Effect of hospital case volume on outcome in congenital diaphragmatic hernia: the experience of the Canadian Pediatric Surgery Network

PurposeDespite advances in neonatal care of congenital diaphragmatic hernia (CDH), a significant variation exists in the mortality rates reported by individual centers. Center experience (reflected by case volume) may contribute to this variation in outcome. The aim of the study was to determine whether CDH mortality is affected by hospital case volume.MethodsThe CDH cases were abstracted from a disease-specific, 16-hospital, national network. Thirteen hospitals participated in this study. Anonymized hospitals were categorized as either high (>6 cases) or low-volume (≤6 cases) centers (HVC, n = 6; LVC, n = 7) according to the median case number per center. Risk-adjusted (Score for Neonatal Acute Physiology, version II [SNAP-II] score) mortality rates were compared between HVC and LVC.ResultsOne hundred twenty-one CDH cases were identified. Overall in-hospital survival was 81%. No significant difference in SNAP-II score was observed between HVC and LVC. Of 97 (15%) infants treated in 6 HVC, 15 (15%) died compared to 8 (33%) of 24 in 7 LVC (P < .05).ConclusionHospital case volume may be partially responsible for mortality rate variation in CDH. This result requires careful analysis, as case volume may merely be a surrogate for other predictive variables.