Cost-effectiveness of atypical antipsychotics for the management of schizophrenia in the UK

Socioeconomic burden of schizophrenia: a targeted literature review of types of costs and associated drivers across 10 countries

AIMS

Schizophrenia has the highest median societal cost per patient of all mental disorders. This review summarizes the different costs/cost drivers (cost components) associated with schizophrenia in 10 countries, including all cost types and stakeholder perspectives, and highlights aspects of disease associated with greatest costs.

MATERIALS AND METHODS

Targeted literature review based on a search of published research from 2006 to 2021 in the United States (US), United Kingdom (UK), France, Germany, Italy, Spain, Canada, Japan, Brazil, and China.

RESULTS

Sixty-four published articles (primary studies and literature reviews) were included. Comprehensive data were available on costs in schizophrenia overall, with very limited data for individual countries except the US. Most data is related to direct and not indirect costs, with extremely scarce data for several key cost components (adverse events, suicide, long-term care). Total schizophrenia-related per person per year (PPPY) costs were $2,004-94,229, with considerable variability among countries. Indirect costs were the main cost driver (50-90% of all costs), ranging from $1,852 to $62,431 PPPY. However, indirect costs are not collected systematically or incorporated in health technology assessments. Total schizophrenia-related PPPY direct costs were $4,394-31,798, with inpatient cost as the main cost driver (∼20-99% of direct costs). Intangible costs were not reported. Despite limited evidence, total schizophrenia-related costs were higher in patients with than without negative symptoms, largely due to increased costs of medication and medical visits.

LIMITATIONS

As this was not a systematic review, prioritization of studies may have resulted in exclusion of potentially relevant data. All costs were converted to USD but not corrected for inflation or subjected to a gross domestic product deflator.

CONCLUSIONS

Direct costs are most commonly reported in schizophrenia. The substantial underreporting of indirect and intangible costs undervalues the true economic burden of schizophrenia from a payer, patient, and societal perspective.

A Systematic Review of Methods and Study Quality of Economic Evaluations for the Treatment of Schizophrenia

Background: Schizophrenia is a severe and complex disease with substantial economic and social burdens. Despite multiple treatment choices, adverse events, and impaired social functions are still challenges in clinical therapy. Pharmacoeconomic evaluations could provide evidence to help decision makers improve the utilization of scarce resources. However, there remains some challenges especially in modeling due to uncertainties in progression of schizophrenia. There are limited summaries about the overall methodologies of schizophrenia economic evaluations.

Objective: The aim of this study is to review the existing economic evaluations of antipsychotics for the treatment of schizophrenia and summarize the evidence and methods applied.

Methods: An electronic literature search was performed in PubMed, Web of Science, EBSCO host, The Cochrane Library and ScienceDirect from January 2014 to December 2020. Search terms included “schizophrenia,” “schizophrenic,” “pharmacoeconomic,” “economic evaluation,” “cost-effectiveness,” and “cost-utility.” The Literature was screened and extracted by two researchers independently and assessed with the Quality of Health Economic Studies (QHES) List and Consolidated Health Economic Evaluation Reporting Standards (CHEERS) Statement.

Results: A total of 25 studies were included in the review. The regions included Europe, North America, Asia and Africa. Most of the studies chose second-generation antipsychotics as comparators and integrated treatment sequences. Time horizons varied from 1 year to lifetime. The healthcare sector was the most common perspective, accordingly, most of the evaluations considered only direct medical costs. The Markov model and decision tree model were the most common choices. Adverse events, compliance and persistence were considered important parameters. Quality-adjusted life-years were the major outcomes applied to the economic evaluations. All utilities for health states and adverse events were collected from published literature. All of the studies applied uncertainty analysis to explore the robustness of the results. The quality of the studies was generally satisfactory. However, improvements were needed in the choice of time horizons, the measurements of outcomes and the descriptions of assumptions.

Conclusions: This study highlights the methodology of economic evaluation of schizophrenia. Recommendations for modeling method and future study are provided.

Schizophrenia Treatment with Second-Generation Antipsychotics: A Multi-Country Comparison of the Costs of Cardiovascular and Metabolic Adverse Events and Weight Gain

PURPOSE

Cardiovascular and metabolic adverse events are costly to treat, and their incidence is increased amongst people with schizophrenia, with different rates observed for second-generation antipsychotics. To inform treatment choice, this study sought to estimate the lifetime costs associated with antipsychotic choice, and how these costs varied across European countries.

METHODS

Systematic searches were conducted to identify evidence on effectiveness and costs. A Markov model was developed to assess the costs of ten antipsychotics: aripiprazole, brexpiprazole, cariprazine, lumateperone, lurasidone, olanzapine, paliperidone, quetiapine, risperidone and ziprasidone. Costs were obtained for seven countries: Italy, Hungary, France, Slovenia, Spain, Sweden and the UK. The costs considered were adverse events (including diabetes, myocardial infarction, stroke and weight gain), drug costs, relapse, treatment discontinuation and schizophrenia management. Two adult populations were modelled; initiating either acute or maintenance treatment, with a lifetime horizon for both.

RESULTS

Lurasidone was associated with the lowest lifetime costs amongst patients initiating acute treatment compared to all other atypical antipsychotics considered. The second lowest costs were for ziprasidone. These results were observed for all seven countries. The main drivers of cost differences were rates of diabetes and cardiovascular diseases, which were lowest for lurasidone, followed by ziprasidone then lumateperone. Costs for managing weight gain were lowest for lurasidone and ziprasidone. Similar results were observed for patients initiating maintenance treatment.

CONCLUSION

Diabetes and cardiovascular events are large drivers of lifetime costs for people with schizophrenia. Lurasidone is predicted to have the lowest rates of these adverse events, and so the lowest costs amongst patients initiating acute treatment in seven European countries compared to nine other antipsychotics. Future research should investigate the individual costs of relapse management, including differences in the costs and proportions of hospitalizations.

Quantitative Evidence Synthesis Methods for the Assessment of the Effectiveness of Treatment Sequences for Clinical and Economic Decision Making: A Review and Taxonomy of Simplifying Assumptions

Sequential use of alternative treatments for chronic conditions represents a complex intervention pathway; previous treatment and patient characteristics affect both the choice and effectiveness of subsequent treatments. This paper critically explores the methods for quantitative evidence synthesis of the effectiveness of sequential treatment options within a health technology assessment (HTA) or similar process. It covers methods for developing summary estimates of clinical effectiveness or the clinical inputs for the cost-effectiveness assessment and can encompass any disease condition. A comprehensive review of current approaches is presented, which considers meta-analytic methods for assessing the clinical effectiveness of treatment sequences and decision-analytic modelling approaches used to evaluate the effectiveness of treatment sequences. Estimating the effectiveness of a sequence of treatments is not straightforward or trivial and is severely hampered by the limitations of the evidence base. Randomised controlled trials (RCTs) of sequences were often absent or very limited. In the absence of sufficient RCTs of whole sequences, there is no single best way to evaluate treatment sequences; however, some approaches could be re-used or adapted, sharing ideas across different disease conditions. Each has advantages and disadvantages, and is influenced by the evidence available, extent of treatment sequences (number of treatment lines or permutations), and complexity of the decision problem. Due to the scarcity of data, modelling studies applied simplifying assumptions to data on discrete treatments. A taxonomy for all possible assumptions was developed, providing a unique resource to aid the critique of existing decision-analytic models.

Systematic review of the methods of health economic models assessing antipsychotic medication for schizophrenia

BACKGROUND

Numerous economic models have assessed the cost-effectiveness of antipsychotic medications in schizophrenia. It is important to understand what key impacts of antipsychotic medications were considered in the existing models and limitations of existing models in order to inform the development of future models.

OBJECTIVES

This systematic review aims to identify which clinical benefits, clinical harms, costs and cost savings of antipsychotic medication have been considered by existing models, to assess quality of existing models and to suggest good practice recommendations for future economic models of antipsychotic medications.

METHODS

An electronic search was performed on multiple databases (MEDLINE, EMBASE, PsycInfo, Cochrane database of systematic reviews, The NHS Economic Evaluation Database and Health Technology Assessment database) to identify economic models of schizophrenia published between 2005-2020. Two independent reviewers selected studies for inclusion. Study quality was assessed using the National Institute for Health and Care Excellence (NICE) checklist and the Cooper hierarchy. Key impacts of antipsychotic medications considered by exiting models were descriptively summarised.

RESULTS

Sixty models were included. Existing models varied greatly in key impacts of antipsychotic medication included in the model, especially in clinical outcomes used for assessing reduction in psychotic symptoms and types of adverse events considered in the model. Quality of existing models was generally low due to failure to capture the health and cost impact of adverse events of antipsychotic medications and input data not obtained from best available source. Good practices for modelling antipsychotic medications are suggested.

DISCUSSIONS

This review highlights inconsistency in key impacts considered by different models, and limitations of the existing models. Recommendations on future research are provided.

Economic evaluations on the use of aripiprazole for patients with schizophrenia: A systematic review

WHAT IS KNOWN AND OBJECTIVES

Schizophrenia is a serious mental disorder and is associated with substantial economic and social burden. Cost-effectiveness analysis is important to assess the costs of different therapeutic options. However, there is a lack of information on the reporting quality of economic evaluations, cost drivers, as well as updated data focused on aripiprazole, an antipsychotic drug commonly prescribed in schizophrenia. This study evaluates and summarizes the evidence of economic evaluations of the use of aripiprazole in schizophrenia. In addition, we aimed to identify cost drivers and critically assess the reporting qualities of these studies.

METHODS

A comprehensive literature research was conducted using PubMed, NHS Economic Evaluation Database, CEA Registry and LILACS databases dated until March 2018. Full economic analyses of aripiprazole in schizophrenia that were based on decision analytical models and published in English, Portuguese or Spanish languages were included. Two independent authors identified the studies and performed data extraction and quality assessment using 24 items from the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) statement.

RESULTS AND DISCUSSION

A total of 79 potential studies were identified, of which 17 studies performing model-based economic evaluations fully met the eligibility criteria. Of these, 15 were industry-funded studies. A trend favouring olanzapine, lurasidone and paliperidone could be observed, whereas aripiprazole was extensively described as a dominated alternative. However, notably, 93% of the industry-funded studies presented results favouring their sponsors, only two of them being the manufacturer of aripiprazole. Cost drivers were usually related to the relapse rates/probabilities regardless of the funding source. The overall quality of reporting of the economic analyses was poor, with most studies scoring around 12-13 points. The most frequent problems were the lack of description of relevance of the outcome measures, characteristics of the base case population and report of precision measures for all the parameters of the model.

WHAT IS NEW AND CONCLUSION

No consistent conclusion on the cost-effectiveness of aripiprazole could be drawn due to the context-specific costs, conflicting parameters of effectiveness and safety, and bias related to industry sponsorship. Cost drivers, though, were usually related to the relapse rates/probabilities. In addition, poor reporting quality of the studies performing full economic analysis requires further improvement to ensure greater transparency of the findings.

Systematic review of utility values used in the pharmacoeconomic evaluations for schizophrenia: implications on cost-effectiveness results

Background and Objectives: Utility elicitation studies for schizophrenia generate different utility values for the same health states. We reviewed utility values used in schizophrenia pharmacoeconomic evaluations and evaluated the impact of their selection on the incremental cost-effectiveness ratio (ICER). Methods: A systematic search was performed in Medline and Embase. Health state definitions, associated utility values, elicitation studies, and value selection processes were extracted. Sets of utility values for all schizophrenia health states were used in a cost-effectiveness model to evaluate the ICER. Results: Thirty-five cost-utility analyses (CUAs) referring to 11 utility elicitation studies were included. The most frequent health states were 'stable' (28 CUAs, 7 utility elicitation studies, 10 values, value range 0.650-0.919), 'relapse requiring hospitalisation' (18, 5, 7, 0.270-0.604), 'relapse not requiring hospitalisation' (18, 5, 10, 0.460-0.762), and 'relapse only' (10, 5, 6, 0.498-0.700). Seventeen sets of utility values were identified with difference in utility values between relapse and stable ranging from -0.358 to -0.050, resulting in ICERs ranging from -56.2% to +222.6% from average. Conclusion: The use of utility values for schizophrenia health states differs among CUAs and impacts on the ICER. More rigorous and transparent use of utility values and sensitivity analysis with different sets of utility values are suggested for future CUAs.

Systematic review of pharmacoeconomic models for schizophrenia

Background: Economic models are broadly used in the economic evaluation of antipsychotics in schizophrenia. Our objective was to summarize the structure of these models. Methods: Model-based economic evaluations of antipsychotics in schizophrenia were identified through Medline and Embase. General information was extracted including analysis type, model type, perspective, population, comparator, outcome, and timeframe. Model-specific structures for decision tree (DT), cohort- and patient-level Markov model (CLMM, PLMM), and discrete-event simulation (DES) models were extracted. Results: A screen of 1870 records identified 79 studies. These were mostly cost-utility analyses (n = 48) with CLMM (n = 32) or DT models (n = 29). They mostly applied payer perspective (n = 68), focused on general schizophrenia for relapse prevention (n = 73), compared pharmacotherapies as first-line (n = 71), and evaluated incremental cost per quality-adjusted life year (QALY) gained (n = 40) with a 1-year (n = 32) or 5-year (n = 26) projection. DT models progressed with the branching points of response, relapse, discontinuation, and adherence. CLMM models transitioned between disease states, whereas PLMM models transitioned between adverse event states with/without disease state. DES models moved forward with times to remission, relapse, psychiatrist visit, and death. Conclusions: A pattern of pharmacoeconomic models for schizophrenia was identified. More subtle structures and patient-level models are suggested for a future modelling exercise.

A systematic review of health economic models and utility estimation methods in schizophrenia

INTRODUCTION

There is a growing need for economic evaluations describing the disease course, as well as the costs and clinical outcomes related to the treatment of schizophrenia.

AREAS COVERED

A systematic review on studies describing health economic models in schizophrenia and a targeted literature review on utility mapping algorithms in schizophrenia were carried out. Models found in the review were collated and assessed in detail according to their type and various other attributes. Fifty-nine studies were included in the review. Modeling techniques varied from simple decision trees to complex simulation models. The models used various clinical endpoints as value drivers, 47% of the models used quality-adjusted life years, and eight percent used disability-adjusted life years to measure benefits, while others applied various clinical outcomes. Most models considered patients switching between therapies, and therapeutic adherence, compliance or persistence. The targeted literature review identified four main approaches to map PANSS scores to utility values.

EXPERT COMMENTARY

Health economic models developed for schizophrenia showed great variability, with simulation models becoming more frequently used in the last decade. Using PANSS scores as the basis of utility estimations is justifiable.

Weight gain changes in patients with aripiprazole monotherapy compared with aripiprazole-antidepressant polypharmacy in an outpatient sample

OBJECTIVE

This study seeks to evaluate the weight gain effect within a community-based population of patients with diagnoses of depression, mood disorder, and schizophrenia receiving aripiprazole over a period of at least 6 months.

METHOD

The four million members of Kaiser Permanente of Southern California (KPSC) were queried for a four-year period between January 1, 2010 and December 31, 2013. The initial cohort comprised 25,682 KPSC members who received at least one dispense of aripiprazole. This initial cohort was split into those who received aripiprazole as a monotherapy ("Alone" group) and those who were given aripiprazole as part of a combination therapy. The group of patients that received aripiprazole and antidepressant with high serotonin reuptake inhibition we called "High" group while the group receiving aripiprazole and bupropion combination we called "Low" serotonin group. We compared the primary endpoint of mean percent weight change from baseline after 180 days of continuous treatment between the three groups. Three pairwise comparisons were made: High versus Alone, Low versus Alone, and Low versus High, using adjusted and unadjusted linear regression models.

RESULTS

Within this population, patients on aripiprazole monotherapy showed statistically significant weight gain in all three groups. However, there was no statistically significant difference in weight gain between the aripiprazole monotherapy, the high serotonergic combination group, and the low serotonergic combination group. This finding applied even within the subset of patients who were considered obese (body mass index > 30).

CONCLUSIONS

The results suggest that weight gain is unchanged by combination treatments, but further research is required.

The Cost of Relapse in Schizophrenia

INTRODUCTION

Schizophrenia is a chronic and debilitating mental illness characterised by periods of relapse that require resource intensive management. Quantifying the cost of relapse is central to the evaluation of the cost effectiveness of treating schizophrenia.

OBJECTIVES

We aimed to undertake a comprehensive search of the available literature on the cost of relapse.

METHODS

We performed a search on multiple databases (MEDLINE, Embase, PsycINFO and Health Management Information Consortium) for any study reporting a cost of relapse or data from which such a cost could be calculated. Costs are reported in 2015 international dollars.

RESULTS

We found 16 studies reporting costs associated with relapse over a defined period of time and identified a cost associated with hospitalisation for relapse in 43 studies. Eight clinical decision analyses also provided cost estimates. Studies from the US report excess costs of relapse of $6033-$32,753 (2015 Purchasing Power Parity dollars [PPP$]) over periods of 12-15 months. European studies report excess costs of $8665-$18,676 (2015 PPP$) over periods of 6-12 months. Estimates of the cost of hospitalisation for relapse are more diverse, and associated with marked differences in typical length of stay across jurisdictions.

CONCLUSIONS

Wide ranges in the estimated cost of relapse may reflect differences in sample section and relapse definition as well as practice styles and differences in resource costs. Selection of the most appropriate cost estimate should be guided by the definition of relapse and the analysis setting.

Cost-Utility Analysis of Lurasidone Versus Aripiprazole in Adults with Schizophrenia

BACKGROUND

In 2014, lurasidone, an atypical antipsychotic, was approved for the treatment of schizophrenia in adults. It is an alternative treatment option to aripiprazole, and when compared with aripiprazole, lurasidone was associated with improved symptom reduction and reduced risk of weight gain and relapse. We conducted a cost-utility analysis of lurasidone versus aripiprazole from the perspective of healthcare services, using Scotland and Wales as specific case studies.

METHODS

A 10-year Markov model, incorporating a 6-week acute phase and a maintenance phase across three health states (discontinuation, relapse, death) was constructed. Six-week probabilities of discontinuation and adverse events were based on a published independent mixed-treatment comparison; long-term risks of relapse and discontinuation were from an indirect comparison. Costs included drug therapy, relapse, and outpatient, primary and residential care. Costs and benefits were discounted at 3.5 %. Utility estimates were taken from published literature, and cost effectiveness was expressed as total 10-year incremental costs and quality-adjusted life-years (QALYs).

RESULTS

Lurasidone yielded a cost saving of £3383 and an improvement of 0.005 QALYs versus aripiprazole, in Scotland. Deterministic sensitivity analysis demonstrated that results were sensitive to relapse rates, while probabilistic sensitivity analysis suggested that lurasidone had the highest expected net benefit at willingness-to-pay thresholds of £20,000-30,000 per QALY. The probability that lurasidone was a cost-effective treatment strategy was approximately 75 % at all willingness-to-pay thresholds, with similar results being obtained for the Welsh analysis.

CONCLUSIONS

Our analysis suggests that lurasidone would provide an effective, cost-saving alternative for the healthcare service in the treatment of adult patients with schizophrenia.

Cost-effectiveness of second-generation antipsychotics for the treatment of schizophrenia

OBJECTIVE

To compare the cost-effectiveness of alternate treatment strategies using second-generation antipsychotics (SGAs) for patients with schizophrenia.

METHODS

We developed a Markov model to estimate the costs and quality-adjusted life-years (QALYs) for different sequences of treatments for 40-year-old patients with schizophrenia. We considered first-line treatment with one of the four SGAs: olanzapine (OLZ), risperidone (RSP), quetiapine (QTP), and ziprasidone (ZSD). Patients could switch to another of these antipsychotics as second-line therapy, and only clozapine (CLZ) was allowed as third-line treatment. We derived parameter estimates from the Clinical Antipsychotic Trial of Intervention Effectiveness (CATIE) study and published sources.

RESULTS

The ZSD-QTP strategy (first-line treatment with ZSD, change to QTP if ZSD is discontinued, and switch to CLZ if QTP is discontinued) was most costly while yielding the greatest QALYs, with an incremental cost-effective ratio (ICER) of $542,500 per QALY gained compared with the ZSD-RSP strategy. However, the ZSD-RSP strategy had an ICER of $5,200/QALY gained versus the RSP-ZSD strategy and had the greatest probability of being cost-effective given a willingness-to-pay threshold between $50,000 and $100,000 per QALY. All other treatment strategies were more costly and less effective than another strategy or combination of other strategies. Results varied by different time horizons adopted.

CONCLUSIONS

The ZSD-RSP strategy was most cost-effective at a willingness-to-pay threshold between $5,200 and $542,500 per QALY. Our results should be interpreted with caution because they are based largely on the CATIE trial with potentially limited generalizability to all patient populations and doses of SGAs used in practice.

The estimation of utility weights in cost-utility analysis for mental disorders: a systematic review

OBJECTIVE

To systematically review approaches and instruments used to derive utility weights in cost-utility analyses (CUAs) within the field of mental disorders and to identify factors that may have influenced the choice of the approach.

METHODS

We searched the databases DARE (Database of Abstracts of Reviews of Effects), NHS EED (National Health Service Economic Evaluation Database), HTA (Health Technology Assessment), and PubMed for CUAs. Studies were included if they were full economic evaluations and reported quality-adjusted life-years as the health outcome. Study characteristics and instruments used to estimate utility weights were described and a logistic regression analysis was conducted to identify factors associated with the choice of either the direct (e.g. standard gamble) or the preference-based measure (PBM) approach (e.g. EQ-5D).

RESULTS

We identified 227 CUAs with a maximum in 2009, 2010, and 2012. Most CUAs were conducted in depression, dementia, or psychosis, and came from the US or the UK, with the EQ-5D being the most frequently used instrument. The application of the direct approach was significantly associated with depression, psychosis, and model-based studies. The PBM approach was more likely to be used in recent studies, dementia, Europe, and empirical studies. Utility weights used in model-based studies were derived from only a small number of studies.

LIMITATIONS

We only searched four databases and did not evaluate the quality of the included studies.

CONCLUSIONS

Direct instruments and PBMs are used to elicit utility weights in CUAs with different frequencies regarding study type, mental disorder, and country.

Metabolic effects and cost-effectiveness of aripiprazole versus olanzapine in schizophrenia and bipolar disorder

OBJECTIVE

To assess the cost-effectiveness of aripiprazole versus olanzapine in the treatment of patients with schizophrenia or bipolar disorder in Sweden with focus on the metabolic impact of the treatments.

METHOD

A Markov health-state transition model was developed. The risks of developing metabolic syndrome after one year of treatment with aripiprazole or olanzapine were derived from a pooled analysis of three randomised clinical trials. The subsequent risks of developing diabetes or coronary heart disease were based on previously published risk models. A societal perspective was applied, adopting a lifetime horizon. Univariate and probabilistic sensitivity analyses were conducted.

RESULTS

Treatment with aripiprazole dominates over olanzapine in both schizophrenia and bipolar disorder. In schizophrenia, quality-adjusted life-years (QALYs) gained were 0.08 and cost savings Swedish kronor (SEK) 30,570 (USD 4000); in bipolar disorder, QALYs gained were 0.09 and cost savings SEK 28,450 (USD 3720). In probabilistic sensitivity analyses, aripiprazole resulted in a dominant outcome in 84% of cases in schizophrenia and in 77% of cases in bipolar syndrome.

CONCLUSION

The significantly lower risk of developing metabolic syndrome observed with aripiprazole compared with olanzapine is associated with less risk of diabetes and cardiovascular morbidity and mortality that translates into lower overall treatment cost and improved quality of life over time.

Cost of treatment of schizophrenia in six European countries

BACKGROUND AND AIMS

As part of an RCT in six European sites, the direct mental health care cost for 422 patients with schizophrenia was analysed according to how total and medication costs differed across sites and which variables were likely to predict total or service-specific costs.

METHOD

Service use was recorded continuously during a 12-month follow-up. Prescribed psychotropic medication was recorded at baseline and 12 months later. Service use data were transformed into EURO, log-transformed and analysed using linear regression models.

RESULTS

Although samples were homogeneous, large inter-site cost differences were found (annual means ranging from 2958 euro in Spain up to 36978 euro in Switzerland). Psychopharmacologic costs were much more constant across sites than costs for other services. Total costs were associated more with region or socio-demographic characteristics than with disorder related parameters.

CONCLUSIONS

The findings confirm remarkable differences in direct costs of patients with schizophrenia across Europe. However, the relative stability of medication costs suggests a need to analyse mechanisms that influence service-specific costs for schizophrenia.