Table 2 Mean scores for the primary and secondary efficacy variables in men receiving sildenafil or placebo for 8 weeks (intent-to-treat analysis)

From: A double-blind, randomised- placebo, controlled, parallel group, multicentre, flexible-dose escalation study to assess the efficacy and safety of sildenafil administered as required to male outpatients with erectile dysfunction in Korea

Efficacy criteria Baseline (overall) Sildenafil (n=66) Placebo (n=65) P-valuea (vs placebo)
1. Primary efficacy variables (IIEF questions 3 and 4)     
Frequency of penetration (question 3) (minimum score 0: maximum score 5) 2.55b 4.19 2.67 <0.0001
Frequency of maintained erection after penetration (question 4) (minimum score 0: maximum score 5) 1.82a, b 3.74 2.07 <0.0001
2. Secondary efficacy variables     
a) IIEF domain scores     
Erectile function (questions 1–5 and 15) (minimum score 1: maximum score 30) 13.02 23.41 14.50 <0.0001
Intercourse satisfaction (questions 6–8) (minimum score 0: maximum score 15) 6.31 11.42 8.01 <0.0001
Orgasmic function (questions 9, 10) (minimum score 0: maximum score 10) 4.69 7.75 5.36 <0.0001
Sexual desire (questions 11, 12) (minimum score 2: maximum score 10) 5.73 7.28 5.96 <0.0001
Overall satisfaction (questions 13, 14) (minimum score 2: maximum score 10) 3.79 7.28 4.72 <0.0001
b) Sexual activity recorded in patients' event logs:     
Percentage of successful attempts at intercourse 62.01% 25.88% <0.0001
c) Global Efficacy Assessment Question   81.22% 27.60% <0.0001
  1. aP-values calculated according to ANCOVA.
  2. bBaseline values are raw means: others are least-squares means.
  3. IIEF=International Index of Erectile Function.24.