Validity of Erectile Function Assessment Questionnaires in Premature Ejaculation Patients: A Comparative Study Between the Abridged Forms of the International Index of Erectile Function and Proposal for Optimal Cutoff Redefinition

Background: Patients with premature ejaculation (PE) are often diagnosed as having a comorbid erectile dysfunction (ED). When evaluating erectile function in PE patients with the popular International Index of Erectile Function-5 (IIEF-5, or SexualHealth Inventory for Men [SHIM]), question #5 (Q5) about sexual satisfaction in the intercourse often lowers the total score of the questionnaire, giving false-positive results for the presence of ED. Aim: We aimed to compare SHIM with the other abridged form of IIEF, which is IIEF-EF, and to discriminate which tool has the best diagnostic accuracy in the evaluation of erectile function in PE patients. Methods: The study was conducted from March 2019 to January 2020. A total of 189 heterosexual males with lifelong PE (117, 61.9%) or acquired PE (72, 38.1%) were included. They all compiled Premature Ejaculation Diagnostic Tool, IIEF-15, SHIM, and IIEF-EF and underwent a full clinical examination to evaluate their erectile function. Outcomes: The scores of the 2 erectile function assessment questionnaires (SHIM and IIEF- EF) were compared in terms of their sensitivity and specificity in the diagnosis of ED in PE patients. Results: In terms of diagnosing ED in PE patients, the sensitivity of SHIM is 100% while the specificity is only 36%; meanwhile, the sensitivity of IIEF-EF is 100% but specificity is 77.2%. Further analysis demonstrates that decreasing cutoff of SHIM to 17.5 would provide an increased specificity of 82.5%, while sensitivity would lower to 96.0%. However, the highest area under the curve (0.966 vs 0.941) is given by the IIEF- EF with 100% sensitivity and 80.7% specificity at the cutoff of 24.5, which is one point lower than the usual cutoff value of 25.5. Clinical Implications: Our study suggests that when evaluating erection function in PE patients, the cutoff of both SHIM and IIEF-EF should be amended. Strengths & Limitations.: We proposed the solution for the bias of erectile function assessment in PE patients. However, other trials are needed to further validate in larger cohorts of PE patients. Conclusion: We suggest that the cutoff of SHIM and IIEF-EF should be amended (SHIM at 17.5 and IIEF-EF at 24.5, respectively) when assessing erectile function among PE population. Xi Y, Colonnello E, Ma G, et al. Validity of Erectile Function Assessment Questionnaires in Premature Ejaculation Patients: A Comparative Study Between the Abridged Forms of the International Index of Erectile Function and Proposal for Optimal Cutoff Redefinition. J Sex Med 2021;18:440e447. Copyright (C) 2020, International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Automated summary

Our study suggests that the cutoff values of both SHIM and IIEF-EF should be amended (17.5 for SHIM and 24.5 for IIEF-EF) when assessing erectile function among PE population. These adjustments aim to improve the diagnostic accuracy for erectile dysfunction in premature ejaculation patients. Further validation in larger cohorts of PE patients is needed to confirm the findings.