The erection hardness score and its relationship to successful sexual intercourse.

INTRODUCTION: The Erection Hardness Score (EHS), recently validated, was developed in 1998 as a simple (one-item) method to quantify erection outcome data. Although it is intuitive that erection hardness and successful sexual intercourse (SSI) are related, the link has not been directly established.

OBJECTIVE: To evaluate the relationship between erection hardness (assessed by EHS) and SSI, establishing the EHS as a clinically useful tool.

METHODS: The data set (N = 307) was from a multinational, double-blind, placebo-controlled trial (with open-label extension) of sildenafil citrate in men with erectile dysfunction.

MAIN OUTCOME MEASURES: Event-based modeling used every intercourse attempt and the EHS to estimate the odds ratio of SSI between adjacent EHS categories. Mean-based modeling used mean EHS per patient to determine its relationship to percentage of SSI. Mediation-based modeling used mean EHS and mean percentage of SSI over the double-blind phase to estimate the direct effect of sildenafil treatment on SSI and the indirect effect of sildenafil treatment on SSI via erection hardness.

RESULTS: The odds of SSI for EHS 3 (hard enough for penetration but not completely hard) were 41.9 times (95% confidence interval [CI], 33.0-53.2; P < 0.0001) that for EHS 2 (hard but not hard enough for penetration), and the odds of SSI for EHS 4 (completely hard and fully rigid) were 23.7 times (95% CI, 19.5-28.9; P < 0.0001) that for EHS 3. The percentage of SSI increased approximately curvilinearly with the increase in mean EHS, from almost 60% at EHS 3 to 78.5% at EHS 3.5 and to 93.1% at EHS 4. The indirect effect of sildenafil treatment on SSI via erection hardness accounted for almost 90% of the total effect on SSI (P < 0.0001).

CONCLUSION: The close and direct relationship between erection hardness and SSI supports the broader use of the EHS-a simple, valid, reliable, and responsive measure-in clinical practice.