RESULTS	tadalafil experienced a significant mean improvement of 7.9 in International Index of Erectile Function erectile function domain score from baseline ( p < 0.001 versus placebo ) , 75 % of intercourse attempts ( Sexual Encounter Profile question 3 , a secondary efficacy outcome ) were successfully completed ( p < 0.001 versus placebo ) and 81 % reported improved erections at end point compared with 35 % in the control group ( p < 0.001 ) .\