Inter-rater reliability of ACS-NSQIP colorectal procedure coding in Canada

Abstract

Background: The American College of Surgeons National Surgical Quality Improvement Project (ACS-NSQIP) uses Current Procedural Terminology (CPT) codes for risk-adjusted calculations. This study evaluates the inter-rater reliability of coding colorectal resections across Canada by ACS-NSQIP surgical clinical nurse reviewers (SCNR) and its impact on risk predictions.

Methods: SCNRs in Canada were asked to code simulated operative reports. Percent agreement and free-marginal kappa correlation were calculated. The ACS-NSQIP risk calculator was utilized to illustrate its impact on risk prediction.

Results: Responses from 44 of 150 (29.3 ​%) SCNRs revealed 3 to 6 different codes chosen per case, with agreement ranging from 6.7 ​% to 62.3 ​%. Free-marginal kappa correlation ranged from moderate agreement (0.53) to high disagreement (-0.17). ACS-NSQIP risk calculator predicted large absolute differences in risk for serious complications (0.2 ​%-13.7 ​%) and mortality (0.2 ​%-6.3 ​%).

Conclusion: This study demonstrated low inter-rater reliability in coding ACS-NSQIP colorectal procedures in Canada among SCNRs, impacting risk predictions.

Keywords: ACS-NSQIP; CPT code; Colorectal; Inter-rater reliability; Quality improvement.