Effect of hospital volume on the mortality of congenital diaphragmatic hernia in Japan

Background During the last decade, new supportive modalities and new therapeutic strategies to treat congenital diaphragmatic hernia (CDH) have been introduced. In Japan, the large number of hospitals prevents centralizing infants with CDH in tertiary centers. The aim of this study was to evaluate the correlations between the number of CDH patients, survival rates, and the current strategies employed to treat CDH at the individual hospitals. Methods Eighty-three hospitals with 674 CDH cases were analyzed using questionnaires. We classified the hospitals into three groups according to the number of CDH patients treated: Group 1 (G1; more than 21 patients), Group 2 (G2; 11-20 patients), and Group 3 (G3; fewer than 10 patients). Results The median number of CDH patients in G1, G2, and G3 were 28, 14, and 4, respectively. The overall survival rate was 74.5%. When only the isolated CDH cases with a prenatal diagnosis were included, the overall survival rate was 79.3%. The survival rate of isolated CDH cases with a prenatal diagnosis was significantly higher in G1 than that in G2 or G3 (87.2% vs 75.2% vs 74.3%; P < 0.001). There were no differences in perinatal therapeutic strategies among the three groups. Conclusions We concluded that it might therefore be important to centralize infants with CDH, especially those with isolated CDH with a prenatal diagnosis, to tertiary centers in Japan in order to improve the survival rates. Pediatrics International