The comprehensive complication index (CCI): proposal of a new reporting standard for complications in major urological surgery

PURPOSE: The comprehensive complication index (CCI) is a new tool for reporting the cumulative burden of postoperative complications on a continuous scale. This study validates the CCI for urological surgery and its benefits over the Clavien-Dindo-Classification (Clavien). MATERIAL AND METHODS: Data from a prospectively maintained data base of all consecutive patients at a university care-center was analyzed. Complications after radical cystectomy (RC), radical prostatectomy (RP), and partial nephrectomy (PN) were classified using the CCI and Clavien system. Differences in complications between the CCI and the Clavien were assessed and correlation analyses performed. Sample size calculations for hypothetical clinical trials were compared between CCI and Clavien to evaluate whether the CCI would reduce the number of required patients in a clinical trial. RESULTS: 682 patients (172 RC, 297 RP, 213 PN) were analyzed. Overall, 9.4–46.6% of patients had > 1 complication cumulatively assessed with the CCI resulting in an upgrading in the Clavien classification for 2.4–32.4% of patients. Therefore, scores between the systems differed for RC: CCI (mean ± standard deviation) 26.3 ± 20.8 vs. Clavien 20.4 ± 16.7, p < 0.001; PN: CCI 8.4 ± 14.7 vs. Clavien 7.0 ± 11.8, p < 0.001 and RP: CCI 5.8 ± 11.7 vs. Clavien 5.3 ± 10.6, p = 0.102. The CCI was more accurate in predicting LOS after RC than Clavien (p < 0.001). Sample size calculations based in the CCI (for future hypothetical trials) resulted in a reduction of required patients for all procedures (− 25% RC, − 74% PN, − 80% RP). CONCLUSION: The CCI is more accurate to assess surgical complications and reduces required sample sizes that will facilitate the conduction of clinical trials. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s00345-020-03356-z) contains supplementary material, which is available to authorized users.