Validation of the Clavien-Dindo Grading System in Urology by the European Association of Urology Guidelines Ad Hoc Panel

Context: Since 2012 uniformed reporting of complications after urological procedures has been advocated by the European Association of Urology (EAU) guidelines. The Clavien-Dindo grading system was recommended to report the outcomes of urologic procedures.

Objective: To validate the Clavien-Dindo grading system in urology.

Design, setting, and participants: Members of the EAU working group compiled a list of case scenarios including those with minor and major complications. A survey was administered online via Survey Monkey to the members of EAU committees for the appropriate grading according to the Clavien-Dindo classification of surgical complications. Scenarios with intraoperative complications were intentionally included to assess respondents' awareness of the Clavien-Dindo applicability.

Outcome measurements and statistical analysis: Survey data collected were used to calculate agreement rates and to estimate the overall inter-rater agreement on all cases using Fleiss' kappa (κ). Differences in agreement rates for each scenario among groups with different criteria about the system were estimated using the chi-square test.

Results and limitations: Evaluable responses were received from 81 out of 174 invited raters (46.5%). Of them 56.9% believed that the Clavien-Dindo system was adequate for grading postoperative complications. The agreement rate was over a score of ≥80% in nine cases, 60-79% in 10 cases, 40-59% in 14 cases, and <40% in two cases. Interestingly, the agreement rate on the nonapplicability of the Clavien-Dindo system was quite low, ranging from 27.5% to 67.2% (κ=0.147). Being a resident rather than a specialist affected only the distribution of agreement rates in case 1 (ie, score IIIb: 83.3% vs 94.1%). Being an academic or having affiliation did not have any impact on the distribution of agreement rates in all cases but one.

Conclusions: The Clavien-Dindo classification is a standardised approach to grade and report postoperative complications in urology and should be used systematically. However, it does not apply for intraoperative complications, and there is a need for an additional tool.

Patient summary: A rigorous methodology is mandatory when surgeons report about complications after surgery. In this study, the European Association of Urology Guidelines Panel has validated the use of the Clavien-Dindo grading system in urology.