INTRODUCTION: Erectile dysfunction (ED) affects quality of life in patients treated by radical prostatectomy (RP). The Erection Hardness Score (EHS) is a single-item scale that has demonstrated good psychometric properties for assessing erectile function (EF) in patients treated by sildenafil, but its applicability to other treatment contexts has not yet been tested.
AIM: This study aims to test the validity and time and treatment responsiveness of the EHS to assess ED in men with post-RP ED treated with alprostadil injections.
METHODS: This is a 1-year follow-up cohort study of 75 patients treated by RP for localized prostate cancer in a urology department setting between January 2007 and December 2008. Data were prospectively collected at 6 and 12 months post-RP.
MAIN OUTCOME MEASURES: The EHS, the International Index of Erectile Function (IIEF) reference questionnaire, the Global Assessment Questionnaire (GAQ), and Numeric Pain Scale (NPS) were collected. Convergent validity (Spearman correlation coefficients with IIEF domains), known-groups validity (comparing EHS scores across ED severity groups), time and treatment responsiveness (effect size with/without treatment and over the follow-up period), and predictive ability (area under the receiver operating characteristics curve [AUC-ROC]) were analyzed for this study.
RESULTS: The EHS showed good convergent validity (all Spearman coefficients significant at the P<0.05 level), adequate known-groups validity (global differentiation between IIEF-EF severity groups; P<0.001), and treatment responsiveness (effect size: +1.8 [6 months], +2.1 [12 months]), but limited time responsiveness and predictive ability of the EHS for a normal EF at 12 months follow-up when compared with the IIEF-EF domain (AUC-ROC: 0.72 vs. 0.85; P<0.01).
CONCLUSION: Our findings support the overall good psychometric properties of the EHS in patients with post-RP ED treated with alprostadil injections. However, evidence for limited predictive validity and responsiveness to change over time should be considered for its use in clinical follow-up in this population.