Increasing supplemental thyroid hormone use among premature infants born at 23 to 32 weeks' gestation

Area of Science:

• Neonatalogy
• Pediatric Endocrinology
• Clinical Pharmacy

Background:

• Thyroid hormone deficiency is a concern in preterm infants.
• Levothyroxine (l-thyroxine) is used to treat hypothyroidism.
• Evidence supporting routine thyroid supplementation in preterm infants is limited.

Purpose of the Study:

• To assess trends in levo-thyroxine (l-thyroxine) therapy among very premature newborns over a 10-year period.
• To analyze l-thyroxine use based on gestational age and birth year.
• To compare current treatment patterns with existing clinical trial protocols.

Main Methods:

• Retrospective analysis of an electronic database from a large private neonatal practice group.
• Inclusion of 96,813 neonates with gestational ages between 23 and 32 weeks, managed between 1997 and 2006.
• Analysis of l-thyroxine use by birth year and gestational age.

Main Results:

• L-thyroxine use increased with decreasing gestational age, peaking at 8.4% for 24-week infants.
• Overall l-thyroxine supplementation increased 2.6-fold for infants ≤26 weeks' GA from 1997-1999 to 2004-2006.
• The highest treatment rate (12.8%) was observed in 24-week GA infants in 2006; treatment initiation was typically around 23 days of life.

Conclusions:

• L-thyroxine treatment for very preterm infants has significantly increased over the past decade.
• Treatment patterns are not consistent with protocols from published randomized trials.
• Further focused randomized controlled trials are needed to guide l-thyroxine supplementation in this population.