Proper Use of the International Index of Erectile Function 5 (IIEF-5) Questionnaire in Patients Undergoing Transurethral Resection of the Prostate (TURP)

Background: Our goal was to show how the interpretation of the IIEF-5 questionnaire can lead to a significantly different outcome and propose a modification of the possible responses of the IIEF-5 questionnaire to assess erectile function after transurethral resection of the prostate (TURP). Methods: The results of patients treated with TURP in a randomized clinical trial were analyzed under four scenarios characterized by what patients to include and how to codify the answers for statistical interpretation: scenario (A) only patients who reported sexual intercourse; scenario (B) all patients, recording zero response for patients without sexual activity as one more grade of the scoring scale; scenario (C) same as B but coding 0 as “99” (missing value); and scenario (D) all patients are included, but the zero response remains as 0 for patients who reported not having had sexual intercourse due to the “Inability to penetrate (enter) the partner due to penile flaccidity”, whereas zero response is coded as “99” in those patients reporting “Inability to penetrate (enter) the partner due to other causes”. Results: Eighty-four patients qualified for the analysis. The proportion of patients in each ED category was very similar among the four scenarios, except for the “Severe ED” category. At baseline, scenario B had 36.9% of patients categorized as “Severe ED”, scenario D 18.5%, and scenarios A and C 17.2% (p < 0.01). This relative order remained constant in all postoperative visits. The differences in “Severe ED” rates were directly correlated with the inclusion of patients without sexual activity (higher “Severe ED” rate) and the codification of zero responses (when left as zero, they increase “Severe ED” rate, whereas when coded as 99 they are not included in the analysis and “Severe ED” rates decrease). Taking scenario D as a reference, we found a significant overestimation of “Severe ED” in scenario B up to 21.4% and a slight underestimation in scenarios A and B up to –15.7%. Conclusions: Using the IIEF-5 questionnaire with options 0 and 99 (scenario D) may improve the accuracy of detecting patients with “Severe ED” in the postoperative period of TURP. Clinical Trial Registration: NCT03936244 (https://clinicaltrials.gov/ct2/show/NCT03936244).

International Index of Erectile Function 5 (IIEF-5); questionnaire; transurethral resection of the prostate

[1] Rosen R, Cappelleri J, Smith M, Lipsky J, Peña B. Development and evaluation of an abridged, 5-item version of the International Index of Erectile Function (IIEF-5) as a diagnostic tool for erec-tile dysfunction. International Journal of Impotence Research. 1999; 11: 319–326.

[2] Rosen RC, Riley A, Wagner G, Osterloh IH, Kirkpatrick J, Mishra A. The international index of erectile function (IIEF): a multidimensional scale for assessment of erectile dysfunction. Urology. 1997; 49: 822–830.

[3] Cappelleri JC, Rosen RC, Smith MD, Quirk F, Maytom MC, Mishra A, et al. Some Developments on the International Index of Erectile Function (IIEF). Drug Information Journal. 1999; 33: 179–190.

[4] Cappelleri JC, Siegel RL, Osterloh IH, Rosen RC. Relationship between patient self-assessment of erectile function and the erec-tile function domain of the international index of erectile func-tion. Urology. 2000; 56: 477–481.

[5] Rosen R, Cappelleri J. The sexual health inventory for men (IIEF-5): reply to Vroege. International Journal of Impotence Research. 2000; 12: 342–343.

[6] Cappelleri JC, Rosen RC. The Sexual Health Inventory for Men (SHIM): a 5-year review of research and clinical experience. In-ternational Journal of Impotence Research. 2005; 17: 307–319.

[7] Otaola-Arca H, Álvarez-Ardura M, Molina-Escudero R, Fer-nández MI, Páez-Borda Á. A prospective randomized study comparing bipolar plasmakinetic transurethral resection of the prostate and monopolar transurethral resection of the prostate for the treatment of Benign Prostatic Hyperplasia: efficacy, sex-ual function, Quality of Life, and complications. International Brazilian Journal of Urology. 2021; 47: 131–44.

[8] Otaola Arca H. Bipolar Plasmakinetic TURP Vs Monopolar TURP in the Treatment of Lower Urinary Tract Symptoms 2018. Available at: https://clinicaltrials.gov/ct2/show/NCT03936244 (Accessed: 19 May 2021).

[9] Yule M, Davison J, Brotto L. The International Index of Erectile Function: a Methodological Critique and Suggestions for Im-provement. Journal of Sex & Marital Therapy. 2011; 37: 255–269.