Economic evaluation of antiepileptic drug therapy: a methodologic review

Assessment of components included in published societal perspective or QALY outcome economic analyses for antiepileptic drug treatment in chronic epilepsy

INTRODUCTION

Antiepileptic drug (AED) treatments seek to control seizures with minimal or no adverse effects, effects which can substantially impact costs and outcomes for patients, caregivers, and third party payers. The First and Second Panel on Cost-Effectiveness in Health and Medicine recommend inclusion of a societal reference case, even in studies conducted from a healthcare sector perspective, for comparability of findings across studies. Cost and outcome evaluation components include direct medical, non-direct medical-related (e.g. patient-time and transportation costs for treatment) and non-healthcare sectors (e.g. lost productivity).

AREAS COVERED

Guided by Second Panel recommendations, this review developed an overall impact inventory and detailed adverse effect impact inventory to assess the scope and methods in published economic evaluations of AED treatments for adults with chronic epilepsy. Societal perspective evaluations or evaluations that utilized quality-adjusted life-years (QALYs) as an outcome were reviewed. The majority of reviewed articles were healthcare sector perspective studies, methods for estimating QALYs varied widely, and a minority considered specific AED treatment adverse effects.

EXPERT COMMENTARY

Only considering a healthcare sector perspective fails to provide full information for patients on AED treatments. Using an impact inventory to guide study scope and design will facilitate full reporting of costs and benefits.

Antiepileptic drugs prescription utilization behavior and direct costs of treatment in a national hospital of India

Background and Objectives:

The present study evaluated the direct costs of active epilepsy and looked at the pattern of drug prescription and utilization in epileptic patients visiting the neuroscience centre of a national hospital of India.

Materials and Methods:

A total of 134 epileptic patients were studied over a period of 4 months. Patients demography, commonly prescribed antiepileptic drugs (AEDs), socioeconomic status, direct costs, response ratio (RR) for newer drugs, and quality of life (QOLIE-10) was evaluated.

Results and Discussion:

We found a higher percentage of male patients (67.9%) as compared with females. Most of the patients were in the age group 11–30 years and majority of them (39.6%) belonged to lower middle group. A higher percentage (68.7) of drugs was prescribed as polytherapy. Higher monthly cost was observed for some of the newer AEDs including the lamotrigine, levetiracetam, and lacosamide as compared with older drugs. Among the newer drugs, clobazam had the lowest cost. RR was calculated for 12 patients out of which 8 had a RR < –0.50. The QOL domains, following conventional or newer drugs, were not much affected.

Conclusion:

The study indicates an increasing trend toward clinical usage of newer AEDs, increasing trend of poly-therapy with significant escalations in the cost of therapy.

The cost effectiveness of newer epilepsy treatments: a review of the literature on partial-onset seizures

BACKGROUND AND OBJECTIVE

Epilepsy is one of the most common neurological disorders, affecting more than 3 million people in Europe. This paper reviews the published evidence regarding the cost effectiveness of second-generation antiepileptic drugs (AEDs).

METHODS

A systematic literature search was performed, using the databases Academic Search Complete, Econlit, EMBASE and MEDLINE. Health economic evaluations of newer (second-generation) AEDs, published as full-length journal articles, were searched for. We focused on evaluations of newer AEDs as treatment for partial-onset seizures. 470 studies were initially identified and 19 were finally included. Information regarding (i) AEDs studied, (ii) cost effectiveness, and (iii) a variety of health economic modelling specifics was extracted from each study. Then, the included studies were summarized and a quality assessment was performed, according to the British Medical Journal's guidelines for economic studies.

RESULTS

The results were as follows: (i) the cost per additional QALY for newer AEDs used as adjunctive treatment, compared with standard therapy, ranged between $US19 139 (levetiracetam) and $US57 210 (pregabalin) [year 2010 values]; no cost-effectiveness evidence was identified for felbamate, eslicarbazepine, oxcarbazepine or tiagabine; and (ii) all studies met at least 60% of the British Medical Journal's guidelines criteria, and seven studies were found to satisfy more than 80% of the criteria. Guidelines criteria not met involve inadequate reporting of input data and modelling details, including validation and availability of models used for cost-effectiveness calculations.

CONCLUSIONS

Although failure to meet good practice guidelines influences the reliability of the presented evidence adversely, a sufficient number of the included studies were found to comply enough with the guidelines in order for the qualitative content of the cost-effectiveness results - that some of the newer AEDs are cost effective - to be reliable. In fact, this conclusion is likely to be relatively robust, since the effect of improved seizure control on labour market performance was not included in the base-case results in any of the included studies and improved seizure control need only to have a moderate effect on sickness absenteeism in order for the corresponding treatment to be cost effective even when willingness to pay for an additional QALY is low. However, the cost effectiveness of newer AEDs has only been studied for a small number of settings, and hence future studies incorporating additional settings are needed.

Comparative cost-effectiveness of antiviral therapies in patients with chronic hepatitis B: a systematic review of economic evidence

BACKGROUND AND AIM

Economic efficiency of the alternative antiviral therapies for chronic hepatitis B has not been systematically investigated and their quality remains unknown. The aim of the present study was to systematically overview economic evidence of antiviral therapies for chronic hepatitis B.

METHODS

We searched six databases and eight major journals supplemented with screening references of eligible studies. Full economic evaluations comparing alternative antiviral therapies in patients with chronic hepatitis B virus infection were included. Two investigators assessed the study quality and transferability, independently. Data were analyzed qualitatively with adjustment when appropriate.

RESULTS

Fourteen studies (six modeling vs eight trials and database analyses) were included. Quality was high in five studies, moderate in one US and five Chinese studies, and low in three Chinese studies. The major problems of quality are costing methods and analysis and the presentation of results. In Australia and Poland, lamivudine-preferred strategies dominated interferon (IFN)-alpha and its related strategy from the health-care sector perspective. In the US, adefovir salvage produced US$8446 per additional quality-adjusted life years (QALY) compared with IFN-alpha. In Spain, the cost of adefovir was US$34,840 for additional virological response. In Taiwan, the use of pegylated IFN-alpha (pegIFN-alpha) produced US$11,711.4 per additional QALY, compared with lamivudine. In China, the incremental cost-effectiveness ratios of combination therapy lamivudine ranged from US$2860 to US$22,160 per additional loss of hepatitis B e antigen (HBeAg), and IFN-alpha versus lamivudine ranged from US$2490 to US$8890 per additional loss of HBeAg.

CONCLUSION

The cost-effectiveness frontiers of treatment alternatives vary and are influenced by the comparators and socioeconomic conditions of countries. Lamivudine-containing therapy is cost-effective when newer antiviral agents (e.g. adefovir/pegIFN-alpha) were not available. Economic methods should be further improved in studies, particularly in China.

ILAE treatment guidelines: evidence-based analysis of antiepileptic drug efficacy and effectiveness as initial monotherapy for epileptic seizures and syndromes

PURPOSE

To assess which antiepileptic medications (AEDs) have the best evidence for long-term efficacy or effectiveness as initial monotherapy for patients with newly diagnosed or untreated epilepsy.

METHODS

A 10-member subcommission of the Commission on Therapeutic Strategies of The International League Against Epilepsy (ILAE), including adult and pediatric epileptologists, clinical pharmacologists, clinical trialists, and a statistician evaluated available evidence found through a structured literature review including MEDLINE, Current Contents and the Cochrane Library for all applicable articles from 1940 until July 2005. Articles dealing with different seizure types (for different age groups) and two epilepsy syndromes were assessed for quality of evidence (four classes) based on predefined criteria. Criteria for class I classification were a double-blind randomized controlled trial (RCT) design, >or=48-week treatment duration without forced exit criteria, information on >or=24-week seizure freedom data (efficacy) or >or=48-week retention data (effectiveness), demonstration of superiority or 80% power to detect a <or=20% relative difference in efficacy/effectiveness versus an adequate comparator, and appropriate statistical analysis. Class II studies met all class I criteria except for having either treatment duration of 24 to 47 weeks or, for noninferiority analysis, a power to only exclude a 21-30% relative difference. Class III studies included other randomized double-blind and open-label trials, and class IV included other forms of evidence (e.g., expert opinion, case reports). Quality of clinical trial evidence was used to determine the strength of the level of recommendation.

RESULTS

A total of 50 RCTs and seven meta-analyses contributed to the analysis. Only four RCTs had class I evidence, whereas two had class II evidence; the remainder were evaluated as class III evidence. Three seizure types had AEDs with level A or level B efficacy and effectiveness evidence as initial monotherapy: adults with partial-onset seizures (level A, carbamazepine and phenytoin; level B, valproic acid), children with partial-onset seizures (level A, oxcarbazepine; level B, None), and elderly adults with partial-onset seizures (level A, gabapentin and lamotrigine; level B, None). One adult seizure type [adults with generalized-onset tonic-clonic (GTC) seizures], two pediatric seizure types (GTC seizures and absence seizures), and two epilepsy syndromes (benign epilepsy with centrotemporal spikes and juvenile myoclonic epilepsy) had no AEDs with level A or level B efficacy and effectiveness evidence as initial monotherapy.

CONCLUSIONS

This evidence-based guideline focused on AED efficacy or effectiveness as initial monotherapy for patients with newly diagnosed or untreated epilepsy. The absence of rigorous comprehensive adverse effects data makes it impossible to develop an evidence-based guideline aimed at identifying the overall optimal recommended initial-monotherapy AED. There is an especially alarming lack of well-designed, properly conducted RCTs for patients with generalized seizures/epilepsies and for children in general. The majority of relevant existing RCTs have significant methodologic problems that limit their applicability to this guideline's clinically relevant main question. Multicenter, multinational efforts are needed to design, conduct and analyze future clinically relevant RCTs that can answer the many outstanding questions identified in this guideline. The ultimate choice of an AED for any individual patient with newly diagnosed or untreated epilepsy should include consideration of the strength of the efficacy and effectiveness evidence for each AED along with other variables such as the AED safety and tolerability profile, pharmacokinetic properties, formulations, and expense. When selecting a patient's AED, physicians and patients should consider all relevant variables and not just efficacy and effectiveness.

A review of the costs of managing childhood epilepsy

Epilepsy is a chronic treatable condition for which new diagnostic tools and several new drugs and non-pharmacological treatments are now available. The cost profile of these options is assessed here through an overview of the available literature focusing on studies of childhood epilepsy. Several methodological problems arise when interpreting the results of economic studies in epilepsy, including the variability of the study population and costs items, the reliability of the sources of cost, the limitations of the methods of data collection and the deficiencies of the study designs, with reference to the measures of treatment benefits. International comparisons are then difficult because economic results cannot be compared on account of differences in monetary issues, clinical practice patterns and healthcare system frameworks. The economic aspects of epilepsy are different in children and adults. Differences are detectable in the incidence and expression of epileptic syndromes, social and emotional impact, availability of antiepileptic drugs, hospital admissions, diagnostic tests and referral to specialists, social assistants and other healthcare professionals. In addition, children have access to medical services only with the help of a caregiver, for whom there may be lost work days or under-employment. The mean annual cost per child with epilepsy was USD 1853 for controlled epilepsy and USD 4950 for uncontrolled epilepsy in a Spanish study performed in 1998 and the annual direct costs per child with epilepsy ranged from euro 844 for patients in remission to euro 3268 for patients with drug-resistant epilepsy in an Italian study done between 1996 and 1998. The Spanish study showed that direct costs are the major source of expenditure for children with epilepsy. These studies along with a number of other cost-of-illness studies in combined populations of adults and children showed that service use and costs increase with more severe forms of illness and seizure frequency, this being more marked in adults than in children. Moderate cost differences may be expected between children (higher) and adults (lower), particularly with reference to initial investigations. Costs of epilepsy are mostly explained by hospital admissions and drugs; in particular, drug costs tend to dominate in more well controlled epilepsy, while both hospital admissions and drugs are significant costs in less well controlled epilepsy. Newly diagnosed patients can incur significant hospital and diagnostic costs. Costs for epilepsy tend to be lower for patients cared for in general practice or outpatient settings than in hospital settings. Seizure control by drugs, ketogenic diet or surgery is associated with a significant reduction in the costs of epilepsy.

Prescribing antiepileptic drugs: should patients be switched on the basis of cost?

To assess the costs of switching from one antiepileptic drug (AED) to another, all associated direct and indirect costs, not only drug acquisition costs, must be considered. The perspective of the healthcare system evaluated in cost-effectiveness analysis is of crucial importance. Multiple clinical factors can influence clinical decisions regarding switching AEDs. The economic cost of poorly controlled epilepsy is enormous and the most cost-effective intervention is an AED that provides total seizure control. Cost-minimisation studies have evaluated costs associated with various medications. If only efficacy and adverse events were considered, then the 'older' AEDs were generally more cost effective than the 'newer' AEDs. Most studies only examine very specific clinical situations and are not suitable for establishing general clinical recommendations. The pharmacoeconomics of AED choice is highly country specific. While switching to generic formulations is, in general, cost effective, some changes may be detrimental and more costly than remaining on the trade name preparation. For example, as a result of differences in bioavailability and possible loss of seizure control, changing patients to generic phenytoin and carbamazepine can be problematic. Fosphenytoin may only be cost effective in certain clinical situations compared with intravenous phenytoin. Seizure control should not be sacrificed on the basis of costs alone, as the major endpoint in treating epilepsy with AEDs is seizure control without adverse effects. Switching AEDs in clinical practice still depends on the individual clinical situation and choosing AED therapy solely on the basis of initial acquisition costs is unlikely to be cost effective in the long-term care of patients with epilepsy.

Lifetime Cost-Utility Analysis of Patients with Refractory Epilepsy Treated with Adjunctive Topiramate Therapy

OBJECTIVE

To evaluate the cost-effectiveness profile of topiramate as adjunctive treatment in patients with refractory epilepsy.

STUDY DESIGN

Lifetime cost-utility analysis based on a pharmacoeconomic model.

METHODS

Effectiveness data (seizure frequency reduction) were derived from the most recent placebo-controlled clinical trial, whilst quality of life and cost data were retrieved from the published literature. Our pharmacoeconomic model was based on a patient-level approach that incorporated the clinical data of the randomised, controlled trial.

MAIN OUTCOME MEASURES AND RESULTS

Our analysis showed that chronic topiramate treatment costs pound21 353 per quality-adjusted life year (QALY) gained (incremental lifetime cost of pound1 024 941 and incremental utility of 48 QALYs, for every 100 patients) [discounted values with a yearly rate of 3%] (year of costing 2001). Sensitivity analyses suggested a range from pound19 915 to pound24 518 per QALY gained.

CONCLUSIONS

Our results showed that adjunctive topiramate therapy has a favourable pharmacoeconomic profile in patients with refractory epilepsy.