Variation in cost of total thyroidectomy across the United States, 2007 to 2008

•We calculated adjusted total cost for total thyroidectomy across the United States.•The mean cost varied substantially between states.•After adjustment, 27% of the variation in cost remained unexplained.•Only 28% of the variation in cost was explained by patient factors.

BackgroundVariation in cost of surgical care across state lines is poorly understood. We sought to examine state-level variation in wage-adjusted total cost (WATC) of a common surgical procedure.MethodsWe performed a retrospective cohort study of patients undergoing total thyroidectomy in the Nationwide Inpatient Sample (2007 to 2008). WATC was calculated from charges and adjusted for the area wage index. Hierarchical linear modeling was used to investigate the variation in WATC explained by variables at the patient, hospital, and state levels.ResultsWe identified 11,058 eligible patients from 35 states. The overall mean WATC was $8,132; 37% of the WATC variance was because of differences across hospitals, whereas 28% was explained by patient-level factors and 8% because of differences across states.ConclusionsMore than a quarter of the variation in cost of total thyroidectomy was not explained by patient-, hospital-, or state-level factors. Further research is needed to understand the unexplained residual variation.