Objectives: To investigate the relationships between mortality of infants <32 weeks gestation and neonatal intensive care units' (NICUs) volume of activity, daily number of high-dependent infants (HDIs) and geographical area in Italy.
Methods: The study involved 105 neonatal units in 2005. Data were collected prospectically and through monthly cross-sectional investigations. Patients receiving respiratory care were defined as HDIs. Univariate and multivariable methods were used for analysis.
Results: Babies enrolled were 4014. The overall mortality was 18.8%. An adjusted nearly two-fold increase in mortality was found in Southern compared to Northern regions. Volume of activity was not associated with mortality. When compared to infants admitted to NICUs in the highest tertile of the median number of HDIs/day (>2.5 patients/day), the adjusted odds ratios were 1.52 (95% CI = 1.14-2.02) for those in the 2nd tertile (1.1-2.5 patients/day) and 1.47 (95% CI = 1.02-2.13) for those in the lowest tertile (≤1 patient/day). After stratification by geographical area, this relationship was present in Southern, to a lesser extent in Central, but not in Northern regions.
Conclusions: In Italy, striking geographical differences in mortality of very preterm infants are present. NICUs' average daily number of HDIs is a better predictor of mortality than the volume of activity.