Objective: Studies reporting the developmental outcomes for very preterm children often focus on development at age 2. The aim of this study was to assess the stability of the rates of diagnosis of developmental disability from age 2 to age 8 years in a regional cohort of very preterm and extremely low birth weight children and compare these with term controls.
Methods: Very preterm (22 to 27 completed weeks of gestation, VPT) and extremely low birth weight (birthweight 500-999 g, ELBW) children and matched term controls, born in Victoria, Australia, in 1997, were enrolled at birth in a regional prospective longitudinal study. Outcomes were assessed at ages 2 and 8.
Results: Of the 283 VPT/ELBW livebirths, 71% survived to age 8 and 94% were assessed. Of the 199 controls, 100% survived to age 8 and 86.9% were assessed. At age 2, the rates of nil, mild, moderate and severe disabilities in the VPT/ELBW children were 51.9%, 20.9%, 13.4% and 13.9% respectively, and at age 8 were 43.9%, 36.9%, 10.7% and 8.6%, respectively. Cohen's Kappa statistic revealed poor agreement between disability status at age 2 and 8 for VPT/ ELBW children (0.20, P<0.001), but a higher level of agreement (0.37, P<0.001) for the control children. This was primarily driven by differences in classification of cognitive disability between age 2 and 8.
Conclusions: Developmental outcomes at age 2 are only a moderate predictor of long-term outcome and are not a reliable endpoint for follow-up studies of very preterm and ELBW children.