Presented at the Neonatal Society 2016 Spring Meeting.
Binder C, Uthaya S, Longford N, Gale C, Modi N
Imperial College London, Chelsea and Westminster Hospital Campus Section of Neonatal Medicine, Department for Medicine
Background: In this study, we included a subset of preterm infants who were recruited to the NEON Trial (EME NIHR 08/99/04)2 born between 2010 and 2013 and underwent NEC surgery. The control group consisted of infants without clinically diagnosed NEC recruited to the same study. Body composition was measured by whole body MRI in both groups at term equivalent age. Adipose tissue mass (ATM) and non-adipose tissue mass (lean mass) was calculated as previously described2. Linear regression (adjusted for length) was used to compare ATM and lean mass between the two groups. Two-sample t-test was used to compare means of weight, length and corrected gestational age at scan (MRI) for the two groups (p-value <0.05 considered statistically significant). The primary objective was to investigate differences in body composition (ATM and lean mass) between the groups.
Methods: In this study, we included a subset of preterm infants who underwent NEC surgery, born between 2010–2013 and recruited into the NEON study (REC 09/H0707/88). The control group consisted of preterm infants without clinically diagnosed NEC, recruited into the NEON study. Body composition was measured by MRI in both groups at term, as previously described (2). Adipose tissue volume (ATV) was quantified directly and non-adipose tissue mass (non-ATM) was calculated as previously described (3). Linear regression was used to compare ATV and non- ATM between NEC surgery and control groups after adjusting for body size (length) and sex. The primary objective of this study was to investigate differences in body composition (ATV and non-ATM) between the two groups.
Results: Eight infants (6 male/2 female) were included in the NEC surgery group: birth weight, mean (standard deviation): 812 (76) grams and 23 infants (16 male/7 female) in the control group: 902 (170) grams. Mean gestational age was 25+0 (1.4) weeks in the NEC surgery group and 26+3 (1.2) weeks in the control group. Mean weight at scan was 2774 (697) grams (NEC surgery group) and 3403 (709) grams (control group) (p=0.038). Mean length at scan was 48.6 (4.9) cm (NEC surgery group) and 49.5 (3.5) cm (control group) (p=0.49). Corrected gestational age at scan was not significantly different between the groups (p=0.50). Linear regression analysis showed a significantly reduced mean ATM in the NEC surgery group: 0.472 kg (95% CI 0.35 to 0.60) and 0.733 kg (95% CI 0.66 to 0.81) in the control group; p=0.001. There was no significant difference in lean mass between the groups (mean and 95% CI) 2.45 kg (2.10 to 2.80) (NEC surgery group) and 2.60 kg (2.38 to 2.80) (control group); p=0.46.
Conclusion: There were significant differences between the groups in weight at term and ATM was significantly reduced in infants who underwent surgery for NEC. However, there was no difference in lean mass between the groups indicating that lean mass was preserved and the difference in weight was secondary to a reduction in ATM.
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1. Hintz et al., Neurodevelopmental and growth outcomes of extremely low birth weight infants after NEC. Pediatrics. 2005;115(3):696-703
2. Uthaya et al., Nutritional Evaluation and Optimisation in Neonates (NEON) trial of amino acid regimen and intravenous lipid composition in preterm parenteral nutrition: a randomised double-blind controlled trial. Efficacy Mech Eval 2016;3(2)