Development and validation of the quality of erection questionnaire

Abstract

Introduction: There are no psychometrically validated assessment tools designed to solely and specifically evaluate satisfaction with the quality of erections.

Aim: To develop and psychometrically analyze the Quality of Erection Questionnaire (QEQ), a new patient-reported measure developed to evaluate men's satisfaction with the quality of their erections.

Methods: The questionnaire was developed through in-depth qualitative interviews of men with erectile dysfunction (ED) in the United States and Australia. An exploratory methodology study was conducted on 65 men with ED. Subsequently, the psychometric properties were confirmed in a larger dataset of 558 men with ED from two combined clinical trials.

Main outcome measures: Identification of potential redundancy or outliers in items (Pearson inter-item correlations); exploratory factor analysis (unrotated and varimax rotated); internal consistency (Cronbach's alpha); convergent validity (Pearson correlation coefficients between the QEQ total score and domain scores of the International Index of Erectile Function); known-groups validity (ability of the QEQ scores to differentiate between ED severity groups); test-retest reliability (Pearson correlation coefficient).

Results: The QEQ demonstrated excellent convergent and known-groups validity. Additional analysis demonstrated high internal consistency (Cronbach's alpha, 0.92). Item analysis demonstrated a unidimensional structure and suggested that satisfaction with hardness may be the key driver for satisfaction with overall quality of erections (r = 0.8). The smaller exploratory study demonstrated good test-retest reliability (r = 0.82).

Conclusions: The QEQ is a six-item, patient-reported measure with a unidimensional structure, which produces a total score that may be transformed to a 0-100 scale. Psychometric analysis confirmed reliability and validity of the QEQ, which solely and specifically evaluates satisfaction of men with the quality of their erections. The QEQ is a potentially useful measure for monitoring and evaluating treatment in those who are bothered by, or concerned about, their erectile function.