D Wang

University of Birmingham, Birmingham, England, United Kingdom

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Publications (6)15.08 Total impact

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    ABSTRACT: Smoking is harmful to health. On average, lifelong smokers lose 10 years of life, and about half of all lifelong smokers have their lives shortened by smoking. Stopping smoking reverses or prevents many of these harms. However, cessation services in the NHS achieve variable success rates with smokers who want to quit. Approaches to behaviour change can be supplemented with electronic aids, and this may significantly increase quit rates and prevent a proportion of cases that relapse. The primary research question we sought to answer was: What is the effectiveness and cost-effectiveness of internet, pc and other electronic aids to help people stop smoking? We addressed the following three questions: (1) What is the effectiveness of internet sites, computer programs, mobile telephone text messages and other electronic aids for smoking cessation and/or reducing relapse? (2) What is the cost-effectiveness of incorporating internet sites, computer programs, mobile telephone text messages and other electronic aids into current nhs smoking cessation programmes? and (3) What are the current gaps in research into the effectiveness of internet sites, computer programs, mobile telephone text messages and other electronic aids to help people stop smoking? For the effectiveness review, relevant primary studies were sought from The Cochrane Library [Cochrane Central Register of Controlled Trials (CENTRAL)] 2009, Issue 4, and MEDLINE (Ovid), EMBASE (Ovid), PsycINFO (Ovid), Health Management Information Consortium (HMIC) (Ovid) and Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCOhost) from 1980 to December 2009. In addition, NHS Economic Evaluation Database (NHS EED) and Database of Abstracts of Reviews of Effects (DARE) were searched for information on cost-effectiveness and modelling for the same period. Reference lists of included studies and of relevant systematic reviews were examined to identify further potentially relevant studies. Research registries of ongoing studies including National Institute for Health Research (NIHR) Clinical Research Network Portfolio Database, Current Controlled Trials and ClinicalTrials.gov were also searched, and further information was sought from contacts with experts. Randomised controlled trials (RCTs) and quasi-RCTs evaluating smoking cessation programmes that utilise computer, internet, mobile telephone or other electronic aids in adult smokers were included in the effectiveness review. Relevant studies of other design were included in the cost-effectiveness review and supplementary review. Pair-wise meta-analyses using both random- and fixed-effects models were carried out. Bayesian mixed-treatment comparisons (MTCs) were also performed. A de novo decision-analytical model was constructed for estimating the cost-effectiveness of interventions. Expected value of perfect information (EVPI) was calculated. Narrative synthesis of key themes and issues that may influence the acceptability and usability of electronic aids was provided in the supplementary review. This effectiveness review included 60 RCTs/quasi-RCTs reported in 77 publications. Pooled estimate for prolonged abstinence [relative risk (RR) = 1.32, 95% confidence interval (CI) 1.21 to 1.45] and point prevalence abstinence (RR = 1.14, 95% CI 1.07 to 1.22) suggested that computer and other electronic aids increase the likelihood of cessation compared with no intervention or generic self-help materials. There was no significant difference in effect sizes between aid to cessation studies (which provide support to smokers who are ready to quit) and cessation induction studies (which attempt to encourage a cessation attempt in smokers who are not yet ready to quit). Results from MTC also showed small but significant intervention effect (time to relapse, mean hazard ratio 0.87, 95% credible interval 0.83 to 0.92). Cost-threshold analyses indicated some form of electronic intervention is likely to be cost-effective when added to non-electronic behavioural support, but there is substantial uncertainty with regard to what the most effective (thus most cost-effective) type of electronic intervention is, which warrants further research. EVPI calculations suggested the upper limit for the benefit of this research is around £2000-3000 per person. The review focuses on smoking cessation programmes in the adult population, but does not cover smoking cessation in adolescents. Most available evidence relates to interventions with a single tailored component, while evidence for different modes of delivery (e.g. e-mail, text messaging) is limited. Therefore, the findings of lack of sufficient evidence for proving or refuting effectiveness should not be regarded as evidence of ineffectiveness. We have examined only a small number of factors that could potentially influence the effectiveness of the interventions. A comprehensive evaluation of potential effect modifiers at study level in a systematic review of complex interventions remains challenging. Information presented in published papers is often insufficient to allow accurate coding of each intervention or comparator. A limitation of the cost-effectiveness analysis, shared with several previous cost-effectiveness analyses of smoking cessation interventions, is that intervention benefit is restricted to the first quit attempt. Exploring the impact of interventions on subsequent attempts requires more detailed information on patient event histories than is available from current evidence. Our effectiveness review concluded that computer and other electronic aids increase the likelihood of cessation compared with no intervention or generic self-help materials, but the effect is small. The effectiveness does not appear to vary with respect to mode of delivery and concurrent non-electronic co-interventions. Our cost-effectiveness review suggests that making some form of electronic support available to smokers actively seeking to quit is highly likely to be cost-effective. This is true whether the electronic intervention is delivered alongside brief advice or more intensive counselling. The key source of uncertainty is that around the comparative effectiveness of different types of electronic interventions. Our review suggests that further research is needed on the relative benefits of different forms of delivery for electronic aids, the content of delivery, and the acceptability of these technologies for smoking cessation with subpopulations of smokers, particularly disadvantaged groups. More evidence is also required on the relationship between involving users in the design of interventions and the impact this has on effectiveness, and finally on how electronic aids developed and tested in research settings are applied in routine practice and in the community. The National Institute for Health Research Health Technology Assessment programme.
    Full-text · Article · Oct 2012
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    D Wang · S Bayliss · C Meads
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    ABSTRACT: Respiratory syncytial virus (RSV) is a seasonal infectious disease, with epidemics occurring annually from October to March in the UK. It is a very common infection in infants and young children and can lead to hospitalisation, particularly in those who are premature or who have chronic lung disease (CLD) or congenital heart disease (CHD). Palivizumab (Synagis®, MedImmune) is a monoclonal antibody designed to provide passive immunity against RSV and thereby prevent or reduce the severity of RSV infection. It is licensed for the prevention of serious lower respiratory tract infection caused by RSV in children at high risk. While it is recognised that a policy of using palivizumab for all children who meet the licensed indication does not meet conventional UK standards of cost-effectiveness, most clinicians feel that its use is justified in some children. To use systematic review evidence to estimate the cost-effectiveness of immunoprophylaxis of RSV using palivizumab in different subgroups of children with or without CLD or CHD who are at high risk of serious morbidity from RSV infection. A systematic review of the literature and an economic evaluation was carried out. The bibliographic databases included the Cochrane Library [Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Database of Systematic Reviews (CDSR), Database of Abstracts of Reviews of Effects (DARE) and Health Technology Assessment (HTA)] and five other databases, from inception to 2009. Research registries of ongoing trials including Current Controlled Trials metaRegister, Clinical Trials.gov and the National Institute for Health Research Clinical Research Network Portfolio were also searched. Searches were conducted for prognostic and hospitalisation studies covering 1950-2009 (the original report searches conducted in 2007 covering the period 1950-2007 were rerun in August 2009 to cover the period 2007-9) and the database of all references from the original report was sifted to find any relevant studies that may have been missed. The risk factors identified from the systematic review of included studies were analysed and synthesised using stata. The base-case decision tree model developed in the original HTA journal publication [Health Technol Assess 2008;12(36)] was used to derive the cost-effectiveness of immunoprophylaxis of RSV using palivizumab in different subgroups of pre-term infants and young children who are at high risk of serious morbidity from RSV infection. Cost-effective spectra of prophylaxis with palivizumab compared with no prophylaxis for children without CLD/CHD, children with CLD, children with acyanotic CHD and children with cyanotic CHD were derived. Thirteen studies were included in this analysis. Analysis of 16,128 subgroups showed that prophylaxis with palivizumab may be cost-effective [at a willingness-to-pay threshold of £30,000/quality-adjusted life-year (QALY)] for some subgroups. For example, for children without CLD or CHD, the cost-effective subgroups included children under 6 weeks old at the start of the RSV season who had at least two other risk factors that were considered in this report and were born at 24 weeks gestational age (GA) or less, but did not include children who were > 9 months old at the start of the RSV season or had a GA of > 32 weeks. For children with CLD, the cost-effective subgroups included children < 6 months old at the start of the RSV season who were born at 28 weeks GA or less, but did not include children who were > 21 months old at the start of the RSV season. For children with acyanotic CHD, the cost-effective subgroups included children < 6 months old at the start of the RSV season who were born at 24 weeks GA or less, but did not include children who were > 21 months old at the start of the RSV season. For children with cyanotic CHD, the cost-effective subgroups included children < 6 weeks old at the start of the RSV season who were born at 24 weeks GA or less, but did not include children who were > 12 months old at the start of the RSV season. The poor quality of the studies feeding numerical results into this analysis means that the true cost-effectiveness may vary considerably from that estimated here. There is a risk that the relatively high mathematical precision of the point estimates of cost-effectiveness may be quite inaccurate because of poor-quality inputs. Prophylaxis with palivizumab does not represent good value for money based on the current UK incremental cost-effectiveness ratio threshold of £30,000/QALY when used unselectively in children without CLD/CHD or children with CLD or CHD. This subgroup analysis showed that prophylaxis with palivizumab may be cost-effective (at a willingness-to-pay threshold of £30,000/QALY) for some subgroups. In summary, the cost-effective subgroups for children who had no CLD or CHD must contain at least two other risk factors apart from GA and birth age. The cost-effective subgroups for children who had CLD or CHD do not necessarily need to have any other risk factors. Future research should be directed towards conducting much larger, better powered and better reported studies to derive better estimates of the risk factor effect sizes. This report was funded by the HTA programme of the National Institute for Health Research.
    Full-text · Article · Jan 2011
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    ABSTRACT: This paper presents a summary of the evidence review group (ERG) report into the clinical effectiveness and cost-effectiveness of infliximab for the treatment of acute exacerbations of ulcerative colitis, in accordance with the licensed indication, based upon the manufacturer's submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal process. The submitted clinical evidence included four randomised controlled trials (RCTs), two comparing infliximab with placebo in patients not responsive to initial treatment with intravenous corticosteroids and one comparing ciclosporin with placebo. A fourth RCT compared ciclosporin with intravenous corticosteroids as the initial treatment after hospitalisation. The manufacturer's submission concluded that infliximab provides clinical benefit to patients with acute severe, steroid-refractory ulcerative colitis and is well tolerated; it also provides additional clinical benefits over ciclosporin, particularly avoidance of colectomy. A decision tree model was built to compare infliximab with strategies involving ciclosporin, standard care and surgery. After correcting a small number of errors in the model, the revised base-case incremental cost-effectiveness ratio (ICER) for infliximab compared with standard care was 20,000 pounds. However, sensitivity analyses revealed considerable uncertainty emanating from the weight of the patient, the timeframe considered and, most importantly, the colectomy rates used. When a more appropriate mix of trials were included in the estimation of colectomy rates, the ICER for infliximab rose to 48,000 pounds. The guidance issued by NICE on 31 October 2008 states that infliximab is recommended as an option for the treatment of acute exacerbations of severely active ulcerative colitis only in patients in whom ciclosporin is contraindicated or clinically inappropriate, based on a careful assessment of the risks and benefits of treatment in the individual patient; for people who do not meet this criterion, infliximab should only be used for the treatment of acute exacerbations of severely active ulcerative colitis in clinical trials.
    Full-text · Article · May 2010
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    ABSTRACT: To systematically review the effectiveness and cost-effectiveness of palivizumab for the prevention of respiratory syncytial virus (RSV) in children and examine prognostic factors to determine whether subgroups can be identified with important differences in cost-effectiveness. Bibliographic databases were searched from inception to March 2007 for literature on the effectiveness and cost-effectiveness of prophylaxis with palivizumab. The literature was systematically reviewed and current economic evaluations were analysed to identify which parameters were driving the different cost-effectiveness estimates. A probabilistic decision-analytical model was built to assess the cost-effectiveness of prophylaxis with palivizumab for children at risk of RSV infection and the parameters populated with the best estimates thought most applicable to the UK. We also constructed a new model, the Birmingham Economic Evaluation (BrumEE). Cost-effectiveness analyses were undertaken from both NHS and societal perspectives. Two randomised controlled trials (RCTs) were identified. Prophylaxis with palivizumab for preterm infants without chronic lung disease (CLD) or children with CLD resulted in a 55% reduction in RSV hospital admission: 4.8% (48/1002) in the palivizumab group and 10.6% (53/500) in the no prophylaxis group (p = 0.0004). Prophylaxis with palivizumab was associated with a 45% reduction in hospitalisation rate RSV among children with coronary heart disease (CHD). Hospitalisation rates for RSV were 5.3% (34/639) in the palivizumab group and 9.7% (63/648) in the no prophylaxis group (p = 0.003). Of existing economic evaluations, 3 systematic reviews and 18 primary studies were identified. All the systematic reviews concluded that the potential costs of palivizumab were far in excess of any potential savings achieved by decreasing hospital admission rates, and that the use of palivizumab was unlikely to be cost-effective in all children for whom it is recommended, but that its continued use for particularly high-risk children may be justified. The incremental cost-effectiveness ratios (ICERs) of the primary studies varied 17-fold for life-years gained (LYG), from 25,800 pounds/LYG to 404,900 pounds/LYG, and several hundred-fold for quality-adjusted life-years (QALYs), from 3200 pounds/QALY to 1,489,700 pounds/QALY for preterm infants without CLD or children with CLD. For children with CHD, the ICER varied from 5300 pounds/LYG to 7900 pounds/LYG and from 7500 pounds/QALY to 68,700 pounds/QALY. An analysis of what led to the discrepant ICERs showed that the assumed mortality rate for RSV infection was the most important driver. The results of the BrumEE confirm that palivizumab does not reach conventional levels of cost-effectiveness in any of the licensed indications if used for all eligible children. Prophylaxis with palivizumab is clinically effective for the reducing the risk of serious lower respiratory tract infection caused by RSV infection and requiring hospitalisation in high-risk children, but if used unselectively in the licensed population, the ICER is double that considered to represent good value for money in the UK. The BrumEE shows that prophylaxis with palivizumab may be cost-effective (based on a threshold of 30,000 pounds/QALY) for children with CLD when the children have two or more additional risk factors. Future research should initially focus on reviewing systematically the major uncertainties for patient subgroups with CLD and CHD and then on primary research to address the important uncertainties that remain.
    Full-text · Article · Jan 2009 · Health technology assessment (Winchester, England)
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    ABSTRACT: To examine the effectiveness and cost-effectiveness of nicotine replacement therapy (NRT) for 'cut down to quit' (CDTQ) smoking. Major electronic databases were searched up to July 2006. Data from studies meeting the criteria were reviewed and analysed. A decision analytical model was constructed to estimate the cost-effectiveness of CDTQ from the NHS perspective. No systematic reviews of the effectiveness of CDTQ and no randomised controlled trials (RCTs) specifically addressing CDTQ were identified. Seven randomised placebo-controlled trials satisfied the inclusion criteria; six of these were industry sponsored. However, sustained smoking cessation was only reported as a secondary outcome in these trials and required commencement of cessation within the first 6 weeks of treatment. Meta-analyses of the study level results demonstrated statistically significant superiority of NRT compared with placebo. Individual patient data from unpublished reports of five RCTs were used to calculate sustained abstinence of at least 6 months starting at any time during the treatment period (generally 12 months). From this the meta-analysis indicated statistically significant superiority of NRT versus placebo [relative risk 2.06, 95% confidence interval (CI) 1.34 to 3.15]. The proportions achieving this outcome across all five RCTs were 6.75% of participants in receipt of NRT and 3.29% of those receiving placebo. The number-needed-to-treat was 29. This measure of sustained abstinence was used for economic modelling. No existing economic analyses of CDTQ were identified. A de novo decision analytic model was constructed to estimate the cost-effectiveness of making CDTQ with NRT available for smokers unwilling or unable to attempt an abrupt quit. The outcome measure was expected quality-adjusted life-years (QALYs). The model results suggest that CDTQ with NRT delivers incremental cost-effectiveness ratios (ICERs) ranging from around 1500 pounds/QALY to 7700 pounds/QALY depending on the age at which smoking cessation was achieved and the modes of CDTQ delivery. Assuming applicability to a single population, CDTQ was not cost-effective compared with abrupt quitting. If CDTQ with NRT were to be offered on the NHS as a matter of policy, the base-case results suggest that it would only be effective and cost-effective if a substantial majority of the people attempting CDTQ with NRT were those who would otherwise make no attempt to quit. This result is robust to considerable variation in the forms of CDTQ with NRT offered, and to the assumptions about QALY gained per quit success. Meta-analysis of RCT evidence of quit rates in NRT-supported smoking reduction studies indicates that NRT is an effective intervention in achieving sustained smoking abstinence for smokers who declare unwillingness or inability to attempt an abrupt quit. The 12-month sustained abstinence success rate in this population (approximately 5.3% with NRT versus approximately 2.6% with placebo) is considerably less than that documented for an abrupt quit NRT regime in smokers willing to attempt an abrupt quit with NRT (which according to other systematic reviews is around 16% with NRT versus 10% with placebo). Most of the evidence of effectiveness of CDTQ came from trials that required considerable patient-investigator contact. Therefore, for CDTQ with NRT to generate similar abstinence rates for this recalcitrant population in a real-world setting would probably require a similar mode of delivery. The modelling undertaken, which was based on reasonable assumptions about costs, benefits and success rates, suggests that CDTQ is highly cost-effective compared with no quit attempt. CDTQ remains cost-effective if dilution from abrupt quitting forms a small proportion of CDTQ attempts. In an alternative analysis in which smokers who switch from an abrupt quit to CDTQ retain the success rate of abrupt quitters, all forms of CDTQ appear cost-effective. Randomised trials in recalcitrant smokers allowing head-to-head comparison of CDTQ delivered with various modalities would be informative.
    Full-text · Article · Mar 2008 · Health technology assessment (Winchester, England)
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    ABSTRACT: To investigate the clinical effectiveness and cost-effectiveness of naltrexone for relapse prevention in detoxified formerly opioid-dependent individuals compared with any strategy that does not use naltrexone, including treatment with placebo, other pharmacological treatments, psychosocial interventions or no treatment. Major electronic databases were searched from inception to September 2005. Selected studies were screened and quality assessed. Meta-analyses were carried out as appropriate. A decision-analytic model using Monte Carlo simulation was developed that compared naltrexone as an adjunctive therapy to no naltrexone. It assumed compliance rates that were not enhanced by contingent management rewards (because this is current UK practice). Utility values could not be identified from the literature and so were obtained by research specially commissioned from the Value of Health Panel. The methodological quality of the 26 randomised controlled trials (RCTs) that met the inclusion criteria was poor to moderate. The results suggest that naltrexone as maintenance therapy may be better than placebo in terms of retention in treatment, but this was not statistically significant. A meta-analysis of seven included RCTs gave the relative risk (RR) of loss of retention in treatment in the naltrexone arm as 0.94. The pooled hazard ratio (HR) reported in five of the RCTs for retention in treatment data followed up to 35 weeks was calculated as 0.90 in favour of naltrexone and also did not reach statistical significance. The risk of drug abuse in naltrexone versus placebo, with or without psychological support given in both arms, gave a pooled RR of 0.72, which was a statistically significant difference in favour of naltrexone. The pooled HR from three RCTs for opioid relapse-free rates was significantly different from placebo in favour of naltrexone 0.53; however, this fell off over time and may be of limited clinical significance. The RR of reimprisonment while on naltrexone therapy showed results in favour of naltrexone in the combined two studies of parolees or people on probation, but the number of participants was small. One study of 52 participants found that the difference in improvement score for risky sexual behaviour in the naltrexone group compared with the placebo group was not statistically significant. The adverse events data reported showed no significant difference between the naltrexone and placebo arms. The quality of the nine RCTs of interventions designed to increase retention with naltrexone was poor to moderate; however, all three different modalities of enhanced care showed some evidence of effectiveness. All of the contingency management programmes used incentive vouchers; the mean duration of treatment retention was 7.4 weeks for the contingency management intervention compared with 2.3-5.6 weeks for the naltrexone treatment alone. The mean length of time for which patients stayed on naltrexone was 84-103 days with additional psychosocial therapy compared with 43-64 days for the control group. In trials with added pharmacological agents the RRs of stopping treatment were 1.63 at 6 months and 1.31 at 12 months (in favour of naltrexone plus fluoxetine). It became statistically significant at 6 months, but not at 12 months. A meta-analysis of the RR of stopping treatment at week 12 (the minimum follow-up period) was carried out using six of the nine studies. The pooled RR of stopping treatment was 0.81. The results indicated that overall the intervention groups had 19% fewer patients who stopped treatment compared with the control group, but there was only a small number of studies and their quality was relatively poor. No existing economic evaluations were identified. The point estimate for the cost-effectiveness of naltrexone was pound42,500 per quality-adjusted life-year (QALY). Sensitivity analysis was carried out and the incremental cost-effectiveness ratio varied between pound34,600 and pound42,500 per QALY gained. Following successful withdrawal from opioids, naltrexone may be administered on a chronic basis to block any future effects of opioids. Naltrexone appears to have some limited benefit in helping formerly opioid-dependent individuals to remain abstinent, although the quality of the evidence is relatively poor and heterogeneous. The limited quality and extent of the studies precluded an analysis of subgroups likely to benefit from naltrexone prescribing. Oral naltrexone is used infrequently in current UK practice, and this review suggests that this is appropriate as there is little evidence to support its wider implementation. There is an important deficit in information about the quality of life of people who use illicit opioids and this would perhaps be a worthwhile area of research in informing policy questions about the cost-effectiveness of different programmes and interventions.
    Full-text · Article · Mar 2007 · Health technology assessment (Winchester, England)