Measuring the clinical consistency of panelists' appropriateness ratings: the case of coronary artery bypass surgery

Abstract

Objective: To assess the clinical consistency of expert panelists' ratings of appropriateness for coronary artery bypass surgery. Design: Quantitative analysis of panelists' ratings. Participants: Nine physicians (three cardiothoracic surgeons, four cardiologists, and two internists) convened by RAND to establish criteria for the appropriateness of coronary artery bypass surgery. Main outcomes measures: Percentage of indication-pairs given clinically inconsistent ratings (i.e. higher rating assigned to one member of an indication-pair when rating should have been equal or lower). Results: In the final round of appropriateness ratings, among 1785 pairs of indications differing only on a single clinical factor (e.g., three-vessel vs. two-vessel stenosis), 6.6% were assigned clinically inconsistent ratings by individual panelists, but only 2.7% received inconsistent ratings from the panel as a whole (using the median panel rating as the criterion). Internists on the panel provided fewer inconsistent ratings (4.6%) than either cardiologists (7.8%) or cardiothoracic surgeons (6.3%) ( p<0.001). More inconsistencies were noted when the factor distinguishing otherwise identical indications was symptom severity (inconsistency rate, 13.2%) or intensity of medical therapy (13.2%) than when it was number of stenosed vessels (3.8%) or proximal left anterior descending (PLAD) involvement (1.9%). Contrary to expectations, panelists' inconsistency rates increased between the initial and final rounds of appropriateness ratings (from 3.9 to 6.6%, p<0.001). Panelists' mean ratings across indications were only weakly correlated with individual inconsistency rates ( r=0.18, p=ns). Conclusions: The RAND/UCLA method for assessing the appropriateness of coronary revascularization generally produces criteria that are clinically consistent. However, research is needed to understand the sources of panelists' inconsistencies and to reduce inconsistency rates further.