likelihood of receiving a heart transplant, time to transplant, and LVAD costs. Reducing the device cost by 15% decreased the ICER to £50,106 ($79,533)/QALY. Conclusions: Durable implantable continuous flow LVADs deliver greater benefits at higher costs than medical management in Britain. At the current UK threshold of £20,000 to £30,000/QALY LVADs are not cost effective but the ICER now begins to approach that of an intervention for end of life care recently recommended by the British NHS. Cost-effectiveness estimates are hampered by the lack of randomized trials

Cost-effectiveness of left ventricular assist devices (LVADs) for patients with advanced heart failure : analysis of the British NHS Bridge to Transplant (BTT) program

Background: A previous cost-effectiveness analysis showed that bridge to transplant (BTT) with early design left ventricular assist devices (LVADs) for advanced heart failure was more expensive than medical management while appearing less beneficial. Older LVADs were pulsatile, but current second and third generation LVADs are continuous flow pumps. This study aimed to estimate comparative cost-effectiveness of BTT with durable implantable continuous flow LVADs compared to medical management in the British NHS. Methods and results: A semi-Markov multi-state economic model was built using NHS costs data and patient data in the British NHS Blood and Transplant Database (BTDB). Quality-adjusted life years (QALYs) and incremental costs per QALY were calculated for patients receiving LVADs compared to those receiving inotrope supported medical management. LVADs cost £80,569 ($127,887) at 2011 prices and delivered greater benefit than medical management. The estimated probabilistic incremental cost-effectiveness ratio (ICER) was £53,527 ($84,963)/QALY (95%CI: £31,802–£94,853; $50,479–$150,560) (over a lifetime horizon). Estimates were sensitive to choice of comparator population, relative likelihood of receiving a heart transplant, time to transplant, and LVAD costs. Reducing the device cost by 15% decreased the ICER to £50,106 ($79,533)/QALY. Conclusions: Durable implantable continuous flow LVADs deliver greater benefits at higher costs than medical management in Britain. At the current UK threshold of £20,000 to £30,000/QALY LVADs are not cost effective but the ICER now begins to approach that of an intervention for end of life care recently recommended by the British NHS. Cost-effectiveness estimates are hampered by the lack of randomized trials

Challenges Associated with Estimating Utility in Wet Age-Related Macular Degeneration : A Novel Regression Analysis to Capture the Bilateral Nature of the Disease

INTRODUCTION: The estimation of utility values for the economic evaluation of therapies for wet age-related macular degeneration (AMD) is a particular challenge. Previous economic models in wet AMD have been criticized for failing to capture the bilateral nature of wet AMD by modelling visual acuity (VA) and utility values associated with the better-seeing eye only. METHODS: Here we present a de novo regression analysis using generalized estimating equations (GEE) applied to a previous dataset of time trade-off (TTO)-derived utility values from a sample of the UK population that wore contact lenses to simulate visual deterioration in wet AMD. This analysis allows utility values to be estimated as a function of VA in both the better-seeing eye (BSE) and worse-seeing eye (WSE). RESULTS: VAs in both the BSE and WSE were found to be statistically significant (p < 0.05) when regressed separately. When included without an interaction term, only the coefficient for VA in the BSE was significant (p = 0.04), but when an interaction term between VA in the BSE and WSE was included, only the constant term (mean TTO utility value) was significant, potentially a result of the collinearity between the VA of the two eyes. The lack of both formal model fit statistics from the GEE approach and theoretical knowledge to support the superiority of one model over another make it difficult to select the best model. CONCLUSION: Limitations of this analysis arise from the potential influence of collinearity between the VA of both eyes, and the use of contact lenses to reflect VA states to obtain the original dataset. Whilst further research is required to elicit more accurate utility values for wet AMD, this novel regression analysis provides a possible source of utility values to allow future economic models to capture the quality of life impact of changes in VA in both eyes. FUNDING: Novartis Pharmaceuticals UK Limited

Simulation Modelling in Ophthalmology : Application to Cost Effectiveness of Ranibizumab and Aflibercept for the Treatment of Wet Age-Related Macular Degeneration in the United Kingdom

Previously developed models in ophthalmology have generally used a Markovian structure. There are a number of limitations with this approach, most notably the ability to base patient outcomes on best-corrected visual acuity (BCVA) in both eyes, which may be overcome using a different modelling structure. Simulation modelling allows for this to be modelled more precisely, and therefore may provide more accurate and relevant estimates of the cost effectiveness of ophthalmology interventions

Six weeks of home enteral nutrition versus standard care after esophagectomy or total gastrectomy for cancer: study protocol for a randomized controlled trial

Background: Each year approximately 3000 patients in the United Kingdom undergo surgery for esophagogastric cancer. Jejunostomy feeding tubes, placed at the time of surgery for early postoperative nutrition, have been shown to have a positive impact on clinical outcomes in the short term. Whether feeding out of hospital is of benefit is unknown. Local experience has identified that between 15 and 20% of patients required ‘rescue’ jejunostomy feeding for nutritional problems and weight loss while at home. This weight loss and poor nutrition may contribute to the detrimental effect on the overall quality of life (QoL) reported in these patients. Methods/Design: This randomized pilot and feasibility study will provide preliminary information on the routine use of jejunostomy feeding after hospital discharge in terms of clinical benefits and QoL. Sixty participants undergoing esophagectomy or total gastrectomy will be randomized to receive either a planned program of six weeks of home jejunostomy feeding after discharge from hospital (intervention) or treatment-as-usual (control). The intention of this study is to inform a multi-centre randomized controlled trial. The primary outcome measures will be recruitment and retention rates at six weeks and six months. Secondary outcome measures will include disease specific and general QoL measures, nutritional parameters, total and oral nutritional intake, hospital readmission rates, and estimates of healthcare costs. Up to 20 participants will also be enrolled in a qualitative sub-study that will explore participants’ and carers’ experiences of home tube feeding. The results will be disseminated by presentation at surgical, gastroenterological and dietetic meetings and publication in appropriate peer review journals. A patient-friendly lay summary will be made available on the University of Leicester and the University Hospitals of Leicester NHS Trust websites. The study has full ethical and institutional approval and started recruitment in July 2012. Trial registration: UKClinical Research Network ID #12447 (Main study); UKCRN ID#13361 (Qualitative sub study); ClinicalTrials.gov #NCT01870817 (First registered 28 May 2013

A randomised controlled trial of six weeks of home enteral nutrition versus standard care after oesophagectomy or total gastrectomy for cancer: report on a pilot and feasibility study.

BACKGROUND: Poor nutrition in the first months after oesophago-gastric resection is a contributing factor to the reduced quality of life seen in these patients. The aim of this pilot and feasibility study was to ascertain the feasibility of conducting a multi-centre randomised controlled trial to evaluate routine home enteral nutrition in these patients. METHODS: Patients undergoing oesophagectomy or total gastrectomy were randomised to either six weeks of home feeding through a jejunostomy (intervention), or treatment as usual (control). Intervention comprised overnight feeding, providing 50 % of energy and protein requirements, in addition to usual oral intake. Primary outcome measures were recruitment and retention rates at six weeks and six months. Nutritional intake, nutritional parameters, quality of life and healthcare costs were also collected. Interviews were conducted with a sample of participants, to ascertain patient and carer experiences. RESULTS: Fifty-four of 112 (48 %) eligible patients participated in the study over the 20 months. Study retention at six weeks was 41/54 patients (76 %) and at six months was 36/54 (67 %). At six weeks, participants in the control group had lost on average 3.9 kg more than participants in the intervention group (95 % confidence interval [CI] 1.6 to 6.2). These differences remained evident at three months (mean difference 2.5 kg, 95 % CI -0.5 to 5.6) and at six months (mean difference 2.5 kg, 95 % CI -1.2 to 6.1). The mean values observed in the intervention group for mid arm circumference, mid arm muscle circumference, triceps skin fold thickness and right hand grip strength were greater than for the control group at all post hospital discharge time points. The economic evaluation suggested that it was feasible to collect resource use and EQ-5D data for a full cost-effectiveness analysis. Thematic analysis of 15 interviews identified three main themes related to the intervention and the trial: 1) a positive experience, 2) the reasons for taking part, and 3) uncertainty of the study process. CONCLUSIONS: This study demonstrated that home enteral feeding by jejunostomy was feasible, safe and acceptable to patients and their carers. Whether home enteral feeding as 'usual practice' is a cost-effective therapy would require confirmation in an appropriately powered, multi-centre study. TRIAL REGISTRATION: UK Clinical Research Network ID 12447 (main trial, first registered 30 May 2012); UK Clinical Research Network ID 13361 (qualitative substudy, first registered 30 May 2012); ClinicalTrials.gov NCT01870817 (first registered 28 May 2013)