Knowledge, attitudes, beliefs, values, preferences, and feasibility in relation to the use of injection safety devices in healthcare settings: a systematic review

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Fragmentation of J/ψ in jets in pp collisions at √s = 5.02 TeV

The fragmentation of jets containing a J/ψ meson is studied in √s = 5.02 TeV pp data using an integrated luminosity of L = 27.39pb^(−1). The fraction of the jet transverse momentum p_(T,jet) carried by the J/ψ is measured for prompt J/ψ and J/ψcoming from b hadron decays, named nonprompt. Whereas the fragmentation function of nonprompt J/ψ is well-modeled by simulations using a Monte Carlo generator, the prompt J/ψ are found to be accompanied by a larger level of jet activity. The fraction of J/ψ mesons that are produced inside a jet is also reported, and found to be larger in data than in simulation, for both prompt and nonprompt J/ψ

Meta-Analyses Proved Inconsistent in How Missing Data Were Handled Across Their Included Primary Trials: A Methodological Survey

Background: How systematic review authors address missing data among eligible primary studies remains uncertain. Objective: To assess whether systematic review authors are consistent in the way they handle missing data, both across trials included in the same meta-analysis, and with their reported methods. Methods: We first identified 100 eligible systematic reviews that included a statistically significant meta-analysis of a patient-important dichotomous efficacy outcome. Then, we successfully retrieved 638 of the 653 trials included in these systematic reviews' meta-analyses. From each trial report, we extracted statistical data used in the analysis of the outcome of interest to compare with the data used in the meta-analysis. First, we used these comparisons to classify the "analytical method actually used" for handling missing data by the systematic review authors for each included trial. Second, we assessed whether systematic reviews explicitly reported their analytical method of handling missing data. Third, we calculated the proportion of systematic reviews that were consistent in their "analytical method actually used" across trials included in the same meta-analysis. Fourth, among systematic reviews that were consistent in the "analytical method actually used" across trials and explicitly reported on a method for handling missing data, we assessed whether the "analytical method actually used" and the reported methods were consistent. Results: We were unable to determine the "analytical method reviews actually used" for handling missing outcome data among 397 trials. Among the remaining 241, systematic review authors most commonly conducted "complete case analysis" (n=128, 53%) or assumed "none of the participants with missing data had the event of interest" (n=58, 24%). Only eight of 100 systematic reviews were consistent in their approach to handling missing data across included trials, but none of these reported methods for handling missing data. Among seven reviews that did explicitly report their analytical method of handling missing data, only one was consistent in their approach across included trials (using complete case analysis), and their approach was inconsistent with their reported methods (assumed all participants with missing data had the event). Conclusion: The majority of systematic review authors were inconsistent in their approach towards reporting and handling missing outcome data across eligible primary trials, and most did not explicitly report their methods to handle missing data. Systematic review authors should clearly identify missing outcome data among their eligible trials, specify an approach for handling missing data in their analyses, and apply their approach consistently across all primary trials

Potential impact of missing outcome data on treatment effects in systematic reviews: imputation study

AbstractObjective To assess the risk of bias associated with missing outcome data in systematic reviews. Design Imputation study. Setting Systematic reviews. Population 100 systematic reviews that included a group level meta-analysis with a statistically significant effect on a patient important dichotomous efficacy outcome. Main outcome measures Median percentage change in the relative effect estimate when applying each of the following assumption (four commonly discussed but implausible assumptions (best case scenario, none had the event, all had the event, and worst case scenario) and four plausible assumptions for missing data based on the informative missingness odds ratio (IMOR) approach (IMOR 1.5 (least stringent), IMOR 2, IMOR 3, IMOR 5 (most stringent)); percentage of meta-analyses that crossed the threshold of the null effect for each method; and percentage of meta-analyses that qualitatively changed direction of effect for each method. Sensitivity analyses based on the eight different methods of handling missing data were conducted. Results 100 systematic reviews with 653 randomised controlled trials were included. When applying the implausible but commonly discussed assumptions, the median change in the relative effect estimate varied from 0% to 30.4%. The percentage of meta-analyses crossing the threshold of the null effect varied from 1% (best case scenario) to 60% (worst case scenario), and 26% changed direction with the worst case scenario. When applying the plausible assumptions, the median percentage change in relative effect estimate varied from 1.4% to 7.0%. The percentage of meta-analyses crossing the threshold of the null effect varied from 6% (IMOR 1.5) to 22% (IMOR 5) of meta-analyses, and 2% changed direction with the most stringent (IMOR 5). Conclusion Even when applying plausible assumptions to the outcomes of participants with definite missing data, the average change in pooled relative effect estimate is substantive, and almost a quarter (22%) of meta-analyses crossed the threshold of the null effect. Systematic review authors should present the potential impact of missing outcome data on their effect estimates and use this to inform their overall GRADE (grading of recommendations assessment, development, and evaluation) ratings of risk of bias and their interpretation of the results

Impact of missing participant data for dichotomous outcomes on pooled effect estimates in systematic reviews : a protocol for a methodological study

Abstract Background There is no consensus on how authors conducting meta-analysis should deal with trial participants with missing outcome data. The objectives of this study are to assess in Cochrane and non-Cochrane systematic reviews: (1) which categories of trial participants the systematic review authors consider as having missing participant data (MPD), (2) how trialists reported on participants with missing outcome data in trials, (3) whether systematic reviewer authors actually dealt with MPD in their meta-analyses of dichotomous outcomes consistently with their reported methods, and (4) the impact of different methods of dealing with MPD on pooled effect estimates in meta-analyses of dichotomous outcomes. Methods/Design We will conduct a methodological study of Cochrane and non-Cochrane systematic reviews. Eligible systematic reviews will include a group-level meta-analysis of a patient-important dichotomous efficacy outcome, with a statistically significant effect estimate. Teams of two reviewers will determine eligibility and subsequently extract information from each eligible systematic review in duplicate and independently, using standardized, pre-piloted forms. The teams will then use a similar process to extract information from the trials included in the meta-analyses of interest. We will assess first which categories of trial participants the systematic reviewers consider as having MPD. Second, we will assess how trialists reported on participants with missing outcome data in trials. Third, we will compare what systematic reviewers report having done, and what they actually did, in dealing with MPD in their meta-analysis. Fourth, we will conduct imputation studies to assess the effects of different methods of dealing with MPD on the pooled effect estimates of meta-analyses. We will specifically calculate for each method (1) the percentage of systematic reviews that lose statistical significance and (2) the mean change of effect estimates across systematic reviews. Discussion The impact of different methods of dealing with MPD on pooled effect estimates will help judge the associated risk of bias in systematic reviews. Our findings will inform recommendations regarding what assumptions for MPD should be used to test the robustness of meta-analytical results

Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

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