Volume Alone Does Not Predict Quality Outcomes in Hospitals Performing Pediatric Cardiac Surgery

BACKGROUND:Lower institutional volume has been associated with inferior pediatric cardiac surgery outcomes. This study explored the variation in mortality rates among low-, mid-, and high-volume hospitals performing pediatric cardiac surgery in the United States. METHODS:The Kids' Inpatient Database (KID) was explored for the years 2016 and 2019. Hospitals only performing off-bypass coarctation and ventricular septal defect repair were omitted. The hospitals were divided into three groups by their annual case volume. Multivariable logistic regression models were fit to obtain risk adjusted in-hospital mortality rates. RESULTS:A total of 25,749 operations performed by 235 hospitals were included in the study. The risk-adjusted mortality rate for the entire sample was 1.9%. There were 140 hospitals in the low-volume group, 64 hospitals in the mid-volume group, and 31 in the high-volume group. All groups had low-mortality (mortality<1.9%) and high-mortality hospitals (mortality>1.9%). Among low volume hospitals, 53% were low-mortality (n=74) and 47% were high-mortality hospitals (n=66). Among mid-volume hospitals, 58% were low-mortality (n=37) and 42% of hospitals were high-mortality hospitals (n=27). Among high-volume hospitals, 68% were low-mortality (n=21) and 32% were high-mortality hospitals (n=10). There was no statistically significant difference in risk-adjusted in-hospital mortality when comparing low, mid and high-volume centers for seven STS benchmark procedures. CONCLUSIONS:This national, real-world, risk-adjusted volume outcome analysis highlights that volume alone may not be the sole arbiter to predict quality of pediatric cardiac surgery outcomes. Using case volume alone as a surrogate for quality may unfairly asperse high-performing, low-volume programs.