Development and validation of a composite score based on clinically meaningful events for the opioid-related symptom distress scale

Purpose: To develop and validate a composite score based on clinically meaningful events (CMEs) for the opioid-related symptom distress scale (OR-SDS) that would be appropriate for use in postoperative clinical trials. Methods: Secondary analysis of data from 2 multi-site Phase III randomized clinical safety trials: a general surgery trial (N = 1,050) and a coronary artery bypass graft surgery trial (N = 1,636). Validating measures include daily opioid consumption and physician and patient global evaluations of study medication. We empirically defined CMEs for each symptom, using factor analysis and an area under the receiver-operating characteristic analysis of the severity and frequency items of the OR-SDS. Construct validity was examined by testing hypotheses of relationships between composite CME scores and opioid consumption and physician and patient evaluations of study medication. Results: Hypotheses supporting the construct validity of the CME-based composite score were confirmed. Significant associations were found between higher numbers of CMEs with greater opioid consumption and lower likelihood of a positive evaluation of the study medication. Conclusions: The OR-SDS CME-based composite score demonstrates evidence of construct validity and appears appropriate for use in evaluating patients' opioid-related side effect burden in future postoperative clinical trials.