PURPOSE: Despite the high incidence of perioperative complications following cystectomy, there is a lack of evidence regarding patients' perceptions. Moreover, discrepancies between established complication grading systems and the patient's perspective remain unexplored. METHODS: We prospectively evaluated perioperative complications after cystectomy using the Clavien-Dindo Classification (CDC) and the Comprehensive Complication Index (CCI). The CDC and CCI were compared to patient-reported complication grades through Spearman correlation analysis. Discrepancies between physician-assessed and patient-reported complication grades were then evaluated. The study was registered at ClinicalTrials.gov (NCT05153694). RESULTS: Between December 2021 and March 2024, 172 patients underwent open cystectomy at our department. Of those, 154 provided written consent to participate in the study, and 111 completed the post-discharge questionnaire. We found a moderate correlation between physician-assessed and patient-reported complication grades (CDC: r = 0.34, CCI: r = 0.39
p <
0.001). Patients with matching grades were defined as realists (50%). Those who reported lower complication grades than assessed by physicians were defined as optimists (38%), while those who reported higher grades were defined as pessimists (12%). Optimists rated the preoperative medical information better than pessimists ("very good": 79% vs. 38%, p = 0.006). We found no significant differences between optimists and pessimists regarding age, gender, tumor characteristics or educational level. CONCLUSION: In our prospective study, the correlation between physician-assessed and patient-reported complication grades was only moderate. Only half of the cystectomy patients accurately perceived the severity of their complications. Our findings represent the first study to investigate patients' perspectives on complications in urology and underscore the importance of thorough preoperative medical information.