A rapid and systematic review and economic evaluation of the clinical and cost-effectiveness of newer drugs for treatment of mania associated with bipolar affective disorder

[About diagnosis and therapy of bipolar disorder]

The author describes diagnostic criteria and clinical symptoms of bipolar affective disorder (BAD) and summarizes the results of clinical studies on using modern antipsychotics to optimize BAD treatment. Preliminary recommendations for the use of aripiprazole in treatment of BAD, including exacerbation therapy and long-term maintenance therapy to prevent relapses, are presented.

A Guide to Medications Inducing Salivary Gland Dysfunction, Xerostomia, and Subjective Sialorrhea: A Systematic Review Sponsored by the World Workshop on Oral Medicine VI

BACKGROUND

Medication-induced salivary gland dysfunction (MISGD), xerostomia (sensation of oral dryness), and subjective sialorrhea cause significant morbidity and impair quality of life. However, no evidence-based lists of the medications that cause these disorders exist.

OBJECTIVE

Our objective was to compile a list of medications affecting salivary gland function and inducing xerostomia or subjective sialorrhea.

DATA SOURCES

Electronic databases were searched for relevant articles published until June 2013. Of 3867 screened records, 269 had an acceptable degree of relevance, quality of methodology, and strength of evidence. We found 56 chemical substances with a higher level of evidence and 50 with a moderate level of evidence of causing the above-mentioned disorders. At the first level of the Anatomical Therapeutic Chemical (ATC) classification system, 9 of 14 anatomical groups were represented, mainly the alimentary, cardiovascular, genitourinary, nervous, and respiratory systems. Management strategies include substitution or discontinuation of medications whenever possible, oral or systemic therapy with sialogogues, administration of saliva substitutes, and use of electro-stimulating devices.

LIMITATIONS

While xerostomia was a commonly reported outcome, objectively measured salivary flow rate was rarely reported. Moreover, xerostomia was mostly assessed as an adverse effect rather than the primary outcome of medication use. This study may not include some medications that could cause xerostomia when administered in conjunction with others or for which xerostomia as an adverse reaction has not been reported in the literature or was not detected in our search.

CONCLUSIONS

We compiled a comprehensive list of medications with documented effects on salivary gland function or symptoms that may assist practitioners in assessing patients who complain of dry mouth while taking medications. The list may also prove useful in helping practitioners anticipate adverse effects and consider alternative medications.

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.

Economic evaluations in bipolar disorder: a systematic review and critical appraisal

BACKGROUND

Bipolar disorder (BD) is a chronic illness and is one of the worldwide leading causes of disability. It is often a lifelong illness and incurs a substantial economic burden on the health care system, the patients, and society as a whole. However, there are few studies evaluating the economic impact of alternative strategies in the management of BD.

OBJECTIVES

We reviewed and critically appraised the available published economic evidence on BD management. In addition, we explored advantages and disadvantages of different methods used in the economic evaluation of the management of BD.

METHODS

A systematic literature search was undertaken using seven electronic databases to identify all English language articles published between January 1980 and March 2012 that provided data on complete economic evaluations for any treatment strategy for BD. The quality of included studies was appraised according to recommendations from the Cochrane Collaboration.

RESULTS

A total of 7,284 citations were obtained. After initial screening, 20 eligible studies were identified, five of which were trial-based, and 15 of which were model-based economic evaluations. Given the variability in methods and the quality of the identified studies, no conclusive recommendation for the most cost-effective therapy for BD could be provided.

CONCLUSIONS

The cost-effectiveness of different treatment strategies varied between settings, and transferability of these results across settings remains questionable. Although additional research using a longer time horizon is required to validate the findings for trial-based economic evaluations, discrete event simulation appears to be the most natural and plausible technique for modeling the cost-effectiveness of alternative BD treatment strategies.

Cost-effectiveness of asenapine in the treatment of bipolar I disorder patients with mixed episodes

OBJECTIVE

Around one-third of patients with bipolar I disorder (BD-I) experience mixed episodes, characterized by both mania and depression, which tend to be more difficult and costly to treat. Atypical antipsychotics are recommended for the treatment of mixed episodes, although evidence of their efficacy, tolerability, and cost in these patients is limited. This study evaluates, from a UK National Health Service perspective, the cost-effectiveness of asenapine vs olanzapine in BD-I patients with mixed episodes.

METHODS

Cost-effectiveness was assessed using a Markov model. Efficacy was informed by a post-hoc analysis of two short-term clinical trials, with response measured as a composite Young Mania Rating Score and Montgomery-Åsberg Depression Rating Scale end-point. Probabilities of discontinuation and relapse to manic, mixed, and depressive episodes were sourced from published meta-analyses. Direct costs (2012-2013 values) included drug acquisition, monitoring, and resource use related to bipolar disorder as well as selected adverse events. Benefits were measured as quality-adjusted life years (QALYs).

RESULTS

For treating mixed episodes, asenapine generated 0.0187 more QALYs for an additional cost of £24 compared to olanzapine over a 5-year period, corresponding to a £1302 incremental cost-effectiveness ratio. The higher acquisition cost of asenapine was roughly offset by the healthcare savings conferred through its greater efficacy in treating these patients. The model shows that benefits were driven by earlier response to asenapine during acute treatment and were maintained during longer-term follow-up. RESULTS were sensitive to changes in key parameters including short and longer-term efficacy, unit cost, and utilities, but conclusions remained relatively robust.

CONCLUSIONS

RESULTS suggest that asenapine is a cost-effective alternative to olanzapine in mixed episode BD-I patients, and may have specific advantages in this population, potentially leading to healthcare sector savings and improved outcomes. Limitations of the analysis stem from gaps in clinical and economic evidence for these patients and should be addressed by future clinical trials.

Pharmacotherapy of Bipolar Affective Disorder: A Hospital based Study from Sub Himalayan Valley of Nepal

INTRODUCTION

In Bipolar disorder the mood of the patients fluctuates between depression and mania. The main objective of the study was to find out the commonest mood stabilizers used for the treatment of Bipolar affective disorders in Western Nepal in hospitalized patients in an actual clinical set up.

METHODS

This was a cross-sectional study which was conducted between October 2009 and September 2010 at Psychiatric ward at Manipal teaching hospital, Pokhara, Nepal, a tertiary care hospital situated in Western Nepal. The diagnosis of the disease was based on ICD-10 (Tenth revision) Classification of mental and Behavioural disorders, Diagnostic Criteria for Research. We calculated odds ratio and their 95% confidence intervals (95% CI). p< 0.05 was considered as statistically significant.

RESULTS

62.1% of the patients were less than 40 yrs, 56.3% were male, 72.4% were unemployed and 75.9% of the patients were having monthly income <10,000/month. As far as ethnicity is concerned 37.9% of the cases were Brahmin and by occupation 29.9% of the patients were students followed by housewife 25.3%, labour 17.2%, retired 13.8% respectively. Drugs and Psychotherapy [OR 1.4, 95% (CI 0.575, 3.4017)] was prescribed in age <40 years as compared to age>40 yrs. Male patients [OR 7.22, 95% (CI 0.862, 60.499)] and [OR 2.353, 95% (CI 0.857, 6.455)] received drugs by trade names and drugs not from the national drug list of Nepal as compared to females. Monthly income <10,000/month and [OR 2.8, 95% (CI 0.742, 10.56)] tendency of receiving drugs by trade names. Among the mood elevators Sodium valproate was the commonest drug to be prescribed in 51/87(58.6%) patients followed by Lithium in 30/87 (34.5%) cases and Carbamazepine in 6/87 (6.9%) cases. Sodium valproate was prescribed at 1,000 mg/day, Lithium was prescribed at 900 mg/day in and Carbamazepine was prescribed at 800 mg/day.

CONCLUSION

Among all the mood elevators Sodium valproate is the commonest drug prescribed for the treatment of bipolar affective disorder, recommended that there is a trend of using newer drugs like sodium valproate rather than the conventional mood stabilizers like Lithium for bipolar affective disorder in Western Development region of Nepal.

Cost effectiveness of a pharmacist-led information technology intervention for reducing rates of clinically important errors in medicines management in general practices (PINCER)

BACKGROUND AND OBJECTIVE

We recently showed that a pharmacist-led information technology-based intervention (PINCER) was significantly more effective in reducing medication errors in general practices than providing simple feedback on errors, with cost per error avoided at £79 (US$131). We aimed to estimate cost effectiveness of the PINCER intervention by combining effectiveness in error reduction and intervention costs with the effect of the individual errors on patient outcomes and healthcare costs, to estimate the effect on costs and QALYs.

METHODS

We developed Markov models for each of six medication errors targeted by PINCER. Clinical event probability, treatment pathway, resource use and costs were extracted from literature and costing tariffs. A composite probabilistic model combined patient-level error models with practice-level error rates and intervention costs from the trial. Cost per extra QALY and cost-effectiveness acceptability curves were generated from the perspective of NHS England, with a 5-year time horizon.

RESULTS

The PINCER intervention generated £2,679 less cost and 0.81 more QALYs per practice [incremental cost-effectiveness ratio (ICER): -£3,037 per QALY] in the deterministic analysis. In the probabilistic analysis, PINCER generated 0.001 extra QALYs per practice compared with simple feedback, at £4.20 less per practice. Despite this extremely small set of differences in costs and outcomes, PINCER dominated simple feedback with a mean ICER of -£3,936 (standard error £2,970). At a ceiling 'willingness-to-pay' of £20,000/QALY, PINCER reaches 59 % probability of being cost effective.

CONCLUSIONS

PINCER produced marginal health gain at slightly reduced overall cost. Results are uncertain due to the poor quality of data to inform the effect of avoiding errors.

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.

Second generation antipsychotic-induced type 2 diabetes: a role for the muscarinic M3 receptor

Second generation antipsychotics (SGAs) are widely prescribed to treat various disorders, most notably schizophrenia and bipolar disorder; however, SGAs can cause abnormal glucose metabolism that can lead to insulin-resistance and type 2 diabetes mellitus side-effects by largely unknown mechanisms. This review explores the potential candidature of the acetylcholine (ACh) muscarinic M3 receptor (M3R) as a prime mechanistic and possible therapeutic target of interest in SGA-induced insulin dysregulation. Studies have identified that SGA binding affinity to the M3R is a predictor of diabetes risk; indeed, olanzapine and clozapine, SGAs with the highest clinical incidence of diabetes side-effects, are potent M3R antagonists. Pancreatic M3Rs regulate the glucose-stimulated cholinergic pathway of insulin secretion; their activation on β-cells stimulates insulin secretion, while M3R blockade decreases insulin secretion. Genetic modification of M3Rs causes robust alterations in insulin levels and glucose tolerance in mice. Olanzapine alters M3R density in discrete nuclei of the hypothalamus and caudal brainstem, regions that regulate glucose homeostasis and insulin secretion through vagal innervation of the pancreas. Furthermore, studies have demonstrated a dynamic sensitivity of hypothalamic and brainstem M3Rs to altered glucometabolic status of the body. Therefore, the M3R is in a prime position to influence glucose homeostasis through direct effects on pancreatic β-cells and by potentially altering signalling in the hypothalamus and brainstem. SGA-induced insulin dysregulation may be partly due to blockade of central and peripheral M3Rs, causing an initial disruption to insulin secretion and glucose homeostasis that can progressively lead to insulin resistance and diabetes during chronic treatment.

Cost-effectiveness of ethyl-eicosapentaenoic acid in the treatment of bipolar disorder

BACKGROUND

This study develops an economic model to evaluate the cost-effectiveness of ethyl-eicosapentaenoic acid (ethyl-EPA) as an adjunct treatment of bipolar I disorder.

METHODS

A 1-year Markov model is used incorporating three health states: euthymic, manic and depressive. The model was populated using outcomes from a clinical trial on clinical efficacy and other published literature.

RESULTS

The incremental cost-effectiveness ratio (ICER) per quality-adjusted life year (QALY) of ethyl-EPA in comparison with placebo was estimated to be -£2,782 in 2008/09 prices, the negative ICER indicating ethyl-EPA to be a more effective and less costly treatment option than placebo in terms of cost savings of other resource use.

CONCLUSIONS

The sensitivity analysis indicated that the results were robust. Future research covering a longer time period using broader costs of the disease will be required to consolidate these findings.

Quetiapine: a pharmacoeconomic review of its use in bipolar disorder

This article briefly summarizes the burden of bipolar disorder and the clinical profile of quetiapine (Seroquel®) in the management of bipolar disorder, followed by a detailed review of pharmacoeconomic analyses. Quetiapine is an atypical antipsychotic that is available in numerous countries as immediate-release and extended-release tablets for the treatment of major psychiatric disorders, including bipolar disorder. Randomized, double-blind, placebo-controlled trials with quetiapine have demonstrated its efficacy in bipolar I and II disorders, and the drug has been generally well tolerated in clinical trials. Three cost-effectiveness analyses of maintenance therapy in bipolar I disorder, which used similar Markov models and incorporated data from key clinical trials and a number of other sources, showed that quetiapine, as adjunctive therapy with mood stabilizers (lithium or divalproex), was a cost-effective treatment option from the healthcare payer perspective in the UK and the US. Quetiapine either dominated comparators (typically mood stabilizers alone) or was associated with incremental cost-effectiveness ratios that were usually well below widely accepted thresholds of cost effectiveness. One of the studies evaluated extended-release quetiapine, although clinical efficacy data used in the Markov model were for the immediate-release formulation. In another analysis, which used a discrete-event simulation model and was conducted from the perspective of the UK healthcare payer, quetiapine monotherapy was cost effective compared with olanzapine monotherapy as maintenance treatment for all phases of bipolar I or II disorder. In this model, favourable results were also shown for quetiapine (with or without mood stabilizers) compared with a wide range of maintenance therapy regimens. Another modelled analysis conducted from the UK healthcare payer perspective showed that quetiapine was dominated by haloperidol in the short-term treatment of a manic episode in patients with bipolar I disorder. Both favourable and unfavourable results have been reported in cost analyses of quetiapine in bipolar disorder (type I or type not specified). Possible explanations for some of the variability in results of the pharmacoeconomic analyses include heterogeneity among the models in terms of input parameters or assumptions in the base-case analyses, country- or region-specific differences in estimates of healthcare resource use and associated costs, variability in treatment alternatives, and differences in the year of costing and discounting used in the analyses. In addition, some of the studies had short time horizons and focused on acute manic episodes only, whereas others were longer-term analyses that considered the full spectrum of health states in patients with bipolar disorder. Various limitations of the studies have been recognized, and results from one country may not be applicable to other countries. In conclusion, results of available pharmacoeconomic analyses provide evidence of the cost effectiveness of quetiapine as an adjunct to mood stabilizers for maintenance therapy in (primarily type I) bipolar disorder from a healthcare payer perspective in the UK and the US. Some evidence is available to support the cost effectiveness of quetiapine monotherapy or the use of extended-release quetiapine as adjunctive therapy with mood stabilizers in this setting, although further analyses appear to be warranted. Whether these findings apply to other geographical regions requires further study. Evidence for the long-term (>2-year) cost effectiveness of quetiapine in bipolar disorder is currently limited and further studies are also needed to address the cost effectiveness of quetiapine from a societal perspective and in bipolar II disorder.

Cost effectiveness of quetiapine in patients with acute bipolar depression and in maintenance treatment after an acute depressive episode

BACKGROUND

Bipolar disorder has a significant impact upon a patient's quality of life, imposing a considerable economic burden on the individual, family members and society as a whole. Several medications are indicated for the acute treatment of mania and depression associated with bipolar disorder as well as for maintenance therapy; however, these have varying efficacy, tolerability and costs.

OBJECTIVE

The objective of this study was to develop a new discrete-event simulation model to analyse the long-term consequences of pharmacological therapy for the management of bipolar I and II disorders (acute treatment of episodes of mania and depression as well as maintenance therapy).

METHODS

Probabilities of remission and relapse were obtained from clinical trial data and meta-analyses. Costs (year 2011 values) were assessed from a UK healthcare payer's perspective, and included pharmacological therapy and resource use associated with the treatment of mood events and selected adverse events. The health effects were measured in terms of QALYs.

RESULTS

For a patient starting with acute depression or in remission at 40 years of age (which was the average age in the clinical trials), quetiapine 300 mg/day was a cost-effective strategy compared with olanzapine 15 mg/day over a 5-year time frame. With acute bipolar depression as a starting episode, the 5-year medical costs were £323 higher and QALYs were 0.038 higher for quetiapine compared with olanzapine, corresponding to a cost-effectiveness ratio of £8600 per QALY gained.

CONCLUSION

Compared with olanzapine, the results suggest that quetiapine is cost effective as a maintenance treatment for bipolar depression.

Alterations to melanocortinergic, GABAergic and cannabinoid neurotransmission associated with olanzapine-induced weight gain

Background/Aim

Second generation antipsychotics (SGAs) are used to treat schizophrenia but can cause serious metabolic side-effects, such as obesity and diabetes. This study examined the effects of low to high doses of olanzapine on appetite/metabolic regulatory signals in the hypothalamus and brainstem to elucidate the mechanisms underlying olanzapine-induced obesity.

Methodology/Results

Levels of pro-opiomelanocortin (POMC), neuropeptide Y (NPY) and glutamic acid decarboxylase (GAD₆₅, enzyme for GABA synthesis) mRNA expression, and cannabinoid CB1 receptor (CB1R) binding density (using [³H]SR-141716A) were examined in the arcuate nucleus (Arc) and dorsal vagal complex (DVC) of female Sprague Dawley rats following 0.25, 0.5, 1.0 or 2.0 mg/kg olanzapine or vehicle (3×/day, 14-days). Consistent with its weight gain liability, olanzapine significantly decreased anorexigenic POMC and increased orexigenic NPY mRNA expression in a dose-sensitive manner in the Arc. GAD₆₅ mRNA expression increased and CB1R binding density decreased in the Arc and DVC. Alterations to neurotransmission signals in the brain significantly correlated with body weight and adiposity. The minimum dosage threshold required to induce weight gain in the rat was 0.5 mg/kg olanzapine.

Conclusions

Olanzapine-induced weight gain is associated with reduced appetite-inhibiting POMC and increased NPY. This study also supports a role for the CB1R and GABA in the mechanisms underlying weight gain side-effects, possibly by altering POMC transmission. Metabolic dysfunction can be modelled in the female rat using low, clinically-comparable olanzapine doses when administered in-line with the half-life of the drug.

Economic outcomes associated with atypical antipsychotics in bipolar disorder: a systematic review

OBJECTIVE

Bipolar disorder is a serious condition that is costly to the health care system. Atypical antipsychotics are more expensive than conventional treatments. From a policy-making perspective, the additional cost must be justified by improved outcomes. The objective of this study was to conduct a systematic review to determine the relative costs and cost-effectiveness associated with atypical antipsychotics in bipolar disorder.

DATA SOURCES

We conducted a systematic review of the literature in PubMed and EMBASE from January 1985 through October 2005, including published studies and conference proceedings. Databases were searched using predefined terms.

STUDY SELECTION

Studies were included if they were claims data analyses, trial-based economic evaluations, or cost-effectiveness analyses using models. Data were extracted using predefined tables.

DATA SYNTHESIS

Fourteen studies were identified. Seven were medical claims database analyses, 4 were trial-based economic evaluations, and 3 were cost-effectiveness models. Eight of these studies were conference proceedings. The studies did not provide sufficient information to determine any ranking of interventions in terms of least to most costly in overall resource consumption or in terms of their relative cost-effectiveness. Where comparable, results tended to be inconsistent.

CONCLUSION

There is a scarcity of economic studies in this field. A reference case outlining how to address the complex interplay between effectiveness, safety, adherence, and quality of life and their impact on resource use and costs is needed to contribute to improving the treatment of patients with bipolar disorder while making the best use of scarce health resources.

Validation of a specific measure to assess health-related quality of life in patients with schizophrenia and bipolar disorder: the 'Tolerability and quality of life' (TOOL) questionnaire

BACKGROUND

Perception of quality of life may differ depending on the perspective. The aim of the study was to assess the psychometric properties of the Spanish version of the 'TOlerability and quality Of Life' (TOOL) questionnaire, a specific self-rated instrument to evaluate the impact of side effects of antipsychotic drugs on health-related quality of life (HRQoL). The questionnaire consists of eight items answered on a four-point Likert scale.

METHODS

A psychometric study was conducted with clinically stable outpatients with schizophrenia and bipolar disorder under antipsychotic treatment. The translation and cultural adaptation of the questionnaire was performed according to international standards. Internal consistency using the Cronbach α coefficient and test-retest reliability using the intraclass correlation coefficient (ICC) was used to assess the reliability of the instrument. Patients completed generic and specific measures of quality of life and clinical severity.

RESULTS

A total of 238 patients were analysed, with a mean age of 42 years (SD 10.9). The mean completion time was 4.9 min (SD 4.4). Internal consistency and intraclass correlation coefficient were adequate (Cronbach α = 0.757 and ICC = 0.90). Factorial analysis showed a unidimensional structure (a single eigenvalue >1, accounting for 39.1% of variance). Significant Spearman's rank correlations between the TOOL and both generic and specific measures were found. The questionnaire was able to discriminate among the Clinical Global Impression - Severity scores (Mann-Whitney U test, P < 0.001).

CONCLUSIONS

The TOOL questionnaire shows appropriate feasibility, reliability, and discriminative performance as a patient-reported outcome. TOOL constitutes a valuable addition to measure the impact of adverse events of antipsychotic drugs from the patient perspective.

Cost analysis in a Medicaid program for patients with bipolar disorder who initiated atypical antipsychotic monotherapy

BACKGROUND

Use of atypical antipsychotics in treatment of patients with bipolar disorder is increasingly common, yet few studies have systematically investigated or compared medical costs associated with use of specific atypical antipsychotics.

OBJECTIVE

To evaluate the direct healthcare costs associated with olanzapine, risperidone, or quetiapine monotherapy among Medicaid patients diagnosed with bipolar disorder (ICD-9: 296.4x-296.8x).

METHODS

North Carolina Medicaid patients with bipolar disorder were followed for 12 months after initiation of atypical antipsychotic monotherapy (index date). They had no bipolar-related medical visit, hospitalization, or use of atypical antipsychotics 90-days prior to the treatment initiation. Costs of index drug, all bipolar-related medical care, and all health-related costs were examined. A two-stage sample selection model was employed to account for potential confounders and sample selection bias. Medication adherence measures using cumulative medication acquisition and cumulative medication gap were calculated as separate outcomes.

RESULTS

Inclusion criteria were met by 838 continuously eligible patients (393 olanzapine, 262 risperidone, 183 quetiapine). Drug-taking adherence was similar across the drug cohorts. After adjusting for potential confounders, patients taking olanzapine incurred $863 (p < 0.001) and $449 higher (p < 0.01) index drug costs than patients taking risperidone and quetiapine, respectively. Bipolar-related medical costs for patients taking olanzapine were higher ($616; p = 0.06) than for patients taking risperidone at 10% significance level, while such costs for patients taking olanzapine and quetiapine were similar. Total health-related costs did not differ across patient cohorts, including or excluding the index drug costs.

LIMITATIONS

The final study sample is a highly selected one based on the study design. This sample may not represent the entire bipolar population. The criteria used to guard against omitting bipolar disorder patients misdiagnosed with major depression need further validation.

CONCLUSIONS

No evidence was identified that there is any difference for total health-related costs in using olanzapine, risperidone, or quetiapine monotherapy to treat bipolar disorder, from a Medicaid payer's perspective. The clinical difference between these atypical antipsychotic drugs for the treatment of bipolar disorder could be of more interest than the economic difference.

A systematic review of the evidence of the burden of bipolar disorder in Europe

Background

Bipolar disorder is recognized as a major mental health issue, and its economic impact has been examined in the United States. However, there exists a general scarcity of published studies and lack of standardized data on the burden of the illness across European countries. In this systematic literature review, we highlight the epidemiological, clinical, and economic outcomes of bipolar disorder in Europe.

Methods

A systematic review of publications from the last 10 years relating to the burden of bipolar disorder was conducted, including studies on epidemiology, patient-related issues, and costs.

Results

Data from the UK, Germany, and Italy indicated a prevalence of bipolar disorder of ~1%, and a misdiagnosis rate of 70% from Spain. In one study, up to 75% of patients had at least one DSM-IV comorbidity, commonly anxiety disorders and substance/alcohol abuse. Attempted suicide rates varied between 21%–54%. In the UK, the estimated rate of premature mortality of patients with bipolar I disorder was 18%. The chronicity of bipolar disorder exerted a profound and debilitating effect on the patient. In Germany, 70% of patients were underemployed, and 72% received disability payments. In Italy, 63%–67% of patients were unemployed. In the UK, the annual costs of unemployment and suicide were £1510 million and £179 million, respectively, at 1999/2000 prices. The estimated UK national cost of bipolar disorder was £4.59 billion, with hospitalization during acute episodes representing the largest component.

Conclusion

Bipolar disorder is a major and underestimated health problem in Europe. A number of issues impact on the economic burden of the disease, such as comorbidities, suicide, early death, unemployment or underemployment. Direct costs of bipolar disorder are mainly associated with hospitalization during acute episodes. Indirect costs are a major contributor to the overall economic burden but are not always recognized in research studies.

Multiparameter evidence synthesis in epidemiology and medical decision-making

Meta-analysis has been well-established for many years, but has been largely confined to pooling evidence on pair-wise contrasts. Broader forms of synthesis have also been described, apparently re-invented in disparate fields, each time taking different computational approaches. The potential value of Bayesian estimation of a joint posterior parameter distribution and simultaneously sampling from it for decision analysis has also been appreciated. However, applications have been relatively few in number, sometimes stylized, and presented mainly to a statistical methods audience. As a result, the potential for multiparameter evidence synthesis in both epidemiology and health technology assessment has remained largely unrecognized. The advent of flexible software for Bayesian Markov chain Monte Carlo in the shape of WinBUGS has the made these earlier strands of work more widely available. Researchers can now carry out synthesis at a realistic level of complexity. The Bristol programme has not only contributed to a growing body of literature on how to synthesize different evidence structures, but also on how to check the consistency of multiple information sources and how to use the resulting models to prioritize future research.

Cost analysis of divalproex sodium extended-release compared to valproic acid in the treatment of bipolar disorder

OBJECTIVES

To analyze, from a payer perspective, the net pharmaceutical and medical costs of prescribing divalproex sodium extended-release (DVPX-ER) versus valproic acid (VPA) in patients with bipolar disorder.

METHODS

The study used a decision analytic framework to compare the total costs associated with DVPX-ER relative to VPA in the treatment of bipolar disease. The decision model incorporated two primary outcomes: GI side effects and treatment success. Levels of health service utilization and probability values were obtained from an expert panel comprised of 15 psychiatrists. Unit costs were obtained from an academic medical center. Two-way sensitivity analysis and a Monte Carlo simulation were conducted to examine the stability of the results.

RESULTS

The average probability of GI side effects associated with VPA and DVPX-ER estimated by the expert panel was 0.36 and 0.10 respectively. The average probability of treatment success for VPA and DVPX-ER was estimated to be 0.45 and 0.58 respectively. In the base case analysis, the expected total cost per patient was $34 208.84 and $25 336.13 for VPA and DVPX-ER respectively, a difference (incremental cost) of -$8188.87. Probabilistic sensitivity analysis using Monte Carlo simulation indicated a negative incremental cost of using DVPX-ER relative to VPA in a majority (approximately 70%) of cases.

CONCLUSIONS

The results from this decision analysis, based on probabilities of major events and associated utilization from an expert panel, suggest that divalproex sodium extended-release results in lower total costs than valproic acid in the treatment of bipolar disorder. Limitations of this study primarily involved the sources of data used in the model, including that derived from expert opinion.

Acute bipolar mania: a systematic review and meta-analysis of co-therapy vs. monotherapy

INTRODUCTION

The aim of this meta-analysis was to systematically review the effectiveness of co-therapy compared with monotherapy for people with bipolar mania.

METHOD

MEDLINE, Embase, Psychinfo, The Cochrane Library and reference lists of retrieved studies were searched without language restrictions for randomized controlled trials evaluating co-therapy compared with monotherapy for acute bipolar mania. Each trial was assessed for susceptibility to bias. Data on mania outcomes, withdrawals, extrapyramidal symptoms and weight were extracted and pooled effect estimates summarized as relative risks (RR) or differences in mean values (MD) where appropriate.

RESULTS

Eight eligible studies were included (1124 participants). Significant reductions in mania (Young Mania Rating Scale, YMRS) scores were shown for haloperidol, olanzapine, risperidone and quetiapine as co-therapy compared with monotherapy with a mood stabilizer. For atypical antipsychotics combined, the pooled difference in mean scores was 4.41 (95% CI: 2.74, 6.07). Significantly more participants on co-therapy met the response criterion (at least 50% reduction in YMRS score), RR 1.53 (1.31, 1.80). With some drugs, co-therapy decreased tolerability compared with monotherapy, and resulted in greater weight gain. There were insufficient data to compare one co-therapy regimen with another.

CONCLUSION

The addition of antipsychotic treatment to established mood-stabilizer treatment is more effective than mood-stabilizer treatment alone.

Economics of atypical antipsychotics in bipolar disorder: a review of the literature

Economic evaluations are increasingly being used by policy makers to evaluate the relative costs and benefits of healthcare interventions. These analyses provide economic and clinical evidence to decision makers seeking to make recommendations on treatment alternatives for patients. This article describes the economic evidence on the atypical antipsychotics currently approved for the treatment of bipolar disorder. This area remains under-researched. A literature search identified only six relevant studies of atypical antipsychotics in bipolar disorder: two retrospective database analyses, three economic analyses alongside clinical trials and one cost-effectiveness analysis. Based on the limited available studies, there appears to be no significant difference in healthcare resource use between olanzapine, quetiapine, risperidone and valproate semisodium (divalproex sodium; an antiepileptic drug and a standard treatment for mania associated with bipolar disorder). While a cost-effectiveness study for the UK found haloperidol (a conventional antipsychotic) to be more cost effective than atypical antipsychotics, these results must be considered with caution because of the non-inclusion of adverse effects in the model. No economic data are available for aripiprazole, clozapine or ziprasidone in bipolar disorder. Until more economic evidence becomes available, the economic implications of atypical antipsychotic treatment in patients with bipolar disorder are unlikely to significantly impact on prescribing and treatment patterns. Future economic studies evaluating atypical antipsychotics in bipolar disorder should address the issue of long-term costs and effectiveness to reflect the chronic nature of the disease, the variety of health states that patients may experience and the range of treatments they may receive. A better understanding of the complex interplay between effectiveness, safety, quality of life, adherence and resource use should ultimately contribute to improving the treatment of bipolar disorder.

Evidence synthesis, parameter correlation and probabilistic sensitivity analysis

Over the last decade or so, there have been many developments in methods to handle uncertainty in cost-effectiveness studies. In decision modelling, it is widely accepted that there needs to be an assessment of how sensitive the decision is to uncertainty in parameter values. The rationale for probabilistic sensitivity analysis (PSA) is primarily based on a consideration of the needs of decision makers in assessing the consequences of decision uncertainty. In this paper, we highlight some further compelling reasons for adopting probabilistic methods for decision modelling and sensitivity analysis, and specifically for adopting simulation from a Bayesian posterior distribution. Our reasoning is as follows. Firstly, cost-effectiveness analyses need to be based on all the available evidence, not a selected subset, and the uncertainties in the data need to be propagated through the model in order to provide a correct analysis of the uncertainties in the decision. In many--perhaps most--cases the evidence structure requires a statistical analysis that inevitably induces correlations between parameters. Deterministic sensitivity analysis requires that models are run with parameters fixed at 'extreme' values, but where parameter correlation exists it is not possible to identify sets of parameter values that can be considered 'extreme' in a meaningful sense. However, a correct probabilistic analysis can be readily achieved by Monte Carlo sampling from the joint posterior distribution of parameters. In this paper, we review some evidence structures commonly occurring in decision models, where analyses that correctly reflect the uncertainty in the data induce correlations between parameters. Frequently, this is because the evidence base includes information on functions of several parameters. It follows that, if health technology assessments are to be based on a correct analysis of all available data, then probabilistic methods must be used both for sensitivity analysis and for estimation of expected costs and benefits.

Incorporating direct and indirect evidence using bayesian methods: an applied case study in ovarian cancer

OBJECTIVE

To demonstrate the application of a Bayesian mixed treatment comparison (MTC) model to synthesize data from clinical trials to inform decisions based on all relevant evidence.

METHODS

The value of an MTC model is demonstrated using a probabilistic decision-analytic model developed to assess the cost-effectiveness of second-line chemotherapy in ovarian cancer. Three clinical trials were found that each made a different pair-wise comparison of three treatments of interest in the overall patient population. As no common comparator existed between the three trials, an MTC model was used to assess the combined weight of evidence on survival from all three trials simultaneously. This analysis was compared to an alternative approach that combined two of the trials to make the same comparison of all three treatments using a common comparator, and an informal approach that did not synthesize the available evidence.

RESULTS

By including all three trials using an MTC model, the credible intervals around estimated overall survival were reduced compared with making the same comparison using only two trials and a common comparator. Nevertheless, the survival estimates from the MTC model result in greater uncertainty around the optimal treatment strategy at a cost-effectiveness threshold of 30,000 pounds per quality-adjusted life-year.

CONCLUSIONS

MTC models can be used to combine more data than would typically be included in a traditional meta-analysis that relies on a common comparator. They can formally quantify the combined uncertainty from all available evidence, and can be conducted using the same analytical approaches as standard meta-analyses.

Evidence for three distinct classes of 'typical', 'psychotic' and 'dual' mania: results from the EMBLEM study

OBJECTIVE

To describe patients included in the European Mania in Bipolar Longitudinal Evaluation of Medication (EMBLEM) study and to assess and clinically validate the presence of clinical subtypes of patients with acute mania.

METHOD

The EMBLEM study is a 2-year prospective, observational study on the treatment and outcome of patients who are treated for a manic or mixed episode. Latent Class Analysis was used to define discrete groups of patients at baseline.

RESULTS

Three groups were identified: 'typical mania' (59% of patients); 'psychotic mania' (27%) with more severe mania and presence of psychotic symptoms; and 'dual mania' (13%) with a high proportion of substance abuse. Patient groups differed in age of onset, social functioning and service needs.

CONCLUSION

Dual mania represents a distinct and not infrequent subgroup of patients with mania. The exclusion of patients with comorbid substance problems from clinical trials creates a gap in our knowledge on treatment effectiveness.

Simultaneous comparison of multiple treatments: combining direct and indirect evidence

How can policy makers decide which of five treatments is the best? Standard meta-analysis provides little help but evidence based decisions are possible