Cost-effectiveness evaluation of ertapenem versus piperacillin/tazobactam in the treatment of complicated intraabdominal infections accounting for antibiotic resistance

Capturing Value Attributes in the Economic Evaluation of Ceftazidime with Avibactam for Treating Severe Aerobic Gram-Negative Bacterial Infections in the United Kingdom

INTRODUCTION

Antimicrobial resistance remains a serious and growing threat to public health, both globally and in the UK, leading to diminishing effectiveness of antimicrobials. Despite a clear need for new antimicrobials, the clinical pipeline is insufficient, driven by high research and development costs and limited expected returns on investment. To counteract this, National Institute for Health and Care Excellence (NICE) and National Health Service (NHS) England have launched a reimbursement mechanism, de-linked from volume of sales, that aims to reduce economic risk by recognising the broader population-level value of antimicrobials. The objective of this study was to quantify the value of ceftazidime-avibactam for treating gram-negative infections in the UK considering some of these broader value elements unique to antimicrobials.

METHODS

A previously developed dynamic disease transmission and cost-effectiveness model was applied to assess the value of introducing ceftazidime-avibactam to UK treatment practice in the management of gram-negative hospital-acquired infections in line with the licenced indications for ceftazidime-avibactam. Model inputs were parameterised using sources aligned to the UK perspective.

RESULTS

The introduction of ceftazidime-avibactam into a two-line treatment sequence saved over 2300 lives, leading to a gain of 27,600 life years and 22,000 quality-adjusted life years (QALY) at an additional cost of £17 million, over a ten-year transmission period. Ceftazidime-avibactam was associated with a net monetary benefit of £642 million at willingness to pay threshold of £30,000 per QALY; even at a lower threshold of £20,000 per QALY, the net monetary benefit is £422 million.

DISCUSSION

Increasing the diversity of antimicrobial treatments through the introduction of an additional antimicrobial, in this instance ceftazidime-avibactam, was associated with substantial clinical and economic benefits, when considering broader population-level value. Despite revealing considerable benefits, the value of ceftazidime-avibactam is only partially reflected in this analysis. Further efforts are required to fully operationalise the spectrum, transmission, enablement, diversity and insurance (STEDI) value framework and accurately reflect the population-level value of antimicrobials.

A systematic literature review of economic evaluation studies of interventions impacting antimicrobial resistance

BACKGROUND

Antimicrobial resistance (AMR) is accelerated by widespread and inappropriate use of antimicrobials. Many countries, including those in low- and middle- income contexts, have started implementing interventions to tackle AMR. However, for many interventions there is little or no economic evidence with respect to their cost-effectiveness. To help better understand the scale of this evidence gap, we conducted a systematic literature review to provide a comprehensive summary on the value for money of different interventions affecting AMR.

METHODS

A systematic literature review was conducted of economic evaluations on interventions addressing AMR. a narrative synthesis of findings was produced. Systematic searches for relevant studies were performed across relevant databases and grey literature sources such as unpublished studies, reports, and other relevant documents. All identified economic evaluation studies were included provided that they reported an economic outcome and stated that the analysed intervention aimed to affect AMR or antimicrobial use in the abstract. Studies that reported clinical endpoints alone were excluded. Selection for final inclusion and data extraction was performed by two independent reviewers. A quality assessment of the evidence used in the included studies was also conducted.

RESULTS

28,597 articles were screened and 35 articles were identified that satisfied the inclusion criteria. The review attempted to answer the following questions: (1) What interventions to address AMR have been the subject of an economic evaluation? (2) In what types of setting (e.g. high-income, low-income, regions etc.) have these economic evaluations been focused? (3) Which interventions have been estimated to be cost-effective, and has this result been replicated in other settings/contexts? (4) What economic evaluation methods or techniques have been used to evaluate these interventions? (5) What kind and quality of data has been used in conducting economic evaluations for these interventions?

DISCUSSION

The review is one of the first of its kind, and the most recent, to systematically review the literature on the cost-effectiveness of AMR interventions. This review addresses an important evidence gap in the economics of AMR and can assist AMR researchers' understanding of the state of the economic evaluation literature, and therefore inform future research. Systematic review registration PROSPERO (CRD42020190310).

Estimating the Value of New Antimicrobials in the Context of Antimicrobial Resistance: Development and Application of a Dynamic Disease Transmission Model

OBJECTIVES

Antimicrobial resistance (AMR) represents a significant threat to patient and population health. The study aim was to develop and validate a model of AMR that defines and quantifies the value of new antibiotics.

METHODS

A dynamic disease transmission and cost-effectiveness model of AMR consisting of three components (disease transmission, treatment pathway and optimisation) was developed to evaluate the health economic value of new antibiotics. The model is based on the relationship between AMR, antimicrobial availability and consumption. Model analysis explored the impact of different antibiotic treatment strategies on the development of AMR, patient and population estimates of health benefit, across three common treatment indications and pathogens in the UK.

RESULTS

Population-level resistance to existing antimicrobials was estimated to increase from 10.3 to 16.1% over 10 years based on current antibiotic availability and consumption. In comparison, the diversified use of a new antibiotic was associated with significant reduction in AMR (12.8% vs. 16.1%) and quality-adjusted life year (QALY) gains at a patient (7.7-10.3, dependent on antimicrobial efficacy) and population level (3657-8197, dependent on antimicrobial efficacy and the prevalence of AMR). Validation across several real-world data sources showed that the model output does not tend to systematically under- or over-estimate observed data.

CONCLUSIONS

The development of new antibiotics and the appropriate use of existing antibiotics are key to addressing the threat of AMR. This study presents a validated model that quantifies the value of new antibiotics through clinical and economic outcomes of relevance, and accounts for disease transmission of infection and development of AMR. In this context, the model may be a useful tool that could contribute to the decision-making process alongside other potential models and expert advice.

Quantifying the economic cost of antibiotic resistance and the impact of related interventions: rapid methodological review, conceptual framework and recommendations for future studies

BACKGROUND

Antibiotic resistance (ABR) poses a major threat to health and economic wellbeing worldwide. Reducing ABR will require government interventions to incentivise antibiotic development, prudent antibiotic use, infection control and deployment of partial substitutes such as rapid diagnostics and vaccines. The scale of such interventions needs to be calibrated to accurate and comprehensive estimates of the economic cost of ABR.

METHODS

A conceptual framework for estimating costs attributable to ABR was developed based on previous literature highlighting methodological shortcomings in the field and additional deductive epidemiological and economic reasoning. The framework was supplemented by a rapid methodological review.

RESULTS

The review identified 110 articles quantifying ABR costs. Most were based in high-income countries only (91/110), set in hospitals (95/110), used a healthcare provider or payer perspective (97/110), and used matched cohort approaches to compare costs of patients with antibiotic-resistant infections and antibiotic-susceptible infections (or no infection) (87/110). Better use of methods to correct biases and confounding when making this comparison is needed. Findings also need to be extended beyond their limitations in (1) time (projecting present costs into the future), (2) perspective (from the healthcare sector to entire societies and economies), (3) scope (from individuals to communities and ecosystems), and (4) space (from single sites to countries and the world). Analyses of the impact of interventions need to be extended to examine the impact of the intervention on ABR, rather than considering ABR as an exogeneous factor.

CONCLUSIONS

Quantifying the economic cost of resistance will require greater rigour and innovation in the use of existing methods to design studies that accurately collect relevant outcomes and further research into new techniques for capturing broader economic outcomes.

Application of dynamic modelling techniques to the problem of antibacterial use and resistance: a scoping review

Selective pressure exerted by the widespread use of antibacterial drugs is accelerating the development of resistant bacterial populations. The purpose of this scoping review was to summarise the range of studies that use dynamic models to analyse the problem of bacterial resistance in relation to antibacterial use in human and animal populations. A comprehensive search of the peer-reviewed literature was performed and non-duplicate articles (n = 1486) were screened in several stages. Charting questions were used to extract information from the articles included in the final subset (n = 81). Most studies (86%) represent the system of interest with an aggregate model; individual-based models are constructed in only seven articles. There are few examples of inter-host models outside of human healthcare (41%) and community settings (38%). Resistance is modelled for a non-specific bacterial organism and/or antibiotic in 40% and 74% of the included articles, respectively. Interventions with implications for antibacterial use were investigated in 67 articles and included changes to total antibiotic consumption, strategies for drug management and shifts in category/class use. The quality of documentation related to model assumptions and uncertainty varies considerably across this subset of articles. There is substantial room to improve the transparency of reporting in the antibacterial resistance modelling literature as is recommended by best practice guidelines.

Cost-effectiveness of ceftolozane/tazobactam plus metronidazole versus piperacillin/tazobactam as initial empiric therapy for the treatment of complicated intra-abdominal infections based on pathogen distributions drawn from national surveillance data in the United States

BACKGROUND

The prevalence of antimicrobial resistance among gram-negative pathogens in complicated intra-abdominal infections (cIAIs) has increased. In the absence of timely information on the infecting pathogens and their susceptibilities, local or regional epidemiology may guide initial empirical therapy and reduce treatment failure, length of stay and mortality. The objective of this study was to assess the cost-effectiveness of ceftolozane/tazobactam + metronidazole compared with piperacillin/tazobactam in the treatment of hospitalized US patients with cIAI at risk of infection with resistant pathogens.

METHODS

We used a decision-analytic Monte Carlo simulation model to compare the costs and quality-adjusted life years (QALYs) of persons infected with nosocomial gram-negative cIAI treated empirically with either ceftolozane/tazobactam + metronidazole or piperacillin/tazobactam. Pathogen isolates were randomly drawn from the Program to Assess Ceftolozane/Tazobactam Susceptibility (PACTS) database, a surveillance database of non-duplicate bacterial isolates collected from patients with cIAIs in medical centers in the USA from 2011 to 2013. Susceptibility to initial therapy was based on the measured susceptibilities reported in the PACTS database determined using standard broth micro-dilution methods as described by the Clinical and Laboratory Standards Institute (CLSI).

RESULTS

Our model results, with baseline resistance levels from the PACTS database, indicated that ceftolozane/tazobactam + metronidazole dominated piperacillin/tazobactam, with lower costs ($44,226/patient vs. $44,811/patient respectively) and higher QALYs (12.85/patient vs. 12.70/patient, respectively). Ceftolozane/tazobactam + metronidazole remained the dominant choice in one-way and probabilistic sensitivity analyses.

CONCLUSIONS

Based on surveillance data, ceftolozane/tazobactam is more likely to be an appropriate empiric therapy for cIAI in the US. Results from a decision-analytic simulation model indicate that use of ceftolozane/tazobactam + metronidazole would result in cost savings and improves QALYs, compared with piperacillin/tazobactam.

Cost-effectiveness of ceftolozane/tazobactam plus metronidazole compared with piperacillin/tazobactam as empiric therapy for the treatment of complicated intra-abdominal infections based on the in-vitro surveillance of bacterial isolates in the UK

AIMS

An increase in the prevalence of antimicrobial resistance among gram-negative pathogens has been noted recently. A challenge in empiric treatment of complicated intra-abdominal infection (cIAI) is identifying initial appropriate antibiotic therapy, which is associated with reduced length of stay and mortality compared with inappropriate therapy. The objective of this study was to assess the cost-effectiveness of ceftolozane/tazobactam + metronidazole compared with piperacillin/tazobactam (commonly used in this indication) in the treatment of patients with cIAI in UK hospitals.

METHODS

A decision-analytic Monte Carlo simulation model was used to compare costs (antibiotic and hospitalization costs) and quality-adjusted life years (QALYs) of patients infected with gram-negative cIAI and treated empirically with either ceftolozane/tazobactam + metronidazole or piperacillin/tazobactam. Bacterial isolates were randomly drawn from the Program to Assess Ceftolozane/Tazobactam Susceptibility (PACTS) database, a surveillance database of non-duplicate bacterial isolates collected from patients in the UK infected with gram-negative pathogens. Susceptibility to initial empiric therapy was based on the measured susceptibilities reported in the PACTS database.

RESULTS

Ceftolozane/tazobactam + metronidazole was cost-effective when compared with piperacillin/tazobactam, with an incremental cost-effectiveness ratio (ICER) of £4,350/QALY and 0.36 hospitalization days/patient saved. Costs in the ceftolozane/tazobactam + metronidazole arm were £2,576/patient, compared with £2,168/patient in the piperacillin/tazobactam arm. The ceftolozane/tazobactam + metronidazole arm experienced a greater number of QALYs than the piperacillin/tazobactam arm (14.31/patient vs 14.21/patient, respectively). Ceftolozane/tazobactam + metronidazole remained cost-effective in one-way sensitivity and probabilistic sensitivity analyses.

CONCLUSIONS

Economic models can help to identify the appropriate choice of empiric therapy for the treatment of cIAI. Results indicated that empiric use of ceftolozane/tazobactam + metronidazole is cost-effective vs piperacillin/tazobactam in UK patients with cIAI at risk of resistant infection. This will be valuable to commissioners and clinicians to aid decision-making on the targeting of resources for appropriate antibiotic therapy under the premise of antimicrobial stewardship.

How externalities impact an evaluation of strategies to prevent antimicrobial resistance in health care organizations

Background

The rates of antimicrobial-resistant organisms (ARO) continue to increase for both hospitalized and community patients. Few resources have been allocated to reduce the spread of resistance on global, national and local levels, in part because the broader economic impact of antimicrobial resistance (i.e. the externality) is not fully considered when determining how much to invest to prevent AROs, including strategies to contain antimicrobial resistance, such as antimicrobial stewardship programs. To determine how best to measure and incorporate the impact of externalities associated with the antimicrobial resistance when making resource allocation decisions aimed to reduce antimicrobial resistance within healthcare facilities, we reviewed the literature to identify publications which 1) described the externalities of antimicrobial resistance, 2) described approaches to quantifying the externalities associated with antimicrobial resistance or 3) described macro-level policy options to consider the impact of externalities. Medline was reviewed to identify published studies up to September 2016.

Main body

An externality is a cost or a benefit associated with one person’s activity that impacts others who did not choose to incur that cost or benefit. We did not identify a well-accepted method of accurately quantifying the externality associated with antimicrobial resistance. We did identify three main methods that have gained popularity to try to take into account the externalities of antimicrobial resistance, including regulation, charges or taxes on the use of antimicrobials, and the right to trade permits or licenses for antimicrobial use. To our knowledge, regulating use of antimicrobials is the only strategy currently being used by health care systems to reduce antimicrobial use, and thereby reduce AROs. To justify expenditures on programs that reduce AROs (i.e. to formally incorporate the impact of the negative externality of antimicrobial resistance associated with antimicrobial use), we propose an alternative approach that quantifies the externalities of antimicrobial use, combining the attributable cost of AROs with time-series analyses showing the relationship between antimicrobial utilization and incidence of AROs.

Conclusion

Based on the findings of this review, we propose a methodology that healthcare organizations can use to incorporate the impact of negative externalities when making resource allocation decisions on strategies to reduce AROs.

Electronic supplementary material

The online version of this article (doi:10.1186/s13756-017-0211-2) contains supplementary material, which is available to authorized users.

Cost-effectiveness of ceftolozane/tazobactam compared with piperacillin/tazobactam as empiric therapy based on the in-vitro surveillance of bacterial isolates in the United States for the treatment of complicated urinary tract infections

Background

A challenge in the empiric treatment of complicated urinary tract infection (cUTI) is identifying the initial appropriate antibiotic therapy (IAAT), which is associated with reduced length of stay and mortality compared with initial inappropriate antibiotic therapy (IIAT). We evaluated the cost-effectiveness of ceftolozane/tazobactam compared with piperacillin/tazobactam (one of the standard of care antibiotics), for the treatment of hospitalized patients with cUTI.

Methods

A decision-analytic Monte Carlo simulation model was developed to compare the costs and effectiveness of empiric treatment with either ceftolozane/tazobactam or piperacillin/tazobactam in hospitalized adult patients with cUTI infected with Gram-negative pathogens in the US. The model applies the baseline prevalence of resistance as reported by national in-vitro surveillance data.

Results

In a cohort of 1000 patients, treatment with ceftolozane/tazobactam resulted in higher total costs compared with piperacillin/tazobactam ($36,413 /patient vs. $36,028/patient, respectively), greater quality-adjusted life years (QALYs) (9.19/patient vs. 9.13/patient, respectively) and an incremental cost-effectiveness ratio (ICER) of $6128/QALY. Ceftolozane/tazobactam remained cost-effective at a willingness to pay of $100,000 per QALY compared to piperacillin/tazobactam over a range of input parameter values during one-way and probabilistic sensitivity analysis.

Conclusions

Model results show that ceftolozane/tazobactam is likely to be cost-effective compared with piperacillin/tazobactam for the empiric treatment of hospitalized cUTI patients in the United States.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2408-7) contains supplementary material, which is available to authorized users.

Cost-effectiveness and pricing of antibacterial drugs

Growing resistance to antibacterial agents has increased the need for the development of new drugs to treat bacterial infections. Given increasing pressure on limited health budgets, it is important to study the cost-effectiveness of these drugs, as well as their safety and efficacy, to find out whether or not they provide value for money and should be reimbursed. In this article, we systematically reviewed 38 cost-effectiveness analyses of new antibacterial agents. Most studies showed the new antibacterial drugs were cost-effective compared to older generation drugs. Drug pricing is a complicated process, involving different stakeholders, and has a large influence on cost-effectiveness. Value-based pricing is a method to determine the price of a drug at which it can be cost-effective. It is currently unclear what the influence of value-based pricing will be on the prices of new antibacterial agents, but an important factor will be the definition of ‘value’, which as well as the impact of the drug on patient health might also include other factors such as wider social impact and the health impact of disease.

Impact of a Dynamic Microbiological Environment on the Clinical Efficacy of Ertapenem and Piperacillin/Tazobactam in the Treatment of Complicated Community-Acquired Intra-Abdominal Infection in Spain: A Cost-Consequence Analysis

BACKGROUND AND OBJECTIVE

The microbial susceptibility of many antibiotics has been affected by prescribing patterns and their extensive use. The purpose of this evaluation was to assess how these changes could affect the initial efficacy of ertapenem and piperacillin/tazobactam in the treatment of complicated intra-abdominal infections (IAIs) acquired in the community and the potential consequences this may have in healthcare costs in Spain.

METHODS

The Initial efficacy of ertapenem and piperacillin/tazobactam for patients with APACHE (Acute Physiology and Chronic Health Evaluation) II scores <10 was extracted from a multicenter randomized study and were combined with the current microbial susceptibilities obtained from the SMART study, a multinational surveillance program. Country-specific pathogens distribution was extracted from a national study in patients with community-acquired IAI. The estimated effectiveness was used in a decision-analytic model to compare total costs between ertapenem and piperacillin/tazobactam in the treatment of complicated IAI. The model performs extensive one-way and probabilistic sensitivity analyses.

RESULTS

The model suggested a savings of €209 (year 2012 values) per patient when complicated IAIs acquired in the community (APACHE II <10) were treated with ertapenem instead of piperacillin/tazobactam. One-way sensitivity analyses showed length of stay as the key driver parameter. Further analysis of this parameter and probabilistic sensitivity analysis confirmed the robustness of our evaluation, with a 58% likelihood of ertapenem being dominant.

CONCLUSIONS

Ertapenem appears to be a cost-saving strategy over piperacillin/tazobactam for the treatment of patients with complicated IAIs acquired in the community in Spain.

Antibiotic expected effectiveness and cost under real life microbiology: evaluation of ertapenem and ceftriaxone in the treatment of community-acquired pneumonia for elderly patients in Spain

Background

Clinical efficacy of antibiotics may be affected by changes in the susceptibility of microorganisms to antimicrobial agents. The purpose of this study is to assess how these changes could affect the initial efficacy of ertapenem and ceftriaxone in the treatment of community-acquired pneumonia (CAP) in elderly patients and the potential consequences this may have in health care costs.

Methods

Initial efficacy in elderly was obtained from a combined analysis of two multicenter, randomized studies. An alternative scenario was carried out using initial efficacy data according to the pneumonia severity index (PSI). Country-specific pathogens distribution was obtained from a national epidemiological study, and microbiological susceptibilities to first- and second-line therapies were obtained from Spanish or European surveillance studies. A decision analytic model was used to compare ertapenem versus ceftriaxone for CAP inpatient treatment. Inputs of the model were the expected effectiveness previously estimated and resource use considering a Spanish national health system perspective. Outcomes include difference in proportion of successfully treated patients and difference in total costs between ertapenem and ceftriaxone. The model performed one-way and probabilistic sensitivity analyses.

Results

First-line treatment of CAP with ertapenem led to a higher proportion of successfully treated patients compared with ceftriaxone in Spain. One-way sensitivity analysis showed that length of stay was the key parameter of the model. Probabilistic sensitivity analysis showed that ertapenem can be a cost-saving strategy compared with ceftriaxone, with a 59% probability of being dominant (lower costs with additional health benefits) for both, elderly patients (>65 years) and patients with PSI >3.

Conclusion

The incorporation of the current antimicrobial susceptibility into the initial clinical efficacy has a significant impact in outcomes and costs in CAP treatment. The treatment with ertapenem compared with ceftriaxone resulted in better clinical outcomes and lower treatment costs for two segments of the Spanish population: elderly patients and patients with severe pneumonia (PSI >3).

A modeling framework for the evolution and spread of antibiotic resistance: literature review and model categorization

Antibiotic-resistant infections complicate treatment and increase morbidity and mortality. Mathematical modeling has played an integral role in improving our understanding of antibiotic resistance. In these models, parameter sensitivity is often assessed, while model structure sensitivity is not. To examine the implications of this, we first reviewed the literature on antibiotic-resistance modeling published between 1993 and 2011. We then classified each article's model structure into one or more of 6 categories based on the assumptions made in those articles regarding within-host and population-level competition between antibiotic-sensitive and antibiotic-resistant strains. Each model category has different dynamic implications with respect to how antibiotic use affects resistance prevalence, and therefore each may produce different conclusions about optimal treatment protocols that minimize resistance. Thus, even if all parameter values are correctly estimated, inferences may be incorrect because of the incorrect selection of model structure. Our framework provides insight into model selection.

Clinical experience with ertapenem in the treatment of infections of the biliary tract in daily practice in five Spanish hospitals

Efficacy of ertapenem in biliary tract infections in daily practice was retrospectively analyzed. Records of patients admitted to five Spanish hospitals (January 2007/February 2011) with biliary infections (cholecystitis/cholangitis) treated with ertapenem for ≥72 hours were reviewed. A total of 187 patients (mean 63.8±19.3 years, 52.9% males) were identified. Up to 96 (51.3%) were operated, with cholecystectomy (97.9%) and primary laparoscopy approach (75%) as most frequent intervention. Non-operated patients presented higher age (71.0±17.5 vs 56.9±18.5 years; P<0.001), heart insufficiency (11.0 vs 3.1%; P = 0.044) and the Mortality in Emergency Department Sepsis score (2.99±2.26 vs 1.94±2.34; P<0.001); and longer length of stay (10.3±6.6 vs 9.1±7.0; P = 0.005). Mean duration of treatment was 6.89±3.38 days. Overall favourable response was 87.7% (95% CI = 83.0-92.4) at the end of treatment. In the multivariate analysis (P<0.001, R² Cox = 0.10), non-favourable response was associated with Charlson index≥5 (OR = 18.71; 95% CI: 1.26-278.55; P = 0.034), pericholecystic abscess (OR = 5.30; 95% CI: 1.26-22.37; P = 0.023) and >3 days from symptoms start to admission (OR = 3.02; 95% CI: 1.13-8.04; P = 0.027).