Investigation of publication bias in meta-analyses of diagnostic test accuracy: a meta-epidemiological study

Abstract

BackgroundThe validity of a meta-analysis can be understood better in light of the possible impact of publication bias. The majority of the methods to investigate publication bias in terms of small study-effects are developed for meta-analyses of intervention studies, leaving authors of diagnostic test accuracy (DTA) systematic reviews with limited guidance. The aim of this study was to evaluate if and how publication bias was assessed in meta-analyses of DTA, and to compare the results of various statistical methods used to assess publication bias.MethodsA systematic search was initiated to identify DTA reviews with a meta-analysis published between September 2011 and January 2012. We extracted all information about publication bias from the reviews and the two-by-two tables. Existing statistical methods for the detection of publication bias were applied on data from the included studies.ResultsOut of 1,335 references, 114 reviews could be included. Publication bias was explicitly mentioned in 75 reviews (65.8%) and 47 of these had performed statistical methods to investigate publication bias in terms of small study-effects: 6 by drawing funnel plots, 16 by statistical testing and 25 by applying both methods. The applied tests were Egger’s test (n = 18), Deeks’ test (n = 12), Begg’s test (n = 5), both the Egger and Begg tests (n = 4), and other tests (n = 2). Our own comparison of the results of Begg’s, Egger’s and Deeks’ test for 92 meta-analyses indicated that up to 34% of the results did not correspond with one another.ConclusionsThe majority of DTA review authors mention or investigate publication bias. They mainly use suboptimal methods like the Begg and Egger tests that are not developed for DTA meta-analyses. Our comparison of the Begg, Egger and Deeks tests indicated that these tests do give different results and thus are not interchangeable. Deeks’ test is recommended for DTA meta-analyses and should be preferred.

Screening Accuracy for Aspiration Using Bedside Water Swallow Tests

“…Hierarchical summary receiver operating characteristic (HSROC) curves with both 95% CIs and 95% prediction contours were also created. Publication bias was tested using Deeks test 39,40 with an a priori significance of P < .10.…”

Importance of Meta-Analysis and Practical Obstacles in Oncological and Epidemiological Studies: Statistics Very Close but Also Far!

“…There are many terms used to describe biases related to the selective dissemination of evidence, such as language bias, funding bias, database bias, citation bias, location bias, reviewer bias (Bax and Moons, 2011) and outcome reporting bias (selective reporting of positive outcomes). These forms of biases tend to have more effect on small studies and contribute to the phenomenon of "small study-effects" (van Enst et al, 2014). This means that published studies with small sample sizes tend to have larger and more favourable effects compared to studies with larger sample sizes.…”

“…In the absence of bias, the plot sould resemble a 'funnel shape', in the presence of publication bias, some smaller studies reporting negative results will be missing and an asymmetrical funnel plot will be observed thus publication bias is not the only possible reason for observed funnel plot asymmetry (Peters et al, 2006). Egger's and Begg's regression tests are commonly used statistical tests for publication bias (van Enst et al, 2014).…”

“…A recent simulation study in DTA meta-analyses showed that the trim and fill method is more powerful than other tests like the Begg, Egger or Deeks test to detect possible publication bias. Therefore, this method may be used more frequently in future (van Enst et al, 2014).…”

Effect Comparison between Egger’s Test and Begg’s Test in Publication Bias Diagnosis in Meta-Analyses: Evidence from a Pilot Survey

“…Even so, van Enst et al had found that most systematic reviews of diagnostic test mentioned the issue, but only with 41% measuring PB [4]. Ioannidis and Trikalinos explored PB problem in 1,669 Cochrane reviews, ultimately analyzed 6,873 meta-analyses, and they found a half of the metaanalyses had no statistically significant results.…”