Background: Male infertility is a worldwide problem with limitations in the treatment. Phosphodiesterase-5 inhibitors (PDE5is) is the first choice for the treatment of erectile dysfunction (ED), but more and more studies show that it has a certain effect on male infertility in recent years. The literatures of PDE5is related to male infertility have shown inconsistent results, and there is currently no high quality of systematic review to evaluate the effects of PDE5is on semen quality in male infertility patients.
Methods: The electronic databases of MEDLINE, PubMed, Web of Science, EMBASE, Clinicaltrials.org, China National Knowledge Infrastructure Database (CNKI), Wan fang Database, China Biology Medicine Database (CBM), VIP Science Technology Periodical Database, Chinese Clinical Trial Registry and Cochrane Library were retrieved. Grey literature will be searched in Open Grey. Related Randomized controlled trials (RCTs) were collected and selected before October 20, 2019. We will search English literature and Chinese literature with search terms "male infertility", "phosphodiesterase-5 inhibitors", "PDE5i", "Tadalafil", "Sildenafil", "Vardenafil", "Udenafil", "Avanafil", "semen" and "sperm". Sperm concentration, motility and morphology, sperm DNA fragmentation index, number of per ejaculate, sperm viability and adverse events will be evaluated. RevMan 5.3 and Stata 14.0 will be used for Systematic review and Meta-analysis. This protocol reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) statement, and we will report the systematic review by following the PRISMA statement.
Conclusion and dissemination: Efficacy and safety of PDE5is on male sperm quality in infertile men will be assessed. The results will be published in a public issue journal to provide evidence-based medical evidence for urologists and andrologists to make clinical decisions.
Registration information: PROSPERO CRD42019142980.