Inter-hospital variations in the respiratory outcomes of very and extremely pre-term infants: A cohort study in Japan.

Background: Hospital-level and international variations exist in the management strategies of bronchopulmonary dysplasia (BPD). However, studies evaluating hospital-level variations in the respiratory outcomes of pre-term infants associated with differing management strategies of BPD are lacking.

Objective: Herein, we aimed to assess inter-hospital variations in the respiratory outcomes of BPD in very pre-term and extremely pre-term infants.

Methods: In this cohort study, the administrative claims and discharge summary data were extracted from 276 hospitals in Japan between April 2014 and March 2016. This study assessed neonates of a gestational age of 22-31 weeks old, who had been hospitalised for ≥7 days. The primary outcome was a BPD defined using any respiratory support, such as supplemental oxygen, high-flow nasal cannula, CPAP, or mechanical ventilation at 36 weeks PMA. The median odds ratio (MOR) was calculated using a multilevel logistic regression model, including baseline characteristics, comorbidities, and treatment as covariates, to evaluate the inter-hospital variation of the outcome.

Results: Of the 8143 neonates from across 132 hospitals, 53.7% were male, with a mean gestational age (standard deviation) of 28.0 (2.5)-weeks-old and birthweight of 1086 (386) g. Among these patients, BPD occurred in 2737 (33.6%). The MOR was 2.49, representing the median value of odds ratios when comparing two neonates with identical covariates from hospitals with high and low propensity for the outcomes to occur.

Conclusions: Outcome variations in the BPD were observed among hospitals in Japan, even after adjusting for individual factors, including gestational age, birthweight, comorbidities, and treatments. Thus, in Japan, developing strategies is essential to decrease the BPD rates, while minimising inter-hospital heterogeneity, to improve the healthcare quality for pre-term neonates.