Bias in Evaluating Erectile Function in Lifelong Premature Ejaculation Patients with the International Index of Erectile Function-5.

Abstract

Lifelong premature ejaculation (LPE) is the most important ejaculating dysfunction. Relatively little is known about erectile function in this population. We attempted to evaluate the erectile function of patients with LPE using the International Index of Erectile Function-5 (IIEF-5) to determine if it is sufficiently reliable and accurate to make such an assessment. A total of 406 patients with LPE were enrolled in our study. The participants voluntarily answered the Premature Ejaculation Diagnostic Tool (PEDT) and IIEF-5 questionnaires and underwent a full history evaluation and clinical examination by doctors. Their answers were converted into data analyzed by a statistic software. The patients were diagnosed with LPE based on the diagnostic criteria and PEDT scores. The intravaginal ejaculation latency time was recorded according to patient self-reports. The IIEF-5 was used to evaluate their erectile function. Thorough history and clinical examination helped doctors make more correct diagnoses of erectile dysfunction (ED). Of the 406 patients, 70 (17.24%) patients had ED, as confirmed by doctors. IIEF-5 was accurate for the assessment of the erectile function of LPE patients when the cutoff was decreased to 15.5. Question 5 (1.34 ± 0.53) was the main reason for the drop in the total IIEF-5 score. Questions 1 and 5 shared low consistency with the other three IIEF-5 items, thus they lowered the reliability of the IIEF-5 scores. These questions created a confounding bias that decreased the diagnostic threshold of IIEF-5. However, they could not be removed from the IIEF-5 because they did not reduce its diagnostic accuracy in patients with LPE. Bias from questions 1 and 5 lowered the reliability of the IIEF-5 scores; however, it did not reduce the diagnostic accuracy of the IIEF-5. The recommendation is to edit questions 1 and 5 when they are applied to populations with LPE.