Aggressive nutrition in extremely low birth weight infants: impact on parenteral nutrition associated cholestasis and growth

BACKGROUND Parenteral nutrition associated cholestasis (PNAC) is a frequently observed pathology in extremely low birth weight (ELBW) infants. Its pathogenesis is determined by the composition and duration of parenteral nutrition (PN) as well as the tolerance of enteral feeds (EF). "Aggressive" nutrition is increasingly used in ELBW infants to improve postnatal growth. Little is known about the effect of "aggressive" nutrition on the incidence of PNAC. We analyzed the influence of implementing an "aggressive" nutritional regimen on the incidence of PNAC and growth in a cohort of ELBW infants. METHODS ELBW infants were nourished using a "conservative" (2005-6; n = 77) or "aggressive" (2007-9; n = 85) nutritional regimen that differed in the composition of PN after birth as well as the composition and timing of advancement of EFs. We analyzed the incidence of PNAC (conjugated bilirubin > 1.5 mg/dl (25 µmol/l)) corrected for confounders of cholestasis (i.e., NEC and/or gastrointestinal surgery, sepsis, birth weight, Z-score of birth weight, time on PN and male sex), growth until discharge (as the most important secondary outcome) and neonatal morbidities. RESULTS The incidence of PNAC was significantly lower during the period of "aggressive" vs. "conservative "nutrition (27% vs. 46%, P < 0.05; adjusted OR 0.275 [0.116-0.651], P < 0.01). Body weight (+411g), head circumference (+1 cm) and length (+1 cm) at discharge were significantly higher. Extra-uterine growth failure (defined as a Z-score difference from birth to discharge lower than -1) was significantly reduced for body weight (85% vs. 35%), head circumference (77% vs. 45%) and length (85% vs. 65%) (P < 0.05). The body mass index (BMI) at discharge was significantly higher (11.1 vs. 12.4) using "aggressive" nutrition and growth became more proportionate with significantly less infants being discharged below the 10th BMI percentile (44% vs. 9%), while the percentage of infants discharged over the 90th BMI percentile (3% vs. 5%) did not significantly increase. DISCUSSION "Aggressive" nutrition of ELBW infants was associated with a significant decrease of PNAC and marked improvement of postnatal growth.