Figure 4. Relationship of clinical variables and treatment procedures in the Erection Hardness Score (EHS). (a) The studies using the 9-week protocol of LI-ESWT more possibly contributed to effective treatment (risk ratio [RR]: 22.59; 95% confidence interval [Cl]: 4.65-109.79; p=0.95), than using 5-week protocol (RR: 6.14; 95% Cl: 2.58-14.64), although it did not reach statistical significance (p=0.16). (b) LI-ESWT for PDE5I non-responders more possibly contributed to effective treatment (RR: 20.50; 95% CI:1.31-320.94), than for responders (RR: 8.58; 95% Cl: 3.17-23.23; p=0.32), but it did not reach statistical significance (p=0.56). (c) The outcome of studies with consistent risk factor of ED between treatment and control group is lower (RR: 7.41; 95% Cl: 3.36-16.38; p=0.52), than that with inconsistent risk factors (RR: 32.16; 95% Cl: 2.09-495.35), but it did not reach statistical significance (p=0.31).