Letter to the Editor regarding the paper by Sang-Hee Yoon et al., Bilateral salpingectomy can reduce the risk of ovarian cancer in the general population: A meta-analysis

We have read with interest the article by Sang-Hee Yoon et al. [1] entitled ‘Bilateral salpingectomy can reduce the risk of ovarian cancer in the general population: a meta-analysis’ published recently in the Journal. We have found some methodological issues in the paper that deserve a commentary. First, the authors did not use adjusted effects for the meta-analysis. In consequence, the effect could be affected by confounders which have not been considered [2]. Second, the effects expressed as odds ratio (OR) and hazard ratio (HR) could have been analysed together in the analysis. The paper of Falconer et al. [3] showed its results as HR which could have been transformed, using the methodology of Chinn [4], into OR.