Using different definitions affected the reported prevalence of neurodevelopmental impairment in children born very preterm

Abstract

Aim We investigated the impact of varying definitions on the prevalence of neurodevelopmental impairment (NDI) in children born very preterm at 6.5 years of age. Methods Cognitive development and neurosensory impairments were assessed in 91 children (40/51 girls/boys) born <32 gestational weeks, in 2004‐2007 in Uppsala county, Sweden. The results were compared with data from a reference group of 67 children born full term. The prevalence of NDI in the present cohort was reported according to definitions used by seven contemporary studies of children born very or extremely preterm. Results The prevalence of severe NDI varied from 2% to 23% depending on the definition used. The prevalence of cognitive impairment varied from 2% (−3 SD according to test norms) to 16% (−2 SD according to control group), the prevalence of cerebral palsy from 0% (severe) to 9% (any) and the prevalence of severe visual impairment from 0% (blindness) to 1% (visual acuity < 0.3). There were no children with severe hearing impairment. Conclusion A high variability in definitions affects the reporting of the prevalence of NDI in long‐term follow‐up studies of very or extremely preterm born children. There is a need for a better consensus to enable comparisons across studies.

Retrospective evaluation of ophthalmological and neurological outcomes for infants born before 24 weeks gestational age in a Swedish cohort

“…Comparisons with other populations are difficult due to variability in definitions in ophthalmological outcomes and the large age span in the present study. 23 However, the conclusion that infants born extremely immature are especially vulnerable to ophthalmological and neurological injury is in line with previous studies. 1 5 8 10 In EXPRESS, including infants born before 27 weeks GA and full-term infants in Sweden, Hellgren et al reported strabismus at 6 years of age in 17.4% versus none, and spectacles wear in 36.4% versus 5.7%, respectively, as compared with in our study of children born before 24 weeks GA where we found strabismus were found in 34.8%, and 51.0% had been prescribed spectacles.…”

“…Visual impairment was found in 21.9% and most of the children had ocular and/or visual problems requiring ophthalmological follow-up. Comparisons with other populations are difficult due to variability in definitions in ophthalmological outcomes and the large age span in the present study 23. However, the conclusion that infants born extremely immature are especially vulnerable to ophthalmological and neurological injury is in line with previous studies 1 5 8 10.…”