The cost-effectiveness of atypicals in the UK

Modeling disease progression and treatment pathways for depression jointly using agent based modeling and system dynamics

Introduction

Depression is a common mental health condition that affects millions of people worldwide. Care pathways for depression are complex and the demand across different parts of the healthcare system is often uncertain and not entirely understood. Clinical progression with depression can be equally complex and relates to whether or not a patient is seeking care, the care pathway they are on, and the ability for timely access to healthcare services. Considering both pathways and progression for depression are however rarely studied together in the literature.

Methods

This paper presents a hybrid simulation modeling framework that is uniquely able to capture both disease progression, using Agent Based Modeling, and related care pathways, using a System Dynamics. The two simulation paradigms within the framework are connected to run synchronously to investigate the impact of depression progression on healthcare services and, conversely, how any limitations in access to services may impact clinical progression. The use of the developed framework is illustrated by parametrising it with published clinical data and local service level data from Wales, UK.

Results and discussion

The framework is able to quantify demand, service capacities and costs across all care pathways for a range of different scenarios. These include those for varying service coverage and provision, such as the cost-effectiveness of treating patients more quickly in community settings to reduce patient progression to more severe states of depression, and thus reducing the costs and utilization of more expensive specialist settings.

Pharmacogenomic-guided clozapine administration based on HLA-DQB1, HLA-B and SLCO1B3-SLCO1B7 variants: an effectiveness and cost-effectiveness analysis

The identification of pharmacogenetic factors that increase the susceptibility to clozapine-induced agranulocytosis or granulocytopenia (CIAG) has received increasing interest. The SLCO1B3-SCLO1B7 variant (rs149104283) and single amino acid changes in human leukocyte antigen (HLA) HLA-DQB1 (126Q) and HLA-B (158T) were associated with an increased risk of CIAG. In this study, we evaluated the effectiveness and cost-effectiveness of adding the SLCO1B3-SCLO1B7 to HLA variants as a new pharmacogenomic (PGx) approach and explored the evolution of a cohort of schizophrenic patients taking long-term clozapine as a third-line antipsychotic medication. The decision model included probabilistic and deterministic sensitivity analyses to assess the expected costs and quality-adjusted life-years (QALYs). The current monitoring scheme was compared with the PGx-guided strategy, where all patients underwent pre-emptively a genetic test before taking clozapine, over 10 years. By adding the SLCO1B3-SCLO1B7 variant into HLA variants, CIAG sensitivity increased from 36.0% to 43.0%, the specificity decreased from 89.0% to 86.9%, and the probability of cost-effectiveness improved from 74.1% to 87.8%. The incremental cost-effectiveness ratio was £16,215 per QALY and remained below the conventional decision threshold (£30,000 or US$50,000 per QALY). Therefore, the SLCO1B3-SCLO1B7 variant, as an additional risk allele to HLA variants, increases preemptive test sensitivity and improves the effectiveness and cost-effectiveness of PGx-guided clozapine administration.

Cost effectiveness of pharmacogenetic-guided clozapine administration based on risk of HLA variants in Japan and the UK

Pharmacogenetics/pharmacogenomics have enabled the detection of risk of human leukocyte antigen (HLA) variants for clozapine-induced agranulocytosis/granulocytopenia (CIAG). To apply this evidence to the clinical setting, we compared the cost-effectiveness of the proposed "HLA-guided treatment schedule" and the "current schedule" being used in Japan and the United Kingdom (UK) (absolute neutrophil count (ANC) cutoff at 1500/mm³); in the "HLA-guided treatment schedules," we considered a situation wherein the HLA test performed before clozapine initiation could provide "a priori information" by detecting patients harboring risk of HLA variants (HLA-B*59:01 and "HLA-B 158T/HLA-DQB1 126Q" for Japanese and Caucasian populations, respectively), a part of whom can then avoid CIAG onset (assumed 30% "prevention rate"). For the primary analysis, we estimated the incremental cost-effectiveness ratio (ICER) of "HLA-guided treatment schedule" and "current schedule" used in Japan and the UK, using a Markov model to calculate the cost and quality-adjusted life years (QALYs) over a 10-year time period. Furthermore, as an explorative analysis, we simulated several situations with various ANC cutoffs (1000/mm³ and 500/mm³) and plotted the cost/QALYs for each option to identify the best, or estimate the next best candidate option applicable in actual clinical settings. The primary probabilistic analysis showed that the "HLA-guided treatment schedule" was more cost effective than the "current schedule"; the ICER was £20,995 and £21,373 for the Japanese and the UK populations, respectively. Additional simulation revealed that the treatment option of ANC cutoff at 500/mm³ without HLA screening was the most cost-effective option; however, several options may be candidates to break away from the "current schedule" of ANC cutoff at 1500/mm³. Owing to its cost-effectiveness, we propose such pharmacogenetic-guided/pharmacogenomic-guided clozapine treatment for use in the real-world setting, which provides key information for optimization of clinical guidelines for high-risk patients for gradual change of clozapine treatment schedule under the safety consideration.

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.

A Systematic Review of Economic Models Across the Entire Schizophrenia Pathway

BACKGROUND

Schizophrenia is associated with a high economic burden. Economic models can help to inform resource allocation decisions to maximise benefits to patients.

OBJECTIVES

This systematic review aims to assess the availability, quality and consistency of conclusions of health economic models evaluating the cost effectiveness of interventions for schizophrenia.

METHODS

An electronic search was performed on multiple databases (MEDLINE, EMBASE, PsycINFO, Cochrane database of systematic reviews, NHS Economic Evaluation Database and Health Technology Assessment database) to identify economic models of interventions for schizophrenia published between 2005 and 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. Model characteristics and conclusions were descriptively summarised.

RESULTS

Seventy-three models met inclusion criteria. Seventy-eight percent of existing models assessed antipsychotics; however, due to inconsistent conclusions reported by different studies, no antipsychotic can be considered clearly cost effective compared with the others. A very limited number of models suggest that the following non-pharmacological interventions might be cost effective: psychosocial interventions, stratified tests, employment intervention and intensive intervention to improve liaison between primary and secondary care. The quality of included models is generally low due to use of a short time horizon, omission of adverse events of interventions, poor data quality and potential conflicts of interest.

CONCLUSIONS

This review highlights a lack of models for non-pharmacological interventions, and limitations of the existing models, including low quality and inconsistency in conclusions. Recommendations on future modelling approaches for schizophrenia are provided.

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 and Critical Appraisal of Economic Evaluations of Pharmacological Interventions for People with Bipolar Disorder

BACKGROUND

Bipolar disorder (BD) is a chronic mood disorder that causes substantial psychological and financial burden. Various pharmacological treatments are effective in the management and prevention of acute episodes of BD. In an era of tighter healthcare budgets and a need for more efficient use of resources, several economic evaluations have evaluated the cost effectiveness of treatments for BD.

OBJECTIVE

The aim of this study was to systematically review and appraise published economic evaluations of pharmacological interventions for BD.

METHODS

A systematic search combining search terms specific to BD with a health economics search filter was conducted on six bibliographic databases (EMBASE, MEDLINE, PsycINFO, HTA, NHS EED, CENTRAL) in order to identify trial- or model-based full economic evaluations of pharmacological treatments of any phase of the disorder that were published between 1 January 1990 and 18 December 2015. Studies that met the inclusion criteria were critically appraised using the Quality of Health Economic Studies (QHES) checklist, and synthesised in a narrative way.

RESULTS

The review included 19 economic studies, which varied with regard to the type and number of interventions assessed, the study design, the phase of treatment (acute or maintenance), the source of efficacy data and the method for evidence synthesis, the outcome measures, the time horizon and the countries/settings in which the studies were conducted. The study quality was variable but the majority of studies were of high or fair quality.

CONCLUSION

Pharmacological interventions are cost effective, compared with no treatment, in the management of BD, both in the acute and maintenance phases. However, it is difficult to draw safe conclusions on the relative cost effectiveness between drugs due to differences across studies and limitations characterising many of them. Future economic evaluations need to consider the whole range of treatment options available for the management of BD and adopt appropriate methods for evidence synthesis and economic modelling, to explore more robustly the relative cost effectiveness of pharmacological interventions for people with BD.

Pharmacoeconomics of long-acting atypical antipsychotics for acutely relapsed chronic schizophrenia in Finland

BACKGROUND

Atypical long-acting injectable (LAI) antipsychotics are increasingly available for treating chronic schizophrenia in patients chronically non-adherent to prescribed regimens. Few economic studies have compared these products.

PURPOSE

To determine the cost-effectiveness of aripiprazole (ARI-LAI), paliperidone (PP-LAI), olanzapine (OLZ-LAI), and risperidone (RIS-LAI) in patients with chronic schizophrenia in Finland.

METHODS

A 1-year decision tree model was adapted with guidance from an expert panel. Patients started hospitalized in relapse; those who responded continued treatment, others were switched to secondary drugs, then clozapine in the event of 2nd line failure. Rates of adherence, stable disease, relapse, and hospitalization were taken from pivotal trials, and utilities from published research. Included were direct costs paid by the Finnish Ministry of Health, in 2015 euros. Outcomes included quality-adjusted life-years (QALYs), hospitalization rates, and rates of relapse not requiring hospitalization. Model robustness was assessed using a series of 1-way and multivariate sensitivity analyses.

RESULTS

Expected costs were lowest for PP-LAI at 41,148€, followed by 41,543€ for ARI-LAI, 42,067€ for RIS-LAI and 45,406€ for OLZ-LAI. Respective QALYs were 0.683, 0.671, 0.666, and 0.672. Re-hospitalization rates and non-admitted relapses were 23.6% and 3.9% for PP-LAI, 28.5% and 4.1% for ARI-LAI, 28.8% and 5.0% for RIS-LAI, 28.3% and 5.2% for OLZ-LAI. PP-LAI treatment was associated with the most days with stable disease (132.0), followed by OLZ-LAI (125.5), ARI-LAI (122.6), and RIS-LAI (114.4). Sensitive inputs between PP-LAI and ARI-LAI included rates of adherence, dropouts, and relapses plus drug prices; dropout and relapse rates for RIS-LAI; OLZ-LAI results were insensitive. In probability sensitivity analyses, PP-LAI dominated ARI-LAI in 75.8% of the 10,000 iterations, RIS-LAI in 83.1% and OLZ-LAI in 95.7%.

CONCLUSIONS

PP-LAI dominated the other atypicals. It appears to be the preferred option for treating chronic relapsing schizophrenia.

An economic evaluation of a contingency-management intervention for stimulant use among community mental health patients with serious mental illness

BACKGROUND

This study examines the cost-effectiveness of contingency-management (CM) for stimulant dependence among community mental health patients with serious mental illness (SMI) METHODS: Economic evaluation of a 12-week randomized controlled trial investigating the efficacy of CM added to treatment-as-usual (CM+TAU), relative to TAU without CM, for treating stimulant dependence among patients with a SMI. The trial included 176 participants diagnosed with SMI and stimulant dependency who were receiving community mental health and addiction treatment at one community mental health center in Seattle, Washington. Participants were also assessed during a 12-week follow-up period. Positive and negative syndrome scale (PANSS) scores were used to calculate quality-adjusted life-years (QALYs) for the primary economic outcome. The primary clinical outcome, the stimulant-free year (SFY) is a weighted measure of time free from stimulants. Two perspectives were adopted, those of the provider and the payer.

RESULTS

At 12-weeks neither the provider ($2652, p=0.74) nor the payer ($2611, p=0.99) cost differentials were statistically significant. This was also true for the payer at 24-weeks (-$125, p=1.00). QALYs gained were similar across groups, resulting in small, insignificant differences (0.04, p=0.23 at 12-weeks; 0.01, p=0.70 at 24 weeks). CM+TAU experienced significantly more SFYs, 0.24 (p<0.001) at 12 weeks and 0.20 (p=0.002) at 24 weeks, resulting in at least an 85% chance of being considered cost-effective at a threshold of $200,000/SFY.

CONCLUSION

Contingency management appears to be a wise investment for both the provider and the payer with regard to the clinical outcome of time free from stimulants.

Long-acting olanzapine versus long-acting risperidone for schizophrenia in Spain - a cost-effectiveness comparison

BACKGROUND

In schizophrenia, medication adherence is critical to achieve better patient outcomes and to avoid relapses, which are responsible for a significant proportion of total healthcare costs for this chronic illness. The aim of this study was to assess the cost-effectiveness of olanzapine long-acting injection (OLAI) compared with risperidone long-acting injection (RLAI) in patients with schizophrenia in Spain.

METHODS

A discrete event simulation (DES) model was developed from a Spanish healthcare system perspective to estimate clinical and economic outcomes for patients with schizophrenia over a five-year period. Patients who had earlier responded to oral medication and have a history of relapse due to adherence problems were considered. Identical model populations were treated with either OLAI or RLAI. In the absence of a head-to-head clinical trial, discontinuation and relapse rates were obtained from open-label studies. The model accounted for age, gender, risks of relapse and discontinuation, relapse management, hospitalization, treatment switching and adverse events. Direct medical costs for the year 2011 and outcomes including relapse avoided, life years (LYs), and quality-adjusted life years (QALYs) were discounted at a rate of 3%.

RESULTS

When comparing RLAI and OLAI, the model predicts that OLAI would decrease 5-year costs by €2,940 (Standard Deviation between replications 300.83), and result in a QALY and LY gains of 0.07 (SD 0.019) and 0.04 (SD 0.025), respectively. Patients on OLAI had fewer relapses compared to RLAI (1.392 [SD 0.035] vs. 1.815 [SD 0.035]) and fewer discontinuations (1.222 [SD 0.031] vs. 1.710 [SD 0.039]). Sensitivity analysis indicated that the study was robust and conclusions were largely unaffected by changes in a wide range of parameters.

CONCLUSIONS

The present evaluation results in OLAI being dominant over RLAI, meaning that OLAI represents a more effective and less costly alternative compared to RLAI in the treatment of patients with schizophrenia in the Spanish setting.

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.

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.

Aripiprazole for the treatment and prevention of acute manic and mixed episodes in bipolar I disorder in children and adolescents: a NICE single technology appraisal

As part of its single technology process, the National Institute for Health and Care Excellence (NICE) invited the manufacturers of aripiprazole (Otsuka Pharmaceutical Co. and Bristol Myers Squibb) to submit evidence of the clinical and cost effectiveness of aripiprazole for the treatment and prevention of acute manic and mixed episodes in bipolar I disorder in children and adolescents. The School of Health and Related Research Technology Appraisal Group at the University of Sheffield was commissioned to act as the independent Evidence Review Group (ERG). The ERG produced a critical review of the evidence for the clinical and cost effectiveness of the technology, based upon the manufacturers' submission to NICE. The evidence, which was derived mainly from a double-blind, phase III, placebo-controlled trial of aripiprazole in patients aged 10-17 years, showed that aripiprazole performed significantly better than placebo in reducing mania according to the primary outcome measurement (the Young Mania Rating Scale at 4 weeks). Safety outcomes indicated that aripiprazole was significantly more likely to cause extrapyramidal symptoms and somnolence than placebo. The manufacturers also presented a network meta-analysis of aripiprazole versus other atypical antipsychotics commonly used to treat manic episodes (olanzapine, quetiapine and risperidone) to show that aripiprazole performed similarly to the comparator drugs in terms of efficacy and safety. Aripiprazole was demonstrated to perform better in safety outcomes of (1) less weight gain than olanzapine and quetiapine; and (2) less prolactin increase than olanzapine, quetiapine and risperidone. Results from the manufacturers' economic evaluation showed that use of aripiprazole second-line dominated all of the other treatment strategies that were considered. However, there was considerable uncertainty in this result, and clinical advisors indicated that the actual treatment strategy employed in practice is likely to be dependent upon the patient's characteristics. The ERG demonstrated that if this personalised medicine resulted in improved cost effectiveness for any of the other treatment strategies, then they had the potential to dominate use of aripiprazole second-line. In conclusion, whilst a strategy including aripiprazole appeared to be cost effective relative to a strategy without it, there was not robust enough evidence to recommend a specific place for aripiprazole within the treatment pathway.

The cost effectiveness of long-acting/extended-release antipsychotics for the treatment of schizophrenia: a systematic review of economic evaluations

BACKGROUND

Antipsychotic medication is the mainstay of treatment in schizophrenia. Long-acting medication has potential advantages over daily medication in improving compliance and thus reducing hospitalization and relapse rates. The high acquisition and administration costs of such formulations raise the need for pharmacoeconomic evaluation.

OBJECTIVE

The aim of this article is to provide a comprehensive review of the available evidence on the cost effectiveness of long-acting/extended-release antipsychotic medication and critically appraise the strength of evidence reported in the studies from a methodological viewpoint.

METHODS

Relevant studies were identified by searching five electronic databases: PsycINFO, MEDLINE, EMBASE, the NHS Economic Evaluation Database and the Health Technology Assessment database (HTA). Search terms included, but were not limited to, 'long-acting injection', 'economic evaluation', 'cost-effectiveness' and 'cost-utility'. No limits were applied for publication dates and language. Full economic evaluations on long-acting/extended-release antipsychotics were eligible for inclusion. Observational studies and clinical trials were also checked for cost-effectiveness information. Conference abstracts and poster presentations on the cost effectiveness of long-acting antipsychotics were excluded. Thirty-two percent of identified studies met the selection criteria. Pertinent abstracts were reviewed independently by two reviewers. Relevant studies underwent data extraction by one reviewer and were checked by a second, with any discrepancies being clarified during consensus meetings. Eligible studies were assessed for methodological quality using the quality checklist for economic studies recommended by the NICE guideline on interventions in the treatment and management of schizophrenia.

RESULTS

After applying the selection criteria, the final sample consisted of 28 studies. The majority of studies demonstrated that risperidone long-acting injection, relative to oral or other long-acting injectable drugs, was associated with cost savings and additional clinical benefits and was the dominant strategy in terms of cost effectiveness. However, olanzapine in either oral or long-acting injectable formulation dominated risperidone long-acting injection in a Slovenian and a US study. Furthermore, in two UK studies, the use of long-acting risperidone increased the hospitalization days and overall healthcare costs, relative to other atypical or typical long-acting antipsychotics. Finally, paliperidone extended-release was the most cost-effective treatment compared with atypical oral or typical long-acting formulations. From a methodological viewpoint, most studies employed decision analytic models, presented results using average cost-effectiveness ratios and conducted comprehensive sensitivity analyses to test the robustness of the results.

LIMITATIONS

Variations in study methodologies restrict consistent and direct comparisons across countries. The exclusion of a large body of potentially relevant conference abstracts as well as some papers being unobtainable may have increased the likelihood of misrepresenting the overall cost effectiveness of long-acting antipsychotics. Finally, the review process was restricted to qualitative assessment rather than a quantitative synthesis of results, which could provide more robust conclusions.

CONCLUSIONS

Atypical long-acting (especially risperidone)/extended-release antipsychotic medication is likely to be a cost-effective, first-line strategy for managing schizophrenia, compared with long-acting haloperidol and other oral or depot formulations, irrespective of country-specific differences. However, inconsistencies in study methodologies and in the reporting of study findings suggest caution needs to be applied in interpreting these findings.

Cost effectiveness of guanfacine extended release as an adjunctive therapy to a stimulant compared with stimulant monotherapy for the treatment of attention-deficit hyperactivity disorder in children and adolescents

BACKGROUND

Attention-deficit hyperactivity disorder (ADHD) is a common psychiatric disorder in childhood, affecting 3-7% of school-age children in the US and imposing substantial economic burden. Stimulants are considered first-line pharmacological treatment and are the most prescribed treatment for ADHD. However, approximately 30% of children with ADHD do not have an optimal response to a single stimulant and may require adjunctive therapy.

OBJECTIVE

Our objective was to conduct a cost-effectiveness analysis (CEA) of adding a non-stimulant, guanfacine extended release (GXR), to stimulants versus maintaining existing stimulant monotherapy in the treatment of ADHD in children and adolescents with suboptimal response to stimulant monotherapy.

METHODS

A 1-year Markov model was developed to estimate costs and effectiveness from a US third-party payer perspective. Effectiveness was measured by the QALY. The model assumed that patients transitioned among four health states (normal, mild, moderate and severe), defined by the Clinical Global Impression-Severity (CGI-S) scale. Transition probabilities were estimated in an ordered logit model using patient-level data from a multicentre, 9-week, double-blind, placebo-controlled, dose-optimization study, where subjects (n = 461) continued their stable morning stimulant and were randomized to GXR administered in the morning, GXR administered in the evening, or placebo. The model assumed that patients in moderate/severe health states after week 8 would discontinue ADHD treatment and remain in that state for the rest of the study period. Direct costs included drug wholesale acquisition costs and health state costs, all in $US, year 2010 values. Utility associated with each health state was obtained from the literature and disutilities associated with adverse events were applied for the first 4 weeks. One-way sensitivity analyses and probabilistic sensitivity analysis (PSA) were conducted by varying costs, utilities, adverse-event duration, and transition probabilities.

RESULTS

Compared with maintaining existing stimulant monotherapy, adding GXR to existing stimulant monotherapy was associated with an incremental drug cost of $US1016 but a lower medical cost of $US124, resulting in a total incremental cost of $US892 at 1 year. The addition of GXR to stimulants led to an incremental QALY of 0.03 and an incremental cost-effectiveness ratio (ICER) of $US31,660/QALY. In one-way sensitivity analysis, ICER values ranged from $US19,723, when 100% of patients were assumed to be severe in their initial health state, to $US46,631, when the last observed states from the clinical trial were carried forward to the end of the 1-year analysis period. PSA demonstrated a 94.6% likelihood that the ICER falls below $US50,000/QALY.

CONCLUSIONS

The impairment associated with residual ADHD symptoms after stimulant therapy is becoming increasingly recognized. This is the first analysis of the cost effectiveness of stimulants combined with an adjunctive medication. This study suggests that the adjunctive therapy of GXR with stimulants is a cost-effective treatment based on a willingness-to-pay threshold of $US50,000/QALY. This may address an unmet need among patients with suboptimal response to stimulant monotherapy.

Cost effectiveness of long-acting risperidone in Sweden

BACKGROUND

In Sweden, risperidone long-acting injectable (RLAI) is generally used in a population of schizophrenia patients who are at a high risk of being non-compliant. However, RLAI might also be suitable for use in the general schizophrenia population.

OBJECTIVES

To analyse the clinical and economic effects of RLAI in the Swedish treatment practice using a discrete-event simulation (DES) model. Treatment outcomes and direct costs were analysed for both the high-risk non-compliant patient population and the general schizophrenia population.

METHODS

An existing DES model was adapted to simulate the treatment of schizophrenia in Sweden. Model inputs were based on literature research and supplemented with expert opinion. In the high-risk non-compliant schizophrenia population, RLAI was compared with haloperidol LAI. The analysis was built upon differences in symptom reduction, time between relapses, compliance and adverse effect profile between the two drugs. Main outcomes were the predicted incremental (discounted) costs (€) and effects (QALYs). In the general schizophrenia population, RLAI was compared with oral olanzapine. This analysis was built upon differences in compliance and adverse effects between the drugs. Multivariate probabilistic sensitivity analyses (PSA) were carried out to assess the sensitivity of the results of the two analyses.

RESULTS

In the high-risk non-compliant patient population, RLAI was predicted to generate 0.103 QALYs per patient over 3 years while realizing cost savings of €5013 (year 2007 values) compared with haloperidol LAI. The main driver of the cost effectiveness of RLAI was the difference in Positive and Negative Syndrome Scale (PANSS) reduction between the two drugs, followed by the difference in adverse effects. The PSA showed that, in this setting, RLAI had a probability of 100% of being cost effective at a willingness-to-pay (WTP) threshold of €43,300 per QALY gained, compared with haloperidol LAI. The probability that RLAI combines additional effectiveness with cost savings compared with haloperidol LAI was estimated at 94%. When analysing RLAI in the general schizophrenia population, it was predicted to generate 0.043 QALYs and save €239 per patient over 5 years compared with olanzapine. Compliance was the main driver of the cost effectiveness of RLAI in this scenario. In the PSA it was shown that RLAI had a probability of 78% of being cost effective at a WTP threshold of €43,300 per QALY gained, compared with olanzapine. The estimated probability that RLAI combines additional effectiveness with cost savings was 50% and the probability that RLAI is less effective and more costly than olanzapine was negligible (0.2%).

CONCLUSIONS

Treatment with RLAI is suggested to result in improved QALYs combined with cost savings compared with haloperidol LAI among the Swedish, high-risk non-compliant schizophrenia patient population. In the general schizophrenia population, RLAI also resulted in positive incremental QALYs and cost savings, when compared with olanzapine. However, the estimates used in the model for compliance and symptom reduction need further validation through naturalistic-based studies with reasonable follow-up to more definitely establish the real-life differences between RLAI and the comparators in the considered patient populations and to further reduce the uncertainty of these parameters.

Relapse and long-acting injectable risperidone: a 1-year mirror image study with a national claims database in Taiwan

OBJECTIVES

The development of long-acting, injectable atypical antipsychotics has provided a new paradigm for schizophrenia treatment. The study was designed to assess whether a risperidone long-acting injection (RLAI) is associated with reduced relapses and service utilization in the real world.

METHODS

The Psychiatric Inpatients Medical Claims dataset was used for the analysis. It is a longitudinal dataset that includes the National Health Insurance claims of service uses by a cohort of mentally ill patients. The inclusion criteria for this analysis were patients who: 1) had available information for at least 12 months after the first dose of RLAI; 2) had a primary diagnosis of schizophrenia; and 3) were regularly treated with RLAI for at least 1 year. Patients who accumulatively received at least 75-mg RLAI per 3-month period were considered to be undergoing regular treatment. Wilcoxon signed rank tests were performed to compare differences in numbers of acute admissions, hospital days, emergency room visits, and relapses between the pre- and post-RLAI periods in this 1-year mirror-image study.

RESULTS

In total, 108 patients were eligible for analysis. Significant reductions in the total annual numbers of acute hospital admissions by 55% (80 vs. 36, P = 0.0003), hospital days by 48% (4106 vs. 2126, P = 0.0021), and relapses by 54% (115 vs. 53, P = 0.0005) were observed. A reduction of emergency room visits was also observed, but did not reach statistical significance (55 vs. 25, P = 0.1255).

CONCLUSIONS

This 1-year mirror-image analysis with claims-based data demonstrated that RLAI treatment was associated with reductions in relapses and hospital service utilization.

A pharmaco-economic analysis of patients with schizophrenia switching to generic risperidone involving a possible compliance loss

Background

As schizophrenia patients are typically suspicious of, or are hostile to changes they may be reluctant to accept generic substitution, possibly affecting compliance. This may counteract drug costs savings due to less symptom control and increased hospitalization risk. Although compliance losses following generic substitution have not been quantified so far, one can estimate the possible health-economic consequences. The current study aims to do so by considering the case of risperidone in Germany.

Methods

An existing DES model was adapted to compare staying on branded risperidone with generic substitution. Differences include the probability of non-compliance and medication costs. Incremental probability of non-compliance after generic substitution was varied between 2.5% and 10%, while generic medication costs were assumed to be 40% lower. Effect of medication price was assessed as well as the effect of applying compliance losses to all treatment settings. The probability of staying on branded risperidone being cost-effective was calculated for various outcomes of a hypothetical study that would investigate non-compliance following generic substitution of risperidone.

Results

If the incremental probability of non-compliance after generic substitution is 2.5%, 5.0%, 7.5% and 10% respectively, incremental effects of staying on branded risperidone are 0.004, 0.007, 0.011 and 0.015 Quality Adjusted Life Years (QALYs). Incremental costs are €757, €343, -€123 and -€554 respectively. Benefits of staying on branded risperidone include improved symptom control and fewer hospitalizations. If generic substitution results in a 5.2% higher probability of non-compliance, the model predicts staying on branded risperidone to be cost-effective (NICE threshold of ₤30,000 per QALY gained). Compliance losses of more than 6.9% makes branded risperidone the dominant alternative. Results are sensitive to the locations at which compliance loss is applied and the price of generic risperidone. The probability that staying on branded risperidone is cost-effective would increase with larger compliance differences and more patients included in the hypothetical study.

Conclusion

The model predicts that it is cost-effective to keep a patient with schizophrenia in Germany on branded risperidone instead of switching him/her to generic risperidone (assuming a 40% reduction in medication costs), if the incremental probability of becoming non-compliant after generic substitution exceeds 5.2%.