Comparing four immunosuppressive agents for chronic spontaneous urticaria-A network meta-analysis

BACKGROUND

Immunosuppression is an integral part of treating chronic spontaneous urticaria (CSU), but there is no literature to evaluate the efficacy of multiple immunosuppressive agents.

OBJECTIVE

The comparison of the efficacy, safety, and incidence of adverse effects of four immunosuppressive medicines (tripterygium glycosides, methotrexate, cyclosporine A, and azathioprine) in combination with antihistamines in treating CSU provides a clinical reference and evidence-based medicine for treating CSU.

METHODS

PUBMED, The Cochrane Library, EMBASE, WANFANG, CNKI, CBM, and clinical trial registration platform were searched to collect relevant randomized controlled trials (RCT) and cohort studies of four immunosuppressive medicines combined with antihistamines for treating CSU. The primary outcomes were the efficacy of weekly urticaria activity score 7 (UAS7) and adverse effects.

RESULTS

This study pooled data from seven randomized clinical trials with 410 participants. The standardized mean differences for change in UAS7 were 0.10 (95% confidence interval (CI), 0.01 to 0.68) for cyclosporine A plus antihistamine; 0.03 (95% CI, 0.00 to 0.23) for azathioprine plus antihistamine; 0.52 (95% CI, 0.32 to 0.85) for tripterygium glycosides plus antihistamine; and 1.54 (95% CI, 0.64 to 3.67) for methotrexate plus antihistamine. There were no significant differences in side effects between these medicines in the limited number of trials and clinical samples.

CONCLUSION

Our results indicate that cyclosporine A combined with antihistamine resulted in greater improvements regarding the UAS7 in CSU patients and that tripterygium glycosides are also effective in treating CSU.

Efficacy of PARP Inhibitor, Platinum, and Immunotherapy in BRCA-Mutated HER2-Negative Breast Cancer Patients: A Systematic Review and Network Meta-Analysis

The optimal treatment regimen for breast cancer patients with gBRCA mutations remains controversial given the availability of numerous options, such as platinum-based agents, polymerase inhibitors (PARPis), and other agents. We included phase II or III RCTs and estimated the HR with 95% CI for OS, PFS, and DFS, in addition to the OR with 95% CI for ORR and pCR. We determined the treatment arm rankings by P-scores. Furthermore, we carried out a subgroup analysis in TNBC and HR-positive patients. We conducted this network meta-analysis using R 4.2.0 and a random-effects model. A total of 22 RCTs were eligible, involving 4253 patients. In the pairwise comparisons, PARPi + Platinum + Chemo was better than PARPi + Chemo for OS (in whole study group and in both subgroups) as well as PFS. The ranking tests demonstrated that PARPi + Platinum + Chemo ranked first in PFS, DFS, and ORR. Platinum + Chemo showed higher OS than PARPi + Chemo. The ranking tests for PFS, DFS, and pCR indicated that, except for the best treatment (PARPi + Platinum + Chemo) containing PARPi, the second and third treatments were platinum monotherapy or platinum-based chemotherapy. In conclusion, PARPi + Platinum + Chemo might be the best regime for gBRCA-mutated BC. Platinum drugs showed more favorable efficacy than PARPi in both combination and monotherapy.

Denosumab, raloxifene, romosozumab and teriparatide to prevent osteoporotic fragility fractures: a systematic review and economic evaluation

BACKGROUND

Fragility fractures are fractures that result from mechanical forces that would not ordinarily result in fracture.

OBJECTIVES

The objectives were to evaluate the clinical effectiveness, safety and cost-effectiveness of non-bisphosphonates {denosumab [Prolia^®; Amgen Inc., Thousand Oaks, CA, USA], raloxifene [Evista^®; Daiichi Sankyo Company, Ltd, Tokyo, Japan], romosozumab [Evenity^®; Union Chimique Belge (UCB) S.A. (Brussels, Belgium) and Amgen Inc.] and teriparatide [Forsteo^®; Eli Lilly and Company, Indianapolis, IN, USA]}, compared with each other, bisphosphonates or no treatment, for the prevention of fragility fracture.

DATA SOURCES

For the clinical effectiveness review, nine electronic databases (including MEDLINE, EMBASE and the World Health Organization International Clinical Trials Registry Platform) were searched up to July 2018.

REVIEW METHODS

A systematic review and network meta-analysis of fracture and femoral neck bone mineral density were conducted. A review of published economic analyses was undertaken and a model previously used to evaluate bisphosphonates was adapted. Discrete event simulation was used to estimate lifetime costs and quality-adjusted life-years for a simulated cohort of patients with heterogeneous characteristics. This was done for each non-bisphosphonate treatment, a strategy of no treatment, and the five bisphosphonate treatments previously evaluated. The model was populated with effectiveness evidence from the systematic review and network meta-analysis. All other parameters were estimated from published sources. An NHS and Personal Social Services perspective was taken, and costs and benefits were discounted at 3.5% per annum. Fracture risk was estimated from patient characteristics using the QFracture^® (QFracture-2012 open source revision 38, Clinrisk Ltd, Leeds, UK) and FRAX^® (web version 3.9, University of Sheffield, Sheffield, UK) tools. The relationship between fracture risk and incremental net monetary benefit was estimated using non-parametric regression. A probabilistic sensitivity analysis and scenario analyses were used to assess uncertainty.

RESULTS

Fifty-two randomised controlled trials of non-bisphosphonates were included in the clinical effectiveness systematic review and an additional 51 randomised controlled trials of bisphosphonates were included in the network meta-analysis. All treatments had beneficial effects compared with placebo for vertebral, non-vertebral and hip fractures, with hazard ratios varying from 0.23 to 0.94, depending on treatment and fracture type. The effects on vertebral fractures and the percentage change in bone mineral density were statistically significant for all treatments. The rate of serious adverse events varied across trials (0-33%), with most between-group differences not being statistically significant for comparisons with placebo/no active treatment, non-bisphosphonates or bisphosphonates. The incremental cost-effectiveness ratios were > £20,000 per quality-adjusted life-year for all non-bisphosphonate interventions compared with no treatment across the range of QFracture and FRAX scores expected in the population eligible for fracture risk assessment. The incremental cost-effectiveness ratio for denosumab may fall below £30,000 per quality-adjusted life-year at very high levels of risk or for high-risk patients with specific characteristics. Raloxifene was dominated by no treatment (resulted in fewer quality-adjusted life-years) in most risk categories.

LIMITATIONS

The incremental cost-effectiveness ratios are uncertain for very high-risk patients.

CONCLUSIONS

Non-bisphosphonates are effective in preventing fragility fractures, but the incremental cost-effectiveness ratios are generally greater than the commonly applied threshold of £20,000-30,000 per quality-adjusted life-year.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42018107651.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 29. See the NIHR Journals Library website for further project information.

Classifying information-sharing methods

BACKGROUND

Sparse relative effectiveness evidence is a frequent problem in Health Technology Assessment (HTA). Where evidence directly pertaining to the decision problem is sparse, it may be feasible to expand the evidence-base to include studies that relate to the decision problem only indirectly: for instance, when there is no evidence on a comparator, evidence on other treatments of the same molecular class could be used; similarly, a decision on children may borrow-strength from evidence on adults. Usually, in HTA, such indirect evidence is either included by ignoring any differences ('lumping') or not included at all ('splitting'). However, a range of more sophisticated methods exists, primarily in the biostatistics literature. The objective of this study is to identify and classify the breadth of the available information-sharing methods.

METHODS

Forwards and backwards citation-mining techniques were used on a set of seminal papers on the topic of information-sharing. Papers were included if they specified (network) meta-analytic methods for combining information from distinct populations, interventions, outcomes or study-designs.

RESULTS

Overall, 89 papers were included. A plethora of evidence synthesis methods have been used for information-sharing. Most papers (n=79) described methods that shared information on relative treatment effects. Amongst these, there was a strong emphasis on methods for information-sharing across multiple outcomes (n=42) and treatments (n=25), with fewer papers focusing on study-designs (n=23) or populations (n=8). We categorise and discuss the methods under four 'core' relationships of information-sharing: functional, exchangeability-based, prior-based and multivariate relationships, and explain the assumptions made within each of these core approaches.

CONCLUSIONS

This study highlights the range of information-sharing methods available. These methods often impose more moderate assumptions than lumping or splitting. Hence, the degree of information-sharing that they impose could potentially be considered more appropriate. Our identification of four 'core' methods of information-sharing allows for an improved understanding of the assumptions underpinning the different methods. Further research is required to understand how the methods differ in terms of the strength of sharing they impose and the implications of this for health care decisions.

A bibliometric analysis of global research output on network meta-analysis

Background

Network meta-analysis (NMA) has been widely used in the field of medicine and health, but the research topics and development trends are still unclear. This study aimed to identify the cooperation of countries and institutes and explore the hot topics and future prospects in the field of NMA.

Methods

Data of publications were downloaded from the Web of Science Core Collection. We used CiteSpace V, HistCite 2.1, and Excel 2016 to analyze literature information, including years, journals, countries, institutes, authors, keywords, and co-cited references.

Results

NMA research developed gradually before 2010 and rapidly in the following years. 2846 NMA studies were published in 771 journals in six languages. The PLoS One (110, 3.9%) was the most productive journal, and N Engl J Med (5904 co-citations) was the most co-cited journal. The most productive country was the United States (889, 31%) and the most productive institute was the University of Bristol (113, 4.0%). The active collaborations were observed between developed countries and between productive institutes. Of the top 10 authors, four were from the UK, and among the top 10 co-cited authors, six were from the UK. Randomized evidence, oral anti-diabetic drugs, coronary artery bypass, certolizumab pegol, non-valvular atrial fibrillation, and second-line antihyperglycemic therapy were the hot topics in this field.

Conclusions

NMA studies have significantly increased over the past decade, especially from 2015 to 2017. Compared with developing countries, developed countries have contributed more to these publications and have closer cooperation, indicating that cooperation between developed and developing countries should be further strengthened. The treatment of diabetes, cardiovascular diseases, and immune rheumatism are the main hot topics.

A review of the quantitative effectiveness evidence synthesis methods used in public health intervention guidelines

BACKGROUND

The complexity of public health interventions create challenges in evaluating their effectiveness. There have been huge advancements in quantitative evidence synthesis methods development (including meta-analysis) for dealing with heterogeneity of intervention effects, inappropriate 'lumping' of interventions, adjusting for different populations and outcomes and the inclusion of various study types. Growing awareness of the importance of using all available evidence has led to the publication of guidance documents for implementing methods to improve decision making by answering policy relevant questions.

METHODS

The first part of this paper reviews the methods used to synthesise quantitative effectiveness evidence in public health guidelines by the National Institute for Health and Care Excellence (NICE) that had been published or updated since the previous review in 2012 until the 19th August 2019.The second part of this paper provides an update of the statistical methods and explains how they address issues related to evaluating effectiveness evidence of public health interventions.

RESULTS

The proportion of NICE public health guidelines that used a meta-analysis as part of the synthesis of effectiveness evidence has increased since the previous review in 2012 from 23% (9 out of 39) to 31% (14 out of 45). The proportion of NICE guidelines that synthesised the evidence using only a narrative review decreased from 74% (29 out of 39) to 60% (27 out of 45).An application in the prevention of accidents in children at home illustrated how the choice of synthesis methods can enable more informed decision making by defining and estimating the effectiveness of more distinct interventions, including combinations of intervention components, and identifying subgroups in which interventions are most effective.

CONCLUSIONS

Despite methodology development and the publication of guidance documents to address issues in public health intervention evaluation since the original review, NICE public health guidelines are not making full use of meta-analysis and other tools that would provide decision makers with fuller information with which to develop policy. There is an evident need to facilitate the translation of the synthesis methods into a public health context and encourage the use of methods to improve decision making.

Network meta-analysis from a pairwise meta-analysis design: to assess the comparative effectiveness of oral care interventions in preventing ventilator-associated pneumonia in critically ill patients

OBJECTIVE

In this research, we assessed the usefulness of network meta-analysis (NMA), in creating a hierarchy to define the most effective oral care intervention for the prevention and management of ventilation-associated pneumonia (VAP).

MATERIALS AND METHODS

We applied NMA to a previously published robust pairwise meta-analysis. Statistical analyses were based on comparing rates of total VAP events between intervention groups and placebo-usual care groups. We synthesized a netgraph, reported the ranking order of the interventions, and summarized output by a forest plot with a reference treatment placebo/usual care.

RESULTS

The results of this NMA are from the low and high risk of bias studies, and hence, we strongly recommend not to use findings of this NMA for clinical treatment needs, but based on results of the NMA, we highly recommend for future clinical trials. With our inclusion and exclusion criteria for the NMA, we extracted 25 studies (4473 subjects). The NMA included 16 treatments, 29 pairwise comparisons, and 15 designs. Based on results of NMA frequentist-ranking P scores, tooth brushing (P fixed-0.94, P random-0.89), tooth brushing with povidone-iodine (P fixed-0.90, P random-0.88), and furacillin (P fixed-0.88, P random-0.84) were the best three interventions for preventing VAP.

CONCLUSIONS

Any conclusion drawn from this NMA should be taken with caution and recommend future clinical trials with the results.

CLINICAL RELEVANCE

NMA appeared to be an effective platform from which multiple interventions reported in disparate clinical trials could be compared to derive a hierarchical assessment of efficacy in VAP intervention.

Safety of different carotid artery revascularization strategies in the coronary artery bypass graft population: study protocol for a systematic review and network meta-analysis

BACKGROUND

Concomitant significant carotid artery occlusive diseases (CAOD) increase the risk of perioperative stroke and death in patients who undergo coronary artery bypass graft (CABG). Although several surgical strategies can be used in the management of such patients, controversy still surrounds which is the best option for CABG patients with accompanying CAOD.

METHODS

Literature searches will be conducted covering articles published in PubMed, the Cochrane Central Register of Controlled Trials, Web of Science, and Embase between January 1989 and December 2019. Search results will be limited to articles published in English. Six surgical strategies using carotid endarterectomy (CEA) or carotid artery stenting (CAS) with different timings (i.e., before, after, or combined with CABG) will be evaluated. Randomized controlled trials and non-randomized studies comparing these strategies will be included. The quality of studies will be critically appraised using the Cochrane risk-of-bias tool or ROBINS-I tool. Since CEA and CAS have comparable effectiveness for the treatment of significant CAOD, we will integrate direct and indirect evidence using network meta-analysis (NMA) to create hierarchies of the six surgical strategies based on their perioperative safety. The primary outcomes will be the probability of perioperative stroke and the probability of perioperative death. Additionally, we will analyze the probability of perioperative myocardial infarction (MI) as a secondary outcome. Pairwise meta-analyses and Bayesian network meta-analyses will be performed for all related outcome measures. Subgroup analyses, sensitivity analyses, and network meta-regression will be conducted to assess the robustness of the findings.

DISCUSSION

This NMA will summarize the direct and indirect evidence of perioperative safety with the aim of providing a ranking of the various surgical strategies. The results of this meta-analysis will provide useful information on optimal surgical management of CABG patients with concomitant significant CAOD.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42020162611.

Crisaborole Ointment, 2%, for Treatment of Patients with Mild-to-Moderate Atopic Dermatitis: Systematic Literature Review and Network Meta-Analysis

Introduction

There is a need to compare efficacy and safety profiles of crisaborole ointment, 2%, versus other topical treatments across randomized clinical trials (RCTs). We performed this review/network meta-analysis to evaluate the comparative efficacy and safety of crisaborole versus other topical pharmacologic therapies for mild-to-moderate atopic dermatitis (AD) among patients aged ≥ 2 years.

Methods

Searches were conducted in MEDLINE, Embase, the Cochrane Collection Central Register of Clinical Trials, and the Database of Abstracts of Reviews of Effects using Ovid to identify English language articles reporting RCTs of topical anti-inflammatory agents in patients aged ≥ 2 years with mild-to-moderate AD published between inception and 10 March 2020. This review used a prespecified protocol with eligibility criteria for population, interventions, comparisons, outcomes, and study design. Efficacy was evaluated using the Investigator’s Static Global Assessment (ISGA) of clear (0) or almost clear (1) and expressed by hazard ratios (HR) with 95% credible intervals.

Results

Patients treated with crisaborole or tacrolimus ointment, 0.1% or 0.03%, versus vehicle alone were significantly more likely to achieve ISGA 0/1 at 28–42 days, with the greatest point estimate observed for the crisaborole comparison (hazard ratio: 2.07; 95% credible interval 1.76 to − 2.36; probability HR above 1 [p better]: 100.0%). Patients were also more likely to achieve ISGA 0/1 with crisaborole than with pimecrolimus cream, 1% (HR: 1.62; 95% credible interval 1.04–2.48; p better: 98.3%). While network meta-analysis for safety was not feasible because of data limitations, crisaborole pivotal studies (AD-301/AD-302) showed crisaborole was well tolerated.

Conclusions

Crisaborole was shown to be superior to vehicle and pimecrolimus and comparable to tacrolimus, 0.1% or 0.03%, with respect to ISGA 0/1 at 28–42 days in patients aged ≥ 2 years with mild-to-moderate AD. This evaluation of comparative efficacy of crisaborole further supports use of crisaborole as an effective therapeutic option in this population.

Electronic supplementary material

The online version of this article (10.1007/s13555-020-00389-5) contains supplementary material, which is available to authorized users.

Clinical effectiveness of denosumab, raloxifene, romosozumab, and teriparatide for the prevention of osteoporotic fragility fractures: A systematic review and network meta-analysis

OBJECTIVES

To determine the clinical effectiveness of denosumab (DEN), raloxifene (RLX), romosozumab (ROMO) and teriparatide (TPTD), within their licensed (or anticipated licensed) indications, for the treatment of osteoporosis.

METHODS

A systematic review was conducted. Nine electronic databases and trial registries were searched up to the end of July 2018. Studies were eligible for inclusion if they were randomised controlled trials (RCT) in a population at risk of osteoporotic fracture, comparing these four non-bisphosphonates DEN, RLX, ROMO, or TPTD with each other, a non-active treatment, or the bisphosphonates alendronate (ALN), risedronate (RIS), ibandronate (IBN) and zoledronic acid (ZOL). Quality of included studies was assessed using the Cochrane Risk of Bias tool. Network meta-analyses (NMA) were used to determine the relative effectiveness of treatments.

RESULTS

The systematic review identified 7898 citations. Forty-six RCTs of non-bisphosphonates met the inclusion criteria for the review and provided data for analyses. Additionally 49 RCTs of bisphosphonates were used in the NMAs. Forty-six RCTs were included in the NMA of vertebral fracture data, 23 RCTs for hip fractures and 73 RCTs in the NMA of femoral neck bone mineral density (FN BMD). For vertebral fractures, all four non-bisphosphonates showed statistically significant benefit relative to placebo: TPTD HR 0.23 (95% credible internal (CrI) 0.16, 0.32); ROMO followed by ALN 0.25 (95% CrI 0.15, 0.43); DEN HR 0.30 (95% CrI 0.21, 0.43); RLX HR 0.61 (95% CrI 0.44, 0.80). The four non-bisphosphonates interventions studied also showed statistically significant benefit relative to placebo for FN BMD, and for hip fractures TPTD, ROMO followed by ALN, and DEN showed statistically significant benefit relative to placebo.

CONCLUSIONS

The four non-bisphosphonate interventions studied were all statistically significantly clinically effective for reducing vertebral fractures when compared to placebo, and were beneficial for change in FN BMD compared to placebo. All reduced hip fractures, and this was statistically significant for TPTD, ROMO followed by ALN, and DEN.

Combining threshold analysis and GRADE to assess sensitivity to bias in antidepressant treatment recommendations adjusted for depression severity

Threshold analysis has recently been proposed to be used in combination with the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) in order to assess the sensitivity to plausible bias of treatment recommendations derived from Bayesian network meta-analysis (NMA). Here, it was aimed to apply the combination of threshold analysis and GRADE to judge quantitative and qualitative information on risk of bias in antidepressant treatment recommendations. The analysis was based on the data set provided by Cipriani et al. (The Lancet 2018) comparing 21 antidepressants in adult major depressive disorder (MDD). Primary outcomes were efficacy (response rate) and acceptability (dropout rate) adjusted for the covariate depression severity. The combined approach suggested sensitivity to plausible bias to be largest for antidepressant recommendations top ranked by Cipriani et al., that is, amitriptyline, duloxetine, paroxetine, and venlafaxine in terms of efficacy and agomelatine, escitalopram, paroxetine, and venlafaxine in terms of acceptability. Covariate ranges within which recommendations were most sensitive to plausible bias were very severe depression in terms of efficacy (smallest threshold, ie, the largest sensitivity, around 39 Hamilton Depression Rating Scale [HDRS]) and moderate depression in terms of acceptability (smallest thresholds around 16 and 35 HDRS). This indicates that treatment recommendations within these ranges may likely change if plausible bias adjustments take place. The present findings may support decision makers in judging the sensitivity to plausible bias of current antidepressant treatment recommendations to accurately guide treatment decisions in MDD depending on depression severity.

A comparison of arm-based and contrast-based models for network meta-analysis

Differences between arm-based (AB) and contrast-based (CB) models for network meta-analysis (NMA) are controversial. We compare the CB model of Lu and Ades (2006), the AB model of Hong et al(2016), and two intermediate models, using hypothetical data and a selected real data set. Differences between models arise primarily from study intercepts being fixed effects in the Lu-Ades model but random effects in the Hong model, and we identify four key difference. (1) If study intercepts are fixed effects then only within-study information is used, but if they are random effects then between-study information is also used and can cause important bias. (2) Models with random study intercepts are suitable for deriving a wider range of estimands, eg, the marginal risk difference, when underlying risk is derived from the NMA data; but underlying risk is usually best derived from external data, and then models with fixed intercepts are equally good. (3) The Hong model allows treatment effects to be related to study intercepts, but the Lu-Ades model does not. (4) The Hong model is valid under a more relaxed missing data assumption, that arms (rather than contrasts) are missing at random, but this does not appear to reduce bias. We also describe an AB model with fixed study intercepts and a CB model with random study intercepts. We conclude that both AB and CB models are suitable for the analysis of NMA data, but using random study intercepts requires a strong rationale such as relating treatment effects to study intercepts.

Interventions for maintenance of surgically induced remission in Crohn's disease: a network meta-analysis

BACKGROUND

Crohn's disease (CD) is a chronic disease of the gut. About 75% of people with CD undergo surgery at least once in their lifetime to induce remission. However, as there is no known cure for the disease, patients usually experience a recurrence even after surgery. Different interventions are routinely used in maintaining postsurgical remission. There is currently no consensus on which treatment is the most effective.

OBJECTIVES

To assess the effects and harms of interventions for the maintenance of surgically induced remission in Crohn's disease and rank the treatments in order of effectiveness.

SEARCH METHODS

We searched the Cochrane IBD Group Specialized Register, CENTRAL, MEDLINE, and Embase from inception to 15 January 2019. We also searched reference lists of relevant articles, abstracts from major gastroenterology meetings, ClinicalTrials.gov, and the WHO ICTRP. There was no restriction on language, date, or publication status.

SELECTION CRITERIA

We considered for inclusion randomised controlled trials (RCTs) that compared different interventions used for maintaining surgically induced remission in people with CD who were in postsurgical remission. Participants had to have received maintenance treatment for at least three months. We excluded studies assessing enteral diet, diet manipulation, herbal medicine, and nutritional supplementation.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected relevant studies, extracted data, and assessed the risk of bias. Any disagreements were resolved by discussion or by arbitration of a third review author when necessary. We conducted a network meta-analysis (NMA) using a Bayesian approach through Markov Chain Monte Carlo (MCMC) simulation. For the pairwise comparisons carried out in Review Manager 5, we calculated risk ratios (RR) with their corresponding 95% confidence intervals (95% CI). For the NMA, we presented hazard ratios (HR) with corresponding 95% credible intervals (95% CrI) and reported ranking probabilities for each intervention. For the NMA, we focused on three main outcomes: clinical relapse, endoscopic relapse, and withdrawals due to adverse events. Data were insufficient to assess time to relapse and histologic relapse. Adverse events and serious adverse events were not sufficiently or objectively reported to permit an NMA. We used CINeMA (Confidence in Network Meta-Analysis) methods to evaluate our confidence in the findings within networks, and GRADE for entire networks.

MAIN RESULTS

We included 35 RCTs (3249 participants) in the review. The average age of study participants ranged between 33.6 and 38.8 years. Risk of bias was high in 18 studies, low in four studies, and unclear in 13 studies. Of the 35 included RCTs, 26 studies (2581 participants; 9 interventions) were considered eligible for inclusion in the NMA. The interventions studied included 5-aminosalicylic acid (5-ASA), adalimumab, antibiotics, budesonide, infliximab, probiotics, purine analogues, sulfasalazine, and a combination of sulfasalazine and prednisolone. This resulted in 30 direct contrasts, which informed 102 mixed-treatment contrasts.The evidence for the clinical relapse network (21 studies; 2245 participants) and endoscopic relapse (12 studies; 1128 participants) were of low certainty while the evidence for withdrawal due to adverse events (15 studies; 1498 participants) was of very low certainty. This assessment was due to high risk of bias in most of the studies, inconsistency, and imprecision across networks. We mainly judged individual contrasts as of low or very low certainty, except 5-ASA versus placebo, the evidence for which was judged as of moderate certainty.We ranked the treatments based on effectiveness and the certainty of the evidence. For clinical relapse, the five most highly ranked treatments were adalimumab, infliximab, budesonide, 5-ASA, and purine analogues. We found some evidence that adalimumab (HR 0.11, 95% Crl 0.02 to 0.33; low-certainty evidence) and 5-ASA may reduce the probability of clinical relapse compared to placebo (HR 0.69, 95% Crl 0.53 to 0.87; moderate-certainty evidence). However, budesonide may not be effective in preventing clinical relapse (HR 0.66, 95% CrI 0.27 to 1.34; low-certainty evidence). We are less confident about the effectiveness of infliximab (HR 0.36, 95% CrI 0.02 to 1.74; very low-certainty evidence) and purine analogues (HR 0.75, 95% CrI 0.55 to 1.00; low-certainty evidence). It was unclear whether the other interventions reduced the probability of a clinical relapse, as the certainty of the evidence was very low.Due to high risk of bias and limited data across the network, we are uncertain about the effectiveness of interventions for preventing endoscopic relapse. Whilst there might be some evidence of prevention of endoscopic relapse with adalimumab (HR 0.10, 95% CrI 0.01 to 0.32; low-certainty evidence), no other intervention studied appeared to be effective.Due to high risk of bias and limited data across the network, we are uncertain about the effectiveness of interventions for preventing withdrawal due to adverse events. Withdrawal due to adverse events appeared to be least likely with sulfasalazine (HR 1.96, 95% Crl 0.00 to 8.90; very low-certainty evidence) and most likely with antibiotics (HR 53.92, 95% Crl 0.43 to 259.80; very low-certainty evidence). When considering the network as a whole, two adverse events leading to study withdrawal (i.e. pancreatitis and leukopenia) occurred in more than 1% of participants treated with an intervention. Pancreatitis occurred in 2.8% (11/399) of purine analogue participants compared to 0.17% (2/1210) of all other groups studied. Leukopenia occurred in 2.5% (10/399) of purine analogue participants compared to 0.08% (1/1210) of all other groups studied.

AUTHORS' CONCLUSIONS

Due to low-certainty evidence in the networks, we are unable to draw conclusions on which treatment is most effective for preventing clinical relapse and endoscopic relapse. Evidence on the safety of the interventions was inconclusive, however cases of pancreatitis and leukopenia from purine analogues were evident in the studies. Larger trials are needed to further understand the effect of the interventions on endoscopic relapse.

Assessing the relative efficacy of interleukin-17 and interleukin-23 targeted treatments for moderate-to-severe plaque psoriasis: A systematic review and network meta-analysis of PASI response

INTRODUCTION

New generation biologics, including interleukin (IL)-17 and IL-23 inhibitors, have delivered higher rates of skin clearance than older treatments in head-to-head studies. However, studies comparing these new biologics directly to one another are limited.

OBJECTIVES

To compare the short-term efficacy of available (or imminently available) biologic and non-biologic systemic therapies for treating patients with moderate-to-severe plaque psoriasis.

METHODS

A systematic review was undertaken to identify randomised controlled trials evaluating biologic treatments, apremilast and dimethyl fumarate. MEDLINE, MEDLINE In-Process, Embase and the Cochrane Library were searched from the 1st January 2000 to 22nd November 2018. A Bayesian network meta-analysis (NMA) using a random-effects multinomial likelihood model with probit link and meta-regression to adjust for cross-trial variation in placebo responses compared the efficacy of interventions at inducing different levels of Psoriasis Area and Severity Index (PASI) response during the induction period. A range of sensitivity analyses was undertaken.

RESULTS

Seventy-seven trials (34,816 patients) were included in the NMA. The base-case analysis showed that all active treatments were superior to placebo. IL-17 inhibitors, guselkumab and risankizumab were found to be more efficacious than tildrakizumab, ustekinumab, all TNF inhibitors and non-biologic systemic treatments at inducing all levels of PASI response. In addition, brodalumab, ixekizumab and risankizumab were significantly more efficacious than secukinumab; no significant difference was found in the comparison with guselkumab. The greatest benefit of brodalumab, ixekizumab, guselkumab, and risankizumab was seen for PASI 90 and PASI 100 response. Results were consistent across all analyses.

CONCLUSIONS

In the NMA brodalumab, ixekizumab, risankizumab and guselkumab showed the highest levels of short-term efficacy. There were differences in efficacy between treatments within the same class. Longer-term analyses are needed to understand differences between these drugs beyond induction in what is a life-long condition.

Systolic Blood Pressure Reduction and Risk of Cardiovascular Disease and Mortality: A Systematic Review and Network Meta-analysis

Importance

Clinical trials have documented that lowering blood pressure reduces cardiovascular disease and premature deaths. However, the optimal target for reduction of systolic blood pressure (SBP) is uncertain.

Objective

To assess the association of mean achieved SBP levels with the risk of cardiovascular disease and all-cause mortality in adults with hypertension treated with antihypertensive therapy.

Data Sources

MEDLINE and EMBASE were searched from inception to December 15, 2015, supplemented by manual searches of the bibliographies of retrieved articles.

Study Selection

Studies included were clinical trials with random allocation to an antihypertensive medication, control, or treatment target. Studies had to have reported a difference in mean achieved SBP of 5 mm Hg or more between comparison groups.

Data Extraction and Synthesis

Data were extracted from each study independently and in duplicate by at least 2 investigators according to a standardized protocol. Network meta-analysis was used to obtain pooled randomized results comparing the association of each 5-mm Hg SBP category with clinical outcomes after adjusting for baseline risk.

Main Outcomes and Measures

Cardiovascular disease and all-cause mortality.

Results

Forty-two trials, including 144 220 patients, met the eligibility criteria. In general, there were linear associations between mean achieved SBP and risk of cardiovascular disease and mortality, with the lowest risk at 120 to 124 mm Hg. Randomized groups with a mean achieved SBP of 120 to 124 mm Hg had a hazard ratio (HR) for major cardiovascular disease of 0.71 (95% CI, 0.60-0.83) compared with randomized groups with a mean achieved SBP of 130 to 134 mm Hg, an HR of 0.58 (95% CI, 0.48-0.72) compared with those with a mean achieved SBP of 140 to 144 mm Hg, an HR of 0.46 (95% CI, 0.34-0.63) compared with those with a mean achieved SBP of 150 to 154 mm Hg, and an HR of 0.36 (95% CI, 0.26-0.51) compared with those with a mean achieved SBP of 160 mm Hg or more. Likewise, randomized groups with a mean achieved SBP of 120 to 124 mm Hg had an HR for all-cause mortality of 0.73 (95% CI, 0.58-0.93) compared with randomized groups with a mean achieved SBP of 130 to 134 mm Hg, an HR of 0.59 (95% CI, 0.45-0.77) compared with those with a mean achieved SBP of 140 to 144 mm Hg, an HR of 0.51 (95% CI, 0.36-0.71) compared with those with a mean achieved SBP of 150 to 154 mm Hg, and an HR of 0.47 (95% CI, 0.32-0.67) compared with those with a mean achieved SBP of 160 mm Hg or more.

Conclusions and Relevance

This study suggests that reducing SBP to levels below currently recommended targets significantly reduces the risk of cardiovascular disease and all-cause mortality. These findings support more intensive control of SBP among adults with hypertension.

Interventions for maintenance of surgically‐induced remission in Crohn’s disease: a network meta‐analysis

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

To assess the effects and harms of interventions for the maintenance of surgically‐induced remission in Crohn's disease and to rank treatments in order of effectiveness.

Estimating the Association of the 2017 and 2014 Hypertension Guidelines With Cardiovascular Events and Deaths in US Adults: An Analysis of National Data

Importance

The 2017 American College of Cardiology/American Heart Association hypertension guideline recommends lower blood pressure (BP) thresholds for initiating antihypertensive medication and treatment goals than the 2014 evidence-based hypertension guideline.

Objective

To estimate the potential association of the 2017 and 2014 hypertension guidelines with the proportion of US adults defined as being hypertensive or recommended for antihypertensive treatment and with risk reduction of major cardiovascular disease (CVD) and all-cause mortality.

Design, Setting, and Participants

Using data from the National Health and Nutrition Examination Survey 2013 to 2016, we estimated the proportions of US adults with hypertension or recommended for antihypertensive treatment according to the 2017 and 2014 hypertension guidelines. Using data from the National Health and Nutrition Examination Survey, antihypertensive clinical trials, and population-based cohort studies, we estimated risk reductions of CVD and all-cause mortality assuming the entire US adult population achieved guideline-recommended systolic BP (SBP) treatment goals. Data were analyzed between October 2017 and March 2018.

Main Outcomes and Measures

Proportions and numbers of individuals with hypertension or recommended for antihypertensive treatment and numbers of CVD and all-cause mortality reduction.

Results

According to the 2017 hypertension guideline, the prevalence of hypertension (BP level ≥130/80 mm Hg) was 45.4% (95% CI, 43.9%-46.9%), representing 105.3 (95% CI, 101.9-108.8) million US adults, which was significantly higher than estimates per the 2014 hypertension guideline (BP level ≥140/90 mm Hg): 32.0% (95% CI, 30.3%-33.6%) or 74.1 (95% CI, 70.3-77.9) million individuals, respectively. Additionally, the proportion of individuals recommended for antihypertensive treatment was significantly higher according to the 2017 hypertension guideline (35.9%; 95% CI, 34.2%-37.5%) compared with the 2014 hypertension guideline (31.1%; 95% CI, 29.6%-32.7%). Achieving the 2017 hypertension guideline SBP treatment goals is estimated to reduce 610 000 (95% CI, 496 000-734 000) CVD events and 334 000 (95% CI, 245 000-434 000) total deaths in US adults 40 years and older. Corresponding estimates after achieving the 2014 hypertension guideline SBP treatment goals were 270 000 (95% CI, 202 000-349 000) and 177 000 (95% CI, 123 000-241 000), respectively. Implementing the 2017 hypertension guideline is estimated to increase 62 000 hypotension and 79 000 acute kidney injury or failure events.

Conclusions and Relevance

Compared with the 2014 hypertension guideline, the 2017 hypertension guideline was associated with an increase in the proportion of adults recommended for antihypertensive treatment and a further reduction in major CVD events and all-cause mortality, but a possible increase in the number of adverse events in the United States.

Number needed to treat and costs per responder among biologic treatments for moderate-to-severe psoriasis: a network meta-analysis

BACKGROUND

The clinical benefits of biologic therapies for moderate-to-severe psoriasis are well established, but wide variations exist in patient response.

OBJECTIVES

To determine the number needed to treat (NNT) to achieve a 75% and 90% reduction in the Psoriasis Area and Severity Index (PASI-75/90) with FDA-approved agents and evaluate the incremental cost per PASI-75 or PASI-90 responder.

METHODS

The relative probabilities of achieving PASI-75 and PASI-90, as well as NNTs, were estimated using a network meta-analysis. Costs (2017 USD) included drug acquisition and administration. The incremental cost per PASI-75 or PASI-90 responder for each treatment was estimated for the clinical trial period, and annually.

RESULTS

Compared with supportive care, the NNT to achieve PASI-75 was 1.18 for ixekizumab, 1.29 for secukinumab 300 mg, 1.37 for infliximab, 1.48 for adalimumab, 1.53 for secukinumab 150 mg, 1.58 for ustekinumab, 2.25 for etanercept, and 3.71 for apremilast. The one-year incremental cost per PASI-75 responder relative to supportive care was $59,830 for infliximab, $88,775 for secukinumab 300 mg, $91,837 for adalimumab, $95,898 for ixekizumab, $97,363 for ustekinumab, $105,131 for secukinumab 150 mg, $129,665 for apremilast, and $159,328 for etanercept. Results were similar for PASI-90.

CONCLUSION

The NNT and incremental cost per responder are meaningful ways to assess comparative effectiveness and cost effectiveness among psoriasis treatments.

A systematic review and economic evaluation of bisphosphonates for the prevention of fragility fractures

BACKGROUND

Fragility fractures are fractures that result from mechanical forces that would not ordinarily result in fracture.

OBJECTIVES

To evaluate the clinical effectiveness and safety of bisphosphonates [alendronic acid (Fosamax^® and Fosamax^® Once Weekly, Merck Sharp & Dohme Ltd), risedronic acid (Actonel^® and Actonel Once a Week^®, Warner Chilcott UK Ltd), ibandronic acid (Bonviva^®, Roche Products Ltd) and zoledronic acid (Aclasta^®, Novartis Pharmaceuticals UK Ltd)] for the prevention of fragility fracture and to assess their cost-effectiveness at varying levels of fracture risk.

DATA SOURCES

For the clinical effectiveness review, six electronic databases and two trial registries were searched: MEDLINE, EMBASE, The Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, Web of Science and BIOSIS Previews, Clinicaltrials.gov and World Health Organization International Clinical Trials Registry Platform. Searches were limited by date from 2008 until September 2014.

REVIEW METHODS

A systematic review and network meta-analysis (NMA) of effectiveness studies were conducted. A review of published economic analyses was undertaken and a de novo health economic model was constructed. Discrete event simulation was used to estimate lifetime costs and quality-adjusted life-years (QALYs) for each bisphosphonate treatment strategy and a strategy of no treatment for a simulated cohort of patients with heterogeneous characteristics. The model was populated with effectiveness evidence from the systematic review and NMA. All other parameters were estimated from published sources. A NHS and Personal Social Services perspective was taken, and costs and benefits were discounted at 3.5% per annum. Fracture risk was estimated from patient characteristics using the QFracture^® (QFracture-2012 open source revision 38, Clinrisk Ltd, Leeds, UK) and FRAX^® (web version 3.9, University of Sheffield, Sheffield, UK) tools. The relationship between fracture risk and incremental net benefit (INB) was estimated using non-parametric regression. Probabilistic sensitivity analysis (PSA) and scenario analyses were used to assess uncertainty.

RESULTS

Forty-six randomised controlled trials (RCTs) were included in the clinical effectiveness systematic review, with 27 RCTs providing data for the fracture NMA and 35 RCTs providing data for the femoral neck bone mineral density (BMD) NMA. All treatments had beneficial effects on fractures versus placebo, with hazard ratios varying from 0.41 to 0.92 depending on treatment and fracture type. The effects on vertebral fractures and percentage change in BMD were statistically significant for all treatments. There was no evidence of a difference in effect on fractures between bisphosphonates. A statistically significant difference in the incidence of influenza-like symptoms was identified from the RCTs for zoledronic acid compared with placebo. Reviews of observational studies suggest that upper gastrointestinal symptoms are frequently reported in the first month of oral bisphosphonate treatment, but pooled analyses of placebo-controlled trials found no statistically significant difference. A strategy of no treatment was estimated to have the maximum INB for patients with a 10-year QFracture risk under 1.5%, whereas oral bisphosphonates provided maximum INB at higher levels of risk. However, the PSA suggested that there is considerable uncertainty regarding whether or not no treatment is the optimal strategy until the QFracture score is around 5.5%. In the model using FRAX, the mean INBs were positive for all oral bisphosphonate treatments across all risk categories. Intravenous bisphosphonates were estimated to have lower INBs than oral bisphosphonates across all levels of fracture risk when estimated using either QFracture or FRAX.

LIMITATIONS

We assumed that all treatment strategies are viable alternatives across the whole population.

CONCLUSIONS

Bisphosphonates are effective in preventing fragility fractures. However, the benefit-to-risk ratio in the lowest-risk patients may be debatable given the low absolute QALY gains and the potential for adverse events. We plan to extend the analysis to include non-bisphosphonate therapies.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013006883.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

The comparative efficacy of brodalumab in patients with moderate-to-severe psoriasis: a systematic literature review and network meta-analysis

PURPOSE

To evaluate the relative efficacy of brodalumab compared with approved biologic therapies and apremilast for moderate-to-severe psoriasis.

METHODS

We searched MEDLINE, Embase, and Cochrane for randomized controlled trials reporting induction phase responses. The primary analysis examined the proportion of patients achieving Psoriasis Area Severity Index (PASI) 50, 75, 90, or 100 responses using a random-effects Bayesian multinomial likelihood model with probit link, with and without adjustment for variation in study-level placebo responses.

RESULTS

A total of 54 studies were included. Based on PASI 100 response, the most efficacious therapies were brodalumab 210 mg every two weeks (Q2W) and ixekizumab. Brodalumab 210 mg Q2W was significantly more efficacious than adalimumab, apremilast, brodalumab 140 mg Q2W, etanercept, infliximab, secukinumab, and ustekinumab. Results were consistent for PASI 50, 75, and 90 outcomes and all sensitivity analyses.

CONCLUSIONS

Our findings are consistent with pivotal trials which indicate that high levels of complete clearance can be achieved with brodalumab. Based on existing evidence, induction-phase efficacy of brodalumab is similar to ixekizumab and superior to other approved therapies, including anti-TNFs, apremilast, secukinumab, and ustekinumab.

Keeping Children Safe: a multicentre programme of research to increase the evidence base for preventing unintentional injuries in the home in the under-fives

Background

Unintentional injuries among 0- to 4-year-olds are a major public health problem incurring substantial NHS, individual and societal costs. However, evidence on the effectiveness and cost-effectiveness of preventative interventions is lacking.

Aim

To increase the evidence base for thermal injury, falls and poisoning prevention for the under-fives.

Methods

Six work streams comprising five multicentre case–control studies assessing risk and protective factors, a study measuring quality of life and injury costs, national surveys of children’s centres, interviews with children’s centre staff and parents, a systematic review of barriers to, and facilitators of, prevention and systematic overviews, meta-analyses and decision analyses of home safety interventions. Evidence from these studies informed the design of an injury prevention briefing (IPB) for children’s centres for preventing fire-related injuries and implementation support (training and facilitation). This was evaluated by a three-arm cluster randomised controlled trial comparing IPB and support (IPB+), IPB only (no support) and usual care. The primary outcome was parent-reported possession of a fire escape plan. Evidence from all work streams subsequently informed the design of an IPB for preventing thermal injuries, falls and poisoning.

Results

Modifiable risk factors for falls, poisoning and scalds were found. Most injured children and their families incurred small to moderate health-care and non-health-care costs, with a few incurring more substantial costs. Meta-analyses and decision analyses found that home safety interventions increased the use of smoke alarms and stair gates, promoted safe hot tap water temperatures, fire escape planning and storage of medicines and household products, and reduced baby walker use. Generally, more intensive interventions were the most effective, but these were not always the most cost-effective interventions. Children’s centre and parental barriers to, and facilitators of, injury prevention were identified. Children’s centres were interested in preventing injuries, and believed that they could prevent them, but few had an evidence-based strategic approach and they needed support to develop this. The IPB was implemented by children’s centres in both intervention arms, with greater implementation in the IPB+ arm. Compared with usual care, more IPB+ arm families received advice on key safety messages, and more families in each intervention arm attended fire safety sessions. The intervention did not increase the prevalence of fire escape plans [adjusted odds ratio (AOR) IPB only vs. usual care 0.93, 95% confidence interval (CI) 0.58 to 1.49; AOR IPB+ vs. usual care 1.41, 95% CI 0.91 to 2.20] but did increase the proportion of families reporting more fire escape behaviours (AOR IPB only vs. usual care 2.56, 95% CI 1.38 to 4.76; AOR IPB+ vs. usual care 1.78, 95% CI 1.01 to 3.15). IPB-only families were less likely to report match play by children (AOR 0.27, 95% CI 0.08 to 0.94) and reported more bedtime fire safety routines (AOR for a 1-unit increase in the number of routines 1.59, 95% CI 1.09 to 2.31) than usual-care families. The IPB-only intervention was less costly and marginally more effective than usual care. The IPB+ intervention was more costly and marginally more effective than usual care.

Limitations

Our case–control studies demonstrate associations between modifiable risk factors and injuries but not causality. Some injury cost estimates are imprecise because of small numbers. Systematic reviews and meta-analyses were limited by the quality of the included studies, the small numbers of studies reporting outcomes and significant heterogeneity, partly explained by differences in interventions. Network meta-analysis (NMA) categorised interventions more finely, but some variation remained. Decision analyses are likely to underestimate cost-effectiveness for a number of reasons. IPB implementation varied between children’s centres. Greater implementation may have resulted in changes in more fire safety behaviours.

Conclusions

Our studies provide new evidence about the effectiveness of, as well as economic evaluation of, home safety interventions. Evidence-based resources for preventing thermal injuries, falls and scalds were developed. Providing such resources to children’s centres increases their injury prevention activity and some parental safety behaviours.

Future work

Further randomised controlled trials, meta-analyses and NMAs are needed to evaluate the effectiveness and cost-effectiveness of home safety interventions. Further work is required to measure NHS, family and societal costs and utility decrements for childhood home injuries and to evaluate complex multicomponent interventions such as home safety schemes using a single analytical model.

Trial registration

Current Controlled Trials ISRCTN65067450 and ClinicalTrials.gov NCT01452191.

Funding

The National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full inProgramme Grants for Applied Research; Vol. 5, No. 14. See the NIHR Journals Library website for further project information.

Comparative effectiveness of different transarterial embolization therapies alone or in combination with local ablative or adjuvant systemic treatments for unresectable hepatocellular carcinoma: A network meta-analysis of randomized controlled trials

BACKGROUND

The optimal transcatheter embolization strategy for patients with unresectable hepatocellular carcinoma (HCC) remains elusive. We conducted a systematic review and network meta-analysis (NMA) of different embolization options for unresectable HCC.

METHODS

Medical databases were searched for randomized controlled trials evaluating bland transarterial embolization (TAE), conventional TACE, drug-eluting bead chemoembolization (DEB-TACE), or transarterial radioembolization (TARE), either alone or combined with adjuvant chemotherapy, or local liver ablation, or external radiotherapy for unresectable HCC up to June 2017. Random effects Bayesian models with a binomial and normal likelihood were fitted (WinBUGS). Primary endpoint was patient survival expressed as hazard ratios (HR) and 95% credible intervals. An exponential model was used to fit patient survival curves. Safety and objective response were calculated as odds ratios (OR) and accompanying 95% credible intervals. Competing treatments were ranked with the SUCRA statistic. Heterogeneity-adjusted effective sample sizes were calculated to evaluate information size for each comparison. Quality of evidence (QoE) was assessed with the GRADE system adapted for NMA reports. All analyses complied with the ISPOR-AMCP-NCP Task Force Report for good practice in NMA.

FINDINGS

The network of evidence included 55 RCTs (12 direct comparisons) with 5,763 patients with preserved liver function and unresectable HCC (intermediate to advanced stage). All embolization strategies achieved a significant survival gain over control treatment (HR range, 0.42-0.76; very low-to-moderate QoE). However, TACE, DEB-TACE, TARE and adjuvant systemic agents did not confer any survival benefit over bland TAE alone (moderate QoE, except low in case of TARE). There was moderate QoE that TACE combined with external radiation or liver ablation achieved the best patient survival (SUCRA 86% and 96%, respectively). Estimated median survival was 13.9 months in control, 18.1 months in TACE, 20.6 months with DEB-TACE, 20.8 months with bland TAE, 30.1 months in TACE plus external radiotherapy, and 33.3 months in TACE plus liver ablation. TARE was the safest treatment (SUCRA 77%), however, all examined therapies were associated with a significantly higher risk of toxicity over control (OR range, 6.35 to 68.5). TACE, DEB-TACE, TARE and adjuvant systemic agents did not improve objective response over bland embolization alone (OR range, 0.85 to 1.65). There was clinical diversity among included randomized controlled trials, but statistical heterogeneity was low.

CONCLUSIONS

Chemo- and radio-embolization for unresectable hepatocellular carcinoma may improve tumour objective response and patient survival, but are not more effective than bland particle embolization. Chemoembolization combined with external radiotherapy or local liver ablation may significantly improve tumour response and patient survival rates over embolization monotherapies. Quality of evidence remains mostly low to moderate because of clinical diversity.

SYSTEMATIC REVIEW REGISTRATION

CRD42016035796 (http://www.crd.york.ac.uk/PROSPERO).

Comparative Effectiveness of Plain Balloon Angioplasty, Bare Metal Stents, Drug-Coated Balloons, and Drug-Eluting Stents for the Treatment of Infrapopliteal Artery Disease: Systematic Review and Bayesian Network Meta-analysis of Randomized Controlled Trials

PURPOSE

To report a Bayesian network meta-analysis of randomized controlled trials (RCTs) comparing bare metal stents (BMS), paclitaxel-coated balloons (PCBs), and drug-eluting stents (DES) with balloon angioplasty (BA) or with each other in the infrapopliteal arteries.

METHODS

Sixteen RCTs comprising 1805 patients with 1-year median follow-up were analyzed. Bayesian random effects binomial models were employed (WinBUGS). Relative treatment effects were expressed as odds ratios (ORs) with 95% credible intervals (CrI), and the cumulative rank probabilities were calculated to provide hierarchies of competing treatments. Quality of evidence (QoE) was assessed with the GRADE (grading of recommendations assessment, development, and evaluation) system. Sensitivity, heterogeneity, and consistency analyses were performed.

RESULTS

There was high QoE that infrapopliteal DES significantly reduced restenosis compared with BMS (OR 0.26, 95% CrI 0.12 to 0.51) and BA (OR 0.22, 95% CrI 0.11 to 0.45). Likewise, DES significantly reduced target lesion revascularization (TLR) compared with BA (OR 0.41, 95% CrI 0.22 to 0.75) and BMS (OR 0.26, 95% CrI 0.15 to 0.45). Paclitaxel-coated balloons also reduced TLR compared with BA (OR 0.55, 95% CrI 0.34 to 0.90) and BMS (OR 0.35, 95% CrI 0.18 to 0.67), but QoE was low to moderate. BA had lower TLR than BMS (OR 0.63, 95% CrI 0.40 to 0.99) with high QoE. DES was the only treatment that significantly reduced limb amputations compared with BA (OR 0.58, 95% CrI 0.35 to 0.96), PCB (OR 0.51, 95% CrI 0.26 to 0.98), or BMS (OR 0.38, 95% CrI 0.19 to 0.72) with moderate to high QoE. DES also significantly improved wound healing compared with BA (OR 2.02, 95% CrI 1.01 to 4.07) or BMS (OR 3.45, 95% CrI 1.41 to 8.73) with high QoE. Results were stable on sensitivity and meta-regression analyses without any significant publication bias or inconsistency.

CONCLUSION

Infrapopliteal DES were associated with significantly lower rates of restenosis, TLR, and amputations and improved wound healing compared to BA and BMS. DES also significantly reduced amputations compared with PCB.

Clinical effectiveness of bisphosphonates for the prevention of fragility fractures: A systematic review and network meta-analysis

OBJECTIVES

To assess the relative efficacy of bisphosphonates (alendronate, risedronate, ibandronate and zoledronic acid) for the treatment of osteoporosis using network meta-analysis (NMA).

METHODS

A systematic review of the literature was conducted using PRISMA guidelines. A network meta-analysis was used to determine the relative efficacy of treatments on four fracture outcomes (vertebral, non-vertebral, hip and wrist) and percentage change in femoral neck bone mineral density (BMD). Treatment effects were modelled using an exchangeable treatment effects model. Heterogeneity in treatment effects was explored by considering potential treatment effect modifiers using meta-regression. Where appropriate, inconsistency between direct and indirect evidence was assessed using node-splitting.

RESULTS

46 randomised controlled trials (RCTs) were identified. Twenty seven RCTs provided fracture data and 35 RCTs provided BMD data for analysis. Zoledronic acid was associated with the greatest treatment effect on vertebral fractures (HR 0.41, 95% CrI: 0.28, 0.56) and percentage change in BMD (3.21, 95%: CrI 2.52, 3.86) compared to placebo. The greatest treatment effect on non-vertebral and wrist fractures was given by risedronate (HR 0.72, 95%: CrI 0.53, 0.89 and HR 0.77, 95%: CrI 0.44, 1.24, respectively). For hip fractures the greatest treatment effect was given by alendronate (HR 0.78, 95% CrI: 0.44, 1.30).

CONCLUSIONS

All treatments examined were associated with beneficial effects on fractures and femoral neck BMD relative to placebo. For vertebral fractures and percentage change in femoral neck BMD the treatment effects were statistically significant for all treatments. Pairwise comparisons between treatments indicated that no active treatment was statistically significantly more effective than any other active treatment for fracture outcomes. There was some heterogeneity in treatment effects between studies suggesting differential treatment effects according to study characteristics; however, there was no evidence of differential treatment effects with respect to gender and age.

Hierarchical Bayesian approaches for detecting inconsistency in network meta-analysis

Network meta-analysis (NMA), also known as multiple treatment comparisons, is commonly used to incorporate direct and indirect evidence comparing treatments. With recent advances in methods and software, Bayesian approaches to NMA have become quite popular and allow models of previously unanticipated complexity. However, when direct and indirect evidence differ in an NMA, the model is said to suffer from inconsistency. Current inconsistency detection in NMA is usually based on contrast-based (CB) models; however, this approach has certain limitations. In this work, we propose an arm-based random effects model, where we detect discrepancy of direct and indirect evidence for comparing two treatments using the fixed effects in the model while flagging extreme trials using the random effects. We define discrepancy factors to characterize evidence of inconsistency for particular treatment comparisons, which is novel in NMA research. Our approaches permit users to address issues previously tackled via CB models. We compare sources of inconsistency identified by our approach and existing loop-based CB methods using real and simulated datasets and demonstrate that our methods can offer powerful inconsistency detection. Copyright © 2016 John Wiley & Sons, Ltd.

GetReal in network meta-analysis: a review of the methodology

Pairwise meta-analysis is an established statistical tool for synthesizing evidence from multiple trials, but it is informative only about the relative efficacy of two specific interventions. The usefulness of pairwise meta-analysis is thus limited in real-life medical practice, where many competing interventions may be available for a certain condition and studies informing some of the pairwise comparisons may be lacking. This commonly encountered scenario has led to the development of network meta-analysis (NMA). In the last decade, several applications, methodological developments, and empirical studies in NMA have been published, and the area is thriving as its relevance to public health is increasingly recognized. This article presents a review of the relevant literature on NMA methodology aiming to pinpoint the developments that have appeared in the field. Copyright © 2016 John Wiley & Sons, Ltd.

'Arm-based' parameterization for network meta-analysis

We present an alternative to the contrast‐based parameterization used in a number of publications for network meta‐analysis. This alternative “arm‐based” parameterization offers a number of advantages: it allows for a “long” normalized data structure that remains constant regardless of the number of comparators; it can be used to directly incorporate individual patient data into the analysis; the incorporation of multi‐arm trials is straightforward and avoids the need to generate a multivariate distribution describing treatment effects; there is a direct mapping between the parameterization and the analysis script in languages such as WinBUGS and finally, the arm‐based parameterization allows simple extension to treatment‐specific random treatment effect variances.

We validated the parameterization using a published smoking cessation dataset. Network meta‐analysis using arm‐ and contrast‐based parameterizations produced comparable results (with means and standard deviations being within +/− 0.01) for both fixed and random effects models. We recommend that analysts consider using arm‐based parameterization when carrying out network meta‐analyses. © 2015 The Authors Research Synthesis Methods Published by John Wiley & Sons Ltd.

A Bayesian missing data framework for generalized multiple outcome mixed treatment comparisons

Bayesian statistical approaches to mixed treatment comparisons (MTCs) are becoming more popular because of their flexibility and interpretability. Many randomized clinical trials report multiple outcomes with possible inherent correlations. Moreover, MTC data are typically sparse (although richer than standard meta-analysis, comparing only two treatments), and researchers often choose study arms based upon which treatments emerge as superior in previous trials. In this paper, we summarize existing hierarchical Bayesian methods for MTCs with a single outcome and introduce novel Bayesian approaches for multiple outcomes simultaneously, rather than in separate MTC analyses. We do this by incorporating partially observed data and its correlation structure between outcomes through contrast-based and arm-based parameterizations that consider any unobserved treatment arms as missing data to be imputed. We also extend the model to apply to all types of generalized linear model outcomes, such as count or continuous responses. We offer a simulation study under various missingness mechanisms (e.g., missing completely at random, missing at random, and missing not at random) providing evidence that our models outperform existing models in terms of bias, mean squared error, and coverage probability then illustrate our methods with a real MTC dataset. We close with a discussion of our results, several contentious issues in MTC analysis, and a few avenues for future methodological development.

Comparative efficacy and safety of daclatasvir/asunaprevir versus IFN-based regimens in genotype 1b hepatitis C virus infection

AIM

Efficacy and safety comparison of daclatasvir/asunaprevir (DCV + ASV) versus peginterferon-α/ribavirin (A/R) alone or combined with telaprevir, boceprevir, simeprevir or sofosbuvir in chronic genotype 1b hepatitis C virus infection.

METHODS

Network meta-analysis (NMA) and matching-adjusted indirect comparisons (MAICs).

RESULTS

Among treatment-naive patients, DCV + ASV demonstrated higher sustained virologic response (SVR) rates than telaprevir + A/R, boceprevir + A/R and A/R in NMA and MAICs and simeprevir + A/R in NMA. DCV + ASV among treatment-experienced patients had higher SVR rates than telaprevir + A/R, boceprevir + A/R, simeprevir + A/R and A/R in MAICs. DCV + ASV had lower adverse events rates than comparators.

CONCLUSION

DCV + ASV demonstrated superior efficacy and safety compared with A/R-based regimens.

The PRISMA extension statement for reporting of systematic reviews incorporating network meta-analyses of health care interventions: checklist and explanations

The PRISMA statement is a reporting guideline designed to improve the completeness of reporting of systematic reviews and meta-analyses. Authors have used this guideline worldwide to prepare their reviews for publication. In the past, these reports typically compared 2 treatment alternatives. With the evolution of systematic reviews that compare multiple treatments, some of them only indirectly, authors face novel challenges for conducting and reporting their reviews. This extension of the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) statement was developed specifically to improve the reporting of systematic reviews incorporating network meta-analyses. A group of experts participated in a systematic review, Delphi survey, and face-to-face discussion and consensus meeting to establish new checklist items for this extension statement. Current PRISMA items were also clarified. A modified, 32-item PRISMA extension checklist was developed to address what the group considered to be immediately relevant to the reporting of network meta-analyses. This document presents the extension and provides examples of good reporting, as well as elaborations regarding the rationale for new checklist items and the modification of previously existing items from the PRISMA statement. It also highlights educational information related to key considerations in the practice of network meta-analysis. The target audience includes authors and readers of network meta-analyses, as well as journal editors and peer reviewers.

Critical appraisal of network meta-analyses evaluating the efficacy and safety of new oral anticoagulants in atrial fibrillation stroke prevention trials

OBJECTIVES

To critically appraise published network meta-analyses (NMAs) evaluating the efficacy or safety of the new oral anticogulants (NOACs) dabigatran, rivaroxaban, and apixaban for the prevention of stroke in patients with nonvalvular atrial fibrillation (AF).

METHODS

A systematic literature review was performed to identify the relevant NMAs using MEDLINE, EMBASE, Cochrane Library, Database of Abstracts of Reviews of Effects, and Health Technology Assessment. The synthesis studies were evaluated using the "Questionnaire to assess the relevance and credibility of the NMA."

RESULTS

Eleven NMAs evaluating NOACs among adults with nonvalvular AF were identified. Most NMAs included three large phase III randomized controlled trials, comparing NOACs to adjusted-dose warfarin (Randomized Evaluation of Long-Term Anticoagulation Therapy [RE-LY], Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared With Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation [ROCKET-AF], and Apixaban for Reduction of Stroke and Other Thromboembolic Events in Atrial Fibrillation [ARISTOTLE]). The main differences identified related to potential treatment effect modifiers regarding the mean time spent in therapeutic range (TTR) in the warfarin arm, the risk of stroke or systemic embolism across the trials (mean CHADS2 score: C = congestive heart failure, H = hypertension, A = older than age 75 years, D = diabetes mellitus, S2 = prior stroke or history of transient ischemic attack) or primary versus secondary prevention, and type of populations used in the analysis. Kansal et al. [Kansal AR, Sharma M, Bradley-Kennedy C, et al. Dabigatran versus rivaroxaban for the prevention of stroke and systemic embolism in atrial fibrillation in Canada: comparative efficacy and cost-effectiveness. Thromb Haemost 2012;108:672-82] appropriately adjusted the ROCKET-AF TTR to match the RE-LY population on the basis of individual patient data. Meta-regressions are not expected to minimize confounding bias given limited data, whereas subgroup analyses had some impact on the point estimates for the treatment comparisons.

CONCLUSIONS

Results of the synthesis studies were generally comparable and suggested that the NOACs had similar efficacy, although some differences were identified depending on the outcome. The extent to which differences in the distribution of TTR, CHADS2 score, or primary versus secondary prevention biased the results remains unclear.

Comparative Efficacy and Safety of Different Antiplatelet Agents for Prevention of Major Cardiovascular Events and Leg Amputations in Patients with Peripheral Arterial Disease: A Systematic Review and Network Meta-Analysis

There is a lack of consensus regarding which type of antiplatelet agent should be used in patients with peripheral arterial disease (PAD) and little is known on the advantages and disadvantages of dual antiplatelet therapy. We conducted a systematic review and network meta-analysis of available randomized controlled trials (RCT) comparing different antiplatelet drugs (Aspirin, Ticlopidine, Clopidogrel, Ticagrelor, Cilostazol, Picotamide and Vorapaxar as monotherapies or in combination with aspirin) in PAD patients (PROSPERO public database; CRD42014010299).We collated evidence from previous relevant meta-analyses and searched online databases. Primary efficacy endpoints were: (1) the composite rate of major adverse cardiovascular events (MACE; including vascular deaths, non-fatal myocardial infarction and non-fatal stroke), and (2) the rate of major leg amputations. The primary safety endpoint was the rate of severe bleeding events. Bayesian models were employed for multiple treatment comparisons and risk-stratified hierarchies of comparative efficacy were produced to aid medical decision making. Number-Needed-to-Treat (NNT) and Number-Needed-to-Harm (NNH) are reported in case of significant results. We analyzed 49 RCTs comprising 34,518 patients with 88,358 person-years of follow-up with placebo as reference treatment. Aspirin, Cilostazol, Vorapaxar and Picotamide were ineffective in reducing MACE. A significant MACE reduction was noted with Ticagrelor plus aspirin (RR: 0.67; 95%CrI: 0.46-0.96, NNT = 66), Clopidogrel (RR: 0.72; 95%CrI: 0.58-0.91, NNT = 80), Ticlopidine (RR: 0.75; 95%CrI: 0.58-0.96, NNT = 87), and Clopidogrel plus aspirin (RR: 0.78; 95%CrI: 0.61-0.99, NNT = 98). Dual antiplatelet therapy with Clopidogrel plus aspirin significantly reduced major amputations following leg revascularization (RR: 0.68; 95%CrI: 0.46-0.99 compared to aspirin, NNT = 94). The risk of severe bleeding was significantly higher with Ticlopidine (RR: 5.03; 95%CrI: 1.23-39.6, NNH = 25), Vorapaxar (RR: 1.80; 95%CrI: 1.22-2.69, NNH = 130), and Clopidogrel plus aspirin (RR: 1.48; 95%CrI: 1.05-2.10, NNH = 215). Clopidogrel monotherapy showed the most favourable benefit-harm profile (79% cumulative rank probability best and 77% cumulative rank probability safest). In conclusion, Clopidogrel should be the indicated antiplatelet agent in PAD patients. Dual antiplatelet therapy with aspirin and Clopidogrel can reduce the rate of major leg amputations following revascularization, but carries a slightly higher risk of severe bleeding.

Network meta-analysis: development of a three-level hierarchical modeling approach incorporating dose-related constraints

BACKGROUND

Network meta-analysis (NMA) is commonly used in evidence synthesis; however, in situations in which there are a large number of treatment options, which may be subdivided into classes, and relatively few trials, NMAs produce considerable uncertainty in the estimated treatment effects, and consequently, identification of the most beneficial intervention remains inconclusive.

OBJECTIVE

To develop and demonstrate the use of evidence synthesis methods to evaluate extensive treatment networks with a limited number of trials, making use of classes.

METHODS

Using Bayesian Markov chain Monte Carlo methods, we build on the existing work of a random effects NMA to develop a three-level hierarchical NMA model that accounts for the exchangeability between treatments within the same class as well as for the residual between-study heterogeneity. We demonstrate the application of these methods to a continuous and binary outcome, using a motivating example of overactive bladder. We illustrate methods for incorporating ordering constraints in increasing doses, model selection, and assessing inconsistency between the direct and indirect evidence.

RESULTS

The methods were applied to a data set obtained from a systematic literature review of trials for overactive bladder, evaluating the mean reduction in incontinence episodes from baseline and the number of patients reporting one or more adverse events. The data set involved 72 trials comparing 34 interventions that were categorized into nine classes of interventions, including placebo.

CONCLUSIONS

Bayesian three-level hierarchical NMAs have the potential to increase the precision in the effect estimates while maintaining the interpretability of the individual interventions for decision making.

A process for assessing the feasibility of a network meta-analysis: a case study of everolimus in combination with hormonal therapy versus chemotherapy for advanced breast cancer

BACKGROUND

The aim of this study is to outline a general process for assessing the feasibility of performing a valid network meta-analysis (NMA) of randomized controlled trials (RCTs) to synthesize direct and indirect evidence for alternative treatments for a specific disease population.

METHODS

Several steps to assess the feasibility of an NMA are proposed based on existing recommendations. Next, a case study is used to illustrate this NMA feasibility assessment process in order to compare everolimus in combination with hormonal therapy to alternative chemotherapies in terms of progression-free survival for women with advanced breast cancer.

RESULTS

A general process for assessing the feasibility of an NMA is outlined that incorporates explicit steps to visualize the heterogeneity in terms of treatment and outcome characteristics (Part A) as well as the study and patient characteristics (Part B). Additionally, steps are performed to illustrate differences within and across different types of direct comparisons in terms of baseline risk (Part C) and observed treatment effects (Part D) since there is a risk that the treatment effect modifiers identified may not explain the observed heterogeneity or inconsistency in the results due to unexpected, unreported or unmeasured differences. Depending on the data available, alternative approaches are suggested: list assumptions, perform a meta-regression analysis, subgroup analysis, sensitivity analyses, or summarize why an NMA is not feasible.

CONCLUSIONS

The process outlined to assess the feasibility of an NMA provides a stepwise framework that will help to ensure that the underlying assumptions are systematically explored and that the risks (and benefits) of pooling and indirectly comparing treatment effects from RCTs for a particular research question are transparent.

Network meta-analysis of randomized clinical trials: reporting the proper summaries

BACKGROUND

In the absence of sufficient data directly comparing multiple treatments, indirect comparisons using network meta-analyses (NMAs) can provide useful information. Under current contrast-based (CB) methods for binary outcomes, the patient-centered measures including the treatment-specific event rates and risk differences (RDs) are not provided, which may create some unnecessary obstacles for patients to comprehensively trade-off efficacy and safety measures.

PURPOSE

We aim to develop NMA to accurately estimate the treatment-specific event rates.

METHODS

A Bayesian hierarchical model is developed to illustrate how treatment-specific event rates, RDs, and risk ratios (RRs) can be estimated. We first compare our approach to alternative methods using two hypothetical NMAs assuming a fixed RR or RD, and then use two published NMAs to illustrate the improved reporting.

RESULTS

In the hypothetical NMAs, our approach outperforms current CB NMA methods in terms of bias. In the two published NMAs, noticeable differences are observed in the magnitude of relative treatment effects and several pairwise statistical significance tests from previous report.

LIMITATIONS

First, to facilitate the estimation, each study is assumed to hypothetically compare all treatments, with unstudied arms being missing at random. It is plausible that investigators may have selected treatment arms on purpose based on the results of previous trials, which may lead to 'nonignorable missingness' and potentially bias our estimates. Second, we have not considered methods to identify and account for potential inconsistency between direct and indirect comparisons.

CONCLUSIONS

The proposed NMA method can accurately estimate treatment-specific event rates, RDs, and RRs and is recommended.

Bayesian network meta-analysis of nitinol stents, covered stents, drug-eluting stents, and drug-coated balloons in the femoropopliteal artery

OBJECTIVE

Several randomized controlled trials (RCTs) have shown the superiority of some of these technologies over balloon angioplasty, but direct comparisons between these treatment options are lacking. The authors conducted a network meta-analysis of RCTs comparing bare nitinol stents, covered nitinol stents, paclitaxel- or sirolimus-eluting stents (PES or SES), and paclitaxel-coated balloons (PCB) with plain balloon angioplasty or with each other in the femoropopliteal artery (PROSPERO registry: CRD42013004845).

METHODS

Sixteen RCTs comprising 2532 patients with 4227 person-years of follow-up were analyzed on an intention-to-treat basis. Bayesian random effects Poisson and binomial models were used for mixed treatment comparisons (WinBUGS). Clinical heterogeneity was accounted for by incorporating a meta-regression model on trial-specific baseline risk. End points included technical success, vascular restenosis, target lesion revascularization, and major amputations. Pairwise odds ratios and rate ratios (ORs and RRs) of absolute treatment effects were calculated, and the probabilities of each treatment being best are reported. Summary estimates are reported as the posterior median and associated credible intervals (CrIs) that serve the same purpose as confidence intervals in the context of the Bayesian framework. Extensive sensitivity, meta-regression, and network consistency analyses were performed to evaluate heterogeneity.

RESULTS

Technical success was highest with covered stents (pooled OR, 13.6; 95% CrI, 3.3-31.1, probability best 82%) followed by uncovered stents (pooled OR, 7.0; 95% CrI, 2.6-129, probability best 18%) when compared with balloon angioplasty (reference treatment). Vascular restenosis was lowest with PES (RR, 0.43; 95% CrI, 0.16-1.18, probability best 45%) followed by PCB (RR, 0.43; 95% CrI, 0.26-0.67, probability best 42%). Target lesion revascularization was lowest with PCB (RR, 0.36; 95% CrI, 0.23-0.55, probability best 56%) followed by PES (RR, 0.42; 95% CrI, 0.16-1.06, probability best 33%). Major amputations were rare in all treatment and control groups (pooled amputation rate of 0.7 events per 100 person-years).

CONCLUSIONS

Immediate technical success is better with the use of covered stents, whereas paclitaxel-eluting stents and paclitaxel-coated balloons offer the best long-term results in the femoropopliteal artery.

An exploration of synthesis methods in public health evaluations of interventions concludes that the use of modern statistical methods would be beneficial

OBJECTIVES

To review the methods currently used to synthesize evidence in public health evaluations and demonstrate the availability of more sophisticated approaches.

STUDY DESIGN AND SETTING

A systematic review of National Institute for Health and Care Excellence (NICE) public health appraisals published between 2006 and 2012 was performed to assess the methods used for the synthesis of effectiveness evidence. The ability of new developments in evidence synthesis methodology to address the challenges and opportunities present in a public health context is demonstrated.

RESULTS

Nine (23%) of the 39 NICE appraisals included in the review performed pairwise meta-analyses as part of the effectiveness review with one of these also including a network meta-analysis. Of the remainder, 29 (74.4%) presented narrative summaries of the evidence only, and 1 (2.6%) appraisal did not present any review of effectiveness and/or cost-effectiveness evidence. Heterogeneity of outcomes, methods, and interventions were the main reasons given for not pooling the data. Exploration of quantitative synthesis methods shows that pairwise meta-analyses can be extended to incorporate individual participant data (when it is available), extend the number of interventions being compared using a network meta-analysis, and adjust for both subject- and summary-level covariates. All these can contribute to ensuring the analysis answers directly the policy-relevant questions.

CONCLUSION

More sophisticated methods in evidence synthesis should be considered to make evaluations in public health more useful for decision makers.

Assessing key assumptions of network meta-analysis: a review of methods

BACKGROUND

Homogeneity and consistency assumptions underlie network meta-analysis (NMA). Methods exist to assess the assumptions but they are rarely and poorly applied. We review and illustrate methods to assess homogeneity and consistency.

METHODS

Eligible articles focussed on indirect comparison or NMA methodology. Articles were sought by hand-searching and scanning references (March 2013). Assumption assessment methods described in the articles were reviewed, and applied to compare anti-malarial drugs.

RESULTS

116 articles were included. Methods to assess homogeneity were: comparing characteristics across trials; comparing trial-specific treatment effects; using hypothesis tests or statistical measures; applying fixed-effect and random-effects pair-wise meta-analysis; and investigating treatment effect-modifiers. Methods to assess consistency were: comparing characteristics; investigating treatment effect-modifiers; comparing outcome measurements in the referent group; node-splitting; inconsistency modelling; hypothesis tests; back transformation; multidimensional scaling; a two-stage approach; and a graph-theoretical method. For the malaria example, heterogeneity existed for some comparisons that was unexplained by investigating treatment effect-modifiers. Inconsistency was detected using node-splitting and inconsistency modelling. It was unclear whether the covariates explained the inconsistency.

CONCLUSIONS

Presently, we advocate applying existing assessment methods collectively to gain the best understanding possible regarding whether assumptions are reasonable. In our example, consistency was questionable; therefore the NMA results may be unreliable.

Evidence synthesis for decision making 3: heterogeneity--subgroups, meta-regression, bias, and bias-adjustment

In meta-analysis, between-study heterogeneity indicates the presence of effect-modifiers and has implications for the interpretation of results in cost-effectiveness analysis and decision making. A distinction is usually made between true variability in treatment effects due to variation in patient populations or settings and biases related to the way in which trials were conducted. Variability in relative treatment effects threatens the external validity of trial evidence and limits the ability to generalize from the results; imperfections in trial conduct represent threats to internal validity. We provide guidance on methods for meta-regression and bias-adjustment, in pairwise and network meta-analysis (including indirect comparisons), using illustrative examples. We argue that the predictive distribution of a treatment effect in a "new" trial may, in many cases, be more relevant to decision making than the distribution of the mean effect. Investigators should consider the relative contribution of true variability and random variation due to biases when considering their response to heterogeneity. In network meta-analyses, various types of meta-regression models are possible when trial-level effect-modifying covariates are present or suspected. We argue that a model with a single interaction term is the one most likely to be useful in a decision-making context. Illustrative examples of Bayesian meta-regression against a continuous covariate and meta-regression against "baseline" risk are provided. Annotated WinBUGS code is set out in an appendix.