- Email: [email protected]
Correlation between Erection Hardness Score and Nocturnal Penile Tumescence Measurement
1
Correlation between Erection Hardness Score and Nocturnal Penile Tumescence Measurement Yohei Matsuda, MD,* Shin-ichi Hisasue, MD, PhD,*† Yoshiaki Kumamoto, MD,* Ko Kobayashi, MD,* Kohei Hashimoto, MD,* Yoshikazu Sato, MD,‡ and Naoya Masumori, MD* *Department of Urology, School of Medicine, Sapporo Medical University, Sapporo, Hokkaido, Japan; †Department of Urology, School of Medicine, Juntendo University, Bunkyo-ku, Tokyo, Japan; ‡Department of Urology, Sanjukai Hospital, Sapporo, Hokkaido, Japan DOI: 10.1111/jsm.12617
ABSTRACT
Introduction. The Erection Hardness Score (EHS) and the Sexual Health Inventory for men (SHIM) are patientreported outcome scoring systems for erectile function. It is unclear which is more reliable for predicting the objective erectile function. Aim. The aim of this study was to evaluate whether the EHS could predict objective erectile function by measuring the maximal penile circumferential change (MPCC) with an erectometer. Methods. The study included 98 patients who visited our clinic from 2005 to 2010. The erectile function was evaluated using the SHIM, EHS, and MPCC. The MPCC was measured with the largest circumferential change of three consecutive occurrences of nocturnal penile tumescence (NPT) determined using the erectometer. Main Outcome Measures. We defined erectile dysfunction (ED) as MPCC < 20 mm and carried out multivariate analysis using logistic regression analysis to clarify the predictors for ED, with the variables including age, the SHIM score, and the EHS. We compared the tendency for MPCC ≥ 20 mm when EHS was 3 or more with that when EHS was 2 or less. Results. The median age of the patients was 59.5 years (range 18–83). In logistic regression analysis, the EHS was the only predictor for ED with MPCC < 20 mm. The mean EHS in the MPCC < 20 mm group was 1.64 ± 0.20 (mean ± SEM) and that in the MPCC ≥ 20 mm group was 2.46 ± 0.13 (P = 0.0018). There was a correlation between the EHS and the MPCC (correlation coefficient = 0.33). In comparison with the group having an EHS of 2 or less, that with an EHS of 3 or more tended to have MPCC ≥ 20 mm (P = 0.013). Conclusions. The EHS was correlated with the MPCC. The EHS represents the objective erectile function shown by the measurement of NPT. Matsuda Y, Hisasue S, Kumamoto Y, Kobayashi K, Hashimoto K, Sato Y, and Masumori N. Correlation between Erection Hardness Score and Nocturnal Penile Tumescence Measurement. J Sex Med **;**:**–**. Key Words. Erection Hardness Score; Erectile Function; Sexual Health Inventory for Men; Penile Circumferential Change; Axial Rigidity
Introduction
M
ore than 10 years have passed since the first phosphodiesterase-5 inhibitor was introduced for the treatment of erectile dysfunction
Funding: None.
© 2014 International Society for Sexual Medicine
(ED). In the historical first clinical trial for sildenafil, the Erection Hardness Score (EHS) was used for the outcome assessment [1,2]. In 1997, Rosen et al. reported the availability of the International Index of Erectile Function (IIEF) [1]. After that, the IIEF-5 Sexual Health Inventory for Men (SHIM) was introduced in 1999 as an abridged version of the IIEF [2]. The IIEF-5 and J Sex Med **;**:**–**
2 SHIM have been validated in many languages and are widely used for the evaluation of erectile function internationally. The EHS consists of single-item, patient-reported outcome scoring that enables us to obtain subjective information regarding erectile hardness. Recently, Mulhall et al. confirmed its validity for evaluating erectile hardness [3], and it possibly represents the state of erectile function more precisely. On the other hand, several objective erectile function assessment tools have been introduced. They are based on the assessment of nocturnal penile tumescence (NPT) events, which represent the physiological erectile function [4–8]. These include the mercury-filled strain gauge recorder [4], the stamp test [5], the angle of erection in the standing position test [6], the axial penile buckling test [7], and RigiScan [8]. Today, the RigiScan is the gold standard for the objective assessment of erection, and it enables us to investigate the circumferential change and the rigidity of NPT accurately, although it is a relatively expensive and complicated procedure for patients [8]. We previously reported the usefulness of an erectometer to determine the maximal penile circumferential change (MPCC) during NPT compared with the RigiScan [9]. We believe that the erectometer can also be used as an assessment tool for determining objective erectile function. The concern regarding the patient-reported outcome is how accurately the scoring represents objective erectile function. Previous reports suggested limitations in the use of the IIEF in a study investigating its correlation with results obtained using the RigiScan [10,11]. It is still unclear which is the most useful self-reported questionnaire in terms of reproducibility and reliability for predicting objective erectile function. Aims
The goal of this study was to investigate the correlations among the total SHIM score, EHS, and MPCC measured with an erectometer. Methods
We reviewed the medical charts of the patients who presented at our clinic between November 2005 and November 2010. We included the patients whose erectile function was evaluated with a self-administered questionnaire and the erectometer at the first visit. The questionnaires used for the erectile function assessment were the J Sex Med **;**:**–**
Matsuda et al. SHIM and the EHS. In our clinic, the erection hardness was evaluated using a modified version of the EHS (S-EHS; Sapporo Medical University version of the EHS). The S-EHS is a component of the Sapporo Medical University sexual function questionnaire, which was validated in Japanese in 1999 [12]. The appendix shows the S-EHS, which is translated into English, and the original version of the EHS. The difference between the S-EHS and the original version of the EHS is the number of the grades above 3 (penis is hard enough for penetration). We integrated 4 and 5 in the S-EHS into 4 in the original EHS in this study. The MPCC was measured using an erectometer (Nippon Medical Products, Asahikawa, Japan) during sleep for an average of two to three nights. The erectometer was originally developed by Jonas, and we previously adapted it for Japanese men [13,14]. Our modified erectometer consists of a sliding band and slit tube [14]. Briefly, the sliding band is pulled out through the slit tube at the time of penile circumferential expansion during NPT, and the method gives excellent correlation with the RigiScan [9]. According to the results of a previous study, we defined the cutoff point of ED as an MPCC of less than 20 mm [9,15].
Outcome Measures
We used the computer program StatView 5.0 for Windows (SAS Institute, Cary, NC, USA) for statistical analyses. We carried out multivariate analysis to identify factors contributing to the MPCC of 20 mm or less. The variables were age, the EHS, and the total SHIM score. Logistic regression analysis was used for the multivariate analysis. We used the Mann–Whitney U-test for age; chisquare test for hypertension, diabetes mellitus, and smoking; and the t-test for the EHS and the total SHIM score to compare the parameters among groups. The Kruskal–Wallis test and Spearman’s rank correlation coefficient were used to identify the relationship between the EHS and MPCC. We compared the group with an EHS of 3 or more with that having an EHS of 2 or less by Pearson’s chi-square test. A P value of <0.05 was considered to be statistically significant. The details of this study were approved by the Review Board in Sapporo Medical University Hospital (http://web.sapmed.ac.jp/byoin/chiken/ irb.html) (No. 25–122). The patients’ right to refuse to participate in our study is described on our website (http://web.sapmed.ac.jp/uro).
3
EHS and Objective Erectile Function Table 1
Characteristics of patients
n Age HT DM Smoking EHS (mean ± SEM) Total SHIM score (mean ± SEM)
Overall
MPCC < 20 mm
MPCC ≥ 20 mm
P value
98 59.5 22 (22.4%) 16 (16.3%) 55 (56.1%) 2.28 ± 0.11 10.50 ± 0.67
22 60 7 (31.8%) 3 (13.6%) 14 (63.6%) 1.64 ± 0.20 8.09 ± 1.20
76 59 15 (19.7%) 13 (17.1%) 41 (53.9%) 2.46 ± 0.13 11.20 ± 0.78
0.4851 0.2317 0.6983 0.4200 0.0018 0.0537
EHS = Erection Hardness Score; DM = diabetes mellitus; HT = hypertension; MPCC = maximal penile circumferential change
Results
A total of 110 of the 150 patients who presented at our clinic were evaluated. We excluded 12 patients with psychological ED to preclude the influence of the psychological element. Finally, 98 patients were enrolled in this study. Of the 98 patients, 70 were evaluated for their ED, and 28 were evaluated for erectile function before radical prostatectomy. Their median age was 59.5 years (range 18–83). The rates of hypertension, diabetes mellitus, and smoking were 22.4% (22/98), 16.3% (16/98), and 56.1% (55/98), respectively. The mean ± SEM of the EHS and the total SHIM score were 2.28 ± 0.11 and 10.50 ± 0.67, respectively. Table 1 shows the characteristics of the patients who were divided into two groups (MPCC < 20 mm or ≥20 mm). There was no significant difference in age, the rate of hypertension, diabetes mellitus, smoking, or the total SHIM score except for the EHS between the two groups. The relationship between the EHS and the MPCC is shown in Table 2. The patients whose EHS was 0 or 1 were grouped together in the analysis because the number of patients who had a score of 0 was small (n = 10). The mean MPCC increased as the EHS score became higher (P = 0.026). Spearman’s rank correlation coefficient between the EHS and the MPCC was 0.33. In the multivariate analysis, we tried to determine the factors influencing the objective ED from the parameters, including age, the EHS, and the total SHIM score. The EHS was revealed to be a significant predictor of objective erectile function stratified by the MPCC (P = 0.016, Table 3). In comparison with the group having EHS ≤ 2, that with EHS ≥ 3 tended to have an MPCC ≥ 20 mm (P = 0.013 Pearson’s chi-square test, Table 4).
determined by the MPCC measured with an erectometer. Goldstein et al. reported that, in a double-blind study of ED patients, the sildenafil group had higher EHS scores (3 and 4) than a placebo group (P < 0.001) [16]. EHS scores of 3 and 4 indicate that the patient can have sexual intercourse. Recently, Mulhall et al. also reported the validity of the EHS in a double-blind study of sildenafil citrate based on United States Food and Drug Administration guidance for 307 ED patients [3]. Other reports showed correlations between the EHS and other parameters such as the IIEF and successful sexual intercourse [17]. The EHS was again found to be an easy and useful tool for the functional assessment of ED [18–20].
Table 2
Relationship between the EHS and the MPCC
EHS
0/1
2
3
4
Total
n Mean MPCC (mm)
34 20.9
19 26.0
29 28.8
16 28.6
98 25.5
P = 0.026 (Kruskal–Wallis test) EHS = Erection Hardness Score; MPCC = maximal penile circumferential change
Table 3 Multivariate analysis of the MPCC ≥ 20 mm variables Variable
Odds
95% CI
P value
Age EHS Total SHIM score
0.989 2.772 0.951
0.954–1.025 1.207–6.367 0.833–1.086
0.528 0.016 0.457
EHS = Erection Hardness Score; MPCC = maximal penile circumferential change; SHIM = Sexual Health Inventory for Men
Table 4
Comparison of EHS ≥ 3 and EHS ≤ 2 MPCC ≥ 20
MPCC < 20
40 36
5 17
Discussion
EHS ≥ 3 (n = 45) EHS ≤ 2 (n = 53)
Our goal was to determine the potential of the EHS to predict the objective erectile function
P = 0.013 (Pearson’s chi-square test) EHS = Erection Hardness Score; MPCC = maximal penile circumferential change
J Sex Med **;**:**–**
4 In the current study, multivariate analysis showed that the EHS was the only objective predictor of normal erectile function. Therefore, this simple, easy-to-use tool for the assessment of erectile hardness more precisely reflects objective erectile function than the SHIM. The SHIM and the IIEF-5 are validated in many languages and in widespread use internationally. The distinctive feature of the SHIM is that it considers the absence of sexual activity or sexual intercourse. If the patient has not engaged in sexual activity or sexual intercourse in the preceding 6 months, the 4 item score will be 0 and the minimum total score will be 1; on the other hand, the minimum score of the IIEF-5 is 5 [2]. In other words, if the patient does not have sexual activity or has not attempted to have sexual intercourse in the preceding 6 months, he is diagnosed as having severe ED, even if he has a normal erection [21]. There is a huge cultural difference in sexual activity between Japanese and American men, with Japanese men having less sexual intercourse [22]. Therefore, the EHS might be more suitable to assess the objective erectile function of Japanese patients than the SHIM. In 1985, Bradley et al. introduced the RigiScan for the objective evaluation of penile rigidity [23]. However, the RigiScan is expensive and its use is complicated, especially for older persons. By contrast, the erectometer is inexpensive, simple, and easy to handle [24]. The concerns with the use of the erectometer are its reproducibility and accuracy. We previously reported the correlation between RigiScan results and the MPCC measured with an erectometer [9]. The mean ± SD of the MPCC was 25.3 ± 2.6 mm with the RigiScan and 22.0 ± 1.7 mm with the erectometer (correlation coefficient: 0.719). Thus, we believe that the erectometer is a useful tool for the objective evaluation of erectile function. Poor correlation between the IIEF and the RigiScan was suggested previously [10]. Our study showed a similar result and there was no correlation between the SHIM and the MPCC measured using the erectometer. Together, self-assessments with the IIEF and SHIM do not seem to reflect objective erectile function. In this study, the EHS was the only predictor of the objective normal erectile function. In comparison with the group having an EHS 2 or less, that with an EHS of 3 or more tended to have an MPCC ≥20 mm. Therefore, if the EHS is 3 or more, the erectile function has a high possibility of being normal. Adding the EHS J Sex Med **;**:**–**
Matsuda et al. to patient-reported outcomes will lead to the improvement of diagnostic accuracy. There are several limitations in this study. The major one is the small number of patients and biased study population. The study subjects consisted of patients with ED or patients whose erectile function was assessed before radical prostatectomy. Furthermore, we integrated scores 4 and 5 in the modified version of the EHS that we used into 4 in the original one, although that did not influence the results because the key score was 3 in our study. Conclusions
This is the first study examining the correlation between subjective and objective evaluations of erectile function. The EHS reflects the MPCC. If the EHS is 3 or more, the erectile function has a high possibility of being normal. Therefore, we can expect favorable objective erectile function in such patients. Moreover, the MPCC measured by the erectometer itself is a simple and inexpensive parameter, and will be a good index to assess objective erectile function. Corresponding Author: Yohei Matsuda, MD, Department of Urology, School of Medicine, Sapporo Medical University, S1, W16, Chuo-ku, Sapporo, Hokkaido, 060-8543, Japan. Tel: 81-(0)11-611-2111; Fax: 81-(0)11-621-8059; E-mail: [email protected] Conflict of Interest: The authors report no conflicts of interest. Statement of Authorship
Category 1 (a) Conception and Design Naoya Masumori; Yohei Matsuda (b) Acquisition of Data Shin-ichi Hisasue; Yohei Matsuda (c) Analysis and Interpretation of Data Ko Kobayashi; Yohei Matsuda
Category 2 (a) Drafting the Article Shin-ichi Hisasue; Ko Kobayashi; Yohei Matsuda (b) Revising It for Intellectual Content Ko Kobayashi; Yohei Matsuda
Category 3 (a) Final Approval of the Completed Article Yoshiaki Kumamoto; Kohei Hashimoto; Yoshikazu Sato; Naoya Masumori; Yohei Matsuda
5
EHS and Objective Erectile Function References 1 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;49:822–30. 2 Rosen RC, Cappelleri JC, Smith MD, Lipsky J, Pena BM. Development and evaluation of an abridged, 5-item version of the international index of erectile function (IIEF-5) as a diagnostic tool for erectile dysfunction. Int J Impot Res 1999;11:319–26. 3 Mulhall JP, Goldstein I, Bushmakin AG, Cappelleri JC, Hvidsten K. Validation of the erection hardness score. J Sex Med 2007;4:1626–34. 4 Karacan I, Williams RL, Thornby JI, Salis PJ. Sleep-related penile tumescence as a function of age. Am J Psychiatry 1975;132:932–7. 5 Barry JM, Blank B, Boileau M. Nocturnal penile tumescence monitoring with stamps. Urology 1980;15:171–2. 6 Wespes E, Delcour C, Rondeux C, Struyven J, Schulman CC. The erectile angle: Objective criterion to evaluate the papaverine test in impotence. J Urol 1987;138:1171–3. 7 Goldstein I, Udelson D. Axial penile rigidity: Determinants and relation to hemodynamic parameters. Int J Impot Res 1998;10:28–33. 8 Levine LA, Carroll RA. Nocturnal penile tumescence and rigidity in men without complaints of erectile dysfunction using a new quantitative analysis software. J Urol 1994;152: 1103–7. 9 Suzuki K, Sato Y, Horita H, Adachi H, Kato R, Hisasue S, Itoh N, Tsukamoto T. The correlation between penile tumescence measured by the erectometer and penile rigidity by the RigiScan. Int J Urol 2001;8:594–8. 10 Melman A, Fogarty J, Hafron J. Can self-administered questionnaires supplant objective testing of erectile function? A comparison between the international index of erectile function and objective studies. Int J Impot Res 2006;18:126–9. 11 Tokatli Z, Akand M, Yaman O, Gulpinar O, Anafarta K. Comparison of international index of erectile function with nocturnal penile tumescence and rigidity testing in evaluation of erectile dysfunction. Int J Impot Res 2006;18:186–9. 12 Kato R, Sato Y, Horita H, Ito N, Kumamoto Y, Tsukamoto T, Miyake K. Validity analysis of Sapporo medical universitysexual function questionnaire. Nippon Hinyokika Gakkai Zasshi 1999;90:872–7. 13 Jonas U. Erectiometer. ein einfacher und sicherer test in der diagnostik der erektilen impotenz. Akt Urol 1982;13:324–7. 14 Mori K, Kumamoto Y, Ohno K, Aoki M. Evaluation of an erectometer as a new diagnostic method for impotence. Nippon Hinyokika Gakkai Zasshi 1985;76:1478–85. 15 Adachi H, Sato R, Horita H, Kumamoto Y, Tsukamoto T. Maximum increase of penile circumference as a parameter for evaluation of penile erectile capacity. Nippon Hinyokika Gakkai Zasshi 1997;88:788–94.
16 Goldstein I, Lue TF, Padma-Nathan H, Rosen RC, Steers WD, Wicker PA, Sildenafil Study Group. Oral sildenafil in the treatment of erectile dysfunction. N Engl J Med 1998;338: 1397–404. 17 Goldstein I, Mulhall JP, Bushmakin AG, Cappelleri JC, Hvidsten K, Symonds T. The erection hardness score and its relationship to successful sexual intercourse. J Sex Med 2008;5:2374–80. 18 Claes HI, Andrianne R, Opsomer R, Albert A, Patel S, Commers K. The HelpED study: Agreement and impact of the erection hardness score on sexual function and psychosocial outcomes in men with erectile dysfunction and their partners. J Sex Med 2012;9:2652–63. 19 Mazzola CR, Deveci S, Teloken P, Mulhall JP. Exploring the association between erectile rigidity and treatment adherence with sildenafil. J Sex Med 2013;10:1861–6. 20 Costa P, Grandmottet G, Mai HD, Droupy S. Impact of a first treatment with phosphodiesterase inhibitors on men and partners’ quality of sexual life: Results of a prospective study in primary care. J Sex Med 2013;10:1850–60. 21 Vroege JA. The Sexual Health Inventory for Men (IIEF-5): Reply to Cappelleri and Rosen. Int J Impot Res 2000;12: 297–8. 22 Namiki S, Kwan L, Kagawa-Singer M, Saito S, Terai A, Satoh T, Baba S, Arai Y, Litwin MS. Sexual function reported by Japanese and American men. J Urol 2008;179:245–9. 23 Bradley WE, Timm GW, Gallagher JM, Johnson BK. New method for continuous measurement of nocturnal penile tumescence and rigidity. Urology 1985;26:4–9. 24 Chen J, Greenstein A, Sofer M, Matzkin H. Rigiscan versus snap gauge band measurements: Is the extra cost justifiable? Int J Impot Res 1999;11:315–8.
Appendix Erection Hardness Score, Scale for Erectile Rigidity, and Duration of erection Erection Hardness Score (EHS) “How would you rate the hardness of your erection?” 0 Penis does not enlarge. 1 Penis is larger but not hard. 2 Penis is hard but not hard enough for penetration. 3 Penis is hard enough for penetration but not completely hard. 4 Penis is completely hard and fully rigid. The Sapporo Medical University version of the EHS (S-EHS) “How would you rate the hardness of your erection?” 0 Penis does not enlarge. 1 Penis is slightly hard. 2 Penis is hard but not hard enough for penetration. 3 Penis is hard enough for penetration but not completely hard. 4 Penis is almost completely hard. 5 Penis is completely hard and fully rigid.
J Sex Med **;**:**–**
Correlation between Erection Hardness Score and Nocturnal Penile Tumescence Measurement Yohei Matsuda, MD,* Shin-ichi Hisasue, MD, PhD,*† Yoshiaki Kumamoto, MD,* Ko Kobayashi, MD,* Kohei Hashimoto, MD,* Yoshikazu Sato, MD,‡ and Naoya Masumori, MD* *Department of Urology, School of Medicine, Sapporo Medical University, Sapporo, Hokkaido, Japan; †Department of Urology, School of Medicine, Juntendo University, Bunkyo-ku, Tokyo, Japan; ‡Department of Urology, Sanjukai Hospital, Sapporo, Hokkaido, Japan DOI: 10.1111/jsm.12617
ABSTRACT
Introduction. The Erection Hardness Score (EHS) and the Sexual Health Inventory for men (SHIM) are patientreported outcome scoring systems for erectile function. It is unclear which is more reliable for predicting the objective erectile function. Aim. The aim of this study was to evaluate whether the EHS could predict objective erectile function by measuring the maximal penile circumferential change (MPCC) with an erectometer. Methods. The study included 98 patients who visited our clinic from 2005 to 2010. The erectile function was evaluated using the SHIM, EHS, and MPCC. The MPCC was measured with the largest circumferential change of three consecutive occurrences of nocturnal penile tumescence (NPT) determined using the erectometer. Main Outcome Measures. We defined erectile dysfunction (ED) as MPCC < 20 mm and carried out multivariate analysis using logistic regression analysis to clarify the predictors for ED, with the variables including age, the SHIM score, and the EHS. We compared the tendency for MPCC ≥ 20 mm when EHS was 3 or more with that when EHS was 2 or less. Results. The median age of the patients was 59.5 years (range 18–83). In logistic regression analysis, the EHS was the only predictor for ED with MPCC < 20 mm. The mean EHS in the MPCC < 20 mm group was 1.64 ± 0.20 (mean ± SEM) and that in the MPCC ≥ 20 mm group was 2.46 ± 0.13 (P = 0.0018). There was a correlation between the EHS and the MPCC (correlation coefficient = 0.33). In comparison with the group having an EHS of 2 or less, that with an EHS of 3 or more tended to have MPCC ≥ 20 mm (P = 0.013). Conclusions. The EHS was correlated with the MPCC. The EHS represents the objective erectile function shown by the measurement of NPT. Matsuda Y, Hisasue S, Kumamoto Y, Kobayashi K, Hashimoto K, Sato Y, and Masumori N. Correlation between Erection Hardness Score and Nocturnal Penile Tumescence Measurement. J Sex Med **;**:**–**. Key Words. Erection Hardness Score; Erectile Function; Sexual Health Inventory for Men; Penile Circumferential Change; Axial Rigidity
Introduction
M
ore than 10 years have passed since the first phosphodiesterase-5 inhibitor was introduced for the treatment of erectile dysfunction
Funding: None.
© 2014 International Society for Sexual Medicine
(ED). In the historical first clinical trial for sildenafil, the Erection Hardness Score (EHS) was used for the outcome assessment [1,2]. In 1997, Rosen et al. reported the availability of the International Index of Erectile Function (IIEF) [1]. After that, the IIEF-5 Sexual Health Inventory for Men (SHIM) was introduced in 1999 as an abridged version of the IIEF [2]. The IIEF-5 and J Sex Med **;**:**–**
2 SHIM have been validated in many languages and are widely used for the evaluation of erectile function internationally. The EHS consists of single-item, patient-reported outcome scoring that enables us to obtain subjective information regarding erectile hardness. Recently, Mulhall et al. confirmed its validity for evaluating erectile hardness [3], and it possibly represents the state of erectile function more precisely. On the other hand, several objective erectile function assessment tools have been introduced. They are based on the assessment of nocturnal penile tumescence (NPT) events, which represent the physiological erectile function [4–8]. These include the mercury-filled strain gauge recorder [4], the stamp test [5], the angle of erection in the standing position test [6], the axial penile buckling test [7], and RigiScan [8]. Today, the RigiScan is the gold standard for the objective assessment of erection, and it enables us to investigate the circumferential change and the rigidity of NPT accurately, although it is a relatively expensive and complicated procedure for patients [8]. We previously reported the usefulness of an erectometer to determine the maximal penile circumferential change (MPCC) during NPT compared with the RigiScan [9]. We believe that the erectometer can also be used as an assessment tool for determining objective erectile function. The concern regarding the patient-reported outcome is how accurately the scoring represents objective erectile function. Previous reports suggested limitations in the use of the IIEF in a study investigating its correlation with results obtained using the RigiScan [10,11]. It is still unclear which is the most useful self-reported questionnaire in terms of reproducibility and reliability for predicting objective erectile function. Aims
The goal of this study was to investigate the correlations among the total SHIM score, EHS, and MPCC measured with an erectometer. Methods
We reviewed the medical charts of the patients who presented at our clinic between November 2005 and November 2010. We included the patients whose erectile function was evaluated with a self-administered questionnaire and the erectometer at the first visit. The questionnaires used for the erectile function assessment were the J Sex Med **;**:**–**
Matsuda et al. SHIM and the EHS. In our clinic, the erection hardness was evaluated using a modified version of the EHS (S-EHS; Sapporo Medical University version of the EHS). The S-EHS is a component of the Sapporo Medical University sexual function questionnaire, which was validated in Japanese in 1999 [12]. The appendix shows the S-EHS, which is translated into English, and the original version of the EHS. The difference between the S-EHS and the original version of the EHS is the number of the grades above 3 (penis is hard enough for penetration). We integrated 4 and 5 in the S-EHS into 4 in the original EHS in this study. The MPCC was measured using an erectometer (Nippon Medical Products, Asahikawa, Japan) during sleep for an average of two to three nights. The erectometer was originally developed by Jonas, and we previously adapted it for Japanese men [13,14]. Our modified erectometer consists of a sliding band and slit tube [14]. Briefly, the sliding band is pulled out through the slit tube at the time of penile circumferential expansion during NPT, and the method gives excellent correlation with the RigiScan [9]. According to the results of a previous study, we defined the cutoff point of ED as an MPCC of less than 20 mm [9,15].
Outcome Measures
We used the computer program StatView 5.0 for Windows (SAS Institute, Cary, NC, USA) for statistical analyses. We carried out multivariate analysis to identify factors contributing to the MPCC of 20 mm or less. The variables were age, the EHS, and the total SHIM score. Logistic regression analysis was used for the multivariate analysis. We used the Mann–Whitney U-test for age; chisquare test for hypertension, diabetes mellitus, and smoking; and the t-test for the EHS and the total SHIM score to compare the parameters among groups. The Kruskal–Wallis test and Spearman’s rank correlation coefficient were used to identify the relationship between the EHS and MPCC. We compared the group with an EHS of 3 or more with that having an EHS of 2 or less by Pearson’s chi-square test. A P value of <0.05 was considered to be statistically significant. The details of this study were approved by the Review Board in Sapporo Medical University Hospital (http://web.sapmed.ac.jp/byoin/chiken/ irb.html) (No. 25–122). The patients’ right to refuse to participate in our study is described on our website (http://web.sapmed.ac.jp/uro).
3
EHS and Objective Erectile Function Table 1
Characteristics of patients
n Age HT DM Smoking EHS (mean ± SEM) Total SHIM score (mean ± SEM)
Overall
MPCC < 20 mm
MPCC ≥ 20 mm
P value
98 59.5 22 (22.4%) 16 (16.3%) 55 (56.1%) 2.28 ± 0.11 10.50 ± 0.67
22 60 7 (31.8%) 3 (13.6%) 14 (63.6%) 1.64 ± 0.20 8.09 ± 1.20
76 59 15 (19.7%) 13 (17.1%) 41 (53.9%) 2.46 ± 0.13 11.20 ± 0.78
0.4851 0.2317 0.6983 0.4200 0.0018 0.0537
EHS = Erection Hardness Score; DM = diabetes mellitus; HT = hypertension; MPCC = maximal penile circumferential change
Results
A total of 110 of the 150 patients who presented at our clinic were evaluated. We excluded 12 patients with psychological ED to preclude the influence of the psychological element. Finally, 98 patients were enrolled in this study. Of the 98 patients, 70 were evaluated for their ED, and 28 were evaluated for erectile function before radical prostatectomy. Their median age was 59.5 years (range 18–83). The rates of hypertension, diabetes mellitus, and smoking were 22.4% (22/98), 16.3% (16/98), and 56.1% (55/98), respectively. The mean ± SEM of the EHS and the total SHIM score were 2.28 ± 0.11 and 10.50 ± 0.67, respectively. Table 1 shows the characteristics of the patients who were divided into two groups (MPCC < 20 mm or ≥20 mm). There was no significant difference in age, the rate of hypertension, diabetes mellitus, smoking, or the total SHIM score except for the EHS between the two groups. The relationship between the EHS and the MPCC is shown in Table 2. The patients whose EHS was 0 or 1 were grouped together in the analysis because the number of patients who had a score of 0 was small (n = 10). The mean MPCC increased as the EHS score became higher (P = 0.026). Spearman’s rank correlation coefficient between the EHS and the MPCC was 0.33. In the multivariate analysis, we tried to determine the factors influencing the objective ED from the parameters, including age, the EHS, and the total SHIM score. The EHS was revealed to be a significant predictor of objective erectile function stratified by the MPCC (P = 0.016, Table 3). In comparison with the group having EHS ≤ 2, that with EHS ≥ 3 tended to have an MPCC ≥ 20 mm (P = 0.013 Pearson’s chi-square test, Table 4).
determined by the MPCC measured with an erectometer. Goldstein et al. reported that, in a double-blind study of ED patients, the sildenafil group had higher EHS scores (3 and 4) than a placebo group (P < 0.001) [16]. EHS scores of 3 and 4 indicate that the patient can have sexual intercourse. Recently, Mulhall et al. also reported the validity of the EHS in a double-blind study of sildenafil citrate based on United States Food and Drug Administration guidance for 307 ED patients [3]. Other reports showed correlations between the EHS and other parameters such as the IIEF and successful sexual intercourse [17]. The EHS was again found to be an easy and useful tool for the functional assessment of ED [18–20].
Table 2
Relationship between the EHS and the MPCC
EHS
0/1
2
3
4
Total
n Mean MPCC (mm)
34 20.9
19 26.0
29 28.8
16 28.6
98 25.5
P = 0.026 (Kruskal–Wallis test) EHS = Erection Hardness Score; MPCC = maximal penile circumferential change
Table 3 Multivariate analysis of the MPCC ≥ 20 mm variables Variable
Odds
95% CI
P value
Age EHS Total SHIM score
0.989 2.772 0.951
0.954–1.025 1.207–6.367 0.833–1.086
0.528 0.016 0.457
EHS = Erection Hardness Score; MPCC = maximal penile circumferential change; SHIM = Sexual Health Inventory for Men
Table 4
Comparison of EHS ≥ 3 and EHS ≤ 2 MPCC ≥ 20
MPCC < 20
40 36
5 17
Discussion
EHS ≥ 3 (n = 45) EHS ≤ 2 (n = 53)
Our goal was to determine the potential of the EHS to predict the objective erectile function
P = 0.013 (Pearson’s chi-square test) EHS = Erection Hardness Score; MPCC = maximal penile circumferential change
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4 In the current study, multivariate analysis showed that the EHS was the only objective predictor of normal erectile function. Therefore, this simple, easy-to-use tool for the assessment of erectile hardness more precisely reflects objective erectile function than the SHIM. The SHIM and the IIEF-5 are validated in many languages and in widespread use internationally. The distinctive feature of the SHIM is that it considers the absence of sexual activity or sexual intercourse. If the patient has not engaged in sexual activity or sexual intercourse in the preceding 6 months, the 4 item score will be 0 and the minimum total score will be 1; on the other hand, the minimum score of the IIEF-5 is 5 [2]. In other words, if the patient does not have sexual activity or has not attempted to have sexual intercourse in the preceding 6 months, he is diagnosed as having severe ED, even if he has a normal erection [21]. There is a huge cultural difference in sexual activity between Japanese and American men, with Japanese men having less sexual intercourse [22]. Therefore, the EHS might be more suitable to assess the objective erectile function of Japanese patients than the SHIM. In 1985, Bradley et al. introduced the RigiScan for the objective evaluation of penile rigidity [23]. However, the RigiScan is expensive and its use is complicated, especially for older persons. By contrast, the erectometer is inexpensive, simple, and easy to handle [24]. The concerns with the use of the erectometer are its reproducibility and accuracy. We previously reported the correlation between RigiScan results and the MPCC measured with an erectometer [9]. The mean ± SD of the MPCC was 25.3 ± 2.6 mm with the RigiScan and 22.0 ± 1.7 mm with the erectometer (correlation coefficient: 0.719). Thus, we believe that the erectometer is a useful tool for the objective evaluation of erectile function. Poor correlation between the IIEF and the RigiScan was suggested previously [10]. Our study showed a similar result and there was no correlation between the SHIM and the MPCC measured using the erectometer. Together, self-assessments with the IIEF and SHIM do not seem to reflect objective erectile function. In this study, the EHS was the only predictor of the objective normal erectile function. In comparison with the group having an EHS 2 or less, that with an EHS of 3 or more tended to have an MPCC ≥20 mm. Therefore, if the EHS is 3 or more, the erectile function has a high possibility of being normal. Adding the EHS J Sex Med **;**:**–**
Matsuda et al. to patient-reported outcomes will lead to the improvement of diagnostic accuracy. There are several limitations in this study. The major one is the small number of patients and biased study population. The study subjects consisted of patients with ED or patients whose erectile function was assessed before radical prostatectomy. Furthermore, we integrated scores 4 and 5 in the modified version of the EHS that we used into 4 in the original one, although that did not influence the results because the key score was 3 in our study. Conclusions
This is the first study examining the correlation between subjective and objective evaluations of erectile function. The EHS reflects the MPCC. If the EHS is 3 or more, the erectile function has a high possibility of being normal. Therefore, we can expect favorable objective erectile function in such patients. Moreover, the MPCC measured by the erectometer itself is a simple and inexpensive parameter, and will be a good index to assess objective erectile function. Corresponding Author: Yohei Matsuda, MD, Department of Urology, School of Medicine, Sapporo Medical University, S1, W16, Chuo-ku, Sapporo, Hokkaido, 060-8543, Japan. Tel: 81-(0)11-611-2111; Fax: 81-(0)11-621-8059; E-mail: [email protected] Conflict of Interest: The authors report no conflicts of interest. Statement of Authorship
Category 1 (a) Conception and Design Naoya Masumori; Yohei Matsuda (b) Acquisition of Data Shin-ichi Hisasue; Yohei Matsuda (c) Analysis and Interpretation of Data Ko Kobayashi; Yohei Matsuda
Category 2 (a) Drafting the Article Shin-ichi Hisasue; Ko Kobayashi; Yohei Matsuda (b) Revising It for Intellectual Content Ko Kobayashi; Yohei Matsuda
Category 3 (a) Final Approval of the Completed Article Yoshiaki Kumamoto; Kohei Hashimoto; Yoshikazu Sato; Naoya Masumori; Yohei Matsuda
5
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Appendix Erection Hardness Score, Scale for Erectile Rigidity, and Duration of erection Erection Hardness Score (EHS) “How would you rate the hardness of your erection?” 0 Penis does not enlarge. 1 Penis is larger but not hard. 2 Penis is hard but not hard enough for penetration. 3 Penis is hard enough for penetration but not completely hard. 4 Penis is completely hard and fully rigid. The Sapporo Medical University version of the EHS (S-EHS) “How would you rate the hardness of your erection?” 0 Penis does not enlarge. 1 Penis is slightly hard. 2 Penis is hard but not hard enough for penetration. 3 Penis is hard enough for penetration but not completely hard. 4 Penis is almost completely hard. 5 Penis is completely hard and fully rigid.
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