Table 1. Characteristics of the included studies.
| Study ID | Country | Sample size | Intervention(regular) | Intervention(on-demand) | Control | Treatment period | Outcome |
|---|---|---|---|---|---|---|---|
| Bannowsky14 | German | 24 | vardenafil 5 mg/day | no treatment | no use of PDE5-Is | 12 months | IIEF score |
| Canat15 | Turkey | 112 | tadalafil 20 mg 3 times/week | tadalafil on demand | no use of PDE5-Is | 12 months | IIEF score/ TEAEs |
| Montorsi16 | Europe, USA, Canada and South Africa | 628 | vardenafil 10 mg/night plus on-demand placebo | vardenafil 10 mg on demand plus nightly placebo | nightly placebo plus on-demand placebo | 9 months | IIEF score/Proportion of patients achieving IIEF score ≥22/ TEAEs |
| Aydogdu17 | Turkey | 85 | tadalafil 20 mg/day | no treatment | no use of PDE5-Is | 6 months | IIEF score |
| Bannowsky26 | USA | 43 | sildenafil 25 mg/day | no treatment | no use of PDE5-Is | 13 months | IIEF score |
| Pace18 | Italy | 62 | sildenafil 50 or 100 mg/day | no treatment | no use of PDE5-Is | 6 months | IIEF score/ TEAEs |
| Mulhall19 | USA | 298 | No treatment | avanafil 100 mg or 200 mg on-demand | placebo on-demand | 3 months | TEAEs |
| Nathan20 | North America and France | 125 | sildenafil 50 mg/night | no treatment | placebo nightly | 9 months | IIEF score/ TEAEs |
| Brock21 | USA and Canada | 440 | vardenafil 10 mg/day | vardenafil 20 mg on-demand | placebo on-demand | 3 months | IIEF score/ TEAEs |
| Montorsi22 | Canada, Germany, Italy, Netherlands, Spain, USA and UK | 303 | No treatment | tadalafil 20 mg on-demand | placebo on-demand | 3 months | IIEF score/ TEAEs |
| Montorsi23 | Nine European countries and Canada | 423 | Tadalafil 5 mg/day | Tadalafil 20 mg on-demand | placebo on-demand | 9 months | IIEF score/ Proportion of patients achieving IIEF score ≥22/ TEAEs |
| Nehra24 | USA and Canada | 440 | No treatment | 10 mg vardenafil or 20 mg vardenafil on-demand | placebo on-demand | 3 months | IIEF score/ TEAEs |
| Young27 | Korea | 92 | tadalafil 5 mg/day(47) | no treatment | no use of PDE5-Is | 12 months | IIEF score/ TEAEs |
| Pavlovich25 | USA | 100 | Sildenafil 50 mg/day and on-demand placebo | Sildenafil 50 mg on-demand and nightly placebo | no use of PDE5-Is | 12 months | IIEF score/ Proportion of patients achieving IIEF score ≥22/TEAEs |
Phosphodiesterase type-5 inhibitors (PDE5-Is); International Index of Erectile Function (IIEF);Treatment-emergent adverse events (TEAEs).