Has Survival Improved for Congenital Diaphragmatic Hernia? A 25-Year Review of over 5000 Patients from the CDH Study Group
Objective: The Congenital Diaphragmatic Hernia Study Group (CDHSG) is a multicenter, international collaboration focused on evaluation of liveborn infants with congenital diaphragmatic hernia (CDH). We sought to determine if risk-adjusted survival in CDH patients has improved among centers with consistent involvement, and we hypothesized that there was no change in risk-adjusted survival over time.
Methods: We retrospectively studied outcomes at centers with 22-25 years of continuous participation in the CDHSG. We divided the CDHSG into five-year intervals starting with era 1 (E1) beginning in 1995 and analyzed multiple variables (minimally invasive repair rate, defect size, ECMO use, and mortality) over time to assess possible evolution of disease characteristics. For overall mortality analyses, patients were risk stratified using a validated CDH prediction score based on 5-minute Apgar and birth weight. An observed to expected (O:E) mortality model was created using Apgar, major cardiac anomaly, and prenatal diagnosis as risk-stratifiers and using 1995-2000 as a reference. Univariate and multiple regression analyses were performed.
Results: 5015 posterolateral hernia patients from 23 centers were included. Birth weight, 5-minute Apgar, incidence of agenesis, ECMO use, and rate of repair did not vary over time (all p>0.05). Minimally invasive repair and patch repair were more prevalent, and timing of diaphragmatic repair was later in E5 compared to E1 (all p<0.01). Overall, mortality decreased over time: E1 (30.7%), E2 (30.4%), E3 (28.7%), E4 (26.0%), E5 (26.0%) (p=0.04, Chi2) (Figure 1a). Risk-adjusted mortality showed a trend favoring significant improvement in E5 compared to E1 (OR 0.79, 95% CI 0.63-1.01; p=0.06). O:E mortality improved over time (Slope: -0.02, p<0.01), with the most significant improvement occurring in the last five years (Figure 1b).
Conclusions: Among consistent participating CDHSG centers, risk-adjusted CDH mortality has improved over time, with the most significant improvements occurring in the recent eras.