To investigate the use of insulin throughout the first week of life in very low birth weight (VLBW) infants (birth weight <1.5 kg) to improve glucose control and increase insulin-like growth factor-I (IGF-I) levels. IGF-I is the dominant hormone involved in fetal growth, and low levels have been implicated in neonatal morbidities, such as retinopathy of prematurity.

In this pilot randomized controlled study (n = 16), the intervention group received insulin (0.025 U/kg/hr) on days 1 to 7, with 20% dextrose to maintain normoglycemia. Control infants received standard neonatal care. All infants received continuous glucose monitoring.

The intervention and standard care groups had similar mean gestational age (± standard deviation), 26.2 (± 2.5) vs 26.9 (± 2.7) weeks, and birth weight, 0.79 (± 0.26) vs 0.73 (± 0.16) kg. The standard care infants were hyperglycemic (sensor glucose >10 mmol/L [180 mg/dL]) for 35.9% of the study period, compared with 7.6% for the insulin-treated infants (P = .035). The duration of time with hypoglycemia (<2.6 mmol/L [47 mg/dL]) did not differ between the 2 groups (P = .746). The insulin-treated group had a 2.4-fold increase in mean IGF-I bioactivity (P = .005).

Early insulin therapy improves blood glucose control and increases IGF-I bioactivity levels. This could result in less morbidity associated with hyperglycemia and reduced IGF-I levels.