A cost-utility analysis of clopidogrel in patients with ST elevation acute coronary syndromes in the UK

Influenza vaccination in acute coronary syndromes patients in Thailand: the cost-effectiveness analysis of the prevention for cardiovascular events and pneumonia

BACKGROUND

Influenza vaccination has been clinically shown to reduce adverse cardiovascular outcomes in acute coronary syndrome (ACS) patients, but the economic perspectives can provide important data to make informed decisions. This study aimed to perform the economic evaluation of lifelong annual influenza vaccination for cardiovascular events and well-established pneumonia prevention.

METHODS

Lifetime costs, life-expectancy, and quality-adjusted live years (QALYs) were estimated beyond one-year cycle length of a six-health states Markov model condition on whether a hospitalization for ACS, stroke, heart failure, pneumonia, no hospitalizations occurred, or death. The comparison of three age-groups of 40-49, 50-65, and > 65 years scenario was performed. Incremental cost-effectiveness ratio (ICER) and net monetary benefit (NMB) were presented as a societal perspective in 2016. The model robustness was determined by one-way and probabilistic sensitivity analyses.

RESULTS

The influenza vaccination was cost-effective in all age-groups, by dominant ICERs (lower cost with higher effectiveness) which was completely lower than acceptable willingness-to-pay threshold of Thailand [160,000 THB (4,466.8 USD) per QALYs], with a great incremental value of NMB. Especially, the 50-year-old-and-above scenario was shown as the most benefit at 129,092 THB (3,603.9 USD) for each patient.

CONCLUSIONS

The annually additional influenza vaccination to standard treatment in ACS was cost-effective in all age-groups, which should be considered in clinical practice and health-policy making process.

Universal versus platelet reactivity assay-driven use of P2Y12 inhibitors in acute coronary syndrome patients

Platelet reactivity assays (PRAs) can predict patients’ likely response to clopidogrel. As ticagrelor and prasugrel are typically considered first-line agents for acute coronary syndrome in Europe, we assessed the cost-effectiveness of universal compared to PRA-driven selection of these agents. A Markov model was used to calculate five-year costs (2013£/€), quality-adjusted life-years and incremental cost-effectiveness ratios (ICERs) for one-year of universal ticagrelor or prasugrel (given to all) compared to each agents’ corresponding PRA-driven strategy (ticagrelor/prasugrel in those with high platelet reactivity [HPR, >208 on the VerifyNow P2Y12 assay], others given generic clopidogrel). We assumed patients had their index event at 65–70 years of age and had a 42.7% incidence of HPR 24–48 hours post-revascularisation. The analysis was conducted from the perspective of six countries (France, Germany, Italy, Spain, the Netherlands and United Kingdom) and used a one-year cycle length. Event data for P2Y12 inhibitors were taken from multinational randomised trials and adjusted using country-specific epidemiologic data. Neither universal ticagrelor nor prasugrel were found to be cost-effective (all ICERs >40,250€ or £36,600/QALY) compared to their corresponding PRA-driven strategies in any of the countries evaluated. Results were sensitive to differences in P2Y12 Inhibitors costs and drug-specific relative risks of major adverse cardiac events. Monte Carlo simulation suggested universal ticagrelor or prasugrel were cost-effective in only 25–44% and 11–17% of 10,000 iterations compared to their respective PRA-driven strategies, when applying a willingness-to-pay threshold = €30,000 or £20,000/QALY. In conclusion, the universal use of newer P2Y12 inhibitors is not likely cost-effective compared to PRA-driven strategies.

When to use discrete event simulation (DES) for the economic evaluation of health technologies? A review and critique of the costs and benefits of DES

Modelling in economic evaluation is an unavoidable fact of life. Cohort-based state transition models are most common, though discrete event simulation (DES) is increasingly being used to implement more complex model structures. The benefits of DES relate to the greater flexibility around the implementation and population of complex models, which may provide more accurate or valid estimates of the incremental costs and benefits of alternative health technologies. The costs of DES relate to the time and expertise required to implement and review complex models, when perhaps a simpler model would suffice. The costs are not borne solely by the analyst, but also by reviewers. In particular, modelled economic evaluations are often submitted to support reimbursement decisions for new technologies, for which detailed model reviews are generally undertaken on behalf of the funding body. This paper reports the results from a review of published DES-based economic evaluations. Factors underlying the use of DES were defined, and the characteristics of applied models were considered, to inform options for assessing the potential benefits of DES in relation to each factor. Four broad factors underlying the use of DES were identified: baseline heterogeneity, continuous disease markers, time varying event rates, and the influence of prior events on subsequent event rates. If relevant, individual-level data are available, representation of the four factors is likely to improve model validity, and it is possible to assess the importance of their representation in individual cases. A thorough model performance evaluation is required to overcome the costs of DES from the users' perspective, but few of the reviewed DES models reported such a process. More generally, further direct, empirical comparisons of complex models with simpler models would better inform the benefits of DES to implement more complex models, and the circumstances in which such benefits are most likely.

Economic evaluation of using a genetic test to direct breast cancer chemoprevention in white women with a previous breast biopsy

BACKGROUND

Tamoxifen therapy reduces the risk of breast cancer but increases the risk of serious adverse events including endometrial cancer and thromboembolic events.

OBJECTIVES

The cost effectiveness of using a commercially available breast cancer risk assessment test (BREVAGen™) to inform the decision of which women should undergo chemoprevention by tamoxifen was modeled in a simulated population of women who had undergone biopsies but had no diagnosis of cancer.

METHODS

A continuous time, discrete event, mathematical model was used to simulate a population of white women aged 40-69 years, who were at elevated risk for breast cancer because of a history of benign breast biopsy. Women were assessed for clinical risk of breast cancer using the Gail model and for genetic risk using a panel of seven common single nucleotide polymorphisms. We evaluated the cost effectiveness of using genetic risk together with clinical risk, instead of clinical risk alone, to determine eligibility for 5 years of tamoxifen therapy. In addition to breast cancer, the simulation included health states of endometrial cancer, pulmonary embolism, deep-vein thrombosis, stroke, and cataract. Estimates of costs in 2012 US dollars were based on Medicare reimbursement rates reported in the literature and utilities for modeled health states were calculated as an average of utilities reported in the literature. A 50-year time horizon was used to observe lifetime effects including survival benefits.

RESULTS

For those women at intermediate risk of developing breast cancer (1.2-1.66 % 5-year risk), the incremental cost-effectiveness ratio for the combined genetic and clinical risk assessment strategy over the clinical risk assessment-only strategy was US$47,000, US$44,000, and US$65,000 per quality-adjusted life-year gained, for women aged 40-49, 50-59, and 60-69 years, respectively (assuming a price of US$945 for genetic testing). Results were sensitive to assumptions about patient adherence, utility of life while taking tamoxifen, and cost of genetic testing.

CONCLUSIONS

From the US payer's perspective, the combined genetic and clinical risk assessment strategy may be a moderately cost-effective alternative to using clinical risk alone to guide chemoprevention recommendations for women at intermediate risk of developing breast cancer.

The cost effectiveness of genetic testing for CYP2C19 variants to guide thienopyridine treatment in patients with acute coronary syndromes: a New Zealand evaluation

BACKGROUND

A recent clinical trial has demonstrated that patients with acute coronary syndromes (ACS) and the reduced function allele CYP2C19*2 (*2 allele), who are treated with thienopyridines, have an increased risk of adverse cardiac events with clopidogrel, but not with prasugrel. The frequency of the *2 allele varies by ethnicity and the Maoris, Asians and Pacific Islanders of New Zealand have a relatively high incidence.

OBJECTIVE

Our objective was to evaluate, from a New Zealand health system perspective, the cost effectiveness of treating all ACS patients with generic clopidogrel compared with prasugrel, and also compared with the genetically guided strategy that *2 allele carriers receive prasugrel and non-carriers receive clopidogrel.

METHODS

A decision-tree model consisting of five health states (myocardial infarction, stroke, bleeding, stent thrombosis and cardiovascular death) was developed. Clinical outcome data (two TRITON-TIMI 38 genetic sub-studies) comparing clopidogrel and prasugrel for both *2 allele carriers and non-carriers were combined with the prevalence of the heterozygosity for the *2 allele in New Zealand Europeans (15%), Maoris (24%), Asians (29%) and Pacific Islanders (45%) to determine the predicted adverse event rate for the New Zealand population. National hospital diagnosis-related group (DRG) discharge codes were used to determine alternative adverse event rates, along with the costs of hospitalizations during the 15 months after patients presented with an ACS. The primary outcome measure was the incremental cost per QALY (calculated using literature-reported weights). Monte Carlo simulations and alternative scenario analysis based on both clinical trial and national hospital incidence were used. Additional analysis considered the overall TRITON-TIMI 38 rates. Costs (in New Zealand dollars [$NZ], year 2009 values) and benefits were discounted at 3% per annum.

RESULTS

Actual hospital-based adverse event rates were higher than those reported in the TRITON-TIMI 38 randomized controlled trial and the genetic sub-studies, especially for myocardial infarction and cardiovascular death, and for Maoris and Pacific Islanders. For both sources of adverse event rates, treating the population with prasugrel was associated with worse outcomes (QALYs) than clopidogrel. However, prasugrel became cost effective ($NZ31 751/QALY) when the overall TRITON-TIMI 38 rates were used. A genetic test to guide the selected use of prasugrel was cost effective ($NZ8702/QALY versus $NZ24 617/QALY) for hospital and clinical trial incidence, respectively. Based on the hospital rates, the genetically guided strategy was especially cost effective for Maoris ($NZ7312/QALY) and Pacific Islanders ($NZ7041/QALY). These results were robust to the sensitivity analysis, except the genetically guided strategy under the 15-month clinical trial event rate scenario ($NZ168 748/QALY) did not remain cost effective under a $NZ50 000 threshold.

CONCLUSIONS

Use of a genetic test to guide thienopyridine treatment in patients with ACS is a potentially cost-effective treatment strategy, especially for Maoris and Pacific Islanders. This treatment strategy also has the potential to reduce ethnic health disparities that exist in New Zealand. However, the results comparing clopidogrel and prasugrel are sensitive to whether the genetic sub-studies or the overall TRITON-TIMI 38 rates are used. While the national hospital event rates may be more appropriate for the New Zealand population, many assumptions are required when they are used to adjust the genetic sub-studies rates.