How to assess publication bias: funnel plot, trim-and-fill method and selection models

2014 ◽  
Vol 17 (1) ◽  
pp. 30-30 ◽  
Author(s):  
Dimitris Mavridis ◽  
Georgia Salanti
2021 ◽  
Author(s):  
Maximilian Maier ◽  
Tyler VanderWeele ◽  
Maya B Mathur

In meta-analyses, it is critical to assess the extent to which publication bias might have compromised the results. Classical methods based on the funnel plot, including Egger’s test and Trim-and-Fill, have become the de facto default methods to do so, with a large majority of recent meta-analyses in top medical journals (85%) assessing for publication bias exclusively using these methods. However, these classical funnel plot methods have important limitations when used as the sole means of assessing publication bias: they essentially assume that the publication process favors large point estimates for small studies and does not affect the largest studies, and they can perform poorly when effects are heterogeneous. In light of these limitations, we recommend that meta-analyses routinely apply other publication bias methods in addition to or instead of classical funnel plot methods. To this end, we describe how to use and interpret selection models. These methods make the often more realistic assumption that publication bias favors ``statistically significant'' results and that also directly accommodate effect heterogeneity. Selection models are well-established in the statistics literature and are supported by user-friendly software, yet remain rarely reported in many disciplines. We use previously published meta-analyses to demonstrate that selection models can yield insights that extend beyond those provided by funnel plot methods, suggesting the importance of establishing more comprehensive reporting practices for publication bias assessment.


2021 ◽  
Vol 12 ◽  
Author(s):  
Lei Tang ◽  
Fan Zhang ◽  
Ruoyun Yin ◽  
Zhaoya Fan

Objectives: This study aimed to provide a comprehensive understanding of all intervention for learning burnout by meta-analyzing their effects.Methods: Relevant studies that had been published up to September 18, 2020, were identified through a systematic search of the PubMed, Web of Science, the China National Knowledge Infrastructure (CNKI), and Wan Fang databases. Eligible studies included randomized control trials of any learning burnout intervention conducted among students. The Jadad scale was used to evaluate the quality of the study. Random-effect meta-analyses, subgroup analyses, meta-regression analysis, and sensitivity analysis were conducted. Funnel plots and Egger's tests were used to evaluate publication bias. Duval and Tweedie's non-parametric trim-and-fill method was used to adjust the effect of publication bias.Results: Of the 5,245 articles found, 39 met the inclusion criteria for the systematic review. There were 3,400 students, including 1,847 students in the intervention group and 1,553 in the control group. A meta-analysis of 44 studies showed that the interventions were effective. Subgroup analyses were conducted according to education, scales, intervention measures, and intervention time. The results showed that, compared with the control group, the learning burnout scores of undergraduates, secondary vocational students, and middle school students were significantly lower. Based on different scales, all interventions were also effective. The funnel plot was asymmetric and consistent with the results of Egger's test. The trim-and-fill method was used, and seven missing studies were merged to obtain a symmetric funnel plot.Conclusions: This meta-analysis indicated that learning burnout interventions are effective. The subgroup analyses showed that group counseling is the most widely used, exercise intervention is probably the most effective, and 8 weeks or more is the appropriate intervention time. An integrated intervention study based on the factors of learning burnout adds value. More studies are needed to supplement the results in the future.


2021 ◽  
Vol 12 ◽  
pp. 215013272199364
Author(s):  
Robel Hussen Kabthymer ◽  
Solomon Nega Techane ◽  
Temesgen Muche ◽  
Helen Ali Ewune ◽  
Semagn Mekonnen Abate ◽  
...  

Background: Over-nutrition and diet-linked non-communicable morbidities are showing increasing trend overtime. Even if there are different factors that affect the change in BMI other than ART, several authors have reported increases in BMI among PLHIV on treatment that are equal to or surpass the general population. This study is aimed to estimate the prevalence of obesity and overweight among adult HIV infected peoples taking ART in Ethiopia. Method: PubMed, CINAHL, Web of science, global health and Google scholar electronic databases were used to perform a systematic literature search. Two authors independently extracted all the necessary data using a structured data extraction format. Data analysis was done using STATA Version 14. The heterogeneity of the studies was assessed by using I2 test. A random-effects model was used to estimate the pooled prevalence. Publication bias was checked using Funnel plot and Egger’s test. Result: Two thousand seven hundred and fifty-one studies were reviewed and 13 studies fulfilling the inclusion criteria were included in the meta-analysis. The meta-analysis of 13 studies, comprising 4994 participants resulted in pooled prevalence of overweight to be 17.85% (95% CI: 12.22-23.47). Whereas, the pooled prevalence of overweight was found to be 3.90 (95% CI: 2.31-5.49) but after adjusting for publication bias using trim and fill analysis it has become 3.58 (95% CI: 2.04-5.13). Magnitude of both overweight and obesity was higher in studies conducted in Addis Ababa, studies done after 2016 and studies having sample size of less than 400, in subgroup analysis. Conclusion: The magnitude of overweight and obesity among HIV infected peoples taking ART in Ethiopia is high. There is a need to have a routine screening to PLWHA on the risk of over-nutrition in order to facilitate early detection.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Mistire Teshome Guta ◽  
Tiwabwork Tekalign ◽  
Nefsu Awoke ◽  
Robera Olana Fite ◽  
Getahun Dendir ◽  
...  

Aims. This systemic review and meta-analysis were aimed at determining the level of anxiety and depression among cystic fibrosis patients in the world. Methods. We conducted a systematic search of published studies from PubMed, EMBASE, MEDLINE, Cochrane, Scopus, Web of Science, CINAHL, and manually on Google Scholar. This meta-analysis follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The quality of studies was assessed by the modified Newcastle-Ottawa Scale (NOS). Meta-analysis was carried out using a random-effects method using the STATA™ Version 14 software. Trim and fill analysis was done to correct the presence of significant publication bias. Result. From 419,820 obtained studies, 26 studies from 2 different parts of the world including 9766. The overall global pooled prevalence of anxiety and depression after correction for publication bias by trim and fill analysis was found to be 24.91(95% CI: 20.8-28.9) for anxiety. The subgroup analyses revealed with the lowest prevalence, 23.59%, (95% CI: 8.08, 39.09)) in North America and the highest, 26.77%, (95% CI: 22.5, 31.04) seen in Europe for anxiety and with the highest prevalence, 18.67%, (95% CI: 9.82, 27.5) in North America and the lowest, 13.27%, (95% CI: -10.05, 16.5) seen in Europe for depression. Conclusion. The global prevalence of anxiety and depression among cystic fibrosis patients is common. Therefore, close monitoring of the patient, regularly screening for anxiety and depression, and appropriate prevention techniques is recommended.


2018 ◽  
Vol 49 (4) ◽  
pp. 685-696 ◽  
Author(s):  
Martin Taylor-Rowan ◽  
Oyiza Momoh ◽  
Luis Ayerbe ◽  
Jonathan J. Evans ◽  
David J. Stott ◽  
...  

AbstractBackgroundDepression is a common post-stroke complication. Pre-stroke depression may be an important contributor, however the epidemiology of pre-stroke depression is poorly understood. Using systematic review and meta-analysis, we described the prevalence of pre-stroke depression and its association with post-stroke depression.MethodsWe searched multiple cross-disciplinary databases from inception to July 2017 and extracted data on the prevalence of pre-stroke depression and its association with post-stroke depression. We assessed the risk of bias (RoB) using validated tools. We described summary estimates of prevalence and summary odds ratio (OR) for association with post-stroke depression, using random-effects models. We performed subgroup analysis describing the effect of depression assessment method. We used a funnel plot to describe potential publication bias. The strength of evidence presented in this review was summarised via ‘GRADE’.ResultsOf 11 884 studies identified, 29 were included (total participantsn= 164 993). Pre-stroke depression pooled prevalence was 11.6% [95% confidence interval (CI) 9.2–14.7]; range: 0.4–24% (I295.8). Prevalence of pre-stroke depression varied by assessment method (p= 0.02) with clinical interview suggesting greater pre-stroke depression prevalence (~17%) than case-note review (9%) or self-report (11%). Pre-stroke depression was associated with increased odds of post-stroke depression; summary OR 3.0 (95% CI 2.3–4.0). All studies were judged to be at RoB: 59% of included studies had an uncertain RoB in stroke assessment; 83% had high or uncertain RoB for pre-stroke depression assessment. Funnel plot indicated no risk of publication bias. The strength of evidence based on GRADE was ‘very low’.ConclusionsOne in six stroke patients have had pre-stroke depression. Reported rates may be routinely underestimated due to limitations around assessment. Pre-stroke depression significantly increases odds of post-stroke depression.Protocol identifierPROSPERO identifier: CRD42017065544


2021 ◽  
pp. jech-2020-214611
Author(s):  
Michael P Hengartner ◽  
Simone Amendola ◽  
Jakob A Kaminski ◽  
Simone Kindler ◽  
Tom Bschor ◽  
...  

BackgroundThere is ongoing controversy whether antidepressant use alters suicide risk in adults with depression and other treatment indications.MethodsSystematic review of observational studies, searching MEDLINE, PsycINFO, Web of Science, PsycARTICLES and SCOPUS for case–control and cohort studies. We included studies on depression and various indications unspecified (including off-label use) reporting risk of suicide and/or suicide attempt for adult patients using selective serotonin reuptake inhibitors (SSRI) and other new-generation antidepressants relative to non-users. Effects were meta-analytically aggregated with random-effects models, reporting relative risk (RR) estimates with 95% CIs. Publication bias was assessed via funnel-plot asymmetry and trim-and-fill method. Financial conflict of interest (fCOI) was defined present when lead authors’ professorship was industry-sponsored, they received industry-payments, or when the study was industry-sponsored.ResultsWe included 27 studies, 19 on depression and 8 on various indications unspecified (n=1.45 million subjects). SSRI were not definitely related to suicide risk (suicide and suicide attempt combined) in depression (RR=1.03, 0.70–1.51) and all indications (RR=1.19, 0.88–1.60). Any new-generation antidepressant was associated with higher suicide risk in depression (RR=1.29, 1.06–1.57) and all indications (RR=1.45, 1.23–1.70). Studies with fCOI reported significantly lower risk estimates than studies without fCOI. Funnel-plots were asymmetrical and imputation of missing studies with trim-and-fill method produced considerably higher risk estimates.ConclusionsExposure to new-generation antidepressants is associated with higher suicide risk in adult routine-care patients with depression and other treatment indications. Publication bias and fCOI likely contribute to systematic underestimation of risk in the published literature.RegistrationOpen Science Framework, https://osf.io/eaqwn/


Author(s):  
Mariana Feijó ◽  
Roberta V L Martins ◽  
Sílvia Socorro ◽  
Luísa Pereira ◽  
Sara Correia

Abstract Endocrine-disrupting chemicals have become an issue of scientific and public discussion. Vinclozolin (VNZ) is a fungicide that competitively antagonizes the binding of natural androgens to their receptor, disturbing the function of tissues that are sensitive to these hormones, as is the case of the male reproductive organs. A systematic review with meta-analyses of rodent studies was conducted to answer the following question: Does exposure to VNZ affect sperm parameters and testicular/epididymal weight? The methodology was prespecified according to the Cochrane Handbook for Systematic Reviews and PRISMA recommendations. Sixteen articles met the inclusion criteria, comprising a total of 1189 animals. The risk of publication bias was assessed using the Trim and Fill adjustment, funnel plot, and Egger regression test. Heterogeneity and inconsistency across the findings were tested using the Q-statistic and I2 of Higgins, respectively. Sensitivity was also analyzed. Statistical analysis was performed on Comprehensive Meta-Analysis software (Version 2.0), using random models and weighted mean differences along with a 95% confidence interval. Sperm motility, counts, daily sperm production (evidence of publication bias), and epididymis weight were decreased in VNZ-treated animals. Exposure length and dose, as well as the time point of exposure, influenced the obtained results. Despite the moderate/high heterogeneity observed, the sensitivity analysis overall demonstrated the robustness of the findings. The quality scores of the included studies were superior to 4 in a total of 9, then classified as good. The obtained data corroborate the capability of VNZ exposure to disrupt spermatogenic output and compromise male fertility.


2020 ◽  
pp. 000486742096374 ◽  
Author(s):  
Brenton Eyre-Watt ◽  
Eesharnan Mahendran ◽  
Shuichi Suetani ◽  
Joseph Firth ◽  
Steve Kisely ◽  
...  

Background: Lithium in drinking water may have significant mental health benefits. We investigated the evidence on the association between lithium concentrations in drinking water and their neuropsychiatric outcomes. Methods: We conducted a systematic review and meta-analysis and searched Pubmed, Embase, Web of Science, PsycINFO and CINAHL up to 19 January 2020, for peer-reviewed research examining the association between lithium concentrations in drinking water and neuropsychiatric outcomes. We used a pairwise analysis and a random effects model to meta-analyse suicide rates and psychiatric hospital admissions. We assessed for publication bias using Egger’s test and Duval and Tweedie’s Trim and Fill analysis. Results: Twenty-seven studies including 113 million subjects were included in this systematic review. Meta-analysis of 14 studies including 94 million people found higher lithium concentrations were associated with reduced suicide rates ( r = −0.191, 95% confidence interval = [−0.287, −0.090], p < 0.001) and meta-analysis of two studies including 5 million people found higher lithium concentrations were associated with fewer hospital admissions ( r = −0.413, 95% confidence interval = [−0.689, −0.031], p = 0.035). We found significant heterogeneity between studies ( Q = 67.4, p < 0.001, I2 = 80.7%) and the presence of publication bias (Egger’s test; t value = 2.90, p = 0.013). Other included studies did not provide sufficient data to analyse other neuropsychiatric outcomes quantitatively. Conclusion: Higher lithium concentrations in drinking water may be associated with reduced suicide rates and inpatient psychiatric admissions. The relationship with other neuropsychiatric outcomes and complications remains unclear. Further research is required before any public health recommendations can be made. Trial registration number: The study was registered with PROSPERO, number CRD42018090145.


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