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Health Technology Assessment... Feb 2009To evaluate the clinical effectiveness and incremental cost-effectiveness of amantadine, oseltamivir and zanamivir for seasonal and post-exposure prophylaxis of... (Review)
Review
OBJECTIVES
To evaluate the clinical effectiveness and incremental cost-effectiveness of amantadine, oseltamivir and zanamivir for seasonal and post-exposure prophylaxis of influenza.
DATA SOURCES
A MEDLINE search strategy was used and searches were carried out in July 2007.
REVIEW METHODS
An independent health economic model was developed based on a review of existing cost-effectiveness models and clinical advice.The model draws together a broad spectrum of evidence relating to the costs and consequences associated with influenza and its prevention. Where direct evidence concerning the effectiveness of prophylaxis within specific model subgroups was lacking, the model uses estimates from mixed subgroups or extrapolates from other mutually exclusive subgroups.
RESULTS
Twenty-six published references relating to 22 randomised controlled trials (RCTs) were included in the clinical effectiveness review, along with one unpublished report. Eight, six and nine RCTs were included for amantadine, oseltamivir and zanamivir respectively. The study quality was variable and gaps in the evidence base limited the assessment of the clinical effectiveness of the interventions. For seasonal prophylaxis, there was limited evidence for the efficacy of amantadine in preventing symptomatic, laboratory-confirmed influenza (SLCI) in healthy adults [relative risk (RR) 0.40, 95% confidence interval (CI) 0.08-2.03]. Oseltamivir was effective in preventing SLCI, particularly when used in at-risk elderly subjects (RR 0.08, 95% CI 0.01-0.63). The preventative efficacy of zanamivir was most notable in at-risk adults and adolescents (RR 0.17, 95% CI 0.07-0.44), and healthy and at-risk elderly subjects (RR 0.20, 95% CI 0.02-1.72). For post-exposure prophylaxis, data on the use of amantadine were again limited: in adolescents an RR of 0.10 (95% CI 0.03-0.34) was reported for the prevention of SLCI. Oseltamivir was effective in households of mixed composition (RR 0.19, 95% CI 0.08-0.45). The efficacy of zanamivir in post-exposure prophylaxis within households was also reported (RR 0.21, 95% CI 0.13-0.33). Interventions appeared to be well tolerated. Limited evidence was available for the effectiveness of the interventions in preventing complications and hospitalisation and in minimising length of illness and time to return to normal activities. No clinical effectiveness data were identified for health-related quality of life or mortality outcomes. With the exception of at-risk children, the incremental cost-utility of seasonal influenza prophylaxis is expected to be in the range 38,000-428,000 pounds per QALY gained (depending on subgroup). The cost-effectiveness ratios for oseltamivir and zanamivir as post-exposure prophylaxis are expected to be below 30,000 pounds per QALY gained in healthy children, at-risk children, healthy elderly and at-risk elderly individuals. Despite favourable clinical efficacy estimates, the incorporation of recent evidence of viral resistance to amantadine led to it being dominated in every economic comparison.
CONCLUSIONS
All three interventions showed some efficacy for seasonal and post-exposure prophylaxis. However, weaknesses and gaps in the clinical evidence base are directly relevant to the interpretation of the health economic model and rendered the use of advanced statistical analyses inappropriate. These data limitations should be borne in mind in interpreting the findings of the review.
Topics: Amantadine; Antiviral Agents; Cost-Benefit Analysis; Humans; Influenza, Human; Models, Economic; Oseltamivir; Practice Guidelines as Topic; Premedication; Randomized Controlled Trials as Topic; Seasons; Treatment Outcome; Zanamivir
PubMed: 19215705
DOI: 10.3310/hta13110 -
The Cochrane Database of Systematic... Jan 2009Alzheimer's dementia (AD) is the most common form of dementia in people with Down Syndrome (DS). There is an understanding that an increase in L-glutamate contributes to... (Review)
Review
BACKGROUND
Alzheimer's dementia (AD) is the most common form of dementia in people with Down Syndrome (DS). There is an understanding that an increase in L-glutamate contributes to the pathogenesis of cerebral ischemias and AD. Memantine acts as an antagonist of N-methyl-D-aspartate (NMDA) type receptors, which is thought to reduce abnormal activation of glutamate neurotransmission. It binds with a low affinity to the NMDA receptor and so should not prevent learning and the formation of memory. Memantine can improve cognitive function and slow the decline of AD in the general population over time, and is the subject of this review. It is important to note that people with DS tend to present with AD at a much younger age than the normal population as well as having subtle differences in physiology (e.g. metabolism and heart rate) and may therefore have different requirements from the general population.
OBJECTIVES
To determine the effectiveness and safety of memantine for people with DS who develop AD.
SEARCH STRATEGY
CENTRAL, MEDLINE, EMBASE, CINAHL, PsycINFO, BIOSIS, SCI, SSCI and the NRR were searched up to October 2008. We contacted the manufacturers of memantine, as well as experts in the field, to ask about reports of unpublished or ongoing trials.
SELECTION CRITERIA
Randomised controlled trials of participants with DS and AD in which treatment with memantine was administered compared with a placebo group.
DATA COLLECTION AND ANALYSIS
No study was identified which met the inclusion criteria for this review.
MAIN RESULTS
No study was identified which met inclusion criteria for this review, however there is an on-going randomised controlled study being conducted in the UK and data are expected in 2009.
AUTHORS' CONCLUSIONS
As there are no included trials, recommendations cannot be made about memantine for AD in DS. Well-designed, adequately powered studies are required.
Topics: Alzheimer Disease; Down Syndrome; Humans; Memantine; Receptors, N-Methyl-D-Aspartate
PubMed: 19160343
DOI: 10.1002/14651858.CD007657 -
BMJ Clinical Evidence May 2009Multiple sclerosis is the most common cause of neurological disability in young adults. Irreversible disability can occur, but life expectancy is generally not affected. (Review)
Review
INTRODUCTION
Multiple sclerosis is the most common cause of neurological disability in young adults. Irreversible disability can occur, but life expectancy is generally not affected.
METHODS AND OUTCOMES
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of interventions aimed at reducing relapse rates and disability in people with multiple sclerosis? What are the effects of interventions to improve symptoms during acute relapse? What are the effects of treatments for fatigue, spasticity, and multidisciplinary care on disability in people with multiple sclerosis? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2008 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
RESULTS
We found 68 systematic reviews, RCTs, and observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
CONCLUSIONS
In this systematic review, we present information relating to the effectiveness and safety of the following key interventions: amantadine, azathioprine, behaviour modification, botulinum toxin, corticosteroids, exercise, gabapentin, inpatient or outpatient rehabilitation, interferon beta, intrathecal baclofen, intravenous immunoglobulin, methotrexate, mitoxantrone, modafinil, natalizumab, oral drug treatments, parenteral glatiramer acetate, physiotherapy, and plasma exchange.
Topics: Administration, Oral; Adrenal Cortex Hormones; Fatigue; Humans; Interferon-beta; Multiple Sclerosis; Muscle Spasticity; Physical Therapy Modalities
PubMed: 21733201
DOI: No ID Found -
Sao Paulo Medical Journal = Revista... Sep 2006Sexual dysfunction frequently occurs in patients with schizophrenia under antipsychotic therapy, and the presence of sexual side effects may affect compliance. The aim... (Meta-Analysis)
Meta-Analysis Review
INTRODUCTION
Sexual dysfunction frequently occurs in patients with schizophrenia under antipsychotic therapy, and the presence of sexual side effects may affect compliance. The aim of this study was to review and describe clinical findings relating to the appropriate management of such dysfunctions.
MATERIAL AND METHODS
The research was carried out through Medline (from 1966 to March 2005), PsycInfo (from 1974 to March 2005), and Cochrane Library (from 1965 to March 2005) and included any kind of study, from case reports to randomized trials.
RESULTS
The most common sexual dysfunctions found in the literature were libido decrease, difficulties in achieving and maintaining erection, ejaculatory dysfunction, orgasmic dysfunction, and menstrual irregularities. Thirteen papers were found: eight of them were open-label studies, four were descriptions of cases, and only one was a randomized clinical trial. All of them were short-term and had small sample sizes. The agents used were: bromocriptine, cabergoline, cyproheptadine, amantadine, shakuyaku-kanzo-to, sildenafil and selegiline.
DISCUSSION
There was no evidence that those agents had proper efficacy in treating the antipsychotic-induced sexual dysfunction. An algorithm for managing sexual dysfunction induced by antipsychotics is suggested as a support for clinical decisions. Since the outcome from schizophrenia treatment is strongly related to compliance with the antipsychotics, prevention of sexual dysfunction is better than its treatment, since there is a scarcity of data available regarding the efficacy of intervention to deal with these problems.
Topics: Algorithms; Antipsychotic Agents; Dopamine Agonists; Evidence-Based Medicine; Female; Humans; Libido; Male; Menstruation Disturbances; Orgasm; Penile Erection; Phosphodiesterase Inhibitors; Schizophrenia; Serotonin Antagonists; Sexual Dysfunction, Physiological
PubMed: 17262163
DOI: 10.1590/s1516-31802006000500012 -
The Cochrane Database of Systematic... Jan 2007Fatigue is one of the most common and disabling symptoms of people with Multiple Sclerosis (MS). The effective management of fatigue has an important impact on the... (Review)
Review
BACKGROUND
Fatigue is one of the most common and disabling symptoms of people with Multiple Sclerosis (MS). The effective management of fatigue has an important impact on the patient's functioning, abilities, and quality of life. Although a number of strategies have been devised for reducing fatigue, treatment recommendations are based on a limited amount of scientific evidence. Many textbooks report amantadine as a first-choice drug for MS-related fatigue because of published randomised controlled trials (RCTs) showing some benefit.
OBJECTIVES
To determine the effectiveness and safety of amantadine in treating fatigue in people with MS.
SEARCH STRATEGY
We searched The Cochrane MS Group Trials Register (July 2006), The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 1, 2006), MEDLINE (January 1966 to July 2006), EMBASE (January 1974 to July 2006), bibliographies of relevant articles and handsearched relevant journals. We also contacted drug companies and researchers in the field.
SELECTION CRITERIA
Randomised, placebo or other drugs-controlled, double-blind trials of amantadine in MS people with fatigue.
DATA COLLECTION AND ANALYSIS
Three reviewers selected studies for inclusion in the review and they extracted the data reported in the original articles. We requested missing and unclear data by correspondence with the trial's principal investigator. A meta-analysis was not performed due to the inadequacy of available data and heterogeneity of outcome measures.
MAIN RESULTS
Out of 13 pertinent publications, 5 trials met the criteria for inclusion in this review: one study was a parallel arms study, and 4 were crossover trials. The number of randomised participants ranged between 10 and 115, and a total of 272 MS patients were studied. Overall the quality of the studies considered was poor and all trials were open to bias. All studies reported small and inconsistent improvements in fatigue, whereas the clinical relevance of these findings and the impact on patient's functioning and health related quality of life remained undetermined. The number of participants reporting side effects during amantadine therapy ranged from 10% to 57%.
AUTHORS' CONCLUSIONS
The efficacy of amantadine in reducing fatigue in people with MS is poorly documented, as well as its tolerability. It is advisable to: (1) improve knowledge on the underlying mechanisms of MS-related fatigue; (2) achieve anagreement on accurate, reliable and responsive outcome measures of fatigue; (3) perform good quality RCTs.
Topics: Amantadine; Antiviral Agents; Cross-Over Studies; Dopamine Agents; Fatigue; Humans; Multiple Sclerosis; Randomized Controlled Trials as Topic
PubMed: 17253480
DOI: 10.1002/14651858.CD002818.pub2 -
BMJ Clinical Evidence Aug 2007Around 1% of adults have Parkinson's disease, with a median time of 9 years between diagnosis and death. (Review)
Review
INTRODUCTION
Around 1% of adults have Parkinson's disease, with a median time of 9 years between diagnosis and death.
METHODS AND OUTCOMES
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of drug treatments in people with early-stage Parkinson's disease? What are the effects of adding other treatments in people with Parkinson's disease who have motor complications from levodopa? What are the effects of surgery in people with later Parkinson's disease? What are the effects of nursing and rehabilitation treatments in people with Parkinson's disease? We searched: Medline, Embase, The Cochrane Library and other important databases up to November 2006 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
RESULTS
We found 59 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
CONCLUSIONS
In this systematic review we present information relating to the effectiveness and safety of the following interventions: adding a catechol-methyl transferase inhibitor, or dopamine agonist to levodopa; amantadine; dopamine agonists; levodopa (immediate-release, modified-release); monoamine oxidase B inhibitors; occupational therapy; pallidal deep brain stimulation; pallidotomy; Parkinson's disease nurse specialist interventions; physiotherapy; speech and language therapy; subthalamic nucleus deep brain stimulation; subthalamotomy; swallowing therapy; thalamic deep brain stimulation; and thalamotomy.
Topics: Deep Brain Stimulation; Globus Pallidus; Humans; Levodopa; Parkinson Disease; Subthalamic Nucleus
PubMed: 19454106
DOI: No ID Found -
The Cochrane Database of Systematic... Apr 2006Amantadine hydrochloride and rimantadine hydrochloride have antiviral properties, but they are not widely used due to a lack of knowledge of their potential value and... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Amantadine hydrochloride and rimantadine hydrochloride have antiviral properties, but they are not widely used due to a lack of knowledge of their potential value and concerns about possible adverse effects.
OBJECTIVES
The objective of this review was to assess the efficacy, effectiveness and safety ("effects") of amantadine and rimantadine in healthy adults.
SEARCH STRATEGY
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2005), MEDLINE (2003 to August Week 4, 2005), EMBASE (October 2003 to July 2005) and reference lists of articles.
SELECTION CRITERIA
Randomised and quasi-randomised studies comparing amantadine and/or rimantadine with placebo, control medication or no intervention, or comparing doses or schedules of amantadine and/or rimantadine in healthy adults.
DATA COLLECTION AND ANALYSIS
For prophylaxis (prevention) trials the numbers of participants with clinical influenza (influenza-like-illness or ILI) or with confirmed influenza A and adverse effects were analysed. Analysis for treatment trials was of the mean duration of fever, length of hospital stay and adverse effects.
MAIN RESULTS
Amantadine prevented 25% of ILI cases (95% confidence interval (CI) 13% to 36%), and 61% of influenza A cases (95% CI 35% to 76%). Amantadine reduced duration of fever by one day (95% CI 0.7 to 1.2). Rimantadine demonstrated comparable effectiveness, but there were fewer trials and the results for prophylaxis were not statistically significant. Both amantadine and rimantadine induced significant gastrointestinal adverse effects. Adverse effects of the central nervous system and study withdrawals were significantly more common with amantadine than rimantadine. Neither drug affected the rate of viral shedding from the nose and the course of asymptomatic influenza.
AUTHORS' CONCLUSIONS
Amantadine and rimantadine have comparable efficacy and effectiveness in relieving or treating symptoms of influenza A in healthy adults, although rimantadine induces fewer adverse effects than amantadine. The effectiveness of both drugs in interrupting transmission is probably low. Routine use of both drugs should be discouraged and both drugs should only be used when all other measures fail.
Topics: Adult; Aged; Amantadine; Antiviral Agents; Drug Administration Schedule; Emergencies; Humans; Influenza A virus; Influenza, Human; Middle Aged; Randomized Controlled Trials as Topic; Rimantadine; Virus Shedding
PubMed: 16625539
DOI: 10.1002/14651858.CD001169.pub3 -
Health Technology Assessment... Jan 2006To provide an update review of the best quality evidence for the clinical effectiveness and cost-effectiveness of donepezil, rivastigmine and galantamine for mild to... (Review)
Review
OBJECTIVES
To provide an update review of the best quality evidence for the clinical effectiveness and cost-effectiveness of donepezil, rivastigmine and galantamine for mild to moderately severe Alzheimer's disease (AD) and of memantine for moderately severe to severe AD.
DATA SOURCES
Electronic databases, experts in the field and manufacturer submissions to the National Institute for Health and Clinical Excellence (NICE).
REVIEW METHODS
A systematic review of the literature and an economic evaluation were undertaken. The quality of included randomised controlled trials (RCTs) was assessed using criteria developed by the NHS Centre for Reviews and Dissemination. An outline assessment of economic evaluations was undertaken using a standard checklist. The clinical and cost-effectiveness data were synthesised through a narrative review with full tabulation of the results of included studies. Where appropriate, meta-analysis of data was undertaken.
RESULTS
For mild to moderately severe AD, the results of the study suggested that all three treatments were beneficial when assessed using cognitive outcome measures. Global outcome measures were positive for donepezil and rivastigmine, but mixed for galantamine. Results for measures of function were mixed for donepezil and rivastigmine, but positive for galantamine. Behaviour and mood measures were mixed for donepezil and galantamine, but showed no benefit for rivastigmine. For memantine, two published RCTs were included; in one of these trials the participants were already being treated with donepezil. The results suggest that memantine is beneficial when assessed using functional and global measurements. The effect of memantine on cognitive and behaviour and mood outcomes is, however, less clear. Literature on the cost-effectiveness of donepezil, rivastigmine and galantamine was dominated by industry-sponsored studies, and studies varied in methods and results. Of the three UK studies, two report donepezil as not cost-effective, whereas a third study reports an additional cost (1996 pounds sterling) of between 1200 pounds sterling and 7000 pounds sterling per year in a non-severe AD health state (concerns over these estimates are raised, suggesting that they may underestimate the true cost-effectiveness of donepezil). Cost-effectiveness analysis undertaken in this review suggests that donepezil treatment has a cost per quality-adjusted life-year (QALY) in excess of 80,000 pounds sterling, with donepezil treatment reducing the mean time spent in full-time care (delays progression of AD) by 1.42-1.59 months (over a 5-year period). From four published cost-effectiveness studies, two UK studies report additional costs associated with rivastigmine treatment. Cost-effectiveness analysis undertaken in the current review suggests that rivastigmine treatment has a cost per QALY in excess of 57,000 pounds sterling, with rivastigmine treatment reducing the mean time spent in full-time care (delays progression) by 1.43-1.63 months (over a 5-year period). From five published cost-effectiveness studies, one UK study reports a cost per QALY of 8693 pounds sterling for 16-mg galantamine treatment and 10,051 pounds sterling for 24-mg galantamine treatment (concerns raised suggest that this may underestimate the true cost-effectiveness of galantamine). Cost-effectiveness analysis undertaken in the present review suggests that galantamine treatment has a cost per QALY in excess of 68,000 pounds sterling, with galantamine reducing the time spent in full-time care (delays progression) by 1.42-1.73 months (over a 5-year period). From two published cost-effectiveness studies, one reports analysis for the UK, finding that memantine treatment results in cost savings and benefits in terms of delaying disease progression (concerns raised suggest that this may underestimate the true cost-effectiveness of memantine). In the current review, the cost-effectiveness of memantine has not been modelled separately, but where alternative parameter inputs on the cost structure and utility values have been used in a reanalysis using the industry model, the cost-effectiveness is reported at between 37,000 pounds sterling and 52,000 pounds sterling per QALY, with this alternative analysis still based on what is regarded as an optimistic or favourable effectiveness profile for memantine.
CONCLUSIONS
Although results from the clinical effectiveness review suggest that these treatments may be beneficial, a number of issues need to be considered when assessing the results of the present review, such as the characteristics of the participants included in the individual trials, the outcome measures used, the length of study duration, the effects of attrition and the relationship between statistical significance and clinical significance. Many included trials were sponsored by industry. For donepezil, rivastigmine and galantamine, the cost savings associated with reducing the mean time spent in full-time care do not offset the cost of treatment sufficiently to bring estimated cost-effectiveness to levels generally considered acceptable by NHS policy makers. It is difficult to draw conclusions on the cost-effectiveness of memantine; it is suggested that further amendments to the potentially optimistic industry model (measure of effect) would offer higher cost per QALY estimates. Future research should include: information on the quality of the outcome measures used; development of quality of life instruments for patients and carers; studies assessing the effects of these interventions of durations longer than 12 months; comparisons of benefits between interventions; and research on the prediction of disease progression.
Topics: Aged; Aged, 80 and over; Alzheimer Disease; Cost-Benefit Analysis; Donepezil; Dopamine Agents; Evidence-Based Medicine; Female; Galantamine; Humans; Indans; Male; Memantine; Neuroprotective Agents; Nootropic Agents; Phenylcarbamates; Piperidines; Rivastigmine; Treatment Outcome; United Kingdom
PubMed: 16409879
DOI: 10.3310/hta10010 -
The Cochrane Database of Systematic... Oct 2005Lidocaine, mexiletine, tocainide, and flecainide are local anesthetics which give an analgesic effect when administered orally or parenterally. Early reports described... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Lidocaine, mexiletine, tocainide, and flecainide are local anesthetics which give an analgesic effect when administered orally or parenterally. Early reports described the use of intravenous lidocaine or procaine to relieve cancer and postoperative pain (Keats 1951; Gilbert 1951; De Clive-Lowe 1958; Bartlett 1961). Interest reappeared decades later when patient series and clinical trials reported that parenteral lidocaine and its oral analogs tocainide, mexiletine, and flecainide relieved neuropathic pain in some patients (Boas 1982; Lindblom 1984; Petersen 1986; Dunlop 1988; Bach 1990; Awerbuch 1990). With the recent publication of clinical trials with high quality standards, we have reviewed the use of systemic lidocaine and its oral analogs in neuropathic pain to update our knowledge, to measure their benefit and harm, and to better define their role in therapy.
OBJECTIVES
To evaluate pain relief and adverse effect rates between systemic local anesthetic-type drugs and other control interventions.
SEARCH STRATEGY
We searched MEDLINE (1966 through 15 May 2004), EMBASE (January 1980 to December 2002), Cancer Lit (through 15 December 2002), Cochrane Central Register of Controlled Trials (2nd Quarter, 2004), System for Information on Grey Literature in Europe (SIGLE), and LILACS, from January 1966 through March 2001. We also hand searched conference proceedings, textbooks, original articles and reviews.
SELECTION CRITERIA
We included trials with random allocation, that were double blinded, with a parallel or crossover design. The control intervention was a placebo or an analgesic drug for neuropathic pain from any cause.
DATA COLLECTION AND ANALYSIS
We collected efficacy and safety data from all published and unpublished trials. We calculated combined effect sizes using continuous and binary data for pain relief and adverse effects as primary and secondary outcome measurements, respectively.
MAIN RESULTS
Thirty-two controlled clinical trials met the selection criteria; two were duplicate articles. The treatment drugs were intravenous lidocaine (16 trials), mexiletine (12 trials), lidocaine plus mexiletine sequentially (one trial), and tocainide (one trial). Twenty-one trials were crossover studies, and nine were parallel. Lidocaine and mexiletine were superior to placebo [weighted mean difference (WMD) = -11; 95% CI: -15 to -7; P <0.00001], and limited data showed no difference in efficacy (WMD = -0.6; 95% CI: -7 to 6), or adverse effects versus carbamazepine, amantadine, gabapentin or morphine. In these trials, systemic local anesthetics were safe, with no deaths or life-threatening toxicities. Sensitivity analysis identified data distribution in three trials as a probable source of heterogeneity. There was no publication bias.
AUTHORS' CONCLUSIONS
Lidocaine and oral analogs were safe drugs in controlled clinical trials for neuropathic pain, were better than placebo, and were as effective as other analgesics. Future trials should enroll specific diseases and test novel lidocaine analogs with better toxicity profiles. More emphasis is necessary on outcomes measuring patient satisfaction to assess if statistically significant pain relief is clinically meaningful.
Topics: Administration, Oral; Anesthetics, Intravenous; Anesthetics, Local; Flecainide; Humans; Lidocaine; Mexiletine; Nervous System Diseases; Pain; Randomized Controlled Trials as Topic; Tocainide
PubMed: 16235318
DOI: 10.1002/14651858.CD003345.pub2 -
Health Technology Assessment... 2003To establish the clinical and cost-effectiveness of amantadine, oseltamivir and zanamivir compared to standard care for the treatment and prevention of influenza. (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
To establish the clinical and cost-effectiveness of amantadine, oseltamivir and zanamivir compared to standard care for the treatment and prevention of influenza.
DATA SOURCES
Electronic databases. Reference lists of identified articles and key publications. Relevant trials.
REVIEW METHODS
A systematic review and meta-analysis of the randomised evidence was undertaken to investigate the effectiveness of oseltamivir and zanamivir compared to standard care for treatment and prophylaxis use for influenza A and B. An additional systematic review of the effectiveness of amantadine for treatment and prophylaxis use for influenza A in children and the elderly was also undertaken. Economic decision models were constructed to examine the cost-effectiveness and cost-utility of the alternative strategies for treating and preventing influenza A and/or B. This was informed by the systematic reviews outlined above and additional sources of information where required.
RESULTS
The systematic review of the treatment of influenza found that oseltamivir reduced the median duration of symptoms in the influenza positive group by 1.38 days for the otherwise healthy adult population, 0.5 day for the high-risk population, and 1.5 days for the children population. This compared to 1.26 days, 1.99 days, and 1.3 for the similar groups for inhaled zanamivir. The systematic review of the prevention of influenza found that the relative risk reduction for oseltamivir was between approximately 75 and 90% and approximately 70 and 90% for inhaled zanamivir depending on the strategy adopted and the population under consideration. For the economic model a base case was constructed that focussed primarily on the health benefits generated by shortening the period of influenza illness. This base case found that, compared to standard care, the estimated cost per quality-adjusted life year ranged from pound 6190 to pound 31,529 for healthy adults, from pound 4535 to pound 22,502 for the 'high-risk' group, from pound 6117 to pound 30,825 for children, and from pound 5057 to pound 21,781 for the residential care elderly population. The base case model included valuations of the health effects of pneumonia (and otitis media in the children's model) based on observed rates in the trials. However it does not include the cost of hospitalisations as only very limited data was available for the effects of antivirals on hospitalisation rates. As for mortality rates, deaths from influenza were rare in trials of neuraminidase inhibitors (NIs). Therefore, suitable data on mortality were not available from these sources. As avoided hospitalisation costs and avoided mortality are potentially important we also carried out sensitivity analysis that involved extrapolating the observed reductions in pneumonias in the NI trials to hospitalisations and deaths. In all four models the cost-effectiveness of NIs is substantially improved by this extrapolation. For prophylaxis, antiviral drugs were compared with vaccination as preventative strategies. In all cases the cost-effectiveness ratios for vaccination were either low or cost-saving. In the base case the cost-effectiveness of antivirals was relatively unfavourable, there were scenarios relating to the elderly residential care model where antivirals as an additional strategy could be cost-effective.
CONCLUSIONS
The cost-effectiveness varies markedly between the intervention strategies and target populations. The estimate of cost effectiveness is also sensitive to variations in certain key parameters of the model, for example the proportion of all influenza-like illnesses that are influenza. The effectiveness literature that was used to inform the economic decision model spans many decades and hence great caution should be exercised when interpreting the results of indirect intervention comparisons from the model. Further randomised trials making direct comparisons would be valuable to verify the model's findings.
Topics: Antiviral Agents; Cost-Benefit Analysis; Decision Support Techniques; Humans; Influenza Vaccines; Influenza, Human; Quality-Adjusted Life Years; Treatment Outcome
PubMed: 14609480
DOI: 10.3310/hta7350