The efficacy of anastrozole in subfertile men with and without abnormal testosterone to estradiol ratios

Background: Aromatase inhibitors (AIs), such as anastrozole, have shown effectiveness in treating oligoasthenozoospermia due to abnormal testosterone to estradiol (T/E-2) ratio (T/E-2 < 10). However, its efficacy in subfertile men without abnormal T/E-2 ratio (T/E-2 > 10) remained unevaluated. This retrospective study aimed to investigate whether patients with T/E-2 ratio > 10 could also benefit from anastrozole treatment. Methods: One hundred and five subfertile patients treated with 1 mg anastrozole daily were included, in which 62 patients had a T/E-2 ratio of < 10, and 43 patients had this ratio > 10. Semen parameters and sex hormone levels (including FSH, LH, PRL, E-2 and total T) were measured before and after a three-month treatment. T/E-2 ratio and total progressive motility sperm count were calculated from these results. Results: Patients in both groups (T/E-2 ratio < 10 and > 10) showed significant increase in sex hormone levels (FSH, LH and total T), T/E-2 ratio and semen parameters (semen volume, sperm concentration, total sperm count, progressive motility and total progressive motility count). The changes of these parameters between two groups were comparable. A subgroup analysis comparing the effect of anastrozole on overweight and normal patients also showed no significant difference. Improvements in semen parameters were seen in some azoospermic and cryptozoospermic patients. Conclusions: The majority of subfertile men with and without abnormal T/E(2 )ratios responded to anastrozole treatment with significantly improved semen parameters and sex hormone levels. Anastrozole showed potential effectiveness in male subfertile patients with T/E-2 > 10, to be confirmed by future prospective, randomized, controlled studies.