Publication bias: raising awareness of a potential problem in dental research

Abstracts presented at the European Association for Osseointegration (EAO) Congresses: Publication fate and discrepancies with full-length articles

OBJECTIVES

To investigate the full publication proportion (FPP) of abstracts presented at the 2010 and 2011 EAO Congresses, analyse the discrepancies between abstracts and their full publications, and explore potential predictors of FPP and discrepancies.

METHODS

Abstracts presented at the 2010 and 2011 EAO Congresses were retrieved. Associated full publications were identified by searching PubMed, Embase and Google Scholar. Discrepancies between abstracts and full publications were identified, classified and evaluated using a discrepancy score. The Kaplan-Meier survival analysis was used to describe cumulative FPP over time. Predictors for FPP and the discrepancy score were analysed using cox regression modelling and a linear regression model, respectively.

RESULTS

850 abstracts were included. The overall FPP was 36.4% with a median time lapse of 12 months. Higher FPP were significantly associated with oral presentation (HR=2.33; 95% CI: 1.68 to 3.22; p<0.001), multiple affiliations (HR =1.32; 95% CI: 1.00 to 1.73; p=0.048) and presence of statistical tests (HR =1.78; 95% CI: 1.36 to 2.32; p<0.001). 91.3% pairs had at least one minor change from the abstract and 70.9% had at least one major change. Greater discrepancy score was significantly associated with longer time lapse (B=0.06; 95% CI: 0.04 to 0.08; p<0.001) and being clinical research (B=1.30; 95% CI: 0.52 to 2.08; p=0.001).

CONCLUSIONS

Thirty-six percent of abstracts presented at the EAO Congresses were published. Among these, more than two-thirds showed at least one major change in their full publications. Abstracts presented in oral implantology conferences should not be relied upon to inform practice.

Identification of Soluble Mediators in IgG-Mediated Anaphylaxis via Fcγ Receptor: A Meta-Analysis

Background: Anaphylaxis is an acute and life-threatening allergic response. Classically and most commonly, it can be mediated by the crosslinking of allergens to immunoglobulin E (IgE)- high affinity IgE receptor (FcεRI) complex found mostly on mast cells. However, there is another pathway of anaphylaxis that is less well-studied. This pathway known as the alternative pathway is mediated by IgG and its Fc gamma receptor (Fcγ). Though it was not documented in human anaphylaxis, a few studies have found that IgG-mediated anaphylaxis can happen as demonstrated in rodent models of anaphylaxis. In these studies, a variety of soluble mediators were being evaluated and they differ from each study which causes confusion in the suitability, and reliability of choice of soluble mediators to be analyzed for diagnosis or therapeutic purposes. Hence, the objective of this meta-analysis is to identify the potential soluble mediators that are involved in an IgG-mediated anaphylaxis reaction.

Methods: Studies related to IgG-mediated anaphylaxis were sourced from five search engines namely PubMed, Scopus, Ovid, Cochrane Library, and Center for Agricultural Bioscience International (CABI) regardless of publication year. Relevant studies were then reviewed based on specific inclusion factors. The means and standard deviations of each soluble mediator studied were then extracted using ImageJ or Get Data Graph Digitiser software and the data were subjected to meta-analysis.

Results: From our findings, we found that histamine, serotonin, platelet activating factor (PAF), β-hexosaminidase, leukotriene C4 (LTC₄), mucosal mast cell protease-1 (MMCP-1), interleukins (IL)-4,−6, and−13; tumor necrosis factor alpha (TNF-α), and macrophage inflammatory protein-1α (MIP-1α) were often being analyzed. Out of these soluble mediators, histamine, PAF, β-hexosaminidase, IL-6, and−13, MIP-1α and TNF-α were more significant with positive effect size and p < 0.001. As study effect was relatively small, we performed publication bias and found that there was publication bias and this could be due to the small sample size studied.

Conclusion: As such, we proposed that through meta-analysis, the potential soluble mediators involved in rodent IgG-mediated anaphylaxis to be histamine, PAF, β-hexosaminidase, IL-6 and−13 and MIP-1α, and TNF-α but will require further studies with larger sample size.

A Comprehensive Review of the Evidence of the Impact of Surface Water Quality on Property Values

The desirability of living on or close to water is reflected in sometimes substantial property price premiums. Water quality has an important influence on property prices, since it impacts a water body’s appearance, capacity to support wildlife, and recreational potential. As water quality continues to be altered by human use and activity, and in light of new threats posed by projected climate and associated environmental change, understanding the impact of changing quality on property prices, and the associated property tax base, is paramount. This paper reviews the body of evidence on this topic to date. Of the 43 distinct studies represented in the 48 publications reviewed, the expected, statistically significant relationship between water quality and property price was demonstrated in at least one of the models developed in all but two studies. As a whole, they provide convincing evidence that clean water has a positive effect on property values.

Do dental research journals publish only positive results? A retrospective assessment of publication bias

Background:

The study aimed to determine the presence of publication bias in the top five dental journals with high impact factor published during 2007–2016.

Materials and Methods:

The journals included are Journal of Clinical Periodontology, Dental Materials, Clinical Oral Implant Research (COIR), Journal of Endodontics, and Journal of Dental Research (JDR). The content of these journals was hand searched by two authors for scouring the proportion of positive or negative results. Articles showing two outcomes (primary and secondary) were registered depending on the primary result.

Results:

The present study revealed higher percentage of statistically significant results in the published dental literature. Of five journals, JDR has shown fewer tendencies toward publication of nonsignificant results, whereas COIR has evidenced the highest publication of nonsignificant results. The journals with higher impact factor showed significantly different acceptance rate for research with positive results. However, year-wise publication (2007–2016) did not depict any significant difference.

Conclusion:

In dental research journals, articles with positive results are finding a better way in getting published compared to articles with negative results.

Thirty percent of abstracts presented at dental conferences are published in full: a systematic review

OBJECTIVES

To review the publication fate of abstracts presented at dental conferences and investigate the association between full publication proportion (FPP) and abstract characteristics, conference characteristics, and methodological quality of primary studies.

STUDY DESIGN AND SETTING

PubMed, EMBASE, and Google Scholar were searched up to November 2014 for studies that reported at least one FPP of abstracts presented at dental conferences, with a follow-up length of no less than 48 months.

RESULTS

Sixteen studies involving 10,365 abstracts presented at 52 conferences were included. The pooled FPP was 29.62% (95% confidence interval: 22.90%, 36.81%) for all presented abstracts and 51.97% (95% confidence interval: 43.19%, 60.70%) for randomized controlled trial abstracts. Abstract characteristics significantly associated with higher FPP included reporting of statistical analysis (P < 0.001), oral presentation (P < 0.001), basic science research (P = 0.047), and reporting of financial support (P = 0.009). Abstracts with positive (P = 0.29) or statistically significant results (P = 0.33) were not published more often than negative or nonsignificant results, respectively. In multivariable meta-regression analysis, conferences held in Asia (P < 0.001) and at a continental rather than national level (P < 0.001) were significantly associated with higher FPP.

CONCLUSIONS

Less than one-third of abstracts presented at dental conferences were published in full more than 4 years after conference presentation.

Is extracorporeal shock wave therapy clinical efficacy for relief of chronic, recalcitrant plantar fasciitis? A systematic review and meta-analysis of randomized placebo or active-treatment controlled trials

OBJECTIVE

To assess the efficacy of extracorporeal shockwave therapy (ESWT) and provide clinicians with an evidence base for their clinical decision making.

DATA SOURCES

PubMed, MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and Evidence-Based Medicine Reviews.

STUDY SELECTION

All randomized or quasi-randomized controlled trials of ESWT for chronic recalcitrant plantar fasciitis were searched. Searching identified 108 potentially relevant articles; of these, 7 studies with 550 participants met inclusion criteria.

DATA EXTRACTION

Number of patients, population, body mass index, duration of symptoms, adverse effects, blinding method, and details of shockwave therapy were extracted.

DATA SYNTHESIS

For intervention success rate, ESWT of low intensity was more effective than control treatment of low intensity. For pain relief, the pooled data showed a significant difference between the ESWT and control groups. For function, only low-intensity ESWT was significantly superior over the control treatment.

CONCLUSIONS

The efficacy of low-intensity ESWT is worthy of recognition. The short-term pain relief and functional outcomes of this treatment are satisfactory. However, owing to the lack of a long-term follow-up, its long-term efficacy remains unknown.

Is Atraumatic restorative treatment an option for restoring occlusoproximal caries lesions in primary teeth? A systematic review and meta-analysis

BACKGROUND

Atraumatic restorative treatment (ART) has demonstrated good longevity when used for single-surface restorations, but lower success rates are reported for occlusoproximal surfaces.

AIM

This systematic review and meta-analysis aimed to verify the pooled success rate of occlusoproximal ART restorations in primary teeth considering the outcomes: longevity, pulp damage, or caries lesion progression.

DESIGN

Literature searching was carried out on the studies reporting clinical trials indexed in PubMed and in English language, comprising the outcomes. A meta-analysis was undertaken considering the results from reviewed studies.

RESULTS

An initial search resulted in 126 articles, and three of them were finally selected. The main reasons for excluding articles were the absence of control group, as amalgam, composite resin, or compomer restorations to be compared with ART (hand excavation + high-viscous GIC). The pooled estimate (odds ratio; 95% confidence interval) for ART approach success was 1.04 (0.65-1.66).

CONCLUSION

Atraumatic restorative treatment restorations performed with high-viscous GIC present similar survival/success rates to conventional approach using composite resin or amalgam for occlusoproximal restorations in primary teeth and can be suggested as a good option for occlusoproximal cavities in primary molars. In addition, further randomized controlled clinical investigations concerning occlusoproximal restorations in primary teeth are still necessary.

Ethical conundrums in research

Several ethical concerns are central to the field of medical research. A sampling of these ethical conundrums include fraudulent data, publication bias, conflict of interest, IRB compliance, and confidentiality. In this article we attempt to highlight some of the components central to these areas of concern. In doing so we hope to generate discussion regarding some of the main areas of ethical concern in dermatologic and scientific bench side research. Additionally, we suggest that the use of journal publications, presentations, and training sessions, in concert with the development of dermatoethics courses as components of dermatology residency program curricula, can be used to maintain the academic discourse on ethics and minimize the risk of ethical conflict in the field of dermatologic research. These efforts will serve to maintain the quality and integrity of research on skin diseases.

Bias and dispersal in the animal reintroduction literature

We examined the literature on animal reintroductions to assess the challenges facing individual conservation practitioners who wish to access, synthesize and interpret available evidence to inform their decision making. We undertook an extensive search in eight electronic literature databases, using seven different keyword combinations, and added the content of four bibliographies on reintroductions. We found 3,826 potentially relevant publications totalling at least 29,290 pages of text. Taxonomic bias is apparent in the distribution of general and conservation scientific literature and in reintroduction programmes. We examined whether the literature on reintroductions is biased in a similar way. Comparing the distribution of reintroduction publications to numbers of species, reintroduction programmes and the general conservation literature, there is a marked taxonomic bias favouring vertebrates, especially birds and mammals. The bias in relation to reintroduction programmes is surprising and indicates that managers working with invertebrates and amphibians are less willing and/or less able to publish their results than those working with mammals and birds. The reasons for this are unclear. The growth of the cumulative body of literature can be depicted by a sigmoid curve. Almost 40% of the items were scientific journal articles distributed across 335 journals. The large, ever-growing and dispersed evidence base results in an increased need for reviews, which must be systematic to minimize bias.

The efficacy of aloe vera used for burn wound healing: A systematic review

Aloe vera has been traditionally used for burn healing but clinical evidence remains unclear. We conducted a systematic review to determine the efficacy of topical aloe vera for the treatment of burn wounds. We electronically searched relevant studies in MEDLINE, CINAHL, Cochrane Library, HealthSTAR, DARE, South-East Asia Database, Chinese Databases, and several Thai local Databases (1918-June 2004). Only controlled clinical trials for burn healing were included. There were no restrictions on any language of publication. Two reviewers independently extracted data on study characteristics, patient characteristics, intervention, and outcome measure. Four studies with a total of 371 patients were included in this review. Based on a meta-analysis using duration of wound healing as an outcome measure, the summary weighted mean difference in healing time of the aloe vera group was 8.79 days shorter than those in the control group (P=0.006). Due to the differences of products and outcome measures, there is paucity to draw a specific conclusion regarding the effect of aloe vera for burn wound healing. However, cumulative evidence tends to support that aloe vera might be an effective interventions used in burn wound healing for first to second degree burns. Further, well-designed trials with sufficient details of the contents of aloe vera products should be carried out to determine the effectiveness of aloe vera.

A viewpoint on evidence-based health informatics, based on a pilot survey on evaluation studies in health care informatics

Concerned about evidence-based health informatics, the authors conducted a limited pilot survey attempting to determine how many IT evaluation studies in health care are never published, and why. A survey distributed to 722 academics had a low response rate, with 136 respondents giving instructive comments on 217 evaluation studies. Of those studies, half were published in international journals, and more than one-third were never published. Reasons for not publishing (with multiple reasons per study possible) included: "results not of interest for others" (1/3 of all studies), "publication in preparation" (1/3), "no time for publication" (1/5), "limited scientific quality of study" (1/6), "political or legal reasons" (1/7), and "study only conducted for internal use" (1/8). Those reasons for non-publication in health informatics resembled those reported in other fields. Publication bias (preference for positive studies) did not appear to be a major issue. The authors believe that widespread application of guidelines in conducting health informatics evaluation studies and utilization of a registry for evaluation study results could improve the evidence base of the field.

Delay and failure to publish dental research

OBJECTIVE

To investigate the incidence and time taken to full publication of abstracts presented at dental scientific meetings.

DESIGN

A retrospective observational study.

SETTING

All abstracts from the 1993 proceedings of the European Orthodontic Society (EOS) and European Organisation for Caries Research (ORCA) and a 10% random sample of abstracts from the International Association for Dental Research (IADR) conferences.

METHODS

A cross-referenced Medline search of abstract title and authors was undertaken to determine whether abstracts had been published as full papers. Searches were censored 1 year prior to and 5 years post publication as an abstract. Publication rate was compared between abstracts presented orally and as posters.

MAIN OUTCOME MEASURES

Publication as a full paper and time taken to publication.

RESULTS

546 abstracts were investigated. 252 abstracts (46.1%) were found as full reports. Median time to publication of all abstracts was 18 months (IQR 9, 30 months). 99 of the oral abstracts (57%) and 153 (41%) of the poster abstracts were published. Relative Risk Oral vs Poster=1.37 CI (1.19, 1.55).

CONCLUSION

More than half of the research presented at EOS, IADR and ORCA in 1993 remained unpublished 5 years after presentation at the conference. Oral presentations were published more frequently than poster presentations.