Stephanie J. Hubbard

Network meta-analysis of multiple outcome measures accounting for borrowing of information across outcomes

BackgroundNetwork meta-analysis (NMA) enables simultaneous comparison of multiple treatments while preserving randomisation. When summarising evidence to inform an economic evaluation, it is important that the analysis accurately reflects the dependency structure within the data, as correlations between outcomes may have implication for estimating the net benefit associated with treatment. A multivariate NMA offers a framework for evaluating multiple treatments across multiple outcome measures while accounting for the correlation structure between outcomes.MethodsThe standard NMA model is extended to multiple outcome settings in two stages. In the first stage, information is borrowed across outcomes as well across studies through modelling the within-study and between-study correlation structure. In the second stage, we make use of the additional assumption that intervention effects are exchangeable between outcomes to predict effect estimates for all outcomes, including effect estimates on outcomes where evidence is either sparse or the treatment had not been considered by any one of the studies included in the analysis. We apply the methods to binary outcome data from a systematic review evaluating the effectiveness of nine home safety interventions on uptake of three poisoning prevention practices (safe storage of medicines, safe storage of other household products, and possession of poison centre control telephone number) in households with children. Analyses are conducted in WinBUGS using Markov Chain Monte Carlo (MCMC) simulations.ResultsUnivariate and the first stage multivariate models produced broadly similar point estimates of intervention effects but the uncertainty around the multivariate estimates varied depending on the prior distribution specified for the between-study covariance structure. The second stage multivariate analyses produced more precise effect estimates while enabling intervention effects to be predicted for all outcomes, including intervention effects on outcomes not directly considered by the studies included in the analysis.ConclusionsAccounting for the dependency between outcomes in a multivariate meta-analysis may or may not improve the precision of effect estimates from a network meta-analysis compared to analysing each outcome separately.

The Effectiveness of Different Interventions to Promote Poison Prevention Behaviours in Households with Children: A Network Meta-Analysis

Background There is evidence from 2 previous meta-analyses that interventions to promote poison prevention behaviours are effective in increasing a range of poison prevention practices in households with children. The published meta-analyses compared any intervention against a “usual care or no intervention” which potentially limits the usefulness of the analysis to decision makers. We aim to use network meta-analysis to simultaneously evaluate the effectiveness of different interventions to increase prevalence of safe storage of i) Medicines only, ii) Other household products only, iii) Poisons (both medicines and non-medicines), iv) Poisonous plants; and v) Possession of poison control centre (PCC) telephone number in households with children. Methods Data on the effectiveness of poison prevention interventions was extracted from primary studies identified in 2 newly-undertaken systematic reviews. Effect estimates were pooled across studies using a random effects network meta-analysis model. Results 28 of the 47 primary studies identified were included in the analysis. Compared to usual care intervention, the intervention with education and low cost/free equipment elements was most effective in promoting safe storage of medicines (odds ratio 2.51, 95% credible interval 1.01 to 6.00) while interventions with education, low cost/free equipment, home safety inspection and fitting components were most effective in promoting safe storage of other household products (2.52, 1.12 to 7.13), safe storage of poisons (11.10, 1.60 to 141.50) and possession of PCC number (38.82, 2.19 to 687.10). No one intervention package was more effective than the others in promoting safe storage of poisonous plants. Conclusion The most effective interventions varied by poison prevention practice, but education alone was not the most effective intervention for any poison prevention practice. Commissioners and providers of poison prevention interventions should tailor the interventions they commission or provide to the poison prevention practices they wish to promote. Highlights Network meta-analysis is useful for comparing multiple injury-prevention interventions. More intensive poison prevention interventions were more effective than education alone. Education and low cost/free equipment was most effective in promoting safe storage of medicines. Education, low cost/free equipment, home safety inspection and fitting was most effective in promoting safe storage of household products and poisons. Education, low cost/free equipment and home inspection were most effective in promoting possession of a poison control centre number. None of the intervention packages was more effective than the others in promoting safe storage of poisonous plants.

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.

Network meta-analysis to evaluate the effectiveness of interventions to prevent falls in children under age 5 years

Background This study aimed to simultaneously evaluate the effectiveness of a range of interventions to increase the possession of safety equipment or behaviours to prevent falls in children under 5 years of age in the home. Methods A recently published systematic review identified studies to be included in a network meta-analysis; an extension of pairwise meta-analysis that enables comparison of all evaluated interventions simultaneously, including comparisons not directly compared in individual studies. Results 29 primary studies were identified, of which 16 were included in at least 1 of 4 network meta-analyses. For increasing possession of a fitted stair gate, the most intensive intervention (including education, low cost/free home safety equipment, home safety inspection and fitting) was the most likely to be the most effective, with an OR versus usual care of 7.80 (95% CrI 3.08 to 21.3). For reducing possession or use of a baby walker: education only was most likely to be most effective, with an OR versus usual care of 0.48 (95% CrI 0.31 to 0.84). Little difference was found between interventions for possession of window locks (most intensive intervention versus usual care OR=1.56 (95% CrI 0.02 to 89.8)) and for not leaving a child alone on a high surface (education vs usual care OR=0.89 (95% CrI 0.10 to 9.67)). There was insufficient evidence for network meta-analysis for possession and use of bath mats. Conclusions These results will inform healthcare providers of the most effective components of interventions and can be used in cost-effectiveness analyses.

Should the mitral valve be repaired for moderate ischemic mitral regurgitation at the time of revascularization surgery

Ischemic mitral regurgitation (IMR) is associated with increased mortality and recurrent congestive heart failure following coronary artery bypass graft (CABG) surgery. While mitral surgery should be undertaken for severe MR during CABG, the treatment of moderate IMR remains controversial. We conducted a meta‐analysis to determine the outcomes of CABG alone and combine with mitral valve repair (MVr) in moderate IMR.

Systematic review and meta-analysis evaluating the effectiveness of home safety interventions (education and provision of safety equipment) for child injury prevention

Background Injuries are the leading cause of childhood death in industrialised countries with steep social gradients in morbidity and mortality. Most injuries in pre-school children occur at home, however there is little meta-analytic evidence that home safety interventions (HSI) reduce injury rates, improve safety practices or impact on injury inequalities. Aims/Objectives/Purpose To investigate effectiveness of HSI in increasing home safety practices and reducing child injury rates and whether the effect varied by social group. Methods Bibliographic databases, relevant websites, conference proceedings, bibliographies of relevant studies, and previously published reviews were searched. Results/Outcome 54 studies were included in at least one meta-analysis. HSI were effective in promoting safe hot tap water temperatures (OR 1.41, 95% CI 1.07 to 1.86), functional smoke alarms (OR 1.81, 95% CI 1.30 to 2.52), fire escape plans (OR 2.01, 95% CI 1,45 to 2.77), storing medicines (OR 1.53, 95% CI 1.27 to 1.84) and cleaning products (OR 1.55, 95% CI 1.22 to 1.96) out of reach, having syrup of ipecac (OR 3.34, 95% CI 1.50 to 7.44) and poison control centre numbers accessible (OR 3.30, 95% CI 1.70 to 6.39) and fitted stair gates (OR 1.61, 95% CI 1.19 to 2.17). HSI may reduce injury rates especially when delivered at home (IRR 0.75, 95% CI 0.62 to 0.91). There was no consistent evidence that HSI were less effective in those at greater risk of injury. Significance/Contribution to the Field HSI are effective in increasing a range of safety practices and may reduce injury rates without widening existing inequalities.