Sperm DNA Fragmentation in Men with Varicocele: A Systematic Review and Meta-Analysis

Abstract

Purpose: In this systematic review and meta-analysis, we investigated the relationship between varicocele and sperm DNA fragmentation (SDF) alongside conventional semen parameters.

Materials and methods: A comprehensive systematic search was conducted to identify articles on SDF in men with varicocele published in the Scopus and PubMed databases. This included observational studies investigating levels of SDF as a primary outcome and conventional semen parameters as secondary outcomes in men with varicocele compared to men without varicocele.

Results: Out of 476 retrieved articles, 40 met our inclusion criteria, with 35 included in our quantitative synthesis. Our analysis revealed that men with varicocele showed significantly higher SDF than men without varicocele (mean difference [MD] 15.34, 95% confidence interval [95% CI]: 9.74-20.9; p<0.001). The evaluation of SDF using different assays did not affect the results (p=0.7). Our results indicated a significant effect of varicocele on sperm concentration (MD -29 million/mL, 95% CI: -37, -21; p<0.001), total sperm count (MD -188 million/ejaculate, 95% CI: -325, -52; p=0.007), sperm vitality (MD -5.7%, 95% CI: -8.6, -2.8; p<0.001), total sperm motility (MD -17%, 95% CI: -29.0, -5.3; p=0.004), progressive sperm motility (MD -17%, 95% CI: -23,-11, p<0.001), normal sperm forms (MD -3.1%, 95% CI: -4.3, -1.8, p<0.001) and abnormal sperm forms (MD 2.25%, 95% CI: 0.77, 3.73; p=0.003). However, semen volume and the total motile sperm count were not significantly different between both groups (MD -113 million/ejaculate, 95% CI: -244.0, 18.1; p=0.09).

Conclusions: Varicocele negatively impacts male fertility by increasing SDF. Our study supports using SDF analysis in patients with varicocele to aid clinicians in deciding on varicocele repair.

Keywords: DNA fragmentation; Infertility, male; Spermatozoa; Varicocele.