Article Provides Systematic Review of Postoperative Complication Grading Scales

The Current State of Postoperative Complication Grading Scales. Fischer RMJ, Vos TJ, Hoeks SE, et al. Ann Surg. October 18, 2025.

Standardized grading of postoperative complications is essential for accurate benchmarking and cross-study comparability in surgical outcomes research. This systematic review identified 79 studies that developed, modified, compared, or validated postoperative complication grading systems across surgical subspecialties.

Of these, six studies (8%) proposed novel grading systems, seven (9%) introduced modifications to existing scales, and 66 (84%) evaluated or compared established tools. The Clavien–Dindo classification (CDC) and Comprehensive Complication Index (CCI) were by far the most utilized systems, featuring in 52 (66%) and 31 (39%) of studies, respectively.

Among 36 studies directly comparing CDC and CCI, 33 (92%) demonstrated superior correlation of the CCI with key outcome indicators. When length of stay (LoS) was analyzed (n = 46 studies), 26 of 27 (96%) reported a stronger relationship between CCI and LoS compared to CDC. Similar trends were noted for cost (n = 11 studies) and quality of life (n = 4 studies), although the evidence base was smaller. 

The CCI’s advantage derives from its continuous scoring approach, capturing cumulative morbidity by weighting multiple complications per patient, whereas the CDC categorizes only the most severe event. Despite its analytic superiority, CDC remains the dominant classification in clinical reporting due to its simplicity, categorical structure, and familiarity.

For contemporary surgical outcomes assessment, this review supports the CCI as the more sensitive and discriminative metric of postoperative morbidity, particularly for research, quality benchmarking, and health economics. The CDC remains appropriate for clinical documentation and real-time complication tracking. Adoption of standardized grading systems, with clear definitions and consistent reporting, is critical to improve data integrity, enable meta-analyses, and refine risk-adjusted surgical performance metrics across institutions.