446 - Does oxygen dependency at 36 weeks’ postmenstrual age predict respiratory outcomes in children born very prematurely? A nationwide, population-based cohort study in Japan

Poster Number: 446
Publication Number: 446.431

Naoyuki Miyahara, Saitama Medical Center, Kawagoe, Saitama, Japan; Fumihiko Namba, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan; Mitsuhiro Haga, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan; Junichi Ozawa, Saitama Medical Center saitama medical school, kawagoe, Saitama, Japan; Shun Sakatani, Tokyo Metropolitan Children's Medical Center, Fuchu, Tokyo, Japan

Background: The NICHD consensus definition of bronchopulmonary dysplasia (BPD) has been widely used. Severe BPD is defined as a need for ≥30% oxygen and/or positive pressure at 36 weeks’ postmenstrual age (PMA) or discharge. The ability of this definition to predict long-term pulmonary outcomes remains controversial. Therefore, we aimed to determine the optimal oxygen concentration as a cut-off point to define severe BPD in very premature infants.

Objective: This was a multicenter retrospective cohort study including very low birth weight infants ( < 1,500 g) registered in the Neonatal Research Network of Japan between 2006 and 2015.

Design/Methods: Various oxygen concentrations including 25%,30%, 35%, 40%, 45%, and 50% were tested for the optimal cut-off value for severe BPD that can predict serious respiratory morbidity (SRM). SRM was defined as having one or more of the following at 3 years of age: home oxygen therapy, home mechanical ventilation, tracheotomy, asthma, upper respiratory tract infection within one year, or death. Multiple logistic regression models were developed to assess the association between the six cut-off values for severe BPD with long-term outcomes adjusting for potential confounders. The areas under the receiver operating characteristic curves (AUC) of the regression models were calculated for each cut-off value to examine its predictive ability for discrimination.

Results: Of the 38,440 infants born at < 32 weeks of gestation, 34,505 infants who did not receive supplemental oxygen at 36 weeks’ PMA or who had missing data were excluded. Finally, 3,935 infants were evaluated for SRM at 3 years of age, and 820 had SRM. Compared with children without SRM, children with this condition had significantly lower gestational ages (25.7 vs 26.1 weeks), lower birth weights (689 vs 732 g), lower Apgar scores at 5 min, higher rates of chorioamnionitis (53.6% vs. 47.0%), more males, more children who were small for gestational age, and more children with bubbly/cystic appearances on chest-ray (67.4% vs 50.2%). Analyses of each oxygen concentration between 25% and 50% at 36 weeks’ PMA indicated that the predictive ability for SRM increased from 25% (adjusted odds ratio, 1.29; 95% confidence interval [CI], 1.09–1.54; AUC, 0.637) to 35% (adjusted odds ratio, 3.34; 95% CI, 2.61–4.27; AUC, 0.659).Conclusion(s): As the definition of severe BPD, 35% of oxygen concentration at 36 weeks’ PMA was identified as the best predictor of SRM at 3 years of age. Because mild BPD cases were not included in this cohort, further studies including infants with all types of BPD are needed.
Association of Use of 25 to 50% O2 at 36 Weeks’ PMA with Serious Respiratory MorbidityPMA, post postmenstrual age; BPD, bronchopulmonary dysplasia; AOR, adjusted odds ratio; AUC, areas under the receiver operating characteristic curves; Adjusted for chorioamnionitis, gestational age, sex, small for gestational age, Apgar scores at 5 min, and bubbly/cystic appearance on the chest X-ray. The AUC of the regression models were calculated for each cut-off value to examine its predictive ability for discrimination.