BACKGROUND: While outcomes of very low birth weight (VLBW) infants have improved significantly in high-income countries over recent decades, data from Central-Eastern Europe are lacking. The study aimed to evaluate trends in VLBW infant outcomes and hypothesized that a variability exists in the performance of NICUs in Hungary. METHODS: This was a population-based cohort study of VLBW infants, conducted between 2014-2016 (Epoch 1)
and between 2019-2021 (Epoch 2) involving all Level III NICUs in Hungary. The primary composite outcome was death or any of the five major morbidities. Adjustments were made for case-mix and hospital-level factors, and the impact of deprivation, a composite index of socioeconomic status, was assessed. RESULTS: The composite outcome decreased from 39.1% in Epoch 1 (n = 3438) to 34.3% in Epoch 2 (n = 3084) (p <
0.001). Mortality rate reduced significantly by 1.7% (p = 0.028). The rate of late-onset sepsis dropped by 4.8% (p <
0.001). The adjusted odds of adverse composite outcome decreased 5% yearly (aOR 0.95 (95% C.I. 0.92-0.97)). There was a significant between-center variability in the composite outcome, but it showed no correlation with the deprivation. CONCLUSIONS: Composite outcome trends improved over time, but substantial variability persists among NICUs which cannot be explained by patient characteristics, patient volume, or deprivation. IMPACT STATEMENT: Our study presents the first comprehensive, population-based analysis of VLBW infant outcomes in the Central-Eastern European region. Composite outcome trends of death and the five major morbidities have shown significant improvement over the past decade among VLBW infants in Hungary. A substantial variability exists between the performance of level III NICUs, independent of case-mix and patient volume. The odds of adverse outcome in VLBW infants is not correlated with deprivation, a municipal level metric of socioeconomic status.