Objective: To compare rates of a composite outcome of mortality or major morbidity in very-preterm/very low birth weight infants between 8 members of the International Network for Evaluating Outcomes.
Study design: We included 58 004 infants born weighing <1500 g at 24(0)-31(6) weeks' gestation from databases in Australia/New Zealand, Canada, Israel, Japan, Spain, Sweden, Switzerland, and the United Kingdom. We compared a composite outcome (mortality or any of grade ≥3 peri-intraventricular hemorrhage, periventricular echodensity/echolucency, bronchopulmonary dysplasia, or treated retinopathy of prematurity) between each country and all others by using standardized ratios and pairwise using logistic regression analyses.
Results: Despite differences in population coverage, included neonates were similar at baseline. Composite outcome rates varied from 26% to 42%. The overall mortality rate before discharge was 10% (range: 5% [Japan]-17% [Spain]). The standardized ratio (99% CIs) estimates for the composite outcome were significantly greater for Spain 1.09 (1.04-1.14) and the United Kingdom 1.16 (1.11-1.21), lower for Australia/New Zealand 0.93 (0.89-0.97), Japan 0.89 (0.86-0.93), Sweden 0.81 (0.73-0.90), and Switzerland 0.77 (0.69-0.87), and nonsignificant for Canada 1.04 (0.99-1.09) and Israel 1.00 (0.93-1.07). The adjusted odds of the composite outcome varied significantly in pairwise comparisons.
Conclusions: We identified marked variations in neonatal outcomes between countries. Further collaboration and exploration is needed to reduce variations in population coverage, data collection, and case definitions. The goal would be to identify care practices and health care organizational factors, which has the potential to improve neonatal outcomes.
Keywords: bronchopulmonary dysplasia; composite outcome; peri-intraventricular hemorrhage; periventricular echodensity/echolucency; preterm birth; quality improvement; retinopathy of prematurity.
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