Background During the last decades mortality of preterm born neonates has declined in the Western world.
Aim We hypothesised that the decrease in mortality in very preterm neonates over a period of 15 years was associated with a decrease in illness severity scores (SNAPPE-II and CRIB II).
Subjects/methods Inborn neonates (January 1997 until December 2011; n = 928) with a gestational age of 26.0–29.9 weeks and without congenital malformations.
SNAPPE-II and CRIB II scores, mortality (<120 days) and morbidity (severe intraventricular haemorrhage (IVH), severe cystic periventricular leukomalacia (cPVL), bronchopulmonary dysplasia (BPD), perforated necrotizing enterocolitis (NEC) and severe retinopathy of prematurity (ROP)) were recorded. Based on important changes in care, subjects were categorised into three periods of year of birth (1: 1997–1999, 2: 2000–2005, and 3: 2006–2011) and outcomes were analysed using multivariable analysis including SNAPPE-II/CRIB II scores, period, gestational age, gender, and their interactions.
Results SNAPPE-II and CRIB II scores were significantly lower for gestational ages between 26.0 and 29.9 in period 3 versus period 1 (p = 0.002; p = 0.018, respectively) in a cubic model analysis. The risks of mortality and serious morbidity were significantly lower for similar SNAPPE-II and CRIB II scores in period 3 versus period 1 (p = 0.010; p = 0.041, respectively). Females had a significantly lower risk of mortality and serious morbidity than males (p = 0.031; p < 0.0001, respectively).
Conclusions SNAPPE-II and CRIB II scores decreased over a 15-year period. Meanwhile, the risk of mortality and serious morbidity for similar SNAPPE-II and CRIB II scores decreased suggesting substantial improvement in perinatal care.