Validation of the Electronic Version of the International Index of Erectile Function (IIEF-5 and IIEF-15): A Crossover Study

BACKGROUND: Patient-reported outcome measures (PROMs) are increasingly used to measure patient’s perspective of functional well-being, disease burden, treatment effectiveness, and clinical decision making. Electronic versions are increasingly feasible because of smartphone and tablet usage. However, validation of these electronic PROMs (ePROMs) is warranted for justified implementation. The International Index of Erectile Function (IIEF) 5 and 15 are widely used PROMs in urology to measure erectile dysfunction. Measurement reliability and validity testing of the IIEF ePROMs are essential before clinical application. OBJECTIVE: The aim of this study was to assess reliability and validity of an ePROM version of both IIEF-5 and 15. METHODS: This study included 179 patients from our urology outpatient clinic. It also had a randomized crossover design—participants completed either a paper and electronic IIEF-5 or 15 or twice completed an electronic version—with a 5-day delay. Internal consistency was assessed using Cronbach alpha and Spearman-Brown coefficient, test-retest reliability using the intraclass correlation coefficient (ICC), and convergent validity using the Pearson and Spearman correlation coefficient. RESULTS: A total of 122 participants completed the study. Internal consistency was excellent for the electronic IIEF-5 (ICC 0.902) and good to excellent for the domains of the IIEF-15 (ICC 0.962-0.834). Test-retest reliability was excellent for the IIEF-5 (ICC 0.924) and good to excellent for the domains of the IIEF-15 (ICC 0.950-0.778). Convergent validity was excellent for the IIEF-5 and IIEF-15, with a correlation of r=0.923 and r=0.951, respectively. CONCLUSIONS: We successfully introduced patient-acceptable ePROM versions of the IIEF-5 and IIEF-15. This study’s results demonstrate that the ePROM versions of the IIEF-5 and IIEF-15 can be reliably implemented, as outcomes are reliable and in accordance with findings of the paper version. TRIAL REGISTRATION: ClinicalTrials.gov NCT03222388; https://clinicaltrials.gov/ct2/show/NCT03222388