Tight Glycemic Control With Insulin in Hyperglycemic Preterm Babies: A Randomized Controlled Trial

Abstract

The optimal treatment of neonatal hyperglycemia is unclear. The aim of this trial was to determine whether tight glycemic control with insulin improves growth in hyperglycemic preterm infants, without increasing the incidence of hypoglycemia. Randomized, controlled, nonblinded trial of 88 infants born at <30 weeks' gestation or <1500 g who developed hyperglycemia (2 consecutive blood glucose concentrations (BGC) >8.5 mmol/L, 4 hours apart) and were randomly assigned to tight glycemic control with insulin (target BGC 4-6 mmol/L, "tight" group) or standard practice (restrictive guidelines for starting insulin, target BGC 8-10 mmol/L, "control" group). The primary outcome was linear growth rate to 36 weeks' postmenstrual age. Eighty-eight infants were randomly assigned (tight group n = 43; control group n = 45). Infants in the tight group had a lesser lower leg growth rate (P < .05), but greater head circumference growth (P < .0005) and greater weight gain (P < .001) to 36 weeks' postmenstrual age than control infants. Tight group infants had lower daily BGC (median [interquartile range] 5.7 [4.8-6.7] vs 6.5 [5.1-8.2] mmol/L, P < .001) and greater incidence of hypoglycemia (BGC <2.6 mmol/L) (25/43 vs 12/45, P < .01) than controls. There were no significant differences in nutritional intake, or in the incidences of mortality or morbidity. Tight glycemic control with insulin in hyperglycemic preterm infants increases weight gain and head growth, but at the expense of reduced linear growth and increased risk of hypoglycemia. The balance of risks and benefits of insulin treatment in hyperglycemic preterm neonates remains uncertain.