Repeatability in measuring curvature in Peyronie's disease.

Background: Despite guideline recommendations to assess Peyronie's disease (PD) curvature during an intracavernous injection-induced erection, no standardized measurement protocol exists, and considerable interobserver variability remains. Aim: To evaluate the interobserver reliability of penile curvature measurements in patients with PD and to determine if image annotation enhances measurement consistency. Methods: In this study, 4 experienced urologists independently assessed erect penile curvature in 22 male patients enrolled in a prospective PD clinical trial. Two image sets per patient were analyzed: 1 consisting of self-captured photographs taken at home and the other obtained in the clinic after intracavernosal injection of alprostadil. Each image set included standardized lateral and dorsal views. The potential impact of an assisting line on photographic measurements was also evaluated. Outcomes: Interobserver agreement in curvature measurement, the effect of line annotation on measurement accuracy, and the comparison of measurement consistency between home-acquired and clinic-induced erection images. Results: Interobserver agreement was high, with Intraclass Correlation Coefficient values ranging from 0.77 to 0.88 across assessments. No statistically significant improvement in repeatability was observed with the addition of assisting lines. Furthermore, no meaningful difference in reproducibility was detected between home-based and pharmacologically induced image sets. Clinical Implications: Accurate measurement of penile curvature is crucial for comparing studies and evaluating treatment results. Variations in measurement techniques can lead to inconsistent data interpretation and reduce generalizability. Strengths and Limitations: This study highlights the need to standardize PD curvature assessment. While using multiple expert raters increases reliability, the small sample size and subjective interpretation of curvature may limit its broader use. Conclusion: Penile curvature measurements in PD show high interobserver reliability, regardless of photographic conditions or the use of assisting lines.