Table 1.
Characteristics of the trials analyzed
| Study, year, country | Study design | Treatment enclosed | Sample size (n) | Age (year), median (range); mean±s.d. | Infertility etiology, n (%) | Follow-up (month) | LE |
|---|---|---|---|---|---|---|---|
| Clark and Sherins19 1989, USA | Prospective, randomized, double-blind, placebo-controlled crossover (single center) | Testolactone 2 g daily Placebo | Total: 25 | NR | Idiopathic | Baseline, 8, 16 | 1b |
| Pavlovich et al.21 2001, USA | Prospective, nonrandomized, case–control (single center) | Testolactone 100–200 mg daily | Total: 104 Testolactone (n=74) Control (n=40) | 37 (31–43) 40 (37–40) | Idiopathic: 12 (26.6), Klinefelter’s syndrome: 6 (13.3), Chromosome Y microdeletion: 5 (11.1), cryptorchidism: 5 (11.5), varicocele: 14 (21.1) | Baseline, 3 | 2a |
| Raman and Schlegel22 2002, USA | Prospective, nonrandomized, case–control (single center) | Testolactone 100–200 mg daily Anastrozole 1 mg daily | Total: 140 Testolactone (n=74) Anastrozole (n=101) | NR | Testolactone (n=74): Klinefelter’s syndrome: 17 (22.9), varicocele repair: 18 (24.3), varicocele present: 12 (16.2), overweight (BMI >35 kg m−2): NR; Anastrozole (n=101): Klinefelter’s syndrome: NR, varicocele repair: 30 (29.7), varicocele present: 33 (32.6), overweight (BMI >35 kg m−2): 16 (15.8) | Baseline, 3 | 2a |
| Saylam et al.23 2011, Turkey | Prospective, nonrandomized (single center) | Letrozole 2.5 mg daily | Total: 27 | 34.92±6.66 | Idiopathic hypoandrogenic | Baseline, 6 | 2a |
| Gregoriou et al. 2012, Greece24 | Prospective, nonrandomized study (single center) | Letrozole 2.5 mg daily Anastrozole 1 mg daily | Total: 29 Letrozole (n=15) Anastrozole (n=14) | NR | Idiopathic hypoandrogenic | Baseline, 6 | 2a |
| Cavallini et al.20 2013, Italy | Prospective, randomized, double-blind, placebo-controlled (multicentric) | Letrozole 2.5 mg daily Placebo | Total: 45 Letrozole (n=22) Placebo (n=23) | 44 (37–52) 45 (38–53) | Idiopathic hypoandrogenic: 28 (62.2) Cryptorchidism: 17 (37.7) | Baseline, 3, 6 | 1b |
| Helo et al.26 2015, USA | Prospective, randomized, double-blind (single center) | Clomiphene citrate 25 mg daily Anastrozole 1 mg daily | Total: 26 Clomiphene citrate (n=13) Anastrozole (n=13) | 35±6.5 33±3.9 | Idiopathic hypoandrogenic | Baseline, 3 | 1b |
| Shoshany et al.25 2017, USA | Retrospective survey25 (single center) | Anastrozole 1 mg daily | Total: 86 | 37 (32–41) | Idiopathic hypoandrogenic: 71 (82.5), cryptorchidism: 11 (12.7), varicocele repair: 4 (4.6) | Baseline, 4 | 3 |
BMI: body mass index; LE: level of evidence; NR: not reported; s.d.: standard deviation