High estradiol level is associated with erectile dysfunction: A systematic review and meta-analysis

Numerous studies conducted to study the role of testosterone in erectile dysfunction (ED) extensively, but less is known of the association between estradiol level and ED. To assess the strong association between estradiol and ED by quantitatively synthesizing all studies evaluating the relationship between estradiol and ED. An extensive literature search was conducted by two authors independently in three electronic databases, including PubMed, Web of Science and Cochrane Library, up to January 10, 2021. The Patient Population or Problem, Intervention, Comparison, Outcomes and Setting (PICOS) were used for inclusion criteria to identify studies. The Newcastle-Ottawa Scale was applied to assess the quality of studies. The standardized mean difference (SMD) and their corresponding 95% confidence intervals (95% CIs) were used to compare the estradiol level between ED patients and healthy subjects, and the pooled OR and 95%CI were used to evaluate the strong association between estradiol level and ED. Finally, six studies were included in this meta-analysis, satisfying predefined inclusion criteria. Five studies were considered to be high quality, and only one was judged of moderate quality. The estradiol level of ED patients was statistically higher than that in healthy subjects (SMD 0.45, 95%CI 0.28-0.63, p <0.0001). The pooled OR demonstrated that the estradiol was correlated to the ED significantly (OR 1.08, 95%CI 1.05-1.12, p <0.0001). Subgroup analyses were conducted based on age, diagnosis way, country, sample size, detection method and estradiol level. There was no substantial change in the result of SMD ranging from 0.41 (95% CI 0.31-0.51) to 0.53 (95% CI 0.44-0.62) when performing sensitivity analysis. No publication bias was detected by the Begg test or Egger test. This meta-analysis demonstrated that the estradiol level is correlated to ED significantly.