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.