The stability of the diagnosis of developmental disability between ages 2 and 8 in a geographic cohort of very preterm children born in 1997

Abstract

Objective Studies reporting the developmental outcomes for very preterm (VPT) children often focus on development at age 2 years. The aim of this study was to assess the stability of the rates of diagnosis of developmental disability from age 2 to 8 years in a regional cohort of VPT and extremely low–birth weight (ELBW) children and compare these with term controls. Methods VPT (22–27 completed weeks of gestation) and ELBW (birth weight 500–999 g) 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 years. Results Of the 283 VPT/ELBW live births, 71% survived to age 8 years and 94% were assessed. Of the 199 controls, 100% survived to age 8 years and 86.9% were assessed. At age 2 years, the rates of nil, mild, moderate and severe disabilities in the VPT/ELBW children were respectively 51.9%, 20.9%, 13.4% and 13.9%; and at age 8 years, 43.9%, 36.9%, 10.7% and 8.6%. The Cohen κ statistic revealed poor agreement between disability status at ages 2 and 8 years for VPT/ELBW children (0.20, pConclusions Developmental outcomes at age 2 years are only a moderate predictor of long-term outcome and are not a reliable end point for follow-up studies of VPT and ELBW children.