Changes in evidence for studies assessing interventions for COVID-19 reported in preprints: meta-research study

Abstract Background The increasing use of preprints to disseminate evidence on the effect of interventions for the coronavirus disease 2019 (COVID-19) can lead to multiple evidence sources for a single study, which may differ in the reported evidence. We aim to describe the proportion of evidence on the effect of interventions for COVID-19 from preprints and journal articles and map changes in evidence between and within different sources reporting on the same study. Methods Meta-research study. We screened the Cochrane living systematic review and network meta-analysis (COVID-NMA) database to identify all preprints and journal articles on all studies assessing interventions for COVID-19 published up to 15 August 2020. We compared all evidence sources (i.e., preprint and associated journal article) and the first and latest versions of preprints for each study to identify changes in two evidence components: study results (e.g., numeric change in hazard ratio, odds ratio, event rate, or change in p value > or < 0.05 in any outcome) and abstract conclusions (classified as positive, negative or neutral regarding the intervention effect, and as reporting uncertainty in the findings or not). Changes in study results were further classified as important changes if they (1) represented a change in any effect estimate by ≥ 10% and/or (2) led to a change in the p value crossing the threshold of 0.05. Results We identified 556 studies. In total, 338 (61%) had been reported in a preprint: 66 (20%) of these had an associated journal article (median time to publication 76 days [interquartile range (IQR) 55–106]) and 91 (27%) had > 1 preprint version. A total of 139 studies (25% of the overall sample) were reported in multiple evidence sources or versions of the same source: for 63 (45%), there was a change in at least one evidence component between or within sources (42 [30%] had a change in study results, and in 29 [21%] the change was classified as important; 33 [24%] had a change in the abstract conclusion). For studies with both a preprint and an article, a median of 29% (IQR 14–50) of total citations were attributed to the preprint instead of the article. Conclusions Results on the effect of interventions for COVID-19 are often reported in multiple evidence sources or source versions for a single study. Evidence is not stable between and within evidence sources. Real-time linkage of all sources per study could help to keep systematic reviews up-to-date.

Download Full-text

How should systematic reviewers handle conference abstracts? A view from the trenches

Systematic Reviews ◽

10.1186/s13643-019-1188-0 ◽

2019 ◽

Vol 8 (1) ◽

Cited By ~ 18

Author(s):

Roberta W. Scherer ◽

Ian J. Saldanha

Keyword(s):

Systematic Reviews ◽

Treatment Effect ◽

Meta Analysis ◽

Good Practice ◽

Effect Estimate ◽

Main Body ◽

Unpublished Studies ◽

Study Results ◽

Meta Analyses ◽

Positive Results

Abstract Background While identifying and cataloging unpublished studies from conference proceedings is generally recognized as a good practice during systematic reviews, controversy remains whether to include study results that are reported in conference abstracts. Existing guidelines provide conflicting recommendations. Main body The main argument for including conference abstracts in systematic reviews is that abstracts with positive results are preferentially published, and published sooner, as full-length articles compared with other abstracts. Arguments against including conference abstracts are that (1) searching for abstracts is resource-intensive, (2) abstracts may not contain adequate information, and (3) the information in abstracts may not be dependable. However, studies comparing conference abstracts and fully published articles of the same study find only minor differences, usually with conference abstracts presenting preliminary results. Other studies that have examined differences in treatment estimates of meta-analyses with and without conference abstracts report changes in precision, but usually not in the treatment effect estimate. However, in some cases, including conference abstracts has made a difference in the estimate of the treatment effect, not just its precision. Instead of arbitrarily deciding to include or exclude conference abstracts in systematic reviews, we suggest that systematic reviewers should consider the availability of evidence informing the review. If available evidence is sparse or conflicting, it may be worthwhile to search for conference abstracts. Further, attempts to contact authors of abstracts or search for protocols or trial registers to supplement the information presented in conference abstracts is prudent. If unique information from conference abstracts is included in a meta-analysis, a sensitivity analysis with and without the unique results should be conducted. Conclusions Under given circumstances, it is worthwhile to search for and include results from conference abstracts in systematic reviews.

Download Full-text

Research Methods in TEFL Studies: Descriptive Research, Case Study, Error Analysis, and R & D

Journal of Language Teaching and Research ◽

10.17507/jltr.0901.25 ◽

2018 ◽

Vol 9 (1) ◽

pp. 197 ◽

Cited By ~ 3

Author(s):

Haryanto Atmowardoyo

Keyword(s):

Error Analysis ◽

Research Methods ◽

Meta Analysis ◽

Journal Article ◽

Survey Method ◽

Journal Articles ◽

Research Activity ◽

Descriptive Research ◽

The World

Articles published in International journals have rich potentials of learning sources since their publication has been scholarly processed through the hands of journal editors. Readers can get a lot of benefits from them. One lesson we might get is the way the writers conducted their researches. Thus, we can learn the research methods from the models found in journal articles. This paper will elaborate the research methods used in the teaching of English as a foreign language (TEFL). The elaboration is formulated from the research methods used by journal article writers around the world. A number of international journal articles in TEFL are taken as the corpus of the study. Using a grounded theory, varieties of research methods in TEFL are investigated. Among of them are case study, quasi experiment, qualitative experiment, meta analysis, descriptive research, activity theory, error analysis, R & D, action research, research and development (R&D), and survey method. Due to the limited space, however, the paper will only describe four popular methods: descriptive research, case study, error analysis, and R & D. The description of each method is supported with examples found in international journal articles published around the world.

Download Full-text

Metaanalyse

Norsk Epidemiologi ◽

10.5324/nje.v23i2.1636 ◽

2013 ◽

Vol 23 (2) ◽

Cited By ~ 1

Author(s):

Geir Smedslund

Keyword(s):

Random Effects ◽

Effect Size ◽

Meta Analysis ◽

Large Body ◽

Fixed Effect Model ◽

English Summary ◽

Fixed Effect ◽

Effect Estimate ◽

Study Results ◽

Meta Analyses

Metaanalyse er en kvantitativ metode for å oppsummere resultatene av flere enkeltstudier. I en metaanalyse forsøker man å tallfeste behandlingseffekten, og man gir store studier større vekt enn små studier. En mye brukt metode for å vekte er invers variansmetoden. Dersom alle studiene har målt resultatene på samme måte kan resultatene brukes direkte i metaanalysen, men dersom det samme utfallet er målt på ulike måter, må man bruke standardiserte effektstørrelser hvor alle resultatene er omregnet til en felles skala. Dersom man tror at effekten av behandlingen vil være lik for alle, bortsett fra tilfeldige variasjoner, benytter man en fixed-effect modell. Tror man derimot at det vil være systematiske forskjeller i effekt når behandlingen gis i ulike kontekster, legges dette inn i en såkalt random-effects modell. Metaanalyser blir ofte fremstilt grafisk i form av forest plots. Hver linje representerer da én studie, med effektestimatet markert som et punkt, mens ytterpunktene av linjen representerer konfidensintervallet. Metaanalysen blir fremstilt som en diamant hvor bredden viser usikkerheten i estimatet. Dersom resultatene fra alle studiene trekker i samme retning er metaanalysen ”homogen”. Men dersom studiene spriker når det gjelder effektstørrelse og retning på effekt, er det ”heterogenitet”. Styrken ved metaanalyse er at den kan sammenfatte en stor mengde informasjon i ett tall. Samtidig er dette også svakheten ved metoden. Et enkelt tall kan ikke beskrive variasjonen på tvers av flere studier.Smedslund G. Meta-analysis. Nor J Epidemiol 2013; 23 (2): 147-149.ENGLISH SUMMARY Meta-analysis is a quantitative method for summarizing single studies. In a meta-analysis, one tries to quantify the treatment effect, assigning more weight to large studies than to small studies. A much used method for weighting is the inverse variance method. If all studies have measured the results in the same way, the results can be used directly in the meta-analysis, but if the same outcome is measured in different ways across different studies, one has to use a standardized effect size where results are converted to a common scale. If it is believed that the effect is consistent across various populations and settings, one can employ a fixed-effect model. If systematic differences in effect can be expected, a random-effects model is used. Meta-analyses are often depicted as forest plots. Each line represents one study where the effect estimate is marked as a point on a line, with each end of the line representing the confidence interval around it. The meta-analysis is shown as a diamond where the width illustrates the uncertainty around the estimate. If all study results point in the same direction, the meta-analysis is considered “homogeneous”. But if the studies vary in their effect size and direction, the findings are “heterogeneous”. The strength of meta-analysis is that it can be used to summarize a large body of information in one number. This is also its limitation. One number cannot describe the variation that exists across different studies.

Download Full-text

Evaluating the Effect of Coaching on SAT Scores: A Meta-Analysis

Harvard Educational Review ◽

10.17763/haer.53.1.n06j5h5356217648 ◽

1983 ◽

Vol 53 (1) ◽

pp. 1-15 ◽

Cited By ~ 76

Author(s):

Rebecca DerSimonian ◽

Nan Laird

Keyword(s):

Quantitative Analysis ◽

Sampling Error ◽

Meta Analysis ◽

Sat Scores ◽

Combining Evidence ◽

Study Results ◽

National Norms ◽

Coaching Effectiveness ◽

Different Sources ◽

Positive Effect

DerSimonian and Laird present a quantitative analysis of published results on the effect of coaching programs on SAT scores. Their analysis differs from previous methods of combining evidence from different sources by separating out the within-study sampling error from the variation in coaching effectiveness. They explicitly model the methodology used in each study in order to analyze the variation in study results. They find that studies which compare the gains achieved by coached students to national norms yield estimated "coaching effects, " which are four to five times greater than corresponding effects estimated for matched or randomized evaluations. In addition, the matched or randomized evaluations show a much greater degree of consistency in their results than do less well-controlled evaluations. The authors conclude that the data do support a positive effect of coaching on SAT scores, but that the size of the coaching effect estimated from the matched or randomized studies (10 points) seems too small to be practically important.

Download Full-text

An Analysis of Pronouns Used in Selected International Journal Articles: Exploring Authors’ Flexibility and Consistency

REiLA: Journal of Research and Innovation in Language ◽

10.31849/reila.v1i3.3204 ◽

2019 ◽

Vol 1 (3) ◽

pp. 73-78

Author(s):

Rumintang Harianja ◽

Ratih Saltri Yudar ◽

Susy Deliani ◽

Mutia Sari Nursafira ◽

Budianto Hamuddin

Keyword(s):

Current Issue ◽

Journal Article ◽

Scientific Article ◽

Journal Articles ◽

The Impact

This study aims at identifying the pronouns used in journal articles in terms of numbers and familiarity. The data taken from three different journals from three various fields, i.e., Education, Medics and Engineering. It consists of 21 articles taken from the current issue 2018, where this study started. It is selected conveniently due to its unique and fame as a discipline and reputable sources. In collecting the data, the researcher accessed the journals published by science direct (Q1 Scopus indexed). The analysis showed that the writer in these three international journals commonly used several pronouns interchangeably. However, some articles in journal from Medical and Engineering consistently used only one chosen pronoun, which was recorded found at different sections in the journal article. The data then coded and transcribed to ease the analysis in this researcher. As a result of the study, it was found out that the data showed 19 kinds of pronouns in total were used in these three different fields. These results showed us that the pronoun usage in a scientific article from these three various fields varies with options of different pronouns. The pronoun seems used to help the impact of imposition and showing politeness or quality of the articles.

Download Full-text

Fibroblast Growth Factor 20 Gene Polymorphism in Parkinson’s Disease in Asian Population: A Meta-Analysis

Genes ◽

10.3390/genes12050674 ◽

2021 ◽

Vol 12 (5) ◽

pp. 674

Author(s):

Han-Lin Chiang ◽

Yih-Ru Wu ◽

Yi-Chun Chen ◽

Hon-Chung Fung ◽

Chiung-Mei Chen

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Meta Analysis ◽

Lewy Bodies ◽

Asian Population ◽

Protective Role ◽

Lewy Neurites ◽

Chinese Populations ◽

Study Results

Parkinson’s disease (PD) is a neurodegenerative disease with the pathological hallmark of Lewy bodies and Lewy neurites composed of α-synuclein. The SNP rs591323 is one of the risk loci located near the FGF20 gene that has been implicated in PD. The variation of FGF20 in the 3′ untranslated region was shown to increase α-synuclein expression. We examined the association of rs591323 with the risk of PD in a Taiwanese population and conducted a meta-analysis, including our study and two other studies from China, to further confirm the role of this SNP in Taiwanese/Chinese populations. A total of 586 patients with PD and 586 health controls (HCs) were included in our study. We found that the minor allele (A) and the AA + GA genotype under the dominant model are significantly less frequent in PD than in controls. The meta-analysis consisted of 1950 patients with PD and 2073 healthy controls from three studies. There was significant association between rs591323 and the risk of PD in the additive (Z = −3.96; p < 0.0001) and the dominant models (Z = −4.01; p < 0.0001). Our study results and the meta-analysis support the possible protective role of the rs591323 A allele in PD in Taiwanese/Chinese populations.

Download Full-text

Seaports during the COVID-19 Pandemic: The Terminal Operators’ Tactical Responses to Disruptions in Maritime Supply Chains

Energies ◽

10.3390/en14144339 ◽

2021 ◽

Vol 14 (14) ◽

pp. 4339

Author(s):

Marta Mańkowska ◽

Michał Pluciński ◽

Izabela Kotowska ◽

Ludmiła Filina-Dawidowicz

Keyword(s):

Supply Chains ◽

Global Economy ◽

Research Study ◽

Inductive Reasoning ◽

Main Function ◽

The Sustainable Development ◽

Study Results ◽

Multiple Case ◽

Tactical Decisions

The world-wide crisis caused by the Coronavirus disease 2019 (COVID-19) pandemic had a significant impact on the global economy functioning and the sustainable development of supply chains. The changes also affected seaports being the key links of maritime supply chains. The purpose of the research study described in this article was to identify the sources and kinds of disruptions observed in various maritime supply chains as a result of the COVID-19 pandemic and their impact on the operations of various types of seaport terminals, namely those serving bulk (universal, specialised) and general cargoes (universal, specialised). An additional purpose was to identify the dependencies between the type of terminal and its main function, and the tactical decisions adopted by the particular terminals. The research was carried out using the multiple-case study method. The study covered some selected port terminals functioning in Polish seaports (Gdańsk, Szczecin, Świnoujście), applying direct, semi-structured in-depth interviews. The analysis of the results was carried out using the inductive reasoning method. The research study has shown that as a result of the COVID-19 pandemic some maritime supply chains ceased to exist, some of them were operating with decreased cargo volumes, while in other cases the transshipment volumes actually rose during the pandemic. Among terminal operators’ tactical responses to disruptions in maritime supply chains, there were pro-active and adaptive measures. Pro-active (offensive) measures included actions taken by an enterprise in order to engage in new maritime supply chains, and even participating in establishing new maritime chains in response to limitations caused by the pandemic. Adaptive (defensive) measures covered actions taken by the port terminals as a consequence of changes in the existing maritime supply chains, caused by the pandemic in the port’s foreland or hinterland. The research study results revealed that the terminals extent of engagement and tactical decisions related to the pandemic were depended on the type of terminal (universal or specialised) and its main function played within a supply chain.

Download Full-text

A Meta-Analysis of Extracorporeal Anticoagulants in Pediatric Continuous Kidney Replacement Therapy

Journal of Intensive Care Medicine ◽

10.1177/0885066621992751 ◽

2021 ◽

pp. 088506662199275

Author(s):

Rupesh Raina ◽

Nirav Agrawal ◽

Kirsten Kusumi ◽

Avisha Pandey ◽

Abhishek Tibrewal ◽

...

Keyword(s):

Replacement Therapy ◽

Meta Analysis ◽

Kidney Injury ◽

Electrolyte Imbalance ◽

Therapeutic Modality ◽

Regional Citrate Anticoagulation ◽

Increased Risk ◽

Study Results ◽

Significant Difference ◽

Kidney Replacement Therapy

Objective: Continuous kidney replacement therapy (CKRT) is the primary therapeutic modality utilized in hemodynamically unstable patients with severe acute kidney injury. As the circuit is extracorporeal, it poses an increased risk of blood clotting and circuit loss; frequent circuit losses affect the provider’s ability to provide optimal treatment. The objective of this meta-analysis is to evaluate the safety and efficacy of the extracorporeal anticoagulants in the pediatric CKRT population. Data Sources: We conducted a literature search on PubMed/Medline and Embase for relevant citations. Study Selection: Studies were included if they involved patients under the age of 18 years undergoing CKRT, with the use of anticoagulation (heparin, citrate, or prostacyclin) as a part of therapy. Only English articles were included in the study. Data Extraction: Initial search yielded 58 articles and a total of 24 articles were included and reviewed. A meta-analysis was performed focusing on the safety and effectiveness of regional citrate anticoagulation (RCA) vs unfractionated heparin (UFH) anticoagulants in children. Data Synthesis: RCA had statistically significantly longer circuit life of 50.65 hours vs. UFH of 42.10 hours. Two major adverse effects metabolic alkalosis and electrolyte imbalance seen more commonly in RCA compared to UFH. There was not a significant difference in the risk of systemic bleeding when comparing RCA vs. UFH. Conclusion: RCA is the preferred anticoagulant over UFH due to its significantly longer circuit life, although vigilant circuit monitoring is required due to the increased risk of electrolyte disturbances. Prostacyclin was not included in the meta-analysis due to the lack of data in pediatric patients. Additional studies are needed to strengthen the study results further.

Download Full-text

Epidemiology of Secondary Warm Autoimmune Haemolytic Anaemia—A Systematic Review and Meta-Analysis

Journal of Clinical Medicine ◽

10.3390/jcm10061244 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1244

Author(s):

Stinne Tranekær ◽

Dennis Lund Hansen ◽

Henrik Frederiksen

Keyword(s):

Haemolytic Anaemia ◽

Lupus Erythematosus ◽

Meta Analysis ◽

Underlying Disease ◽

Age At Diagnosis ◽

Autoimmune Haemolytic Anaemia ◽

Sex Distribution ◽

Number Of Patients ◽

Study Results ◽

Full Text Review

Background: Warm autoimmune haemolytic anaemia (wAIHA) is a haemolytic disorder, most commonly seen among adults and is classified as either primary or secondary to an underlying disease. We describe the age and sex distribution and the proportion of secondary wAIHA. Method: We retrieved 2635 published articles, screened abstracts and titles, and identified 27 articles eligible for full-text review. From these studies, we extracted data regarding number of patients, sex distribution, age at diagnosis, number of patients with secondary wAIHA, and whether the patients were diagnosed through local or referral centres. All data were weighted according to the number of included patients in each study. Results: 27 studies including a total of 4311 patients with wAIHA, of which 66% were females, were included. The median age at diagnosis was 68.7 years, however, wAIHA affected all ages. The mean proportion of secondary wAIHA was 49%, most frequently secondary to systemic lupus erythematosus. The proportions of secondary wAIHA reported from primary vs. referral centres were 35% vs. 59%, respectively. Conclusion: This review consolidates previously reported gender distribution. The higher proportion of secondary wAIHA in referral centres suggests that the most severely affected patients are disproportionally more frequent in such facilities.

Download Full-text

Does Post-Transplant Cytomegalovirus Increase the Risk of Invasive Aspergillosis in Solid Organ Transplant Recipients? A Systematic Review and Meta-Analysis

Journal of Fungi ◽

10.3390/jof7050327 ◽

2021 ◽

Vol 7 (5) ◽

pp. 327

Author(s):

Nipat Chuleerarux ◽

Achitpol Thongkam ◽

Kasama Manothummetha ◽

Saman Nematollahi ◽

Veronica Dioverti-Prono ◽

...

Keyword(s):

Systematic Review ◽

Invasive Aspergillosis ◽

Meta Analysis ◽

Organ Transplant ◽

Solid Organ Transplant ◽

Effect Estimate ◽

Solid Organ ◽

Post Transplant ◽

Cmv Disease ◽

The Impact

Background: Cytomegalovirus (CMV) and invasive aspergillosis (IA) cause high morbidity and mortality in solid organ transplant (SOT) recipients. There are conflicting data with respect to the impact of CMV on IA development in SOT recipients. Methods: A literature search was conducted from existence through to 2 April 2021 using MEDLINE, Embase, and ISI Web of Science databases. This review contained observational studies including cross-sectional, prospective cohort, retrospective cohort, and case-control studies that reported SOT recipients with post-transplant CMV (exposure) and without post-transplant CMV (non-exposure) who developed or did not develop subsequent IA. A random-effects model was used to calculate the pooled effect estimate. Results: A total of 16 studies were included for systematic review and meta-analysis. There were 5437 SOT patients included in the study, with 449 SOT recipients developing post-transplant IA. Post-transplant CMV significantly increased the risk of subsequent IA with pORs of 3.31 (2.34, 4.69), I2 = 30%. Subgroup analyses showed that CMV increased the risk of IA development regardless of the study period (before and after 2003), types of organ transplantation (intra-thoracic and intra-abdominal transplantation), and timing after transplant (early vs. late IA development). Further analyses by CMV definitions showed CMV disease/syndrome increased the risk of IA development, but asymptomatic CMV viremia/infection did not increase the risk of IA. Conclusions: Post-transplant CMV, particularly CMV disease/syndrome, significantly increased the risks of IA, which highlights the importance of CMV prevention strategies in SOT recipients. Further studies are needed to understand the impact of programmatic fungal surveillance or antifungal prophylaxis to prevent this fungal-after-viral phenomenon.

Download Full-text