Surgical volume, hospital quality, and hospitalization cost in congenital heart surgery in the United States.

Hospital volume has been associated with improved outcomes in congenital cardiac surgery. However, the relationship between hospital volume and hospitalization cost remains unclear. This study examines the relationship between hospital surgical volume and hospitalization costs, while accounting for measures of quality, in children undergoing congenital heart surgery. A retrospective, repeated cross-sectional analysis was performed, using discharges from the 2006 and 2009 Kids' Inpatient Database. All pediatric admissions (<18 years) with a Risk Adjustment for Congenital Heart Surgery procedure and hospitalization cost/charge data were included. Multivariate, linear mixed regression models were run on hospitalization costs, with and without adjustment for indicators of quality (hospital mortality rate and complication rate). Both medium and high-volume hospitals (200-400 cases/year and >400 cases/year, respectively) were associated with lower odds of mortality but not occurrence of a complication. Hospital mortality was associated with the largest increase in hospitalization costs. High-volume hospitals (>400 cases/year) were associated with the lowest hospitalization costs per discharge ($37,775, p < 0.01) when compared to low-($43,270) and medium($41,085)-volume hospitals, prior to adjusting for quality indicators. However, when adjusting for hospital mortality rate, high-volume hospitals no longer demonstrated significant cost savings. When adjusting for hospital complication rate, high-volume hospitals continued to have the lowest hospitalization costs. High-volume hospitals are associated with a reduction in hospitalization costs that appear to be mediated through improvements in quality.