Insulin is used to help treat various different types of diabetes, and you may even know someone who takes insulin regularly. However, insulin can also be used as therapy to improve glycemic control to reduce morbidity and mortality in intensive care adults. It’s also been used on infants with very low birth weight, but do the benefits outweigh the risks?

That’s one question researchers from the United Kingdom, Belgium, Amsterdam, and Barcelona sought to answer in 2008. The study, published in the New England Journal of Medicine, found that although insulin therapy benefits infants, it also has some severe consequences as well.

In very low birth weight infants, the presence of hyperglycemia is very common and is associated with both mortality and morbidity. Because of this, it’s reasoned that insulin therapy and tighter glycemic control could help infants gain weight and have reduced chances of sepsis. However, the pathogenesis of hyperglycemia in very low birth weight infants is complicated, and it’s true that what works for adults doesn’t always work for infants. This international study was conducted to determine whether early insulin replacement reduced hyperglycemia and affected outcomes in very low birth weight infants.

For the study, the researchers assigned 195 infants to a continuous infusion of insult at a dose of 0.05 U per kilogram of body weight per hour with 20% dextrose support. Dextrose is a naturally occurring sugar made from corn starch and other plant material. An additional 194 infants were assigned to standard newborn care on the first 7 days. The effectiveness of the glucose was measured through continuous monitoring.

The results showed that the infants in the early-insulin groups had lower mean glucose levels compared to the control group and fewer infants in the insulin group suffered from hyperglycemia for more than the first week of their life. The insulin group also had more weight gain and carbohydrates. However, infants in the early-insulin group also show an increase in hypoglycemia, and it was more significant in infants with birth weights of more than 1 kg. Also, the mortality rate was higher at 28 days than with the control group, which ultimately led the study to be ended early.

The research team concluded that early insulin therapy offered little clinical benefit for very low birth weight infants, and though it reduced hyperglycemia it was also more prone to increasing hypoglycemia and mortality rate was actually increased, not decreased.

Beardsal, K., Vanhaesebrouck, S., Ossuetta, I., Iglesias, I., Theyskens, C., Jong, M. d., et al. (2008). Early insulin therapy in the very low-birth-weight infant. The New England Journal of Medicine, 359(18), 1873-1884.