Regional differences in outcome for very low-birthweight infants: do they persist at 7-8 years of age?

Objective: To determine whether regional differences in early neonatal morbidity in a national cohort of very low-birthweight (VLBW) infants persisted at 7-8 years of age.

Methods: Perinatal data collected prospectively from birth on all VLBW infants born in New Zealand in 1986 and admitted to a neonatal unit included the hospital principally caring for the infant: hospitals A-D being level III hospitals and 'Other' including the smallest level III and all level II hospitals. At 7-8 years of age, 298 surviving children (96% survivors living in New Zealand) were assessed at a home visit. Parents were given a comprehensive questionnaire to complete, the children underwent a visual examination and were tested with the Revised Wechsler Intelligence Scale for Children and the child's teacher was sent a questionnaire to complete.

Results: Neonatal survival was significantly greater in the two largest hospitals (A and B) and this difference in survival remained at 7-8 years of age after adjustment for perinatal factors (P < 0.05). There were no differences between hospitals in risks of long-term sensorineural disability and behavioural or educational outcomes. There were interhospital differences in rates of visual problems and, after adjustment for confounding factors, there remained a marginally significant (P = 0.06) increased risk of myopia in hospital D.

Conclusions: Despite differences in early morbidity favouring larger hospitals, there were no substantive differences in long-term (7-8 years) outcomes across a range of measures in this national cohort of VLBW infants.