Preoperative factors affecting cost and length of stay for isolated off-pump coronary artery bypass grafting: hierarchical linear model analysis

Objective: To determine the effect of preoperative patient and hospital factors on resource use, cost and length of stay (LOS) among patients undergoing off-pump coronary artery bypass grafting (OPCAB). Design: Observational retrospective study. Settings: Data from the Japanese Administrative Database. Participants: Patients who underwent isolated, elective OPCAB between April 2011 and March 2012. Primary outcome measures: The primary outcomes of this study were inpatient cost and LOS associated with OPCAB. A two-level hierarchical linear model was used to examine the effects of patient and hospital characteristics on inpatient costs and LOS. The independent variables were patient and hospital factors. Results: We identified 2491 patients who underwent OPCAB at 268 hospitals. The mean cost of OPCAB was $40 665 +/- 7774, and the mean LOS was 23.4 +/- 8.2 days. The study found that select patient factors and certain comorbidities were associated with a high cost and long LOS. A high hospital OPCAB volume was associated with a low cost (-6.6%; p=0.024) as well as a short LOS (-17.6%, p<0.001). Conclusions: The hospital OPCAB volume is associated with efficient resource use. The findings of the present study indicate the need to focus on hospital elective OPCAB volume in Japan in order to improve cost and LOS.