Begg's funnel plot and Egger's test were performed to determine whether the literature showed a publication bias.
Although our funnel meta-regression analysis showed a limited publication bias (Additional file 1: Fig. S2), the bias was always difficult to ascertain with a small sample number of the included studies.
We first showed a possible publication bias graphically using a funnel plot.
The funnel plot showed a possible publication bias in studies with high variability of the intervention effect.
The NIH example shows a direct publication of GWAS data may cause unintended consequences even if the data are presented to the public in aggregated form (Couzin, 2008).
The only significant difference was with studies sponsored by industry that only showed a 12%% publication rate, compared to around 30%% for other types of sponsors.
Our results showing a positive publication tendency in scientific journals are consistent with the previous work, which demonstrated that antidepressant trials with a positive outcome were published more often than those with negative outcomes.
These are in keeping with our results, which showed a non-publication rate of 33.8% and a ClnicalTrials.gov only publication rate of 6.4%.
An increasing number of publications show a strong genetic component for PD.
Finally, surgical clips in bypasses still pose a problem as already shown an earlier publication using EBCT [ 1] (Fig. 7).
