Pierre-Alain Clavien

In Brief Objective: Although quality assessment is gaining increasing attention, there is still no consensus on how to define and grade postoperative complications. This shortcoming hampers comparison of outcome data among different centers and therapies and over time. Patients and Methods: A classification of complications published by one of the authors in 1992 was critically re-evaluated and modified to increase its accuracy and its acceptability in the surgical community. Modifications mainly focused on the manner of reporting life-threatening and permanently disabling complications. The new grading system still mostly relies on the therapy used to treat the complication. The classification was tested in a cohort of 6336 patients who underwent elective general surgery at our institution. The reproducibility and personal judgment of the classification were evaluated through an international survey with 2 questionnaires sent to 10 surgical centers worldwide. Results: The new ranking system significantly correlated with complexity of surgery (P < 0.0001) as well as with the length of the hospital stay (P < 0.0001). A total of 144 surgeons from 10 different centers around the world and at different levels of training returned the survey. Ninety percent of the case presentations were correctly graded. The classification was considered to be simple (92% of the respondents), reproducible (91%), logical (92%), useful (90%), and comprehensive (89%). The answers of both questionnaires were not dependent on the origin of the reply and the level of training of the surgeons. Conclusions: The new complication classification appears reliable and may represent a compelling tool for quality assessment in surgery in all parts of the world. The lack of a uniform way of reporting complications hampers interpretation of surgical outcome data and quality assessment. The authors revisited a previously reported classification of complications and propose a new grading system. The new classification was tested in a cohort of 6336 patients undergoing general surgery and through an international survey.

OBJECTIVE: To develop and validate a comprehensive complication index (CCI) that integrates all events with their respective severity. BACKGROUND: Reporting of surgical complications is inconsistent and often incomplete. Most studies fail to provide information about the severity of complications, or inform only on the most severe event, ignoring events of lesser severity. METHODS: We used an established classification of complications, adopting methods from operation risk index analysis in marketing research to develop a formula that considers all complications that may occur in a patient. The weights of each grade of complication, defined as median reference values, were obtained from 472 participants, who rated 30 different complications. Validation to assess sensitivity to treatment effects and validity of the CCI was performed by 4 different approaches, based on 1299 patients. RESULTS: The CCI is calculated as the sum of all complications that are weighted for their severity (multiplication of the median reference values from patients and physicians). The final formula yields a continuous scale to rank the severity of any combination of complications from 0 to 100 in a single patient. The CCI was highly sensitive in detecting treatment effect differences in the context of a randomized trial (effect size detected by CCI vs conventional standardized morbidity outcomes). It also showed a negative correlation with postoperative health status (r = -0.24, P = 0.002), and high correlation with the results of patient-rated single and multiple complications on conjoint analysis (r = 0.94, P < 0.001). CONCLUSIONS: The CCI summarizes all postoperative complications and is more sensitive than existing morbidity endpoints. It may serve as a standardized and widely applicable primary endpoint in surgical trials and other interventional fields of medicine. The CCI can be readily computed on the basis of tabulated complications according to the Clavien-Dindo classification (available at www.assessurgery.com).

Lack of uniform reporting of negative outcomes makes interpretation of surgical literature difficult. We attempt to define and classify negative outcomes by differentiating complications, sequelae, and failures. Complications and sequelae result from procedures, adding new problems to the underlying disease. However, complications are unexpected events not intrinsic to the procedure, whereas sequelae are inherent to the procedure. Failures are events in which the purpose of the procedure is not fulfilled. We propose a classification of complications based on four grades: Grade I complications are alterations from the ideal postoperative course, non-life-threatening, and with no lasting disability. Complications of this grade necessitate only bedside procedures and do not significantly extend hospital stay. Grade II complications are potentially life-threatening but without residual disability. Within grade II complications a subdivision is made according to the requirement for invasive procedures. Grade III complications are those with residual disability, including organ resection or persistence of life-threatening conditions. Finally, grade IV complications are deaths as a result of complications. To illustrate the relevance of the classification, we reviewed 650 cases of elective cholecystectomy. Risk factors for development of complications were determined, and the classification was also used to analyze the value of a modified APACHE II as a preoperative prognostic score. Both supported the relevance of the proposed classification. The advantages of such a classification are (1) increased uniformity in reporting results, (2) the ability to compare results of two distinct time periods in a single center, (3) the ability to compare results of surgery between different centers, (4) the ability to compare results of surgical versus nonsurgical measures, (5) the ability to perform adequate metaanalysis, (6) the ability to identify objective preoperative risk factors, and (7) the ability to establish preoperative prognostic scores.

The Samuel Lunenfeld Research Institute and the Department of Surgery, Mount Sinai Hospital and the University of Toronto Liver Transplantation Program, University of Toronto, Toronto, Ontario, Canada