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Background and aims:

Hyperglycemia is common during early life in extremely preterm infants. It has been suggested to increase the risk of later neurological problems. This study investigated the relation between early-life hyperglycemia and neurological outcomes at 6 years of age in children born extremely preterm.

Methods: The study is based on the EXPRESS study cohort, including all 707 infants liveborn before 27 weeks gestational age in Sweden between 2004–2007. Detailed laboratory data was extracted from the hospital records. During a follow-up at 6 years of age, the children performed the Wechsler Intelligence Scale for Children (WISC-IV) test.

Results WISC-IV scores were available for 371 of 494 surviving children. The number of days with severe hyperglycemia (≥1 plasma glucose measurement ≥ 16 mmol/l) during the first 21 days of life was significantly correlated with lower WISC-IV scores, adjusted for gestational age (β=-0.114; p=0.032). Children who had severe hyperglycemia at least one day during the first 21 days of life had significantly lower mean WISC-IV score than children who did not have severe hyperglycemia, adjusted for gestational age (78.9 vs. 85.08, respectively; p=0.02; Figure 1). The results remained significant after adjusting for morbidityrelated variables in those infants without severe neurodevelopmental impairment.

Conclusions Severe hyperglycemia during the first 3 weeks of life in extremely preterm infants is associated with lower intelligence at 6 years of age. Prevention of severe hyperglycemia in these infants may therefore be important. Further research is needed to explore the effect of hyperglycemia on neurodevelopment as well as its mechanism.