Idiopathic secondary azoospermia occurrence in men with oligospermia over time

Purpose: To investigate the occurrence of idiopathic secondary azoospermia (ISA) in men with oligospermia over time and identify risk factors for ISA in this population.

Methods: This was a retrospective cohort study conducted in a university-affiliated male infertility clinic. A total of 1056 oligospermic men (concentration < 15 million/ml (M/ml) and no azoospermia) with at least two SA done between 2000 and 2019 were included. The primary outcome was the occurrence of ISA by oligospermia severity.

Results: In the entire cohort, 31 patients (2.9%) eventually became azoospermic with time. The ≤ 1 M/ml extremely severe oligospermia (ESO) group (283 patients) had significantly higher rates of ISA in each time period compared to the 1-5 M/ml severe oligospermia (SO) (310 patients) and 5-15 M/ml mild oligospermia (MO) (463 patients) groups (p < 0.05 for all comparisons), with rates of 21.1% in the ESO, 4.8% in the SO, and 0% in the MO group (p = 0.02) after 3-5 years, reaching 32% after 5 years in the ESO group compared to no cases in the other two groups (p = 0.006). Parameters shown to predict ISA were initial concentration < 1 M/ml (OR 22.12, p < 0.001) and time interval of > 3 and 5 years (OR 4.83 and 6.84, p = 0.009 and < 0.001, respectively), whereas testosterone levels were negatively associated with ISA (OR 0.88, p = 0.03).

Conclusions: Men with ≤ 1 M/ml, especially those with low testosterone levels, have a dramatically increased chance of becoming azoospermic with time. Therefore, sperm banking should be recommended in these cases. Men with a sperm concentration above 1 M/ml have low chances of becoming azoospermic, even after 3 or more years.