Long-term growth effects of post-discharge formula in moderate-to-late preterm infants: follow-up at 24 months corrected age of a randomized controlled trial.

PDF-fed infants had slightly larger head circumference at 24 months corrected age compared to STF-fed infants.

• Head circumference was 49.0 ± 1.5 cm in PDF-fed infants versus 48.3 ± 1.5 cm in STF-fed infants (p < 0.05).
• Anthropometry was assessed in 64 infants from the original study cohort of 157 at the 24-month corrected age follow-up visit.
• This represents a high loss-to-follow-up from the original randomized controlled trial.

PDF-fed infants had lower fat mass at 24 months corrected age compared to STF-fed infants despite similar total body weight.

• Fat mass was 2392 ± 923 g in PDF-fed infants versus 3615 ± 1359 g in STF-fed infants (p < 0.05).
• Total body weight was similar between the two groups at 24 months corrected age.
• Body composition was estimated using air-displacement plethysmography in 34 infants at the follow-up visit.

PDF-fed infants had higher fat-free mass at 24 months corrected age compared to STF-fed infants.

• Fat-free mass was 10461 ± 1030 g in PDF-fed infants versus 10108 ± 1700 g in STF-fed infants (p < 0.05).
• Body composition was estimated in only 34 infants from the original cohort of 157.
• The post-discharge formula was isocaloric but protein- and mineral-enriched compared to standard term formula.

The study experienced high loss-to-follow-up from the original randomized controlled trial to the 24-month corrected age assessment.

• From the original study of 157 infants, only 64 had anthropometry assessed at 24 months corrected age.
• Only 34 infants had body composition estimated at 24 months corrected age.
• The authors explicitly state that findings 'should be interpreted cautiously, due to high loss-to-follow-up.'

The study enrolled moderate-to-late preterm infants who were randomized at term equivalent age to either continue post-discharge formula or switch to standard term formula until 6 months corrected age.

• Moderate-to-late preterm infants were defined as those born at less than 37 weeks' gestation.
• Enrollment occurred within 7 days postpartum, and PDF was provided when fortified mother's own milk was insufficient.
• Randomization at term equivalent age was applied to infants receiving more than 25% of intake as formula.
• The intervention period ran from term equivalent age to 6 months corrected age, with follow-up assessed at 24 months corrected age.