[Mortality among premature newborns below 32 weeks of gestational age depending on level of care and patient volume in Nordrhein-Westfalen/Germany].

BACKGROUND: It is an ongoing debate in Germany whether there is an association between the number of preterm infants admitted to a neonatal unit per year and neonatal mortality. Data from Germany on this topic are sparse and the generalizability of this data is questionable in face of a heterogeneous organization of perinatal care among federal states.
METHODS: We used data from a state-wide quality assurance program in Nordrhein-Westfalen/Germany, encompassing 3 930 newborns below 32 completed weeks gestation p. m. admitted during the years 2004 and 2005. We hypothesized that there is an association between annually admitted premature infants below 32 completed weeks of gestation and mortality rates among these patients.
RESULTS: Mortality below 28 completed weeks gestation was significantly lower in hospitals admitting more than 50 premature infants < 32 completed weeks gestation per year compared to smaller hospitals (odds ratio 0.55, 95 %-CI 0.41-0.74, p < 0.001). When lowering the critical threshold to hospitals admitting more than 40 premature infants < 32 weeks gestation, only in newborns < 25 completed weeks gestation a significant effect could be demonstrated. The level of care (level 1-3) was off less importance than patient volume.
CONCLUSION: In Nordrhein-Westfalen/Germany, survival rate of immature infants is significantly higher if treated in larger neonatal intensive care units with a minimal annual volume of more than 40-50 premature infants < 32 weeks GA. Patient volume seemed to be a better indicator of performance than formal level of care.