Impact of hospital volume on in-hospital mortality of infants undergoing repair of congenital diaphragmatic hernia.

OBJECTIVES

Congenital diaphragmatic hernia (CDH) remains a significant cause of neonatal morbidity and mortality.

SUMMARY OF BACKGROUND DATA: Previous studies have suggested that hospital volume is an independent predictor of in-hospital mortality. We sought to validate this effect using a large national database incorporating 37 free-standing children's hospitals in the United States.

METHODS

Infants who underwent repair of CDH from 2000 to 2008 at Pediatric Health Information Systems-member hospitals were evaluated. Hospitals were categorized by tertiles into low-volume (≤6 cases/yr), medium-volume (6-10 cases/yr), and high-volume (>10 cases/yr). Using generalized linear mixed models with random effects, we computed the risk-adjusted odds ratio of mortality by yearly hospital volume of CDH repair, after adjustment for salient patient and hospital characteristics.

RESULTS

There were 2203 infants who underwent repair with an overall survival of 82%. Average yearly hospital volume of CDH repair varied from 1.4 to 17.5 cases per year. Smaller birthweight (adjusted odds ratio [aOR]: 0.56 per kg, P < 0.001), year of birth (P < 0.001), chromosomal abnormalities (aOR: 3.83, P < 0.01), longer time to repair (aOR: 1.12 per week, P < 0.05), the thoracic approach for repair (P < 0.02), and requirement for extracorporeal membrane oxygenation (aOR: 10.31, P < 0.0001), or inhaled nitric oxide (aOR: 5.25, P < 0.0001) were each independently associated with mortality. Compared with low-volume hospitals, medium-volume (aOR: 0.56, P < 0.05) and high-volume (aOR: 0.44, P < 0.01) hospitals had a significantly lower mortality. The rate of extracorporeal membrane oxygenation use at each facility was not independently associated with mortality.

CONCLUSIONS

This large study suggests that hospitals which perform high volumes of CDH repair achieve lower in-hospital mortality. These data support the paradigm of regionalized centers of excellence for the management of infants with this morbid condition.