The Efficacy and Safety of Letrozole or Anastrozole in The Treatment of Specific Male Infertility Patients: Meta-Analysis and Systematic Review

Background: Letrozole (LE) or anastrozole (AZ) is clinically beneficial in male infertility patients with a low testosterone-estradiol ratio (T/E2). Many scholars believe it has the potential to become one of the effective drugs to treat male infertility. But some relevant research results are different or even the opposite. Study Question The purpose of this report is to evaluate the efficacy and safety of letrozole or anastrozole in the treatment of specific male infertility patients. Data Sources: We performed a comprehensive literature search using PubMed, Embase, Cochrane, CNKI, VIP, CBM, and Wanfang Date through August 2021 for all studies. Study Design: We conducted a systematic review with meta- analysis of the all available literature reporting sperm conventional parameters, gonadotropin and testosterone levels, and/or the pregnancy rate. Results: : The total of 10 studies involving 280 patients were included. LE or AZ administration increased significantly sperm concentration, total sperm count, and serum luteinizing hormone, follicle-stimulating hormone, testosterone levels and T / E2 compared with baseline values, but E2 levels were significantly reduced. In contrast, LE or AZ did not have any significant effect on sperm concentration and motility and pregnancy rate, but improved total sperm count, sperm morphology, compared to the control group, which included studies done with Selective estrogen receptor modulators (SEMR) or testosterone undecanoate (TU). Conclusion: LE or AZ may be effective in the treatment of low T / E2 male infertility, perhaps better than other anti-estrogen or exogenous testosterone supplementation. In addition, we should pay special attention to the changes of E2 during treatment.