Risk-stratification enables accurate single-center outcomes assessment in congenital diaphragmatic hernia (CDH)

Background: Management of CDH is highly variable from center to center, as are patient outcomes. The purpose of this study was to examine risk-stratified survival and extracorporeal membrane oxygenation (ECMO) rates at a single center, and to determine whether adverse outcomes are related to patient characteristics or management.

Methods: A retrospective single-center review of CDH patients was performed, and outcomes compared to those reported by the CDH Study Group (CDHSG) registry. Patient demographics, disparities, and clinical characteristics were examined to identify unique features of the cohort. A model derived using the registry that estimates probability of ECMO use or death in CDH newborns was used to risk-stratify patients and assess mortality rates. Observed over expected (O/E) ECMO use rates were calculated to measure whether "excess" or "appropriate" ECMO use was occurring.

Results: There were 81 CDH patients treated between 2004-2017, and 5034 in the CDHSG registry. Mortality in ECMO-treated patients was higher than the registry. Socioeconomic variables were not significantly associated with outcomes. The strongest predictors of mortality were ECMO use and early blood gas variables. The risk model accurately predicted ECMO use with a c-statistic of 0.79. Compared with the registry, the disparity in mortality rates was greatest for moderate-risk patients. O/E ECMO use was highest in low and moderate-risk patients.

Conclusions: ECMO use is a more consistent predictor of mortality than CDH severity at a single center, and there is relative overuse of ECMO in lower-risk patients. Risk stratification allows for more accurate institutional assessment of mortality and ECMO use, and other centers could consider such an adjusted analysis to identify opportunities for outcomes improvement.

Level of evidence: III.