Meta-analysis Methodology Research Articles

Genetic Predisposition to Developmental Dysplasia of the Hip

BackgroundThe etiopathogenesis of developmental dysplasia of the hip (DDH) has not been clarified. This systematic review evaluated current literature concerning all known chromosomes, loci, genes, and their polymorphisms that have been associated or not with the prevalence and severity of DDH. MethodsFollowing the established methodology of Meta-analysis of Observational Studies in Epidemiology guidelines, MEDLINE, EMBASE, and Cochrane Register of Controlled Trials were systematically searched from inception to January 2019. ResultsForty-five studies were finally included. The majority of genetic studies were candidate gene association studies assessing Chinese populations with moderate methodological quality. Among the most frequently studied are the first, third, 12th,17th, and 20th chromosomes. No gene was firmly associated with DDH phenotype. Studies from different populations often report conflicting results on the same single-nucleotide polymorphism (SNP). The SNP rs143384 of GDF5 gene on chromosome 20 demonstrated the most robust relationship with DDH phenotype in association studies. The highest odds of coinheritance in linkage studies have been reported for regions of chromosome 3 and 13. Five SNPs have been associated with the severity of DDH. Animal model studies validating previous human findings provided suggestive evidence of an inducing role of mutations of the GDF5, CX3CR1, and TENM3 genes in DDH etiopathogenesis. ConclusionDDH is a complex disorder with environmental and genetic causes. However, no firm correlation between genotype and DDH phenotype currently exists. Systematic genome evaluation in studies with larger sample size, better methodological quality, and assessment of DDH patients is necessary to clarify the DDH heredity. The role of next-generation sequencing techniques is promising.

In the Grand Scheme of Things: Identifying Reproducible Microbial Signatures in Dietary Intervention Studies

Nutrition research is plagued by the reproducibility crisis. Reconciling nutrition studies involving microbiome data presents a modern challenge for researchers. In this issue of Cell Host & Microbe, Bisanz et al., 2019 demonstrate a comprehensive methodology for meta-analysis of microbiome sequence data from high-fat-diet intervention studies.

Qualitative meta-analysis of propensity to trust measurement

ABSTRACTIn a rapidly changing and dynamic world, individuals’ propensity to trust is likely to become an increasingly important facet for understanding human behaviour, yet its measurement has mostly been unexplored. We undertake the first systematic qualitative survey of propensity to trust scales using qualitative meta-analysis methodology to review the literature (1966–2018) and identify 26 measures and their applications in 179 studies. Using content analysis, we thematically organise these scales into six thematic areas and discuss the emerging implications. We find that while most of these scales reflect propensity to trust in terms of a positive belief in human nature, other themes include general trust, role expectations, institutional trust, cautiousness and other personality attributes. We reveal significant methodological concerns regarding several scales and argue for more considered selection of scales for use in research. We examine the case for multidimensionality in measures of propensity to trust used within organisational research. Rather than treating a lack of generalisability of findings in existing organisational studies as purely a problem of measurement design, we instead outline an agenda for further conceptual and empirical study.

Key Factors in Customer Relationship Management Strategy Success in the Local Government Authorities

The aim of the study was to identify critical success factors in customer relationship management strategy success in the local government authorities in Zimbabwe. A thorough abridgment of the literature was conducted, mainly to understand the nature and structure of local government authorities in Zimbabwe as well as to identify critical success factors in CRM strategy success. A Meta-analysis methodology was employed and explanatory research approach was adopted by means of a survey strategy. 197 questionnaires have been collected from twenty one local government authorities in Zimbabwe. The findings of the study revealed that all of the ten critical success factors are significant and positively linked to CRM strategy success. Furthermore, the statistical tests show that success and failure of CRM strategy success are highly dependent on four major critical success factors including Implementation Approach, Change Management, Metrics and Implementation Strategy. However, process design and Buy-in Approach and Adoption have low significance impact in CRM strategy success in local government authorities in Zimbabwe. The results of the data analysis led to the creation of a framework which outlines the critical success factors in CRM strategy success in local government authorities in Zimbabwe and the CRM implementation Index which need to be followed before implementing the CRM strategy. This study has clearly indicated that customer relationship management forms a powerful strategy that local government authorities should apply to manage long-term relationships with their key stakeholders.

Exercise vs metformin for gestational diabetes mellitus: Protocol for a network meta-analysis.

Introduction:The purpose of this protocol is to provide a network meta-analysis methodology that compares the effects of metformin and physical exercise in the prevention and treatment of gestational diabetes mellitus (GDM) and its associated fetal and maternal morbidity.Methods and analysis:This protocol conforms to the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) and the recommendations of the Cochrane Collaboration Handbook. An electronic search will be conducted in MEDLINE, EMBASE, Web of Science and the Cochrane Library, from the inception until July 2019. There will be no language restrictions. The Cochrane Collaboration tool for assessing risk of bias (RoB2) and the quality assessment tool for quantitative studies will be used. The Grading of Recommendations, Assessment, Development and Evaluation scale will be used to evaluate the strength of the evidence. A Bayesian network meta-analysis will be carried out, which allows direct and indirect comparison of the interventions, for the risk of GDM, prematurity, caesarean section, macrosomia, hypertensive disorders, insulin requirement, and differences in basal glucose, maternal weight, and weight of the newborn.Discussion:With this protocol, a methodology is established that resolves the limitations of previous meta-analysis. It will be possible to determine the difference of effect between physical exercise and metformin in the main outcomes of the GDM, as well as the type and intensity of the exercise, and the dose of metformin, more effective.Ethics and dissemination:The data included in the network meta-analysis will be obtained from trials that meet accepted ethical standards and the Declaration of Helsinki. The results will be published in a peer-reviewed journal. The evidence obtained could be included in the guidelines of clinical practice in pregnancy.Strengths and limitations:A comprehensive methodology is established for the analysis, through network meta-analysis, of the comparative efficacy of metformin and physical exercise in gestational diabetes mellitus. The results obtained could help medical professionals by establishing the best evidence-based interventions which may be recommended for these population groups.Registration number:PROSPERO CRD42019121715

Efficacy of acupuncture in the management of fatigue related to breast cancer antineoplastic treatment: a systematic review

INTRODUCTION: Breast cancer is the most prevalent cancer among women worldwide. Similar to chemotherapy, antineoplastic treatment is associated with many side effects, with fatigue being one of the most common. It is important to investigate potential treatments, especially non-pharmacological alternatives, to control symptoms that directly affect women’s quality of life. OBJECTIVE: The objective of this study was to provide scientific evidence to verify the efficacy of acupuncture in the management of fatigue in patients with breast cancer. METHODS: This study involved a systematic review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) methodology. Randomized clinical trials published in indexed scientific journals were compiled. The literature search was performed using the electronic databases, PubMed, PEDro, and BIREME, using the descriptors ‘breast cancer’, ‘fatigue’, ‘acupuncture’, and ‘randomized trial’. Inclusion criteria included fully available online articles that were classified as randomised clinical trials published from 2012 to 2017 in either English or Portuguese. Study eligibility was based on the Population, Intervention, Control, Outcome, and Study (PICO) design criteria, in which the (1) population included women 18–65 years of age with breast cancer, (2) intervention was acupuncture, (3) comparison referred to standard care or sham acupuncture, and (4) outcome was the evaluation of fatigue. The PEDro scale was applied to evaluate the quality of the studies. WebQualis was also used to evaluate the quality of the journals of the selected articles. RESULTS: In total, 66 articles were selected, but only four fulfilled all inclusion criteria, giving a total sample size of 620 women. All trials evaluated the effect of acupuncture on fatigue and other symptoms related to the treatment of breast cancer with different treatment durations. Three articles reported statistically significant results, and all articles described clinical improvement in fatigue after the application of acupuncture. The average PEDro score of the manuscripts was 6.25. All articles were published in non-Brazilian journals with WebQualis scores that ranged from B2 to A1. CONCLUSION: Scientific evidence confirms the efficacy of acupuncture in the management of fatigue reported by women with breast cancer. Acupuncture was effective in reducing fatigue in the studies selected for this review.

Rethinking meta-analysis: Addressing problems of non-transportability when combining treatment effects across patient populations

Introduction Standard methodology for meta-analysis (MA) only focuses on deriving a summary estimate but remains implicit about the patient population for which it describes the treatment effect. However, the evidence about treatment effect in one population cannot always be applied to another population that differs possibly in many aspects from that of the original trial, in which case we say there is lack of transportability. In practice, standard MAs do not always ensure homogeneity in the baseline characteristics of the different trial populations; thereby do not rule out a potential lack of transportability. Besides, standard MAs often overlook the under-representation of low- and middle-income countries in the available evidence for several medical interventions. As a consequence, simply meta-analyzing results of trials conducted in developed countries will be not informative for policymakers in low-income countries to implement the most efficient interventions for their populations. Method In this paper, we remedy these issues by proposing an alternative MA approach for randomized clinical trials, which uses individual patient data (IPD) from all trials to infer the treatment effect for the patient population in a given trial, based on case-mix standardization. Denote Y(1k) and Y(0k) as the counterfactual outcome that would be observed for a given individual if (version of) treatment and control used in trial S = k were administered, respectively. Our focus is on estimating the probabilities P{Y(xk) = 1|S = j} (x = 0,1), which are the chance of successfully treated if the patients in population S = j was given the version of treatment (x = 1) or control (x = 0) used in study S = k. Based on these, the effect of the treatment version in population can be measured–for instance, on the relative risk scale RR(j,k) = P{Y(1k) = 1|S = j}/P{Y(0k) = 1|S = j}. Under certain conditions, RR(j, k) can be estimated by two different approaches, namely: – outcome regression; – inverse probability weighting. The estimates log{RR(j, k)} obtained from the same population j are then summarized by conducting a conventional random-effect MA. The resulting summary estimate thereby represents the effect of treatment for the target population j, while the heterogeneity variance estimate expresses how much results from different trials vary even when considered for the same patient population. Results We illustrate the new approach by considering a MA of numerically simulated RCTs that evaluate a binary treatment versus control with respect to a binary outcome. Results of this simulation point out that the proposed framework does enable better understood heterogeneity assessments. The overall heterogeneity across trial results can now be decomposed into 2 different parts, namely case-mix (CM) and beyond case-mix (BCM) heterogeneity. The new framework is then applied to reanalyze a published IPD MA evaluating the effect of vitamin D on the risk of respiratory infection. Finally, we extend the framework to settings where the IPD is only available for some but not for all trials in the MA. Discussion In conclusion, case-mix standardization prior to evidence synthesis is a good strategy to overcome the lack of transportability and other related issues that complicate most MAs. Not only resulting in more interpretable summary results, this strategy also sheds insightful light onto how and why results of different trials are heterogeneous in practice.

Individual patient data network meta-analysis using either restricted mean survival time difference or hazard ratios: is there a difference? A case study on locoregionally advanced nasopharyngeal carcinomas

BackgroundThis study aimed at applying the restricted mean survival time difference (rmstD) as an absolute outcome measure in a network meta-analysis and comparing the results with those obtained using hazard ratios (HR) from the individual patient data (IPD) network meta-analysis (NMA) on the role of chemotherapy for nasopharyngeal carcinoma (NPC) recently published by the MAC-NPC collaborative group (Meta-Analysis of Chemotherapy [CT] in NPC).Patients and methodsTwenty trials (5144 patients) comparing radiotherapy (RT) with or without CT in non-metastatic NPC were included. Treatments were grouped in seven categories: RT alone (RT), induction CT followed by RT (IC-RT), RT followed by adjuvant CT (RT-AC), IC followed by RT followed by AC (IC-RT-AC), concomitant chemoradiotherapy (CRT), IC followed by CRT (IC-CRT), and CRT followed by AC (CRT-AC). The primary endpoint was overall survival (OS); secondary endpoints were progression-free survival and locoregional control. The rmstD was estimated at t* = 10 years in each trial. Random-effect frequentist NMA models were applied. P score was used to rank treatments. Heterogeneity and inconsistency were evaluated.ResultsThe three treatments that had the highest effect on OS with rmstD were CRT-AC, IC-CRT, and CRT (respective P scores of 92%, 72%, and 64%) compared to CRT-AC, CRT, and IC-CRT when using HR (respective P scores of 96%, 71%, and 63%). Of the 32 HR and rmstD analyzed, 5 had a different interpretation, 3 with a direction change (different direction of treatment effect) and 2 with a change in significance (same direction but a change in statistical significance). Results for secondary endpoints were overall in agreement.ConclusionThe use of either HR or rmstD impacts the results of NMA. Given the sensitivity of HR to non-proportional hazards, this finding could have implications in terms of meta-analysis methodology.

Exploring Campylobacter seasonality across Europe using The European Surveillance System (TESSy), 2008 to 2016.

BackgroundCampylobacteriosis is the most commonly reported food-borne infection in the European Union, with an annual number of cases estimated at around 9 million. In many countries, campylobacteriosis has a striking seasonal peak during early/mid-summer. In the early 2000s, several publications reported on campylobacteriosis seasonality across Europe and associations with temperature and precipitation. Subsequently, many European countries have introduced new measures against this food-borne disease.AimTo examine how the seasonality of campylobacteriosis varied across Europe from 2008–16, to explore associations with temperature and precipitation, and to compare these results with previous studies. We also sought to assess the utility of the European Surveillance System TESSy for cross-European seasonal analysis of campylobacteriosis.MethodsWard’s Minimum Variance Clustering was used to group countries with similar seasonal patterns of campylobacteriosis. A two-stage multivariate meta-analysis methodology was used to explore associations with temperature and precipitation.ResultsNordic countries had a pronounced seasonal campylobacteriosis peak in mid- to late summer (weeks 29–32), while most other European countries had a less pronounced peak earlier in the year. The United Kingdom, Ireland, Hungary and Slovakia had a slightly earlier peak (week 24). Campylobacteriosis cases were positively associated with temperature and, to a lesser degree, precipitation.ConclusionAcross Europe, the strength and timing of campylobacteriosis peaks have remained similar to those observed previously. In addition, TESSy is a useful resource for cross-European seasonal analysis of infectious diseases such as campylobacteriosis, but its utility depends upon each country’s reporting infrastructure.

Unintentional participant observation: a research method to inform peer support in mental health?

Purpose The purpose of this paper is to validate peer support in mental health care. Design/methodology/approach Literature review and meta-analysis methodology are used. Findings The unintentional nature of peer support is a valid methodology for the understanding of mental health issues and mental health care. Research limitations/implications The limitation is that peer experience should be accepted as a valued method for research. Practical implications Professional domains may not keep a monopoly of research approaches in mental health. Social implications Peer support may mean more avenues for empowerment of mental health service users from peer role models who have unintentional acquaintance with mental health issues and care. Originality/value This research refers to ethnographic precedents to describe methodology relevant to twenty-first century peer support in mental health. It is original in valuing the unintentional participant observation acquired from experience of the mental health system.

Deep brain stimulation for Gilles de la Tourette syndrome in children and youth: a meta-analysis with individual participant data.

Gilles de la Tourette syndrome (GTS) is a disorder characterized by motor and vocal tics. Although by definition the onset of GTS is before age 18 years, clinical trials of deep brain stimulation (DBS) have been conducted only in adults. Using individual participant data (IPD) meta-analysis methodology, the current study investigated the safety and efficacy of DBS as a treatment for GTS in children and youth. A systematic review with no date or language restrictions was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. Three electronic databases were searched: PubMed, EMBASE, and Web of Science. From 843 articles screened, the IPD of 58 children and youth (ages 12–21 years) extracted from 21 articles were collected and analyzed. A mixed-effects univariable analysis followed by multivariable hierarchical regression was performed using change in the Yale Global Tic Severity Scale (YGTSS) score as the primary outcome and reported measures of comorbidities as secondary outcomes. The authors’ results showed an average improvement of 57.5% ± 24.6% across studies on the YGTSS. They also found that comorbid depression and stimulation pulse width each correlated negatively with outcome (p < 0.05). In patients with less severe GTS, greater improvements were evident following thalamic stimulation. More than one-quarter (n = 16, 27.6%) of participants experienced side effects, the majority of which were minor. DBS in the pediatric population may be an effective option with a moderate safety profile for treatment of GTS in carefully selected children and youth. Large, prospective studies with long-term follow-up are necessary to understand how DBS influences tic symptoms and may alter the natural course of GTS in children.

General methodology of meta-analysis and data interpretation in surgery

Meta-analysis is a leading methodology used in systematic secondary researches. Review Manager software is the main tool used by leading world expert groups for meta-analysis. The authors analyzed the features of meta-analyzes evaluating the results of surgeries. It is shown that the majority of baseline clinical parameters correspond to normal distribution (in accordance with central limit theorem) considering the fact that surgical outcomes depend on various and often unpredictable factors. Moreover, multiple heterogeneous variables are compared in the meta-analysis due to the differences in diagnostic scales and methods of evaluating the results in primary researches. Therefore, both absolute and standardized measurements are required for these purposes. The authors describe the features of meta-analysis for dichotomous, continuous and skewed data, as well as for ordinal outcomes, time-to-event, counts and ratios. These data are useful to interpret numerical values, objectively evaluate the majority of surgical outcomes and predict the effectiveness of interventions.

Building Students’ Hard and Soft Skills through Innovative Teaching Approaches to Mathematics

The goals of this case study were to (1) analyze the role of innovative mathematics teaching approaches among middle and high school students regarding their hard and soft mathematical skills; (2) to examine students’ perceptions about the mathematical teaching approaches, used by their teachers during class sessions, (3) to analyze aspects of innovation in them. The descriptive case study approach was used to analyze the role of innovative teaching approaches in helping students to develop various mathematical hard and soft skills. A qualitative meta-analysis methodology was applied to ten student theses about mathematics teaching within the Department of Mathematics in the School of Postgraduate studies of IKIP Siliwangi in Cimahi. This paper presents the results based on ten graduate students’ theses research studies, selected purposively from 68 student theses. The selection of articles aimed to include a variety of theses discussing mathematics skills teaching and learning approaches. The results show that, in general, students who were trained with innovative teaching approaches attained higher grades than students taught by conventional teaching methods. It has been established that students’ grades on mathematical hard skills varied after intervention. On the contrary, regarding students mathematical soft skills, some theses reported no difference between students taught using both approaches, while some reported greater differences. Finally, students had good opinions regarding the innovative teaching-learning approaches, used by their teachers.

The use of ultrasound-guided platelet-rich plasma injections in the treatment of hip osteoarthritis: a systematic review of the literature.

Purpose: This review aims to determine whether ultrasound-guided platelet-rich plasma injection has any role in improving clinical outcomes in patients with hip osteoarthritis. Methods: A search of the National Institute for Health and Care Excellence database using the Healthcare Databases Advanced Search tool was conducted. The PubMed database was also utilised to search the Medical Literature Analysis and Retrieval System Online, Excerpta Medica database, Cumulative Index of Nursing and Allied Health and Allied and Complimentary Medicine databases. The Preferred Reporting Items for Systematic Review and Meta-Analysis methodology guidance was employed and a quality assessment was performed using the Jadad score. Results: Three randomised clinical trials met the inclusion criteria and were included for analysis. All three trials were of good quality based on the Jadad score. A total of 115 patients out of 254 received platelet-rich plasma injections under ultrasound guidance. The platelet-rich plasma recipient group included 61 males and 54 females with an age range from 53 to 71 years. Outcome scores show an improvement of symptoms and function maintained up to 12 months following platelet-rich plasma injection. Conclusions: Literature to date concludes that intra-articular platelet-rich plasma injections of the hip, performed under ultrasound guidance to treat hip osteoarthritis, are well tolerated and potentially efficacious in delivering long-term and clinically significant pain reduction and functional improvement in patients with hip osteoarthritis. Larger future trials including a placebo group are required to further evaluate these promising results. Level of evidence: Level I, a systematic review of level I studies.

Estimating the contribution of studies in network meta-analysis: paths, flows and streams.

In network meta-analysis, it is important to assess the influence of the limitations or other characteristics of individual studies on the estimates obtained from the network. The proportion contribution matrix, which shows how much each direct treatment effect contributes to each treatment effect estimate from network meta-analysis, is crucial in this context. We use ideas from graph theory to derive the proportion that is contributed by each direct treatment effect. We start with the 'projection' matrix in a two-step network meta-analysis model, called the H matrix, which is analogous to the hat matrix in a linear regression model. We develop a method to translate H entries to proportion contributions based on the observation that the rows of H can be interpreted as flow networks, where a stream is defined as the composition of a path and its associated flow. We present an algorithm that identifies the flow of evidence in each path and decomposes it into direct comparisons. To illustrate the methodology, we use two published networks of interventions. The first compares no treatment, quinolone antibiotics, non-quinolone antibiotics and antiseptics for underlying eardrum perforations and the second compares 14 antimanic drugs. We believe that this approach is a useful and novel addition to network meta-analysis methodology, which allows the consistent derivation of the proportion contributions of direct evidence from individual studies to network treatment effects.

A network meta-analysis of the susceptibility of apple genotypes to powdery mildew under organic management

The susceptibility of apple tree genotypes to powdery mildew has been quantitatively evaluated in the field by various researchers. Our aim was to attempt to overcome difficulties such as sampling error, and differences in the designs, time periods and geographical locations of studies, to form a consensus about the variation in this susceptibility over different apple genotypes under organic management by applying the methodology of meta-analysis. A systematic search of appropriate databases was conducted for relevant articles published from January 1998 to December 2017. It was required that susceptibility to powdery mildew was measured by incidence in terms of the percentage of affected leaves. Where possible, the incidence levels of the studies that satisfied given criteria were standardized using an association scheme and adjustment factors to the mean environmental conditions in what was chosen to be the base study. The literature search found 22 studies that satisfied all the inclusion criteria of the meta-analysis, and for 20 of these, incidence levels could be standardized. Since the overall virulence of the fungus varied greatly across studies, standardizing incidences was crucial. Of the 12 genotypes having the lowest mean standardized incidences in the main analysis of 94 genotypes, the least well-known are ‘Earlidel’, ‘Florina-Quérina’, ‘Lourdes’, ‘Piros’, ‘Rajka’, ‘Topaz’, ‘436’ and ‘468’ of which the former 6 genotypes are arguably the more appealing to producers in terms of fruit yield and the appearance, taste and texture of their fruits. Many genotypes appear to have susceptibilities relative to other groups of genotypes that are not that sensitive to changes in environmental conditions, including the native strains of the pathogen that are present, however for other genotypes this sensitivity appears to be reasonably high.

The Mortality After Release from Incarceration Consortium (MARIC) study: Strengths of international data linkage

IntroductionAdults released from incarceration experience complex physical and mental health problems, and are at markedly increased risk of preventable death. Despite this, not enough is known about the granular epidemiology of mortality in this population to inform development of targeted, evidence-based responses.&#x0D; Objectives and ApproachWe created the Mortality After Release from Incarceration Consortium (MARIC), a multi-disciplinary collaboration from 12 countries representing 30 cohorts of adults with a history of incarceration. The combined sample size is 1,210,168, with 58,840 deaths recorded over 8,261,743 person-years of follow-up time. In this protocol paper, using a two-step, individual participant data meta-analysis (IPDM-A) methodology involving 22 MARIC cohorts, we calculated 1) a crude mortality rate (CMR; with 95% confidence intervals) for each individual cohort over the first 84 days (12 weeks) following release; and 2) a combined, meta-analysed CMR for the same period.&#x0D; ResultsOf 1,704,208 individual releases, we observed 4,018 deaths over the first 84 days. The overall CMR over the first 84 days after release was 1610.97 deaths per 100,000 person-years (95% CI: 1263.4 - 1958.5). The rate was highest on the day of release (5768.0; 95% CI: 3296.5 - 8239.4), which was significantly higher than on days 4-84.&#x0D; Conclusion/ImplicationsAdults released from incarceration were at an acutely increased risk of death on the day of release, and this risk remained elevated for at least the first 12 weeks. The MARIC study will provide decisive and empirical evidence to guide clinicians and policy makers in reducing mortality in this marginalized

Estimating the contribution of studies in network meta-analysis: paths, flows and streams.

In network meta-analysis, it is important to assess the influence of the limitations or other characteristics of individual studies on the estimates obtained from the network. The percentage contribution matrix, which shows how much each direct treatment effect contributes to each treatment effect estimate from network meta-analysis, is crucial in this context. We use ideas from graph theory to derive the percentage that is contributed by each direct treatment effect. We start with the 'projection' matrix in a two-step network meta-analysis model, called the H matrix, which is analogous to the hat matrix in a linear regression model. We develop a method to translate H entries to percentage contributions based on the observation that the rows of H can be interpreted as flow networks, where a stream is defined as the composition of a path and its associated flow. We present an algorithm that identifies the flow of evidence in each path and decomposes it into direct comparisons. To illustrate the methodology, we use two published networks of interventions. The first compares no treatment, quinolone antibiotics, non-quinolone antibiotics and antiseptics for underlying eardrum perforations and the second compares 14 antimanic drugs. We believe that this approach is a useful and novel addition to network meta-analysis methodology, which allows the consistent derivation of the percentage contributions of direct evidence from individual studies to network treatment effects.

Updated evaluation of sonic boom noise metrics

There is no internationally agreed-upon standard noise metric that can be used to quantify sonic boom levels from overflight of supersonic aircraft. Several laboratory studies have investigated perception of sonic booms in outdoor environments, as well as in indoor environments, where transmission loss alters the spectral content and level of the sonic boom and additional factors such as secondary rattle noise and vibration affect perception. Each study has previously been evaluated separately for performance of noise metrics, and the results do not clearly indicate a preferred metric. Meta-analyses have also been performed to evaluate the performance of metrics across five of these studies. An additional sixth study of human response that incorporates rattle noise resulting from sonic booms at representative levels was recently conducted and has been added to the meta-analysis. The analysis considered thirteen metrics with three meta-analysis methodologies: individual subject ratings for indoor studies, mean ratings for indoor studies, and mean ratings for both indoor and outdoor studies. Considering both indoor and outdoor studies, this latest analysis confirmed previous results on the five metrics with highest correlation (r2) across studies: PL, BSEL, DSEL, ESEL, and ISBAP (Indoor Sonic Boom Annoyance Predictor).

Análisis bibliométrico de la producción científica sobre judo como deporte de combate

El objetivo de este trabajo fue analizar las tendencias de la investigación en judo como deporte de combate por medio de un análisis bibliométrico de la producción científica en la base de datos Web of Science, a través de los 336 artículos publicados entre los años 2007 al 2017. Tras utilizar la metodología Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA-P), la muestra del estudio fueron 88 artículos. Se analizaron diferentes tipos de variables agrupadas en: a) características institucionales; b) características de la muestra; y c) métodos e instrumentos de investigación. Los resultados mostraron que los años más productivos fueron 2014 y 2016, donde el número medio de autores fue de 4,56±1,79, y el de citas en la Web of Science fue de 9,25±11,9. El mayor porcentaje de publicaciones presentó una muestra masculina, de alto rendimiento y bajo la disciplina de la teoría del entrenamiento. La metodología más utilizada fue el estudio observacional con estadística univariante a través de instrumental y hojas de observación. Los parámetros más estudiados fueron los fisiológicos y los técnico-tácticos. Parece ser que el judo como deporte de combate muestra mayor interés científico en su carácter deportivo y competitivo. Se proponen medidas para conseguir un análisis más específico de la modalidad del judo, sin contextualizarlo como deporte de combate.