Early Hyperglycemia in Very Preterm Infants Is Associated with Reduced White Matter Volume and Worse Cognitive and Motor Outcomes at 2.5 Years.

INTRODUCTION: Hyperglycemia in very preterm infants is associated with increased morbidity and mortality. We aimed to investigate potential associations between early hyperglycemia, neonatal cerebral magnetic resonance imaging (MRI), and neurodevelopment at 2.5 years. METHODS: The study population included 69 infants with gestational age (GA) 22.3-31.9 weeks (n = 29 with GA <28 weeks), born 2011-2014. Plasma glucose concentrations during the first week were checked according to clinical routines. Hyperglycemia was defined as glucose concentrations above 8.3 mmol/L (150 mg/dL) and above 10 mmol/L (180 mg/dL), respectively, categorized as the highest glucose days 0-2, number of days above 8.3 and 10 mmol/L, and prolonged (yes/no) 2 days or more above 8.3 and 10 mmol/L. The MRI analysis included morphological assessment, regional brain volumes, and assessment of apparent diffusion coefficient (ADC). Neurodevelopmental impairment (NDI) developed in 13 of 67 infants with available outcomes, of which 57 were assessed with the Bayley-III. Univariate and multiple linear and logistic regressions were performed with adjustments for GA, birth weight z-scores, and illness severity expressed as days on mechanical ventilation. RESULTS: Hyperglycemia above 8.3 mmol/L and 10 mmol/L was present in 47.8% and 31.9% of the infants. Hyperglycemia correlated independently with lower white matter volume, but not with other regional brain volumes, and was also associated with lower ADC values in white matter. Hyperglycemia also correlated with lower Bayley-III cognitive and motor scores in infants with GA <28 weeks, but there was no significant effect on NDI. CONCLUSION: Early hyperglycemia is associated with white matter injury and poorer neurodevelopment in very preterm infants.

Average 2.5-year neurodevelopmental test results in children born very preterm did not rule out cognitive deficits at 6.5 years of age.

AIM: The aim of the study was to investigate cognitive outcomes at 6.5 years in children born very preterm, in relation to neonatal characteristics and 2.5-year neurodevelopment. METHODS: A prospective cohort, with gestational age 22.3-31.9 weeks, born 2004-2007, were examined at 2.5 years with the Bayley Scales of Infant and Toddler Development (Bayley-III) (n = 100) and at 6.5 years with the Wechsler Intelligence Scales (n = 91). RESULTS: Neonatal factors independently related to 6.5-year outcome were gestational age, retinopathy of prematurity and treated persistent ductus arteriosus. The Bayley-III cognitive scores explained only 44% of the Full-Scale Intelligence Quotient result at 6.5 years, and 22% of the children had Wechsler index results below -1 SD, indicating cognitive impairment, after average test results at 2.5 years. The relative risk to score below -1 SD on the Full-Scale IQ was 2.83 (95% CI 1.45-5.53) in children with gestational age below 28 weeks and 2.22 (95% CI 1.18-4.17) at gestational age 28-31 weeks. CONCLUSION: Very preterm infants born in the 2000s had increased risks for impaired cognition at 6.5 years, but individual predictions based on neonatal risks and 2.5-year test results were not enough to identify all high-risk children.

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

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.