Initial gonadotropin levels and sperm parameters differentiate the response to clomiphene citrate in subfertile men.

Background: Efficacy of clomiphene citrate (CC) in the treatment of male subfertility remains unclear, with inconsistent results in the literature and limited guidance from professional organizations. We sought to stratify the response to clomiphene in men based on their initial gonadotropins and semen parameters.

Methods: We conducted a retrospective analysis of 234 patients from an academic center who took CC for subfertility. Patients with pre-treatment and 3 months follow-up total testosterone (TT) and semen analyses were included. Patients with previous hormone therapy, genitourinary surgery, prior success in conceiving pregnancy, or only one semen analysis were excluded. Primary outcomes were magnitudes of improvement in TT and semen parameters at 3 months. Student's -test (alpha =0.05) was used for univariate analyses; multivariable linear regression was used for multivariate analysis.

Results: One hundred and thirty-seven patients met inclusion criteria. Thirty-four percent of patients experienced improvement in sperm concentration after 3 months of CC treatment, 13% decreased, and 53% showed no change. Using a pre-treatment TT cutoff of 300 ng/dL and gonadotropin thresholds of 7 miU/mL, initial TT did not affect magnitude of improvement in semen parameters, while lower initial gonadotropins showed statistical improvement across all outcomes. Multivariate analysis showed pre-treatment follicle stimulating hormone (FSH) was inversely correlated with improvement in TT [odds ratio (OR): 2.64e-05, 95% confidence interval (CI): 1.32e-09 to 5.28e-01, P=0.04] and sperm concentration (OR: 0.22, 95% CI: 5.70e-02 to 8.48e-01, P=0.03). We also provide initial gonadotropin cutoffs that suggest statistical benefit from CC use.

Conclusions: Men with lower gonadotropin levels may expect greater degree of improvement in both hormone and semen parameters with use of CC. Men with azoospermia do not benefit based on semen analyses alone. Degree of non-azoospermia does not affect magnitude of improvement. CC had decreasing efficacy at higher initial gonadotropin levels. These data may provide guidance in stratifying and counseling men for CC treatment.