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


METHODS
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).


CONCLUSIONS
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.
Goldstein
Irwin
I
Sexual Medicine, Alvarado Hospital, University of California, San Diego, CA 92120, USA. irwingoldstein@comcast.net
Mulhall
John P
JP
Bushmakin
Andrew G
AG
Cappelleri
Joseph C
JC
Hvidsten
Kyle
K
Symonds
Tara
T
D000293:Adolescent; D000328:Adult; D003075:Coitus; D016001:Confidence Intervals; D004311:Double-Blind Method; D007172:Erectile Dysfunction / Q000188:drug therapy*; D006305:Health Status Indicators; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D016017:Odds Ratio; D010410:Penile Erection / Q000187:drug effects*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D010879:Piperazines / Q000494:pharmacology* / Q000627:therapeutic use; D011687:Purines / Q000494:pharmacology / Q000627:therapeutic use; D012725:Sexual Behavior; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000494:pharmacology* / Q000627:therapeutic use; D055815:Young Adult
D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate