Wincze J, Fehnel SE, McLeod LD, Granger AL, Merchant S. Development and initial testing of a new patient-reported questionnaire: erection quality scale. Poster presented at the International Society for Pharmacoeconomics and Outcomes Research Sixth Annual European Congress; November 1, 2003. Barcelona, Spain. [abstract] Value Health. 2003 Nov; 6(6):709.

OBJECTIVE: There are currently no available psychometric instruments that measure erection quality. A quantitative measure of erectile quality has potential value as a measure in both clinical research and in the clinical treatment of erectile dysfunction. The objective of this study is to describe the development and evaluation of a new patient-reported questionnaire, designed to measure changes in erection quality.


METHODS: Based on input from interviews with men across the United States and recommendations from an expert panel, seven constructs were selected for inclusion in the questionnaire. Multiple items were drafted to measure each of the key constructs, which included various question wordings, formats, and response category options. An iterative process of cognitive testing, item revision, and item reduction led to the identification of fifteen items and their optimal response scales. At the completion of the cognitive testing, the psychometric properties of the questionnaire were evaluated as a part of a 200-subject test-retest study. Participants were classified into ED-Untreated, ED-Treated, and Normal Sexual Functioning groups in order to gather information about how well the items differentiated among men with different levels of erectile functioning.


RESULTS: The psychometric evaluation demonstrated no floor or ceiling effects. The study results supported a strong one-factor structure, indicating that the EQS should be reported using one overall score. Internal consistency is supported with Cronbach alpha values of 0.94 and 0.95 (for visit 1 and 2, respectively). An intraclass correlation coefficient of 0.79 denotes adequate test-retest reliability. Furthermore, the EQS showed promise for differentiating patients from the three classifications, ED-Untreated, ED-Treated, and Normal Sexual Functioning, a preliminary indication of discriminate validity.


CONCLUSIONS: The results of the development and initial evaluation of the EQS are favorable and provide evidence of the questionnaire’s utility for measuring erection quality. A future study is planned to demonstrate the instrument’s responsiveness.

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