Predictors of severity and outcome of global developmental delay without definitive etiologic yield: a prospective observational study

Background: Although several determinants of global developmental delay (GDD) have been recognized, a significant number of children remain without definitive etiologic diagnosis. The objective of this study was to assess the effect of various prenatal and perinatal factors on the severity and outcome of developmental delay without definitive etiologic yield. Methods: From March 2008 to February 2010, 142 children with developmental quotient (DQ) < 70 and without definitive etiologic diagnosis, were included. Prenatal and perinatal risk factors known to be associated with disordered neonatal brain function were identified. Participants underwent a thorough investigation, an individualized habilitation plan was recommended, and the children were followed-up regularly for a period of 2 years. The effect of prenatal and perinatal risk factors on the severity and outcome of GDD was assessed by regression analysis. Results: The mean age at enrolment was 31 +/- 12 months, and the mean DQ 52.2 +/- 11.4. Prematurity and intrauterine growth restriction (IUGR) were found to be independently associated with lower DQ values. The mean DQ after the 2-year follow-up was 62.5 +/- 12.7, and the DQ difference from the enrollment 10.4 +/- 8.9 (median 10; range-10 to 42). DQ improvement (defined as a DQ difference >= median) was noted in 52.8% of the children. IUGR, low socio-economic status, and poor compliance to habilitation plan were found to be independently associated with poorer developmental outcomes. Conclusions: Prematurity and IUGR were found to be significantly and independently related to the severity of GDD in cases without definitive etiologic yield. Poorer 2-year developmental outcome was associated with IUGR, low socioeconomic status and non compliance to habilitation plan. Prematurity was a significant determinant of the outcome only in association with the above mentioned factors.