Pharmacotherapies for chronic obstructive pulmonary disease: a multiple treatment comparison meta-analysis

Evidence Synthesis for Complex Interventions Using Meta-Regression Models

A goal of evidence synthesis for trials of complex interventions is to inform the design or implementation of novel versions of complex interventions by predicting expected outcomes with each intervention version. Conventional aggregate data meta-analyses of studies comparing complex interventions have limited ability to provide such information. We argue that evidence synthesis for trials of complex interventions should forgo aspirations of estimating causal effects and instead model the response surface of study results to 1) summarize the available evidence and 2) predict the average outcomes of future studies or in new settings. We illustrate this modeling approach using data from a systematic review of diabetes quality improvement (QI) interventions involving at least 1 of 12 QI strategy components. We specify a series of meta-regression models to assess the association of specific components with the posttreatment outcome mean and compare the results to conventional meta-analysis approaches. Compared with conventional approaches, modeling the response surface of study results can better reflect the associations between intervention components and study characteristics with the posttreatment outcome mean. Modeling study results using a response surface approach offers a useful and feasible goal for evidence synthesis of complex interventions that rely on aggregate data.

Twenty years of network meta-analysis: Continuing controversies and recent developments

Network meta-analysis (NMA) is an extension of pairwise meta-analysis (PMA) which combines evidence from trials on multiple treatments in connected networks. NMA delivers internally consistent estimates of relative treatment efficacy, needed for rational decision making. Over its first 20 years NMA's use has grown exponentially, with applications in both health technology assessment (HTA), primarily re-imbursement decisions and clinical guideline development, and clinical research publications. This has been a period of transition in meta-analysis, first from its roots in educational and social psychology, where large heterogeneous datasets could be explored to find effect modifiers, to smaller pairwise meta-analyses in clinical medicine on average with less than six studies. This has been followed by narrowly-focused estimation of the effects of specific treatments at specific doses in specific populations in sparse networks, where direct comparisons are unavailable or informed by only one or two studies. NMA is a powerful and well-established technique but, in spite of the exponential increase in applications, doubts about the reliability and validity of NMA persist. Here we outline the continuing controversies, and review some recent developments. We suggest that heterogeneity should be minimized, as it poses a threat to the reliability of NMA which has not been fully appreciated, perhaps because it has not been seen as a problem in PMA. More research is needed on the extent of heterogeneity and inconsistency in datasets used for decision making, on formal methods for making recommendations based on NMA, and on the further development of multi-level network meta-regression.

Data visualisation approaches for component network meta-analysis: visualising the data structure

BACKGROUND

Health and social care interventions are often complex and can be decomposed into multiple components. Multicomponent interventions are often evaluated in randomised controlled trials. Across trials, interventions often have components in common which are given alongside other components which differ across trials. Multicomponent interventions can be synthesised using component NMA (CNMA). CNMA is limited by the structure of the available evidence, but it is not always straightforward to visualise such complex evidence networks. The aim of this paper is to develop tools to visualise the structure of complex evidence networks to support CNMA.

METHODS

We performed a citation review of two key CNMA methods papers to identify existing published CNMA analyses and reviewed how they graphically represent intervention complexity and comparisons across trials. Building on identified shortcomings of existing visualisation approaches, we propose three approaches to standardise visualising the data structure and/or availability of data: CNMA-UpSet plot, CNMA heat map, CNMA-circle plot. We use a motivating example to illustrate these plots.

RESULTS

We identified 34 articles reporting CNMAs. A network diagram was the most common plot type used to visualise the data structure for CNMA (26/34 papers), but was unable to express the complex data structures and large number of components and potential combinations of components associated with CNMA. Therefore, we focused visualisation development around representing the data structure of a CNMA more completely. The CNMA-UpSet plot presents arm-level data and is suitable for networks with large numbers of components or combinations of components. Heat maps can be utilised to inform decisions about which pairwise interactions to consider for inclusion in a CNMA model. The CNMA-circle plot visualises the combinations of components which differ between trial arms and offers flexibility in presenting additional information such as the number of patients experiencing the outcome of interest in each arm.

CONCLUSIONS

As CNMA becomes more widely used for the evaluation of multicomponent interventions, the novel CNMA-specific visualisations presented in this paper, which improve on the limitations of existing visualisations, will be important to aid understanding of the complex data structure and facilitate interpretation of the CNMA results.

Bayesian unanchored additive models for component network meta-analysis

Component network meta-analysis (CNMA) models are an extension of standard network meta-analysis (NMA) models which account for the use of multicomponent treatments in the network. This article contributes innovatively to several statistical aspects of CNMA. First, by introducing a unified notation, we establish that currently available methods differ in the way they assume additivity, an important distinction that has been overlooked so far in the literature. In particular, one model uses a more restrictive form of additivity than the other which we term an anchored and unanchored model, respectively. We show that an anchored model can provide a poor fit to the data if it is misspecified. Second, given that Bayesian models are often preferred by practitioners, we develop two novel unanchored Bayesian CNMA models presented under the unified notation. An extensive simulation study examining bias, coverage probabilities, and treatment rankings confirms the favorable performance of the novel models. This is the first simulation study to compare the statistical properties of CNMA models in the literature. Finally, the use of our novel models is demonstrated on a real dataset, and the results of CNMA models on the dataset are compared.

Potential clinical and economic impact of optimised maintenance therapy on discharged patients with COPD after hospitalisation for an exacerbation in China

OBJECTIVES

Chronic obstructive pulmonary disease (COPD) exacerbations requiring hospitalisation are a considerable burden, both clinically and economically. Although long-acting maintenance therapy is recommended in both the GOLD (Global Initiative for Chronic Obstructive Lung Disease) and Chinese COPD guidelines, proper implementation is lacking. The objective of this study was to assess the clinical and economic impact of prescribing long-acting maintenance therapy to discharged patients with COPD after hospitalisation for an exacerbation in China by using an outcomes model.

DESIGN

This health economic analysis was conducted using a Markov cohort model from the Chinese healthcare payer perspective. Two health states (alive and dead) were modelled, and exacerbations were included as possible events.

SETTING

The target population was Chinese patients with COPD, >40 years of age, who were hospitalised for an exacerbation, with 1 year of follow-up. A recent COPD national prevalence study was referenced for population calculations.

INTERVENTION

A hypothetical future scenario, where 100% of patients would receive long-acting maintenance therapy after hospitalisation for an exacerbation, was compared with the current scenario, in which only 38.5% of patients are receiving long-acting maintenance therapy after hospitalisation.

OUTCOME MEASURES

Number of exacerbations, deaths and medical costs were measured.

RESULTS

We estimated that there were approximately 4 million Chinese patients with COPD who were hospitalised annually due to an exacerbation. By prescribing long-acting maintenance therapy, our model predicted that 917 360 exacerbations and 4034 deaths could be avoided, translating into cost savings of ¥3.5 billion (US$0.5 billion). Scenario analysis also showed that if the rate of exacerbations requiring hospitalisation was higher than our base case analysis, cost savings could reach up to ¥10.7 billion (US$1.5 billion).

CONCLUSION

Administering long-acting maintenance therapy to more patients with COPD at hospital discharge could considerably reduce exacerbations and healthcare spending in China.

A review of methods for addressing components of interventions in meta-analysis

Many healthcare interventions are complex, consisting of multiple, possibly interacting, components. Several methodological articles addressing complex interventions in the meta-analytical context have been published. We hereby provide an overview of methods used to evaluate the effects of complex interventions with meta-analytical models. We summarized the methodology, highlighted new developments, and described the benefits, drawbacks, and potential challenges of each identified method. We expect meta-analytical methods focusing on components of several multicomponent interventions to become increasingly popular due to recently developed, easy-to-use, software tools that can be used to conduct the relevant analyses. The different meta-analytical methods are illustrated through two examples comparing psychotherapies for panic disorder.

Clinical Relevance of the Anti-inflammatory Effects of Roflumilast on Human Bronchus: Potentiation by a Long-Acting Beta-2-Agonist

Background: Roflumilast is an option for treating patients with severe COPD and frequent exacerbations despite optimal therapy with inhaled drugs. The present study focused on whether the phosphodiesterase (PDE) 4 inhibitor roflumilast and its active metabolite roflumilast N-oxide affect the release of tumor necrosis factor (TNF)-α and chemokines by lipopolysaccharide (LPS)-stimulated human bronchial explants. We also investigated the interactions between roflumilast, roflumilast N-oxide and the β₂-agonist formoterol with regard to cytokine release by the bronchial preparations.

Methods: Bronchial explants from resected lungs were incubated with roflumilast, roflumilast N-oxide and/or formoterol and then stimulated with LPS. An ELISA was used to measure levels of TNF-α and chemokines in the culture supernatants.

Results: At a clinically relevant concentration (1 nM), roflumilast N-oxide and roflumilast consistently reduced the release of TNF-α, CCL2, CCL3, CCL4, CCL5 and CXCL9 (but not CXCL1, CXCL5, CXCL8 and IL-6) from human bronchial explants. Formoterol alone decreased the release of TNF-α, CCL2, and CCL3. The combination of formoterol with roflumilast (1 nM) was more potent than roflumilast alone for inhibiting the LPS-induced release of TNF-α, CCL2, CCL3, CCL4, and CXCL9 by the bronchial explants.

Conclusions: At a clinically relevant concentration, roflumilast N-oxide and its parent compound, roflumilast, reduced the LPS-induced production of TNF-α and chemokines involved in monocyte and T-cell recruitment but did not alter the release of chemokines involved in neutrophil recruitment. The combination of formoterol with roflumilast enhanced the individual drugs’ anti-inflammatory effects.

Clinical relevance of the relaxant effects of roflumilast on human bronchus: potentiation by a long-acting beta-2-agonist

Roflumilast is an oral, add-on option for treating patients with severe COPD and frequent exacerbations despite optimal therapy with inhaled drugs. The present study focused on whether this phosphodiesterase 4 inhibitor and its active metabolite roflumilast N-oxide affect the tone of human bronchial rings. We also investigated the interactions between roflumilast, roflumilast N-oxide and the long-acting β₂ -agonist formoterol with regard to the relaxation of isolated human bronchial rings at basal tone or pre-contracted with histamine. Our results demonstrated for the first time that at a clinically relevant concentration (1 nm), roflumilast N-oxide and roflumilast induce a weak relaxation of the isolated human bronchus either at resting tone (22% and 16%, respectively) or even weaker on pre-contracted bronchus with histamine (7% and 5%, respectively). In addition, the combination of formoterol with roflumilast or roflumilast N-oxide is more potent than each component alone for relaxing pre-contracted isolated bronchi - the apparent pD2 of formoterol was significantly reduced for the threshold concentration of 1 nm of the phosphodiesterase 4 inhibitors by a factor of 2.4 for roflumilast N-oxide and 1.9 for roflumilast. The full inhibition of phosphodiesterase 4 activity is achieved at 100 nm but this high concentration only caused partial relaxations of the human bronchi. At a clinically relevant concentration, these oral phosphodiesterase 4 inhibitors are not effective direct bronchodilators but could enhance the efficacy of inhaled long-acting β2-agonists.

Inhaled therapies for chronic obstructive pulmonary disease: a systematic review and meta-analysis

OBJECTIVES

To integrate evidence from randomised controlled trials (RCTs) and observational studies on the efficacy of inhaled treatments for chronic obstructive pulmonary disease using network meta-analyses.

METHODS

Systematic searches MEDLINE and Embase based on predetermined criteria. Network meta-analyses of RCTs investigated efficacy on exacerbations (long-term: ≥20 weeks of treatment; short-term: <20 weeks), lung function (≥12 weeks), health-related quality of life, mortality and adverse events. Qualitative comparisons of efficacies between RCTs and observational studies.

RESULTS

212 RCTs and 19 observational studies were included. Compared with combined long-acting beta-adrenoceptor agonists and long-acting muscarinic antagonists (LABA+LAMA), triple therapy (LABA+LAMA+inhaled corticosteroid) was significantly more effective at reducing exacerbations (long-term 0.85 (95% CI: 0.78 to 0.94; short-term 0.67 (95% CI: 0.49 to 0.92)) and mortality (0.72 (95% CI: 0.59 to 0.89)) but was also associated with increased pneumonia (1.35 (95% CI: 1.10 to 1.67)). No differences in lung function (0.02 (95% CI: -0.10 to 0.14)), health-related quality of life (-1.12 (95% CI: -3.83 to 1.59)) or other adverse events (1.02 (95% CI: 0.96 to 1.08)) were found. Most of the observational evidence trended in the same direction as pooled RCT data.

CONCLUSION

Further evidence, especially pragmatic trials, are needed to fully understand the characteristics of patient subgroups who may benefit from triple therapy and for those whom the extra risk of adverse events, such as pneumonia, may outweigh any benefits.

PROSPERO REGISTRATION NUMBER

CRD42018088013.

Comparative effectiveness of six Chinese herb formulas for acute exacerbation of chronic obstructive pulmonary disease: a systematic review and network meta-analysis

BACKGROUND

Six Chinese herb formulas, namely, the Weijing decoction (WJ), the Maxingshigan decoction (MXSG), the Yuebijiabanxia decoction (YBBX), the Qingqihuatan decoction (QQHT), the Dingchuan decoction (DC) and the Sangbaipi decoction (SBP), are commonly used, along with routine pharmacotherapy, to manage the acute exacerbation of chronic obstructive pulmonary disease (AECOPD). In this study, we conducted a systematic review to summarize the efficacy of these six formulas, and we also conducted a network meta-analysis (NMA) to rank these formulas.

METHODS

We searched five English databases and four Chinese databases, with dates ranging from the starting dates of these databases to December 2016. Randomized controlled trials that evaluated any of the six Chinese herb formulas combined with the use of pharmacotherapy for AECOPD were identified.

RESULTS

Fifty-five studies involving 4560 participants were included. The pairwise meta-analyses showed that WJ and QQHT had superior effects on the improvement of lung function (forced expiratory volume in 1 seconds; FEV1) (mean difference (MD): 0.25, 95% confidence interval (CI): 0.19-0.30 and 0.34, 95%CI: 0.10-0.58). MXSG, WJ and QQHT were found to be more effective for improving arterial blood gases (PaO2 and PaCO2). In terms of effective rates, all of these formulas had additional favourable effects compared to routine pharmacotherapy. The results of the NMA analyses indicated that only MXSG showed superior add-on effects for the improvement of FEV1 (MD: 0.37, 95% credible interval (CrI): 0.03-0.72). Most of the formulas combined with routine pharmacotherapy were superior to pharmacotherapy alone for the improvement of arterial blood gases and effective rates. The ranking tests suggested that QQHT and MXSG combined with routine pharmacotherapy might be optimal options for the treatment of AECOPD.

CONCLUSIONS

This NMA indicated that QQHT and MXSG might be more effective treatment regimens for AECOPD. Further well-designed studies that specifically examine the direct comparisons of these formulas are needed to support our conclusions.

Decline of COPD exacerbations in clinical trials over two decades - a systematic review and meta-regression

Background

An important goal of chronic obstructive pulmonary disease (COPD) treatment is to reduce the frequency of exacerbations. Some observations suggest a decline in exacerbation rates in clinical trials over time. A more systematic understanding would help to improve the design and interpretation of COPD trials.

Methods

We performed a systematic review and meta-regression of the placebo groups in published randomized controlled trials reporting exacerbations as an outcome. A Bayesian negative binomial model was developed to accommodate results that are reported in different formats; results are reported with credible intervals (CI) and posterior tail probabilities (p_B).

Results

Of 1114 studies identified by our search, 55 were ultimately included. Exacerbation rates decreased by 6.7% (95% CI (4.4, 9.0); p_B <  0.001) per year, or 50% (95% CI (36, 61)) per decade. Adjusting for available study and baseline characteristics such as forced expiratory volume in 1 s (FEV₁) did not alter the observed trend considerably. Two subsets of studies, one using a true placebo group and the other allowing inhaled corticosteroids in the “placebo” group, also yielded consistent results.

Conclusions

In conclusion, this meta-regression indicates that the rate of COPD exacerbations decreased over the past two decades to a clinically relevant extent independent of important prognostic factors. This suggests that care is needed in the design of new trials or when comparing results from older trials with more recent ones. Also a considerable effect of adjunct therapy on COPD exacerbations can be assumed.

Registration

PROSPERO 2018 CRD4218118823.

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1163-2) contains supplementary material, which is available to authorized users.

Network meta-analysis of multicomponent interventions

In network meta‐analysis (NMA), treatments can be complex interventions, for example, some treatments may be combinations of others or of common components. In standard NMA, all existing (single or combined) treatments are different nodes in the network. However, sometimes an alternative model is of interest that utilizes the information that some treatments are combinations of common components, called component network meta‐analysis (CNMA) model. The additive CNMA model assumes that the effect of a treatment combined of two components A and B is the sum of the effects of A and B, which is easily extended to treatments composed of more than two components. This implies that in comparisons equal components cancel out. Interaction CNMA models also allow interactions between the components. Bayesian analyses have been suggested. We report an implementation of CNMA models in the frequentist R package netmeta. All parameters are estimated using weighted least squares regression. We illustrate the application of CNMA models using an NMA of treatments for depression in primary care. Moreover, we show that these models can even be applied to disconnected networks, if the composite treatments in the subnetworks contain common components.

Roles of roflumilast, a selective phosphodiesterase 4 inhibitor, in airway diseases

Asthma and chronic obstructive pulmonary disease (COPD) are common chronic respiratory diseases. Both diseases have incompletely distinct pathophysiology, clinical manifestation, and treatment responsiveness. Pulmonary and systemic inflammations are the hallmarks of COPD. Most asthma responds to inhaled corticosteroid (ICS) treatment. In contrast, COPD is a corticosteroid-resistant disease. Bronchodilators are a preferred treatment method of COPD, with the aim of improving symptoms and preventing exacerbation. In addition, corticosteroid insensitivity is an underlying mechanism in severe asthma. An overlap of features between asthma and COPD, which was described as asthma-COPD overlap syndrome (ACOS) is not uncommon in practice. Novel nonsteroidal therapies focusing on inflammation in asthma and COPD have been developed. Selective phosphodiesterase 4 (PDE4) inhibitor is a promising class of drugs that has been studied for the treatment of COPD. Selective PDE4 inhibitor is different from xanthine in terms of mechanisms and pharmacokinetic profiles. This review focuses on clinical data on PDE4 inhibitors and its future roles in asthma, COPD, bronchiectasis, ACOS and other chronic non-pulmonary diseases.

Pharmacological strategies to reduce exacerbation risk in COPD: a narrative review

Identifying patients at risk of exacerbations and managing them appropriately to reduce this risk represents an important clinical challenge. Numerous treatments have been assessed for the prevention of exacerbations and their efficacy may differ by patient phenotype. Given their centrality in the treatment of COPD, there is strong rationale for maximizing bronchodilation as an initial strategy to reduce exacerbation risk irrespective of patient phenotype. Therefore, in patients assessed as frequent exacerbators (>1 exacerbation/year) we propose initial bronchodilator treatment with a long-acting muscarinic antagonist (LAMA)/ long-acting β2-agonist (LABA). For those patients who continue to experience >1 exacerbation/year despite maximal bronchodilation, we advocate treating according to patient phenotype. Based on currently available data on adding inhaled corticosteroids (ICS) to a LABA, ICS might be added to a LABA/LAMA combination in exacerbating patients who have an asthma-COPD overlap syndrome or high blood eosinophil counts, while in exacerbators with chronic bronchitis, consideration should be given to treating with a phosphodiesterase (PDE)-4 inhibitor (roflumilast) or high-dose mucolytic agents. For those patients who experience frequent bacterial exacerbations and/or bronchiectasis, addition of mucolytic agents or a macrolide antibiotic (e.g. azithromycin) should be considered. In all patients at risk of exacerbations, pulmonary rehabilitation should be included as part of a comprehensive management plan.

The safety and effectiveness of the current treatment regimen with or without roflumilast in advanced COPD patients: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory disease, which reduces the lung function and causes respiratory symptoms over time, and it is primarily associated with shortness of breath, cough and sputum production. Roflumilast, which is a long-acting selective inhibitor, reduces the anti-inflammatory effect of the main symptoms of COPD. The aim of this study was to compare the clinical effectiveness of adding roflumilast to the current treatment regimen of patients with severe COPD.

METHODS

To retrieve the marker studies, medical databases were searched up to February 2014. We included studies, which compared the clinical effectiveness and safety of roflumilast as concomitant to Long-acting ß2-agonist/Long-acting muscarinic antagonist (LABA/LAMA) regimen, in adult patients with severe COPD. The number of exacerbations, changes in the lung function FEV1, FEV1/FVC and quality of life were the major predefined outcomes. Meta-analysis of outcomes was performed by the RevMan software, with I(2)> 50%, representing considerable heterogeneity.

RESULTS

Seven randomized controlled trials and two systematic reviews were included. In terms of safety, participants were likely to experience more side effects from roflumilast compared to placebo, particularly gastrointestinal effects (diarrhea, nausea, vomiting), headache and weight loss. There was no significant difference in the risk of cardiac complications or flu-like symptoms or upper respiratory tract infection in the two groups. In terms of effectiveness, only a small improvement was observed in SGRQ (St George's Respiratory Questionnaire) index. Roflumilast reduced moderate to severe attacks, and caused significant improvements in the lung function regardless of the severity of the disease and the concurrent use of other standard COPD therapies.

CONCLUSION

Roflumilast anti-inflammatory therapy reduces the chronic bronchitis symptoms in patients with moderate to severe COPD, and it can be safely used with other drugs simultaneously.

Once-daily fluticasone furoate/vilanterol versus twice daily combination therapies in asthma-mixed treatment comparisons of clinical efficacy

Background

Fluticasone furoate (FF)/vilanterol (VI) is a once-daily inhaled corticosteroid (ICS)/long-acting beta₂ agonist (LABA) combination. FF/VI, 92/22mcg and 184/22mcg, are approved in Europe as maintenance therapy in persistent asthma. We report data from mixed treatment comparisons (MTC) of once-daily FF/VI against established twice-daily ICS/LABA combination therapies on clinical efficacy outcomes.

Methods

Data from 31 parallel-group randomised controlled trials (RCTs) of ICS/LABA, of ≥8 weeks’ duration in patients aged ≥12 years with asthma, identified by systematic review, were analysed using covariate-adjusted Bayesian hierarchical models for four efficacy outcomes (primary analysis). Lung function, assessed by change from baseline morning peak expiratory flow (PEF) (n = 18 studies) and forced expiratory volume in 1 s (FEV₁) (n = 28), was the outcome of primary interest. Secondary objectives were assessment of relative efficacy in terms of exacerbation rates (n = 6) and health status (n = 7). Overall, 24 different treatment arms were included in the MTC; we report findings comparing FF/VI (92/22mcg and 184/22mcg) with fluticasone propionate/salmeterol (FP/SAL) (250/50mcg and 500/50mcg) and budesonide/formoterol (BUD/FORM) (320/9mcg and 640/18mcg).

Results

For PEF (margin = 12 l/min), FF/VI 92/22mcg demonstrated ≥94 % probability and FF/VI 184/22mcg >99 % probability of non-inferiority to corresponding doses of both FP/SAL and BUD/FORM. For FEV₁ (margin = 100 ml), FF/VI demonstrated ≥98 % (92/22mcg) and >99 % (184/22mcg) probability of non-inferiority to both FP/SAL and BUD/FORM. Findings for exacerbations were inconclusive due to lack of data: FF/VI 92/22mcg demonstrated 74 % and 82 % probability of non-inferiority (margin = 10 %) to FP/SAL 250/50mcg and BUD/FORM 320/9mcg, respectively. For Asthma Quality of Life Questionnaire (AQLQ) score, FF/VI 92/22mcg demonstrated >99 % and 90 % probability of non-inferiority (margin = 0.25) to FP/SAL 250/50mcg and BUD/FORM 320/9mcg. Data were unavailable to assess non-inferiority of FF/VI 184/22mcg on exacerbations or AQLQ.

Conclusions

Both strengths of once-daily FF/VI in asthma were comparable with corresponding doses of twice-daily FP/SAL and BUD/FORM in terms of lung function in this MTC analysis. FF/VI 92/22mcg was comparable with FP/SAL and BUD/FORM on AQLQ, but exacerbation results were inconclusive. Model limitations include disconnected treatment networks and variability across studies. Our data support previous RCT findings suggesting that the efficacy of once-daily FF/VI in improving lung function and health status in asthma is comparable with twice-daily ICS/LABAs.

Electronic supplementary material

The online version of this article (doi:10.1186/s40733-015-0016-0) contains supplementary material, which is available to authorized users.

Systematic review of models used in economic analyses in moderate-to-severe asthma and COPD

BACKGROUND

Respiratory diseases exert a substantial burden on society, with newer drugs increasingly adding to the burden. Economic models are often used, but seldom reviewed.

PURPOSE

To summarize economic models used in economic analyses of drugs treating moderate-to-severe/very severe asthma or chronic obstructive pulmonary disease (COPD).

METHODS

This study searched Medline and Embase from inception to the end of February 2015 for cost-effectiveness/utility analyses that examined at least one drug against placebo, another drug, or other standard therapy in asthma or COPD. Two reviewers independently searched and extracted data with differences adjudicated via consensus discussion. Data extracted included model used and its qualities, validation methods, treatments compared, disease severity, analytic perspective, time horizon, data collection (pro- or retrospective), input rates and sources, costs and sources, planned sensitivity analyses, criteria for cost-effectiveness, reported outcomes, and sponsor.

RESULTS

This study analyzed 53 articles; 14 (25%) on asthma and 39 (75%) COPD. Markov models were commonly used for both asthma and COPD-related economic evaluations. Relatively few studies validated their model. For asthma-related studies, 10 examined inhaled corticosteroids and nine studied omalizumab. Placebo or standard therapy was the comparison in 11 studies and active drugs in the remainder.

CONCLUSIONS

Few studies include validation of their models. Furthermore, controversy concerning some results was uncovered in this study, which needs to be avoided in the future.

Comparative safety and effectiveness of long-acting inhaled agents for treating chronic obstructive pulmonary disease: a systematic review and network meta-analysis

OBJECTIVE

To compare the safety and effectiveness of long-acting β-antagonists (LABA), long-acting antimuscarinic agents (LAMA) and inhaled corticosteroids (ICS) for managing chronic obstructive pulmonary disease (COPD).

SETTING

Systematic review and network meta-analysis (NMA).

PARTICIPANTS

208 randomised clinical trials (RCTs) including 134,692 adults with COPD.

INTERVENTIONS

LABA, LAMA and/or ICS, alone or in combination, versus each other or placebo.

PRIMARY AND SECONDARY OUTCOMES

The proportion of patients with moderate-to-severe exacerbations. The number of patients experiencing mortality, pneumonia, serious arrhythmia and cardiovascular-related mortality (CVM) were secondary outcomes.

RESULTS

NMA was conducted including 20 RCTs for moderate-to-severe exacerbations for 26,141 patients with an exacerbation in the past year. 32 treatments were effective versus placebo including: tiotropium, budesonide/formoterol, salmeterol, indacaterol, fluticasone/salmeterol, indacaterol/glycopyrronium, tiotropium/fluticasone/salmeterol and tiotropium/budesonide/formoterol. Tiotropium/budesonide/formoterol was most effective (99.2% probability of being the most effective according to the Surface Under the Cumulative RAnking (SUCRA) curve). NMA was conducted on mortality (88 RCTs, 97 526 patients); fluticasone/salmeterol was more effective in reducing mortality than placebo, formoterol and fluticasone alone, and was the most effective (SUCRA=71%). NMA was conducted on CVM (37 RCTs, 55,156 patients) and the following were safest: salmeterol versus each OF placebo, tiotropium and tiotropium (Soft Mist Inhaler (SMR)); fluticasone versus tiotropium (SMR); and salmeterol/fluticasone versus tiotropium and tiotropium (SMR). Triamcinolone acetonide was the most harmful (SUCRA=81%). NMA was conducted on pneumonia occurrence (54 RCTs, 61 551 patients). 24 treatments were more harmful, including 2 that increased risk of pneumonia versus placebo; fluticasone and fluticasone/salmeterol. The most harmful agent was fluticasone/salmeterol (SUCRA=89%). NMA was conducted for arrhythmia; no statistically significant differences between agents were identified.

CONCLUSIONS

Many inhaled agents are available for COPD, some are safer and more effective than others. Our results can be used by patients and physicians to tailor administration of these agents.

PROTOCOL REGISTRATION NUMBER

PROSPERO # CRD42013006725.

Impact of ABCB1 single-nucleotide polymorphisms on treatment outcomes with salmeterol/fluticasone combination therapy for stable chronic obstructive pulmonary disease

OBJECTIVES

To investigate the relationship between ABCB1 single-nucleotide polymorphisms and the efficacy of salmeterol/fluticasone combination (SFC) inhalation therapy for stable chronic obstructive pulmonary disease (COPD) in a Chinese Han population.

METHODS

A total of 362 patients with stable COPD were recruited between July 2012 and March 2014. Based on the therapeutic effects of lung function improvement and COPD Assessment Test (CAT) scores, all patients were either placed into the effective group (n = 138) or the ineffective group (n = 224). Three common polymorphisms (rs1045642C > T, rs1128503C > T, and rs1202184A > G) in the ABCB1 gene were analyzed by polymerase chain reaction-restriction fragment length polymorphism in these patients. All data were analyzed by SPSS version 18.0 software.

RESULTS

The genotype and allele frequencies of the ABCB1 rs1045642C > T polymorphic locus were significantly different between the effective group and the ineffective group under the codominant, recessive, and allele models (all p < 0.05). Haplotype analysis of ABCB1 indicated that CTA (rs1045642C-rs1128503T-rs1202184A) haplotype frequencies in the effective group were significantly lower than the ineffective group (p = 0.022), but TCG (rs1045642T-rs1128503C-rs1202184G) haplotype frequencies in the effective group were significantly higher than the ineffective group (p = 0.048). Logistic regression analysis showed that smoking history and rs1045642 CT + CC/TT may be correlated with the efficacy of SFC inhalation therapy in stable COPD patients.

CONCLUSION

ABCB1 rs1045642C > T polymorphism and CTA/TCG haplotypes, as well as smoking history may influence the efficacy of SFC inhalation therapy in stable COPD patients in the Chinese Han population.

Network Meta-analysis: Users' Guide for Surgeons: Part I - Credibility

Conventional meta-analyses quantify the relative effectiveness of two interventions based on direct (that is, head-to-head) evidence typically derived from randomized controlled trials (RCTs). For many medical conditions, however, multiple treatment options exist and not all have been compared directly. This issue limits the utility of traditional synthetic techniques such as meta-analyses, since these approaches can only pool and compare evidence across interventions that have been compared directly by source studies. Network meta-analyses (NMA) use direct and indirect comparisons to quantify the relative effectiveness of three or more treatment options. Interpreting the methodologic quality and results of NMAs may be challenging, as they use complex methods that may be unfamiliar to surgeons; yet for these surgeons to use these studies in their practices, they need to be able to determine whether they can trust the results of NMAs. The first judgment of trust requires an assessment of the credibility of the NMA methodology; the second judgment of trust requires a determination of certainty in effect sizes and directions. In this Users' Guide for Surgeons, Part I, we show the application of evaluation criteria for determining the credibility of a NMA through an example pertinent to clinical orthopaedics. In the subsequent article (Part II), we help readers evaluate the level of certainty NMAs can provide in terms of treatment effect sizes and directions.

Once-daily fluticasone furoate/vilanterol 100/25 mcg versus twice daily combination therapies in COPD - mixed treatment comparisons of clinical efficacy

BACKGROUND

Fluticasone furoate (FF)/vilanterol (VI) 100/25 mcg is a once-daily inhaled corticosteroid (ICS)/long-acting beta2 agonist (LABA) treatment approved in the United States, Canada and Europe for the long-term maintenance therapy of COPD. We report data from mixed treatment comparisons (MTC) of once-daily FF/VI against established twice-daily ICS/LABA combination therapies on clinical efficacy outcomes.

METHODS

Data from 33 parallel-group randomised controlled trials (RCTs) of ICS/LABAs, of ≥8 weeks' duration in patients ≥12 years of age with COPD, identified by systematic review, were analysed using covariate-adjusted Bayesian hierarchical models for three efficacy outcomes. Lung function, assessed by change from baseline in forced expiratory volume in one second (FEV1), was the outcome of primary interest (n = 28 studies). Secondary objectives were assessment of annual rate of moderate/severe exacerbations (n = 15) and patient-reported health status, measured by change from baseline in St George's Respiratory Questionnaire (SGRQ) Total score (n = 20). Overall, 25 different treatments were included in the MTC; we report findings, including probabilities of non-inferiority, for comparisons of once-daily FF/VI 100/25 mcg with twice-daily fluticasone propionate (FP)/salmeterol (SAL) 500/50 mcg and budesonide (BUD)/formoterol (FORM) 400/12 mcg.

RESULTS

For FEV1, FF/VI 100/25 mcg demonstrated >99% probability of non-inferiority to FP/SAL 500/50 mcg and BUD/FORM 400/12 mcg using a 50 mL margin. For annual rate of moderate/severe exacerbations, FF/VI 100/25 mcg demonstrated 73% and 77% probability of non-inferiority to FP/SAL 500/50 mcg and BUD/FORM 400/12 mcg, respectively, using a 10% rate ratio margin. For SGRQ Total score, the corresponding probabilities of non-inferiority were 99% and 98%, respectively, on a 2-unit margin. Significant covariate effects were identified: increased age was associated with deterioration in FEV1 and reduced exacerbation frequency; shorter study duration was associated with reduced exacerbation frequency.

CONCLUSIONS

FF/VI 100/25 mcg was comparable with corresponding doses of FP/SAL and BUD/FORM on lung function and health status outcomes. Non-inferiority on moderate/severe exacerbation rate was not demonstrated to the same degree of confidence, though observed rates were similar. Model limitations include a weak treatment network for the exacerbation analysis and variability across the included studies. Our data support previous RCT findings suggesting that the efficacy of FF/VI 100/25 mcg on lung function and health status in COPD is comparable with twice-daily ICS/LABAs.

Network vs. pairwise meta-analyses: a case study of the impact of an evidence-synthesis paradigm on value of information outcomes

OBJECTIVE

To evaluate the impact of using two evidence-synthesis paradigms, pairwise meta-analysis (PMA) vs. network meta-analysis (NMA), on the expected value of information (EVI) outcomes, using pharmacotherapy of chronic obstructive pulmonary disease as a case study.

METHODS

Bayesian random-effects PMAs were performed for each pharmacotherapy vs. placebo, and a Bayesian random-effects NMA was performed combining both placebo-controlled and head-to-head trials. Both provided comparative rate ratio (RR) estimates between each pharmacotherapy vs. placebo. A Markov model was developed to project costs and quality-adjusted life-years of five commonly used treatments for chronic obsructive pulmonary disorder. RRs for the treatment effect compared with placebo derived using PMA and NMA were used alongside values from the literature to populate the model. In addition to standard cost-effectiveness outputs, we calculated and compared the expected value of perfect information (EVPI) and the expected value of partial perfect information (EVPPI) for treatment effects, for comparisons that included all or a subset of treatments.

RESULTS

The network of evidence included five different treatments, compared in 19 randomized controlled trials (RCTs), which in total included 28,172 individuals. The cost-effectiveness outcomes were similar between the two evidence-synthesis paradigms. The individual EVPI for all treatments was Can$1,262 for PMA-based analyses and Can$572 for NMA-based analyses. For all comparisons involving two, three, or four treatments, the comparison with the highest EVPI was different between the two methods. Similarly, the choice of PMA or NMA had resulted in substantially different EVPPI rankings.

CONCLUSION

Our case study shows that the choice of PMA or NMA can have significant effects on the EVI results. Under comparable conditions, the incorporation of more evidence in the NMA most likely increases the precision of estimates and therefore is likely to result in lower EVI outcomes. As our study demonstrates, the difference in EVI outcomes can be substantial, potentially affecting the decision to conduct research and the design of future research.

Roflumilast in the management of chronic obstructive pulmonary disease

PURPOSE

The pharmacology, pharmacokinetics, efficacy, and safety of roflumilast-the first in a new class of agents for managing chronic obstructive pulmonary disease (COPD)-are reviewed.

SUMMARY

Roflumilast (Daliresp, Forest Pharmaceuticals) is an oral phosphodiesterase-4 (PDE-4) inhibitor that targets inflammatory cells involved in triggering COPD exacerbations. The only PDE-4 inhibitor approved by the Food and Drug Administration, roflumilast is available in 500-μg tablets to be administered once daily. In six placebo-controlled trials involving nearly 4500 patients with COPD of varying severity, the use of roflumilast was associated with reduced COPD exacerbations and improved lung function, as determined by spirometry, with the greatest benefits observed in patients with severe COPD who had chronic bronchitis and a history of frequent exacerbations; clinical efficacy was demonstrated in patients receiving roflumilast alone as well as those receiving concomitant inhaled long-acting β2-agonist (LABA) therapy. The most common adverse events in clinical trials of roflumilast were diarrhea, nausea, and headache. Weight loss and an increased risk of psychiatric events have also been reported in association with roflumilast use. As roflumilast is rapidly converted to its active metabolite via cytochrome P-450 (CYP) isoenzymes, coadministration with strong CYP inducers is not recommended. Research to better define roflumilast's role in COPD management, including a study to determine whether it confers additive benefits when used in combination with standard inhaled therapies other than LABAs, is ongoing.

CONCLUSION

Roflumilast is a safe and effective option for controlling COPD exacerbations in a defined subset of patients for whom the available treatment alternatives are very limited.

Incorporating external evidence in trial-based cost-effectiveness analyses: the use of resampling methods

Background

Cost-effectiveness analyses (CEAs) that use patient-specific data from a randomized controlled trial (RCT) are popular, yet such CEAs are criticized because they neglect to incorporate evidence external to the trial. A popular method for quantifying uncertainty in a RCT-based CEA is the bootstrap. The objective of the present study was to further expand the bootstrap method of RCT-based CEA for the incorporation of external evidence.

Methods

We utilize the Bayesian interpretation of the bootstrap and derive the distribution for the cost and effectiveness outcomes after observing the current RCT data and the external evidence. We propose simple modifications of the bootstrap for sampling from such posterior distributions.

Results

In a proof-of-concept case study, we use data from a clinical trial and incorporate external evidence on the effect size of treatments to illustrate the method in action. Compared to the parametric models of evidence synthesis, the proposed approach requires fewer distributional assumptions, does not require explicit modeling of the relation between external evidence and outcomes of interest, and is generally easier to implement. A drawback of this approach is potential computational inefficiency compared to the parametric Bayesian methods.

Conclusions

The bootstrap method of RCT-based CEA can be extended to incorporate external evidence, while preserving its appealing features such as no requirement for parametric modeling of cost and effectiveness outcomes.

The impact of incorporating Bayesian network meta-analysis in cost-effectiveness analysis - a case study of pharmacotherapies for moderate to severe COPD

OBJECTIVE

To evaluate the impact of using network meta-analysis (NMA) versus pair wise meta-analyses (PMA) for evidence synthesis on key outputs of cost-effectiveness analysis (CEA).

METHODS

We conducted Bayesian NMA of randomized clinical trials providing head-to-head and placebo comparisons of the effect of pharmacotherapies on the exacerbation rate in chronic obstructive pulmonary disease (COPD). Separately, the subset of placebo-comparison trials was used in a Bayesian PMA. The pooled rate ratios (RR) were used to populate a decision-analytic model of COPD treatment to predict 10-year outcomes.

RESULTS

Efficacy estimates from the NMA and PMA were similar, but the NMA provided estimates with higher precision. This resulted in similar incremental cost-effectiveness ratios (ICER). Probabilities of being cost-effective at willingness-to-pay thresholds (WTPs) between $25,000 and $100,000 per quality adjusted life year (QALY) varied considerably between the PMA- and NMA-based approaches. The largest difference in the probabilities of being cost-effective was observed at a WTP of approximately $40,000/QALY. At this threshold, with the PMA-based analysis, ICS, LAMA and placebo had a 43%, 30, and 18% probability of being the most cost-effective. By contrast, with the NMA based approach, ICS, LAMA, and placebo had a 56%, 19%, and 21% probability of being cost-effective. For larger WTP thresholds the probability of LAMA being the most cost-effective became higher than that of ICS. Under the PMA-based analyses the cross-over occurred at a WTP threshold between $60,000/QALY-$65,000/QALY, whereas under the NMA-based approach, the cross-over occurred between $85,000/QALY-$90,000/QALY.

CONCLUSION

Use of NMAs in CEAs is feasible and, as our case study showed, can decrease uncertainty around key cost-effectiveness measures compared with the use of PMAs. The approval process of health technologies in many jurisdictions requires estimates of comparative efficacy and cost-effectiveness. NMAs play an increasingly important role in providing estimates of comparative efficacy. Their use in the CEAs therefore results in methodological consistency and reduced uncertainty.

Cost-effectiveness of roflumilast as an add-on treatment to long-acting bronchodilators in the treatment of COPD associated with chronic bronchitis in the United Kingdom

OBJECTIVE

To estimate the cost-effectiveness of adding a selective phosphodiesterase-4 inhibitor, roflumilast, to a long-acting bronchodilator therapy (LABA) for the treatment of patients with severe-to-very severe chronic obstructive pulmonary disease (COPD) associated with chronic bronchitis with a history of frequent exacerbations from the UK payer perspective.

METHODS

A Markov model was developed to predict the lifetime cost and outcomes [exacerbations rates, life expectancy, and quality-adjusted life years (QALY)] in patients treated with roflumilast, which showed a reduction in the exacerbation rates and lung function improvement in a pooled analysis from two clinical trials, M2-124 and M2-125. Sensitivity analyses were conducted to explore the impact of uncertainties on the cost-effectiveness.

RESULTS

The addition of roflumilast to concomitant LABA reduced the number of exacerbations from 15.6 to 12.7 [2.9 (95 % CI 0.88-4.92) exacerbations avoided] and increased QALYs from 5.45 to 5.61 [0.16 (95 % CI 0.02-0.31) QALYs gained], at an incremental cost of £3,197 (95 % CI £2,135-£4,253). Cost in LABA alone and LABA + roflumilast were £16,161 and £19,358 respectively. The incremental cost-effectiveness ratios in the base case were £19,505 (95 % CI £364-£38,646) per quality-adjusted life-year gained and 18,219 (95 % CI £12,697-£49,135) per life-year gained. Sensitivity analyses suggest that among the main determinants of cost-effectiveness are the reduction of exacerbations and the case fatality rate due to hospital-treated exacerbations. Probabilistic sensitivity analysis suggests that the probability of roflumilast being cost-effective is 82 % at willingness-to-pay £30,000 per QALY.

CONCLUSIONS

The addition of roflumilast to LABA in the treatment of patients with severe-to-very severe COPD reduces the rate of exacerbations and can be cost-effective in the UK setting.

The effects of excluding treatments from network meta-analyses: survey

OBJECTIVE

To examine whether the exclusion of individual treatment comparators, including placebo/no treatment, affects the results of network meta-analysis.

DESIGN

Survey of networks with individual trial data.

DATA SOURCES

PubMed and communication with authors of network meta-analyses.

STUDY SELECTION AND METHODS

We included networks that had five or more treatments, contained at least two closed loops, had at least twice as many studies as treatments, and had trial level data available. Investigators abstracted information about study design, participants, outcomes, network geometry, and the exclusion of eligible treatments.

RESULTS

Among 18 eligible networks involving 757 randomised controlled trials with 750 possible treatment comparisons, 11 had upfront decided not to consider all treatment comparators and only 10 included placebo/no treatment nodes. In 7/18 networks, there was at least one node whose removal caused a more than 1.10-fold average relative change in the estimated treatments effects, and switches in the top three treatments were observed in 9/18 networks. Removal of placebo/no treatment caused large relative changes of the treatment effects (average change 1.16-3.10-fold) for four of the 10 networks that had originally included placebo/no treatment nodes. Exclusion of current uncommonly used drugs resulted in substantial changes of the treatment effects (average 1.21-fold) in one of three networks on systemic treatments for advanced malignancies.

CONCLUSION

Excluding treatments in network meta-analyses sometimes can have important effects on their results and can diminish the usefulness of the research to clinicians if important comparisons are missing.

Missing potential opportunities to reduce repeat COPD exacerbations

INTRODUCTION

Long-acting beta-agonists (LABA) and/or inhaled corticosteroids (ICS) have been shown to reduce COPD exacerbation risk. Using data from a large integrated health-care system, we sought to examine whether these medication classes were initiated after an exacerbation of COPD.

METHODS

We identified patients who experienced an inpatient or outpatient COPD exacerbation within the Veterans Affairs Integrated Service Network (VISN)-20. We assessed the addition of a new inhaled therapy (an ICS, LABA or both) within 180 days after the exacerbation. We assessed independent predictors of adding treatment using logistic regression.

RESULTS

We identified 45,780 patients with COPD, of whom 2,760 patients experienced an exacerbation of COPD. Of these individuals, 2,570 (93.1 %) were on either none or only one long-acting medication studied (LABA or ICS). In the subsequent 180-day period after their exacerbation, only 875 (34.1 %) patients had at least one of these additional therapies dispensed from a VA pharmacy. Among patients who were treated in the outpatient setting, older age [OR 0.98/year, 95 % CI (0.97-0.99)], current tobacco use [OR 0.74, 95 % CI (0.60-0.90)], greater use of ipratropium bromide [OR 0.97/canister, 95 % CI (0.96-0.98)], prior COPD exacerbation [OR 0.55, 95 % CI (0.46-0.67)], depression [OR 0.77, 95 % CI (0.61-0.98)], CHF [OR 0.74, 95 % CI (0.57-0.97)], and diabetes (OR 0.77 (0.60-0.99)] were associated with lower odds of additional therapy. Patients who were treated in the hospital had similar associated predictors.

CONCLUSION

Among patients treated for an exacerbation of COPD, we found relatively few were subsequently prescribed inhaled therapies known to reduce exacerbations.

Cost-effectiveness of roflumilast in combination with bronchodilator therapies in patients with severe and very severe COPD in Switzerland

Objective

Chronic obstructive pulmonary disease (COPD) represents a burden on patients and health systems. Roflumilast, an oral, selective phosphodiesterase-4-inhibitor reduces exacerbations and improves lung function in severe/very severe COPD patients with a history of exacerbations. This study aimed to estimate the lifetime cost and outcomes of roflumilast added-on to commonly used COPD regimens in Switzerland.

Methods

A Markov cohort model was developed to simulate COPD progression in patients with disease states of severe, very severe COPD, and death. The exacerbation rate was assumed to be two per year in severe COPD. COPD progression rates were drawn from the published literature. Efficacy was expressed as relative ratios of exacerbation rates associated with roflumilast, derived from a mixed-treatment comparison. A cost-effectiveness analysis was conducted for roflumilast added to long-acting muscarinic antagonists (LAMA), long-acting β2-agonist/ inhaled corticosteroids (LABA/ICS), and LAMA + LABA/ICS. The analysis was conducted from the Swiss payer perspective, with costs and outcomes discounted at 2.5% annually. Parameter uncertainties were explored in one-way and probabilistic sensitivity analyses.

Results

In each of the comparator regimens mean life expectancy was 9.28 years and quality-adjusted life years (QALYs) gained were 6.19. Mean estimated lifetime costs per patient in the comparator arms were CHF 83,364 (LAMA), CHF 88,161 (LABA/ICS), and CHF 95,564 (LAMA + LABA/ICS) respectively. Adding roflumilast resulted in a mean cost per patient per lifetime of CHF 86,754 (LAMA + roflumilast), CHF 91,470 (LABA/ICS + roflumilast), and CHF 99,364 (LAMA + LABA/ICS + roflumilast), respectively. Life-expectancy and quality-adjusted life-expectancy were 9.63 years and 6.47 QALYs (LAMA + roflumilast), 9.64 years and 6.48 QALYs (LABA/ICS + roflumilast), and 9.63 years and 6.47 QALYs (LAMA + LABA/ ICS + roflumilast). Incremental cost-effectiveness ratios were CHF 12,313, CHF 11,456, and CHF 13,671 per QALY when roflumilast was added to the three regimens.

Conclusion

Treatment with roflumilast is estimated to reduce the health and economic burden of COPD exacerbations and represent a cost-effective treatment option for patients with frequent exacerbations in Switzerland.

Efficacy of supplemental peripheral nerve blockade for hip fracture surgery: multiple treatment comparison

PURPOSE

This study was designed to determine the most effective peripheral nerve block supplement to standard anesthesia management for hip fracture patients.

METHODS

We systematically reviewed randomized controlled trials (RCTs) published from 1990 to 2010 and conducted multiple treatment comparisons using direct and indirect evidence for two outcomes, i.e., acute pain intensity and delirium. We combined trials by type of injection (regardless of time of insertion during the perioperative phase, use of nerve block catheter, local anesthetic type, additives, or duration of treatment).

RESULTS

Twenty-one RCTs comprising 1,422 participants were included. In most cases, the trials were conducted in Europe; they excluded patients with cognitive impairment, and they were unclear or at high risk of bias. The combination of obturator and lateral femoral cutaneous nerve blockade had the highest probability of being the most effective against acute postoperative pain. Fascia iliaca blockade had the highest probability of being the most effective against delirium. There was no difference in outcomes among other nerve blocks.

CONCLUSION

Not all nerve blocks are equally effective in improving outcomes after hip fracture. Multiple treatment comparison, a tool to compare the effectiveness of multiple treatments simultaneously, provides useful guidance to anesthesia providers seeking effective treatment when faced with a body of RCTs wherein each investigates one treatment. More RCTs comparing multiple nerve blocks in hip fracture are needed.

Calculating additive treatment effects from multiple randomized trials provides useful estimates of combination therapies

OBJECTIVE

Many clinicians and decision makers want to know the combined effects of treatments that have not been evaluated in combination. It is possible to determine such treatment effects by making assumptions about the additive effects. We discuss here the prerequisites and methods of applying additivity assumptions in synthesizing the evidence from randomized trials and multiple treatment meta-analyses.

STUDY DESIGN AND SETTING

Using statistical approaches, we demonstrate the utility of additivity of both pairwise randomized trials and multiple treatment comparison meta-analyses.

RESULTS

We present illustratively an example on estimating the treatment effects of drug combinations for chronic obstructive pulmonary disease. We confirm the additive treatment effects by comparing with direct combination treatment trial results.

CONCLUSION

Additive effects may be a useful tool to estimate the effectiveness of treatment combinations.

Clinical Considerations for Roflumilast: A New Treatment for COPD

Chronic obstructive pulmonary disease (COPD) causes significant morbidity and mortality and represents the fourth leading cause of death in the world. Roflumilast is the first oral phosphodiesterase inhibitor indicated to reduce the risk of COPD exacerbations in patients with severe COPD associated with chronic bronchitis and history of exacerbations. Roflumilast and its active metabolite have been associated with increased cyclic adenosine monophosphate (cyclic AMP) in the lungs and positive responses with inflammatory markers. Significant improvements in forced expiratory volume (1 sec) have been observed in clinical trials comparing roflumilast with placebo. Combination therapy of roflumilast (500 μg) with long-acting beta agonists resulted in reduced COPD exacerbations in patients with severe COPD. Adverse effects include weight loss, diarrhea, nausea, and psychiatric disturbances. Roflumilast may be associated with significant drug-drug interactions with CYP3A4 inducers (strong) and immunosuppressants. Roflumilast is a promising new agent in the treatment of COPD; however, additional studies comparing roflumilast with inhaled corticosteroids plus long-acting bronchodilators are needed.

Stability of additive treatment effects in multiple treatment comparison meta-analysis: a simulation study

Background

Many medical interventions are administered in the form of treatment combinations involving two or more individual drugs (eg, drug A + drug B). When the individual drugs and drug combinations have been compared in a number of randomized clinical trials, it is possible to quantify the comparative effectiveness of all drugs simultaneously in a multiple treatment comparison (MTC) meta-analysis. However, current MTC models ignore the dependence between drug combinations (eg, A + B) and the individual drugs that are part of the combination. In particular, current models ignore the possibility that drug effects may be additive, ie, the property that the effect of A and B combined is equal to the sum of the individual effects of A and B. Current MTC models may thus be suboptimal for analyzing data including drug combinations when their effects are additive or approximately additive. However, the extent to which the additivity assumption can be violated before the conventional model becomes the more optimal approach is unknown. The objective of this study was to evaluate the comparative statistical performance of the conventional MTC model and the additive effects MTC model in MTC scenarios where additivity holds true, is mildly violated, or is strongly violated.

Methods

We simulated MTC scenarios in which additivity held true, was mildly violated, or was strongly violated. For each scenario we simulated 500 MTC data sets and applied the conventional and additive effects MTC models in a Bayesian framework. Under each scenario we estimated the proportion of treatment effect estimates that were 20% larger than ‘the truth’ (ie, % overestimates), the proportion that were 20% smaller than ‘the truth’ (ie, % underestimates), the coverage of the 95% credible intervals, and the statistical power. We did this for all the comparisons under both models.

Results

Under true additivity, the additive effects model is superior to the conventional model. Under mildly violated additivity, the additive model generally yields more overestimates or underestimates for a subset of treatment comparisons, but comparable coverage and greater power. Under strongly violated additivity, the proportion of overestimates or underestimates and coverage is considerably worse with the additive effects model.

Conclusion

The additive MTC model is statistically superior when additivity holds true. The two models are comparably advantageous in terms of a bias-precision trade-off when additivity is only mildly violated. When additivity is strongly violated, the additive effects model is statistically inferior.

Cost-effectiveness of available treatment options for patients suffering from severe COPD in the UK: a fully incremental analysis

Purpose

Frequent exacerbations which are both costly and potentially life-threatening are a major concern to patients with chronic obstructive pulmonary disease (COPD), despite the availability of several treatment options. This study aimed to assess the lifetime costs and outcomes associated with alternative treatment regimens for patients with severe COPD in the UK setting.

Patients and methods

A Markov cohort model was developed to predict lifetime costs, outcomes, and cost-effectiveness of various combinations of a long-acting muscarinic antagonist (LAMA), a long-acting beta agonist (LABA), an inhaled corticosteroid (ICS), and roflumilast in a fully incremental analysis. Patients willing and able to take ICS, and those refusing or intolerant to ICS were analyzed separately. Efficacy was expressed as relative rate ratios of COPD exacerbation associated with alternative treatment regimens, taken from a mixed treatment comparison. The analysis was conducted from the UK National Health Service (NHS) perspective. Parameter uncertainty was explored using one-way and probabilistic sensitivity analysis.

Results

Based on the results of the fully incremental analysis a cost-effectiveness frontier was determined, indicating those treatment regimens which represent the most cost-effective use of NHS resources. For ICS-tolerant patients the cost-effectiveness frontier suggested LAMA as initial treatment. Where patients continue to exacerbate and additional therapy is required, LAMA + LABA/ICS can be a cost-effective option, followed by LAMA + LABA/ICS + roflumilast (incremental cost-effectiveness ratio [ICER] versus LAMA + LABA/ICS: £16,566 per quality-adjusted life-year [QALY] gained). The ICER in ICS-intolerant patients, comparing LAMA + LABA + roflumilast versus LAMA + LABA, was £13,764/QALY gained. The relative rate ratio of exacerbations was identified as the primary driver of cost-effectiveness.

Conclusion

The treatment algorithm recommended in UK clinical practice represents a costeffective approach for the management of COPD. The addition of roflumilast to the standard of care regimens is a clinical and cost-effective treatment option for patients with severe COPD, who continue to exacerbate despite existing bronchodilator therapy.