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

K F Kowalewski,F Wessels,T S Worst,J D Hendrie,J Von Hardenberg,P Nuhn,M S Michel,M C Kriegmair,P Honeck,D Müller,J Mühlbauer,M T Walach

doi:10.1007/s00345-020-03356-z

Abstract

PurposeThe 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 methodsData 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.Results682 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).ConclusionThe CCI is more accurate to assess surgical complications and reduces required sample sizes that will facilitate the conduction of clinical trials.

Highlights

Surgery remains the mainstay of treatment for localized urological cancers
Originally designed for general surgery, the Clavien system was validated by the European Association of Urology (EAU) for evaluating postoperative complications of urological surgeries [4]
Sample size calculation for a fictive future superiority trial was based on the assumption of a 30% reduction for complication incidence on the Clavien scale

Summary

Introduction

Postoperative complications are inevitable, especially when elderly and multimorbid patients are deemed candidates for surgery [1, 2]. The Clavien-Dindo-Classification (Clavien) is the present standard to assess perioperative morbidity and mortality [3]. It classifies complications into five grades based on increasing severity, with grade 5 indicating patient death. A strength of the Clavien system is, that its classification is based on the invasiveness of the required treatment thereby taking into account that a certain complication might present with a different severity. Originally designed for general surgery, the Clavien system was validated by the European Association of Urology (EAU) for evaluating postoperative complications of urological surgeries [4].

Methods

Results

Conclusion