The cost-effectiveness of an early interventional strategy in non-ST-elevation acute coronary syndrome based on the RITA 3 trial

Cost Analysis From a Randomized Comparison of Immediate Versus Delayed Angiography After Cardiac Arrest

Background In patients with out-of-hospital cardiac arrest without ST-segment elevation, immediate coronary angiography did not improve clinical outcomes when compared with delayed angiography in the COACT (Coronary Angiography After Cardiac Arrest) trial. Whether 1 of the 2 strategies has benefits in terms of health care resource use and costs is currently unknown. We assess the health care resource use and costs in patients with out-of-hospital cardiac arrest. Methods and Results A total of 538 patients were randomly assigned to a strategy of either immediate or delayed coronary angiography. Detailed health care resource use and cost-prices were collected from the initial hospital episode. A generalized linear model and a gamma distribution were performed. Generic quality of life was measured with the RAND-36 and collected at 12-month follow-up. Overall total mean costs were similar between both groups (EUR 33 575±19 612 versus EUR 33 880±21 044; P=0.86). Generalized linear model: (β, 0.991; 95% CI, 0.894-1.099; P=0.86). Mean procedural costs (coronary angiography and percutaneous coronary intervention, coronary artery bypass graft) were higher in the immediate angiography group (EUR 4384±3447 versus EUR 3028±4220; P<0.001). Costs concerning intensive care unit and ward stay did not show any significant difference. The RAND-36 questionnaire did not differ between both groups. Conclusions The mean total costs between patients with out-of-hospital cardiac arrest randomly assigned to an immediate angiography or a delayed invasive strategy were similar during the initial hospital stay. With respect to the higher invasive procedure costs in the immediate group, a strategy awaiting neurological recovery followed by coronary angiography and planned revascularization may be considered. Registration URL: https://trialregister.nl; Unique identifier: NL4857.

The management of acute coronary syndromes in patients presenting without persistent ST-segment elevation: key points from the ESC 2020 Clinical Practice Guidelines for the general and emergency physician

There have been significant advances in the diagnosis and management of non-ST-segment elevation myocardial infarction over recent years, which has been reflected in an international decline in mortality rates. This article provides an overview of the 2020 European Society of Cardiology Clinical Practice Guidelines for the topic, concentrating on areas relevant to the general or emergency physician. The recommendations and underlying evidence basis are analysed in three key areas: diagnosis (the recommendation to use high sensitivity troponin and how to apply it), pathways (the recommendation to facilitate early invasive coronary angiography to improve outcomes and shorten hospital stays) and treatment (a paradigm shift in the use of early intensive platelet inhibition). Gaps in the evidence base are highlighted, including the optimal management strategy for older people and the antiplatelet regime to consider when angiography may be delayed.

The Importance of Accounting for Parameter Uncertainty in SF-6D Value Sets and Its Impact on Studies that Use the SF-6D to Measure Health Utility

Background: The parameter uncertainty in the six-dimensional health state short form (SF-6D) value sets is commonly ignored. There are two sources of parameter uncertainty: uncertainty around the estimated regression coefficients and uncertainty around the model’s specification. This study explores these two sources of parameter uncertainty in the value sets using probabilistic sensitivity analysis (PSA) and a Bayesian approach. Methods: We used data from the original UK/SF-6D valuation study to evaluate the extent of parameter uncertainty in the value set. First, we re-estimated the Brazier model to replicate the published estimated coefficients. Second, we estimated standard errors around the predicted utility of each SF-6D state to assess the impact of parameter uncertainty on these estimated utilities. Third, we used Monte Carlo simulation technique to account for the uncertainty on these estimates. Finally, we used a Bayesian approach to quantifying parameter uncertainty in the value sets. The extent of parameter uncertainty in SF-6D value sets was assessed using data from the Hong Kong valuation study. Results: Including parameter uncertainty results in wider confidence/credible intervals and improved coverage probability using both approaches. Using PSA, the mean 95% confidence intervals widths for the mean utilities were 0.1394 (range: 0.0565–0.2239) and 0.0989 (0.0048–0.1252) with and without parameter uncertainty whilst, using the Bayesian approach, this was 0.1478 (0.053–0.1665). Upon evaluating the impact of parameter uncertainty on estimates of a population’s mean utility, the true standard error was underestimated by 79.1% (PSA) and 86.15% (Bayesian) when parameter uncertainty was ignored. Conclusions: Parameter uncertainty around the SF-6D value set has a large impact on the predicted utilities and estimated confidence intervals. This uncertainty should be accounted for when using SF-6D utilities in economic evaluations. Ignoring this additional information could impact misleadingly on policy decisions.

Early invasive strategy in senior patients with non-ST-segment elevation myocardial infarction: is it cost-effective? - a decision-analytic model and value of information analysis

BACKGROUND

Non-ST-elevation myocardial infarction (NSTEMI) is the most common type of heart attack in the UK and it is becoming increasingly prevalent among older people. An early invasive treatment strategy may be effective and cost-effective for treating NSTEMI but evidence is currently unclear.

OBJECTIVES

To assess the cost-effectiveness of the early invasive strategy versus medical management in elderly patients with NSTEMI and to provide guidance for future research in this area.

METHODS

A long-term Markov state transition model was developed. Model inputs were systematically derived from a number of sources most appropriate to a UK relevant analysis, such as published studies and national routine data. Costs were estimated from the perspective of National Health Service and Personal Social Services. The model was developed using TreeAge Pro software. Based on a probabilistic sensitivity analysis, a value of information analysis was carried out to establish the value of decision uncertainty both overall and for specific input parameters.

RESULTS

In 2017 UK £, the incremental cost-effectiveness ratio of the early invasive strategy was £46 916 for each additional quality-adjusted life-year (QALY) gained, with a probability of being cost-effective of 23% at a cost-effectiveness threshold of £20 000/QALY. There was a considerable decision uncertainty with these results. The value of removing all this uncertainty was up to £1 920 000 annually. Most uncertainty related to clinical effectiveness parameters and the optimal study design to remove this uncertainty would be a randomised controlled trial.

CONCLUSION

Based on current evidence, the early invasive strategy is not likely to be cost-effective for elderly patients with NSTEMI. This conclusion should be interpreted with caution mainly due to the absence of NSTEMI-specific data and long-term clinical effectiveness estimates.

A national quality improvement programme to improve survival after emergency abdominal surgery: the EPOCH stepped-wedge cluster RCT

Background

Emergency abdominal surgery is associated with poor patient outcomes. We studied the effectiveness of a national quality improvement (QI) programme to implement a care pathway to improve survival for these patients.

Objectives

The objectives were to assess whether or not the QI programme improves 90-day survival after emergency abdominal surgery; to assess effects on 180-day survival, hospital stay and hospital readmission; and to better understand these findings through an integrated process evaluation, ethnographic study and cost-effectiveness analysis.

Design

This was a stepped-wedge cluster randomised trial. Hospitals were organised into 15 geographical clusters, and commenced the QI programme in random order over 85 weeks. Analyses were performed on an intention-to-treat basis. The primary outcome was analysed using a mixed-effects parametric survival model, adjusting for time-related effects. Ethnographic and economics data were collected in six hospitals. The process evaluation included all hospitals.

Setting

The trial was set in acute surgical services of 93 NHS hospitals.

Participants

Patients aged ≥ 40 years who were undergoing emergency abdominal surgery were eligible.

Intervention

The intervention was a QI programme to implement an evidence-based care pathway.

Main outcome measures

The primary outcome measure was mortality within 90 days of surgery. Secondary outcomes were mortality within 180 days, length of hospital stay and hospital readmission within 180 days. The main economic measure was the quality-adjusted life-years.

Data sources

Data were obtained from the National Emergency Laparotomy Audit database; qualitative interviews and ethnographic observations; quality-of-life and NHS resource use data were collected via questionnaires.

Results

Of 15,873 eligible patients from 93 NHS hospitals, primary outcome data were analysed for 8482 participants in the usual care group and 7374 in the QI group. The primary outcome occurred in 1393 participants in the usual care group (16%), compared with 1210 patients in the QI group (16%) [QI vs. usual care hazard ratio (HR) 1.11, 95% confidence interval (CI) 0.96 to 1.28]. No differences were found in mortality at 180 days or hospital readmission; there was a small increase in hospital stay in the QI group (HR for discharge 0.90, 95% CI 0.83 to 0.97). There were only modest improvements in care processes following QI implementation. The ethnographic study revealed good QI engagement, but limited time and resources to implement change, affecting which processes teams addressed, the rate of change and eventual success. In some sites, there were challenges around prioritising the intervention in busy environments and in obtaining senior engagement. The intervention is unlikely to be cost-effective at standard cost-effectiveness thresholds, but may be cost-effective over the lifetime horizon.

Limitations

Substantial delays were encountered in securing data access to national registries. Fewer patients than expected underwent surgery and the mortality rate was lower than anticipated.

Conclusions

There was no survival benefit from a QI programme to implement a care pathway for patients undergoing emergency abdominal surgery. The modest impact of the intervention on process measures, despite good clinician engagement, may have been limited by the time and resources needed to improve patient care.

Future work

Future QI programmes must balance intervention complexity with the practical realities of NHS services to ensure that such programmes can be delivered with the resources available.

Trial registration

Current Controlled Trials ISRCTN80682973 and The Lancet protocol 13PRT/7655.

Funding

This project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full in Health Services and Delivery Research; Vol. 7, No. 32. See the NIHR Journals Library website for further project information.

Quality of health economic evaluations for the ACC/AHA stable ischemic heart disease practice guideline: A systematic review

BACKGROUND

The American College of Cardiology/American Heart Association (ACC/AHA) recently published a rigorous framework to guide integration of economic data into clinical guidelines. We assessed the quality of economic evaluations in a major ACC/AHA clinical guidance report.

METHODS

We systematically identified cost-effectiveness analyses (CEAs) of RCTs cited in the ACC/AHA 2012 Guideline for the Diagnosis and Management of Patients with Stable Ischemic Heart Disease. We extracted: (1) study identifiers; (2) parent RCT information; (3) economic analysis characteristics; and (4) study quality using the Quality of Health Economic Studies instrument (QHES).

RESULTS

Quality scores were categorized as high (≥75 points) or low (<75 points). Of 1,266 citations in the guideline, 219 were RCTs associated with 77 CEAs. Mean quality score was 81 (out of 100) and improved over time, though 29.9% of studies were low-quality. Cost-per-QALY was the most commonly reported primary outcome (39.0%). Low-quality studies were less likely to report study perspective, use appropriate time horizons, or address statistical and clinical uncertainty. Funding was overwhelmingly private (83%). A detailed methodological assessment of high-quality studies revealed domains of additional methodological issues not identified by the QHES.

CONCLUSIONS

Economic evaluations of RCTs in the 2012 ACC/AHA ischemic heart disease guideline largely had high QHES scores but methodological issues existed among "high-quality" studies. Because the ACC/AHA has generally been more systematic in its integration of scientific evidence compared to other professional societies, it is likely that most societies will need to proceed more cautiously in their integration of economic evidence.

Value of External Data in the Extrapolation of Survival Data: A Study Using the NJR Data Set

BACKGROUND

Extrapolation of time-to-event data can be a critical component of cost-effectiveness analysis.

OBJECTIVES

To contrast the value of external data on treatment effects as a selection aid in model fitting to the clinical data or for the direct extrapolation of survival.

METHODS

We assume the existence of external summary data on both treatment and control and consider two scenarios: availability of external individual patient data (IPD) on the control only and an absence of external IPD. We describe how the summary data can be used to extrapolate survival or to assess the plausibility of extrapolations of the clinical data. We assess the merit of either approach using a comparison of cemented and cementless total hip replacement as a case study. Merit is judged by comparing incremental net benefit (INB) obtained in scenarios with incomplete IPD with that derived from modeling external IPD on both treatment and control.

RESULTS

Measures of fit with the external summary data did not identify survival model specifications that best estimated INB. Addition of external IPD for the control only did not improve estimates of INB. Extrapolation of survival using the external summary data comparing treatment and control improved estimates of INB.

CONCLUSIONS

Our case study indicates that summary data comparing treatment and control are more valuable than IPD limited to the control when extrapolating event rates for cost-effectiveness analysis. These data are best exploited in direct extrapolation of event rates rather than as an aid to select extrapolations on the basis of the clinical data.

Regional to tertiary inter-hospital transfer versus in-house percutaneous coronary intervention in acute coronary syndrome

RATIONALE

To address the inaccessibility of interventional cardiac services in North Queensland a new cardiac catheterisation laboratory (CCL) was established in Mackay Base Hospital (MBH) in February 2014.

OBJECTIVE

To determine whether the provision of in-house angiography and/or percutaneous coronary intervention (PCI) 1) minimises treatment delays 2) further reduces the risk of mortality, recurrent myocardial infarction (MI) and recurrent ischaemia 3) improves patient satisfaction and 4) minimises cost expenditure compared with inter-hospital transfer for patients with acute coronary syndrome (ACS).

METHODS

We compared ACS patients who were transferred to tertiary centres from July 2012 to June 2013 with those who received in-house angiography and/or PCI from February 2015 to January 2016. The primary outcome was the composite of all-cause mortality, recurrent myocardial infarction (MI) or recurrent ischaemia at six months. Pre-specified secondary outcomes were the composite of all-cause mortality, recurrent MI or recurrent ischaemia at one month, a summated patient satisfaction score and the proportional cost savings generated between 2015 and 2016.

RESULTS

We included consecutive samples of 203 patients from July 2012 to June 2013 and 229 patients from February 2015 to January 2016. There was a reduction in the median time to treatment of 3.2 days and a reduction in the median length of stay of four days amongst all ACS patients receiving in-house angiography and/or PCI. The primary outcome occurred in 14 (6.9%) patients in the 2012 to 2013 group, as compared with 18 (7.9%) patients in the 2015 to 2016 group (OR = 0.71, 95% CI 0.24-2.1, P = 0.54). The secondary outcome at one month occurred in four (2.0%) patients in the 2012 to 2013 group, as compared with three (1.3%) patients in the 2015 to 2016 group (OR = 1.2, 95% CI 0.11-13.1, P = 0.87). There was a statistically significant improvement in the summated patient satisfaction score amongst patients who received in-house angiography and/or PCI (U = 1918, P <0.05 two tailed). A calculation of estimated cost savings showed a reduction in proportional cost of $14 481 (51%) per ACS patient receiving in house angiography and/or PCI between 2015 and 2016.

CONCLUSION

This study suggests that the provision of regional in-house angiography and/or PCI for the treatment of ACS minimises delays to invasive treatment by 3.2 days, minimises the median length of stay by four days, significantly improves patient satisfaction and reduces proportional treatment costs by $14 481 (51%) per patient. Currently, however, it appears that that in-house treatment does not further reduce the risk of mortality, recurrent MI and recurrent ischaemia at one and six months.

Social value and individual choice: The value of a choice-based decision-making process in a collectively funded health system

Evidence about cost-effectiveness is increasingly being used to inform decisions about the funding of new technologies that are usually implemented as guidelines from centralized decision-making bodies. However, there is also an increasing recognition for the role of patients in determining their preferred treatment option. This paper presents a method to estimate the value of implementing a choice-based decision process using the cost-effectiveness analysis toolbox. This value is estimated for 3 alternative scenarios. First, it compares centralized decisions, based on population average cost-effectiveness, against a decision process based on patient choice. Second, it compares centralized decision based on patients' subgroups versus an individual choice-based decision process. Third, it compares a centralized process based on average cost-effectiveness against a choice-based process where patients choose according to a different measure of outcome to that used by the centralized decision maker. The methods are applied to a case study for the management of acute coronary syndrome. It is concluded that implementing a choice-based process of treatment allocation may be an option in collectively funded health systems. However, its value will depend on the specific health problem and the social values considered relevant to the health system.

How to Appropriately Extrapolate Costs and Utilities in Cost-Effectiveness Analysis

Costs and utilities are key inputs into any cost-effectiveness analysis. Their estimates are typically derived from individual patient-level data collected as part of clinical studies the follow-up duration of which is often too short to allow a robust quantification of the likely costs and benefits a technology will yield over the patient's entire lifetime. In the absence of long-term data, some form of temporal extrapolation-to project short-term evidence over a longer time horizon-is required. Temporal extrapolation inevitably involves assumptions regarding the behaviour of the quantities of interest beyond the time horizon supported by the clinical evidence. Unfortunately, the implications for decisions made on the basis of evidence derived following this practice and the degree of uncertainty surrounding the validity of any assumptions made are often not fully appreciated. The issue is compounded by the absence of methodological guidance concerning the extrapolation of non-time-to-event outcomes such as costs and utilities. This paper considers current approaches to predict long-term costs and utilities, highlights some of the challenges with the existing methods, and provides recommendations for future applications. It finds that, typically, economic evaluation models employ a simplistic approach to temporal extrapolation of costs and utilities. For instance, their parameters (e.g. mean) are typically assumed to be homogeneous with respect to both time and patients' characteristics. Furthermore, costs and utilities have often been modelled to follow the dynamics of the associated time-to-event outcomes. However, cost and utility estimates may be more nuanced, and it is important to ensure extrapolation is carried out appropriately for these parameters.

Extrapolating Survival from Randomized Trials Using External Data: A Review of Methods

This article describes methods used to estimate parameters governing long-term survival, or times to other events, for health economic models. Specifically, the focus is on methods that combine shorter-term individual-level survival data from randomized trials with longer-term external data, thus using the longer-term data to aid extrapolation of the short-term data. This requires assumptions about how trends in survival for each treatment arm will continue after the follow-up period of the trial. Furthermore, using external data requires assumptions about how survival differs between the populations represented by the trial and external data. Study reports from a national health technology assessment program in the United Kingdom were searched, and the findings were combined with “pearl-growing” searches of the academic literature. We categorized the methods that have been used according to the assumptions they made about how the hazards of death vary between the external and internal data and through time, and we discuss the appropriateness of the assumptions in different circumstances. Modeling choices, parameter estimation, and characterization of uncertainty are discussed, and some suggestions for future research priorities in this area are given.

10-Year Mortality Outcome of a Routine Invasive Strategy Versus a Selective Invasive Strategy in Non-ST-Segment Elevation Acute Coronary Syndrome: The British Heart Foundation RITA-3 Randomized Trial

BACKGROUND

The RITA-3 (Third Randomised Intervention Treatment of Angina) trial compared outcomes of a routine early invasive strategy (coronary arteriography and myocardial revascularization, as clinically indicated) to those of a selective invasive strategy (coronary arteriography for recurrent ischemia only) in patients with non-ST-segment elevation acute coronary syndrome (NSTEACS). At a median of 5 years' follow-up, the routine invasive strategy was associated with a 24% reduction in the odds of all-cause mortality.

OBJECTIVES

This study reports 10-year follow-up outcomes of the randomized cohort to determine the impact of a routine invasive strategy on longer-term mortality.

METHODS

We randomized 1,810 patients with NSTEACS to receive routine invasive or selective invasive strategies. All randomized patients had annual follow-up visits up to 5 years, and mortality was documented thereafter using data from the Office of National Statistics.

RESULTS

Over 10 years, there were no differences in mortality between the 2 groups (all-cause deaths in 225 [25.1%] vs. 232 patients [25.4%]: p = 0.94; and cardiovascular deaths in 135 [15.1%] vs. 147 patients [16.1%]: p = 0.65 in the routine invasive and selective invasive groups, respectively). Multivariate analysis identified several independent predictors of 10-year mortality: age, previous myocardial infarction, heart failure, smoking status, diabetes, heart rate, and ST-segment depression. A modified post-discharge Global Registry of Acute Coronary Events (GRACE) score was used to calculate an individual risk score for each patient and to form low-risk, medium-risk, and high-risk groups. Risk of death within 10 years varied markedly from 14.4 % in the low-risk group to 56.2% in the high-risk group. This mortality trend did not depend on the assigned treatment strategy.

CONCLUSIONS

The advantage of reduced mortality of routine early invasive strategy seen at 5 years was attenuated during later follow-up, with no evidence of a difference in outcome at 10 years. Further trials of contemporary intervention strategies in patients with NSTEACS are warranted. (Third Randomised Intervention Treatment of Angina trial [RITA-3]; ISRCTN07752711).

Economic evaluation of ticagrelor for secondary prevention following acute coronary syndromes

INTRODUCTION AND OBJECTIVES

To estimate the cost-effectiveness and cost-utility of ticagrelor in the treatment of patients with acute coronary syndromes (unstable angina or myocardial infarction with or without ST-segment elevation), including patients treated medically and those undergoing percutaneous coronary intervention or coronary artery bypass grafting.

METHODS

A short-term decision tree and a long-term Markov model were used to simulate the evolution of patients' life-cycles. Clinical effectiveness data were collected from the PLATO trial and resource use data were obtained from the Hospital de Santa Marta database, disease-related group legislation and the literature.

RESULTS

Ticagrelor provides increases of 0.1276 life years and 0.1106 quality-adjusted life years (QALYs) per patient. From a societal perspective these clinical gains entail an increase in expenditure of €610. Thus the incremental cost per life year saved is €4780 and the incremental cost per QALY is €5517.

CONCLUSIONS

The simulation results show that ticagrelor reduces events compared to clopidogrel. The costs of ticagrelor are partially offset by lower costs arising from events prevented. The use of ticagrelor in clinical practice is therefore cost-effective compared to generic clopidogrel.

The value of heterogeneity for cost-effectiveness subgroup analysis: conceptual framework and application

This article develops a general framework to guide the use of subgroup cost-effectiveness analysis for decision making in a collectively funded health system. In doing so, it addresses 2 key policy questions, namely, the identification and selection of subgroups, while distinguishing 2 sources of potential value associated with heterogeneity. These are 1) the value of revealing the factors associated with heterogeneity in costs and outcomes using existing evidence (static value) and 2) the value of acquiring further subgroup-related evidence to resolve the uncertainty given the current understanding of heterogeneity (dynamic value). Consideration of these 2 sources of value can guide subgroup-specific treatment decisions and inform whether further research should be conducted to resolve uncertainty to explain variability in costs and outcomes. We apply the proposed methods to a cost-effectiveness analysis for the management of patients with acute coronary syndrome. This study presents the expected net benefits under current and perfect information when subgroups are defined based on the use and combination of 6 binary covariates. The results of the case study confirm the theoretical expectations. As more subgroups are considered, the marginal net benefit gains obtained under the current information show diminishing marginal returns, and the expected value of perfect information shows a decreasing trend. We present a suggested algorithm that synthesizes the results to guide policy.

[Early invasive strategy in diabetic patients with non-ST-segment elevation acute coronary syndromes]

BACKGROUND AND OBJECTIVES

In the management of non-ST-segment elevation acute coronary syndromes (NSTE-ACS), several studies have shown a reduction in mortality with the use of an invasive strategy in high-risk patients, including diabetic patients. Paradoxically, other studies have shown an under-utilization of this invasive strategy in these patients. The aim of this study is to determine the characteristics of patients managed conservatively and identify determinants of the use of invasive or conservative strategy.

PATIENTS AND METHODS

Retrospective cohort study conducted in diabetic patients with NSTE-ACS included in the ARIAM-SEMICYUC registry (n=531) in 2010 and 2011. We performed crude and adjusted unconditional logistic regression.

RESULTS

We analyzed 531 diabetic patients, 264 (49.7%) of which received invasive strategy. Patients managed conservatively were a subgroup characterized by older age and cardiovascular comorbidity, increased risk of bleeding and the absence of high-risk electrocardiogram (ECG). In diabetic patients with NSTE-ACS, independent predictors associated with conservative strategy were low-risk ECG, initial Killip class>1, high risk of bleeding and pretreatment with clopidogrel.

CONCLUSIONS

The fear of bleeding complications or advanced coronary lesions could be the cause of the underutilization of an invasive strategy in diabetic patients with NSTE-ACS.

EVEREST II high risk study based UK cost-effectiveness analysis of MitraClip® in patients with severe mitral regurgitation ineligible for conventional repair/replacement surgery

OBJECTIVES

To evaluate the cost-effectiveness of MitraClip, an interventional procedure for patients with chronic severe mitral regurgitation.

METHODS

A decision analytic model with a lifetime horizon was developed to assess the cost-effectiveness of MitraClip vs conventional medical management in patients with severe mitral regurgitation, ineligible for surgery. The analysis was performed from a UK NHS perspective and the estimates for mortality, adverse events, and cross-sectional NYHA class were obtained from the EVEREST II High Risk Study (HRS). Utility decrements were obtained from a heath technology assessment on Cardiac Resynchronization Therapy, while unit costs were obtained from national databases. The concept model was clinically validated. Costs (2011 £UK) and benefits were discounted at an annual rate of 3.5%.

RESULTS

Compared to medical management, over 2- and 10-year periods MitraClip had incremental Quality Adjusted Life Year (QALY) gains of 0.48 and 2.04, respectively. The Incremental Cost-Effectiveness Ratios for MitraClip at 2 and 10 years are £52,947 and £14,800 per QALY gained. Overall, the model was most sensitive to the choice of time horizon, the discount rate applied to benefits, the starting age of cohort, the utility decrement associated with NYHA II, and cost of the MitraClip procedure. The model was insensitive to changes in all other parameters. MitraClip was also found to be cost-effective, regardless of the modelling approach, and insensitive to the key assumptions of the procedure cost.

STUDY LIMITATIONS

The primary limitation of the analysis is the reliance on aggregate data from a modestly sized non-randomized study with a short-term follow-up period. Aligned to this was the need to extrapolate survival well beyond the study period in order to generate meaningful results. The impact of both of these limitations was explored via extensive sensitivity analyses.

CONCLUSION

Compared to medical management, MitraClip is a cost-effective interventional procedure at conventional threshold values.

Cost-effectiveness of 12-month treatment with ticagrelor compared with clopidogrel in the management of acute coronary syndromes

BACKGROUND

The PLATO (Platelet Inhibition and Patient Outcomes) randomized trial (NCT00391872) in patients with acute coronary syndromes (ACS) reported that ticagrelor (in addition to aspirin) reduced the rate of the composite end point of myocardial infarction (MI), stroke, or cardiovascular death compared with clopidogrel (in addition to aspirin) by 16% over 12 months (P < 0.001). No significant difference in the incidence of major bleeding was noted, but ticagrelor was associated with a higher rate of major bleeding not related to coronary artery bypass grafting.

OBJECTIVE

By extrapolating the key findings of PLATO, we sought to assess the cost-effectiveness of ticagrelor compared with clopidogrel in the management of ACS in a contemporary Australian setting.

METHODS

A Markov model with 4 health states (free from further ACS events, MI, stroke, and death) was developed to simulate the long-term costs and outcomes associated with ACS. Event risks were based on data derived directly from PLATO, and costs and utilities were drawn from published sources. A 10-year time horizon was simulated, and future costs and benefits were discounted at a 5% annual rate. However, treatment with ticagrelor and clopidogrel was only assumed for the first 12 months, with no benefits applied beyond drug cessation. Sensitivity analyses were undertaken based on variations to key data inputs. All costs for resource use applied in the analysis were based on published Australian prices (in 2010/2011 dollars [A$]).

RESULTS

Over 10 years, the estimated quality-adjusted life-years lived per-patient were 5.74 and 5.68 for ticagrelor and clopidogrel, respectively. Net costs were A$19,132 for ticagrelor and A$18,428 for clopidogrel. These equated to an incremental cost-effectiveness ratio of A$9031 per quality-adjusted life-year gained for ticagrelor compared with clopidogrel. Sensitivity analyses indicated the result to be robust.

CONCLUSIONS

When assessed from the perspective of the Australian health care system, ticagrelor is likely to be cost-effective compared with clopidogrel in preventing downstream morbidity and mortality associated with ACS.

Cost-effectiveness of ticagrelor in acute coronary syndromes

Ticagrelor is a reversibly binding oral P2Y(12) inhibitor, which belongs to a novel chemical class of antiplatelet agents named cyclopentyl-triazolo-pyrimidines. Ticagrelor administered with acetylsalicylic acid has been shown to reduce the rate of the composite end point of death from vascular causes, myocardial infarction or stroke without an increase in the rate of overall major bleeding compared with clopidogrel plus acetylsalicylic acid in patients with acute coronary syndromes. In addition to these clinical findings, it has been shown that the cost per quality-adjusted life year with ticagrelor is below the generally acceptable thresholds for cost-effectiveness compared with clopidogrel. Healthcare decision-makers need to consider the costs and cost-effectiveness when prioritizing treatments among scarce healthcare resources. This is of particular importance in cases similar to ticagrelor, where the novel treatment is expected to improve effectiveness at a higher acquisition cost. In this article, the authors review and discuss the health-economic evidence of ticagrelor.

Diagnostic accuracy of prehospital clinical prediction models to identify short-term outcomes in patients with acute coronary syndromes: a systematic review

BACKGROUND

Although cardiac risk prediction is widely used in various clinical settings, its potential role in enhancing prehospital triage is yet to be understood.

OBJECTIVE

To systematically review the diagnostic accuracy of short-term clinical prediction models for potential use in a prehospital population with suspected acute coronary syndrome.

METHODS

Eleven electronic medical databases were searched from 1990 to the end of August 2010 for all English-language observational and interventional studies. An online search strategy tool was used to identify grey-literature studies. Eligibility criteria were: 1) an unselected population of adult acute coronary syndrome patients; 2) recruited within the Emergency Department or Emergency Medical Services; 3) reported multivariate analysis encompassing patient history or physical examination; 4) reported short-term outcome measures; 5) were not solely computer protocols; and 6) were not reliant on tests unavailable out of the hospital. Data extraction was conducted by a single reviewer and verified by a second reviewer. Study quality was assessed independently by two reviewers using a validated quality assessment tool.

RESULTS

A total of seven clinical prediction models were identified. Only two models reported were derived from a prehospital study population. Six clinical prediction models described good discriminate abilities (c-statistic) of 0.72 to 0.87. Among the range of independent predictors identified, electrocardiogram abnormalities, age, heart rate, and systolic blood pressure provided the strongest prognostic information.

CONCLUSION

The models identified provided reasonable diagnostic accuracy for determining short-term outcomes. Methodological weaknesses and variability in the populations investigated limit their use in clinical practice.

Continuous time simulation and discretized models for cost-effectiveness analysis

The design of decision-analytic models for cost-effectiveness analysis has been the subject of discussion. The current work addresses this issue by noting that, when time is to be explicitly modelled, we need to represent phenomena occurring in continuous time. Models evaluated in continuous time may not have closed-form solutions, and in this case, two approximations can be used: simulation models in continuous time and discretized models at the aggregate level. Stylized examples were set up where both approximations could be implemented. These aimed to illustrate determinants of the use of the two approximations: cycle length and precision, the use of continuity corrections in discretized models and the discretization of rates into probabilities. The examples were also used to explore the impact of the approximations not only in terms of absolute survival but also cost effectiveness and incremental comparisons. Discretized models better approximate continuous time results if lower cycle lengths are used. Continuous time simulation models are inherently stochastic, and the precision of the results is determined by the simulation sample size. The use of continuity corrections in discretized models allows the use of greater cycle lengths, producing no significant bias from the discretization. How the process is discretized (the conversion of rates into probabilities) is key. Results show that appropriate discretization coupled with the use of a continuity correction produces results unbiased for higher cycle lengths. Alternative methods of discretization are less efficient, i.e. lower cycle lengths are needed to obtain unbiased results. The developed work showed the importance of acknowledging bias in estimating cost effectiveness. When the alternative approximations can be applied, we argue that it is preferable to implement a cohort discretized model rather than a simulation model in continuous time. In practice, however, it may not be possible to represent the decision problem by any conventionally defined discretized model, in which case other model designs need to be applied, e.g. a simulation model.

Deriving input parameters for cost-effectiveness modeling: taxonomy of data types and approaches to their statistical synthesis

BACKGROUND

The evidence base informing economic evaluation models is rarely derived from a single source. Researchers are typically expected to identify and combine available data to inform the estimation of model parameters for a particular decision problem. The absence of clear guidelines on what data can be used and how to effectively synthesize this evidence base under different scenarios inevitably leads to different approaches being used by different modelers.

OBJECTIVES

The aim of this article is to produce a taxonomy that can help modelers identify the most appropriate methods to use when synthesizing the available data for a given model parameter.

METHODS

This article developed a taxonomy based on possible scenarios faced by the analyst when dealing with the available evidence. While mainly focusing on clinical effectiveness parameters, this article also discusses strategies relevant to other key input parameters in any economic model (i.e., disease natural history, resource use/costs, and preferences).

RESULTS

The taxonomy categorizes the evidence base for health economic modeling according to whether 1) single or multiple data sources are available, 2) individual or aggregate data are available (or both), or 3) individual or multiple decision model parameters are to be estimated from the data. References to examples of the key methodological developments for each entry in the taxonomy together with citations to where such methods have been used in practice are provided throughout.

CONCLUSIONS

The use of the taxonomy developed in this article hopes to improve the quality of the synthesis of evidence informing decision models by bringing to the attention of health economics modelers recent methodological developments in this field.

Is there an additional benefit from coronary revascularization in diabetic patients with acute coronary syndromes or stable angina who are already on optimal medical treatment?

Cardiovascular disease (CVD) is common in patients with diabetes mellitus (DM) and related clinical outcomes are worse compared with non-diabetics. The optimal treatment in diabetic patients with coronary heart disease (CHD) is currently not established. We searched MEDLINE (1975-2010) using the key terms diabetes mellitus, coronary heart disease, revascularization, coronary artery bypass, angioplasty, coronary intervention and medical treatment. Most studies comparing different revascularization procedures in patients with CHD favoured coronary artery bypass graft (CABG) surgery in patients with DM. However, most of this evidence comes from subgroup analyses. Recent evidence suggests that advanced percutaneous coronary intervention (PCI) techniques along with best medical treatment may be non-inferior and more cost-effective compared with CABG. Treatment of vascular risk factors is a key option in terms of improving CVD outcomes in diabetic patients with CHD. The choice between medical therapy and revascularization warrants further assessment.

Economic evaluation of increasing population rates of cardiac catheterization

BACKGROUND

Increasing population rates of cardiac catheterization can lead to the detection of more people with high risk coronary disease and opportunity for subsequent revascularization. However, such a strategy should only be undertaken if it is cost-effective.

METHODS

Based on data from a cohort of patients undergoing cardiac catheterization, and efficacy data from clinical trials, we used a Markov model that considered 1) the yield of high-risk cases as the catheterization rate increases, 2) the long-term survival, quality of life and costs for patients with high risk disease, and 3) the impact of revascularization on survival, quality of life and costs. The cost per quality-adjusted life year was calculated overall, and by indication, age, and sex subgroups.

RESULTS

Increasing the catheterization rate was associated with a cost per QALY of CAN$26,470. The cost per QALY was most attractive in females with Acute Coronary Syndromes (ACS) ($20,320 per QALY gained), and for ACS patients over 75 years of age ($16,538 per QALY gained). However, there is significant model uncertainty associated with the efficacy of revascularization.

CONCLUSION

A strategy of increasing cardiac catheterization rates among eligible patients is associated with a cost per QALY similar to that of other funded interventions. However, there is significant model uncertainty. A decision to increase population rates of catheterization requires consideration of the accompanying opportunity costs, and careful thought towards the most appropriate strategy.

Usefulness of contrast echocardiography for predicting the severity of angiographic coronary disease in non-ST-elevation myocardial infarction

Guidelines recommend coronary angiography in patients with non-ST-elevation myocardial infarction (NSTEMI) within 24 to 72 hours, a requirement that cannot always be met. The aim of this study was to evaluate the potential use of contrast echocardiography in prioritizing these patients by identifying those with NSTEMI and angiographically severe coronary artery disease (CAD). Echocardiography was performed before coronary angiography in 110 patients with NSTEMI (67 ± 12 years old, 31% women). Segmental myocardial perfusion and wall motion was scored using a 17-segment left ventricular model. CAD was assessed by quantitative coronary angiography. In the total study population, median troponin T level was 0.27 μg/L (0.13 to 0.86) and Thrombolysis In Myocardial Infarction risk score 3.1 ± 1.5. By quantitative coronary angiography 15% had normal coronary angiographic findings, whereas 1-, 2-, and 3-vessel disease were present in 35%, 27%, and 23%, respectively. Severe CAD (left main stem stenosis, 3-vessel disease, or multivessel disease including proximal stenosis in left anterior descending artery) was found in 42%. Number of segments with hypoperfusion increased with CAD severity from 4.1 ± 2.0 in patients with normal coronary arteries to 5.9 ± 2.4, 7.8 ± 3.5, and 10.4 ± 2.8 in patients with 1-, 2-, and 3-vessel disease, respectively (p<0.01). In multiple logistic regression analysis risk of severe CAD increased by 39% for every additional hypoperfused segment by echocardiography independent of wall motion abnormalities and Thrombolysis In Myocardial Infarction risk score. In conclusion, contrast echocardiography may be used for prediction of angiographic CAD severity in patients with NSTEMI awaiting coronary angiography.

Clinical evaluation of magnetic resonance imaging in coronary heart disease: the CE-MARC study

Background

Several investigations are currently available to establish the diagnosis of coronary heart disease (CHD). Of these, cardiovascular magnetic resonance (CMR) offers the greatest information from a single test, allowing the assessment of myocardial function, perfusion, viability and coronary artery anatomy. However, data from large scale studies that prospectively evaluate the diagnostic accuracy of multi-parametric CMR for the detection of CHD in unselected populations are lacking, and there are few data on the performance of CMR compared with current diagnostic tests, its prognostic value and cost-effectiveness.

Methods/design

This is a prospective diagnostic accuracy cohort study of 750 patients referred to a cardiologist with suspected CHD. Exercise tolerance testing (ETT) will be preformed if patients are physically able. Recruited patients will then undergo CMR and single photon emission tomography (SPECT) followed in all patients by invasive X-ray coronary angiography. The order of the CMR and SPECT tests will be randomised. The CMR study will comprise rest and adenosine stress perfusion, cine imaging, late gadolinium enhancement and whole-heart MR coronary angiography. SPECT will use a gated stress/rest protocol. The primary objective of the study is to determine the diagnostic accuracy of CMR in detecting significant coronary stenosis, as defined by X-ray coronary angiography. Secondary objectives include an assessment of the prognostic value of CMR imaging, a comparison of its diagnostic accuracy against SPECT and ETT, and an assessment of cost-effectiveness.

Discussion

The CE-MARC study is a prospective, diagnostic accuracy cohort study of 750 patients assessing the performance of a multi-parametric CMR study in detecting CHD using invasive X-ray coronary angiography as the reference standard and comparing it with ETT and SPECT.

Trial Registration

Current Controlled Trials ISRCTN77246133

Financial impact of coronary stenting in emergency for acute coronary syndromes

BACKGROUND

Since the prospective payment system, health institutions have only specific payments for the emergency care in the emergency room. The direct urgent admissions in coronary care units for acute coronary syndrome (ACS) do not collect this complementary refund. For the patient's stay, hospital is remunerated with fixed national prices which are similar even in case of emergent or planed coronary revascularization when realized.

AIMS

To analyze and compare the financial impact between emergent and planed coronary stenting in the setting of ACS.

PATIENTS AND METHODS

This retrospective study was based on patients suffering from ACS who experienced emergent coronary stenting during the year 2005. On 154 patients, 127 were age-, sex- and diagnosis-related group (called "groupe homogène de malades" in the French Health Care system)-matched with 127 suffering from same ACS but with planed "ad hoc" coronary stenting. The overall charges (medical and paramedical team, pharmacy, biology, implantable coronary devices, radiology) were compared between the two groups.

RESULTS

Mean stay duration was 6.7 days and did not differ between the two groups. Mean financial retributions were significantly higher in the emergent group (7338 euro [6831-7846] IC95 vs 6509 euro [5994-7023]; p=0,02) but with a much more raised consumption (6810 euro [6283-7336] vs 5223 euro [4632-5814]; p=0,001). This overcost was due especially to drugs and biological expenses. The hospitalization payments did not cover the overall expenses for 25% of the patients' stays (N=64) among whom 39 have had emergent coronary stenting (30.7%, p=0.04). Among the different GHM, the most important difference was observed in non-STEMI without complication with a negative receipts/costs ratio for 37.8% of the stay with coronary stenting in emergency.

CONCLUSION

The application of the recent guidelines for coronary revascularization in the management of ACS represents a financial venture for hospital institutions. The engaged charges for emergent coronary stenting are covered with difficulties contrary to planed revascularization.

Subgroups and heterogeneity in cost-effectiveness analysis

The National Institute for Health and Clinical Excellence (NICE) is required to consider cost effectiveness when issuing guidance about the use of health technologies within the UK NHS. Cost effectiveness is a means of supporting a system objective of maximizing population health gain from the available budget. There is a range of sources of variation between individuals in disease prognosis, and in the costs and effects of health technologies. It is often possible to explain some of this variation on the basis of the clinical and sociodemographic characteristics of patients. This facilitates subgroup-specific estimates of parameters in decision analytic models and provides a means of assessing heterogeneity in cost effectiveness between different types of patient. Given the objective of the NHS, there is a clear need for NICE, and similar decision makers in other systems, to reflect this heterogeneity by being as specific as possible about the characteristics of the recipients of new treatments. The use of subgroup analysis in cost-effectiveness analysis raises a number of methodological questions that have been given little consideration in the literature. They include a need to define the possible sources of heterogeneity that exist, which extends beyond relative treatment effect (which is the focus of clinical trial analysis) to include, for example, sources relating to baseline event rates. There is also the issue of how heterogeneity in model parameters should be estimated and how uncertainty should be appropriately quantified. A major issue also exists concerning the appropriateness, in terms of equity, of using all or some of the subgroup analyses as a basis of decision making. NICE needed to consider these and other issues when updating its methods guidance.