Publication Bias in Urology Systematic Reviews and Meta-Analyses

Background Publication bias is one of the most important biases in systematic reviews and meta-analyses. This bias occurs when the results of an article affect its publication, in other words positive or significant findings are more likely to be published than the other probable results. Previous studies have shown that publication bias has been a matter of concern in the meta-analysis and systematic reviews conducted in some medical fields.  There is not a study that has evaluated the status of publication bias assessment in urology systematic reviews. We decided to assess the status of publication bias evaluation in systematic reviews and meta-analyses published in high impact urology journals.   Methods This cross-sectional study was performed on 200 systematic reviews and meta-analysis published in four top urology journals based on their impact factor (European Urology, The Journal of Urology, BJU International and Prostate Cancer and Prostatic Diseases). Two independent reviewers performed data extraction about publication bias evaluation in included systematic reviews.   Results From the 200 included studies only 65 (32.5%) evaluated the publication bias in the review process and 31 reviews had reported publication bias in their study. Visual inspection of a funnel plot was the most frequent method used for evaluation of publication bias (61 from 65, 93.85%); this method was used alone in 34 articles and in combination with other methods in 27 papers.   Conclusion The present study confirms that publication bias was formally evaluated in a small number of reviews and meta-analysis published in urology journals, therefore, this may be a risk factor that could decrease the robustness of outcomes and results of these studies. It seems that there is an essential need for authors, reviewers, and editors to pay better attention to evaluation of publication bias besides reporting it based on the aforementioned reporting guidelines.