Primary Research on Correlation between Erectile Function Assessment through International Index of Erectile Function Score and Nocturnal Penile Tumescence and Rigidity Measurements in Men with Erectile Dysfunction

Introduction Erectile dysfunction (ED) affects approximately 40% of men; however, the true prevalence remains uncertain owing to various factors. Diagnosing ED is challenging, and tools like the International Index of Erectile Function (IIEF) and its shorter version, the IIEF-5, are commonly used to assess its severity. Although nocturnal penile tumescence and rigidity (NPTR) monitoring, as an objective test, can help diagnose ED, it is complex and not economical. Therefore, this study aimed to compare NPTR with the IIEF to assess the IIEF’s potential as a cost-effective diagnostic tool for ED. Methods A correlation analysis study was performed on 139 men with ED between August 2017 and March 2023 who had undergone NPTR assessment in Jakarta, Indonesia. ED was assessed using detailed evaluations and IIEF-5 questionnaires. NPTR data was collected using a Rigiscan® device. Serum testosterone, total cholesterol, HbA1c, and vitamin D-25(OH) from blood samples were also evaluated. Bivariate analysis was used to explore the correlations between IIEF-5 scores, NPTR measurements, and blood parameters. Results In total, 139 men with ED (median age: 42 years) were included. The median IIEF-5 score was 11, and comorbidities included dyslipidemia (20%) and diabetes (12%). There are significant correlations between IIEF scores and NPTR variables (number of erections recorded, base tumescence increment, average base tumescence, and duration of base erection with ˃ 60% rigidity). Additionally, significant negative correlations were observed between HbA1c levels and several NPTR variables, including the number and quality of nocturnal erections. Significant correlations were also found between HbA1c and various NPTR variables. Conclusion This study underscores the value of subjective questionnaires such as the IIEF-5 in diagnosing ED, especially in the absence of advanced tests like the NPTR assessment. We found correlations between IIEF scores and nocturnal erection frequency, as well as specific erection characteristics. Our findings highlight the importance of a personalized approach to ED diagnosis. We also observed that higher HbA1c levels were associated with reduced nocturnal erection quality, highlighting the metabolic influence on erectile function. Although IIEF aids in cost-effective assessments, it should not replace objective testing.