122 - Refeeding-Like Syndrome in Very Low Birth Weight Infants: Incidence and Risk Factors

Poster Number: 122
Publication Number: 122.4

Background: Very low birth weight (VLBW, < 1500g) infants frequently experience undernutrition, which adversely affects their long-term health and development. Early parenteral amino acid provision minimizes protein deficits but may also contribute to a refeeding- like syndrome (RLS) characterized by severe hypophosphatemia and other electrolyte derangements. RLS is associated with severe adverse outcomes including mortality. The incidence of RLS among VLBW infants receiving parenteral nutrition ranged from 20–90% in previous studies. Infant factors such as low weight for gestational age (GA) and low gestational age (GA) at birth may increase the risk of RLS.

Objective: In this single-center cohort study of VLBW infants, we aimed to 1) define RLS incidence and 2) identify risk factors for RLS.

Design/Methods: We collected medical record data for all VLBW infants (n=658) from June 2015 – March 2023. We defined RLS as any serum phosphorous (phos) < 4 mg/dL in the first 7 days of life and severe RLS as any phos < 2.5 mg/dL. We examined these potential risk factors for RLS: extremely low birth weight (ELBW) < 1000 vs. 1000-1500; GA < 27 weeks vs. >27 weeks; small for GA (SGA) vs. appropriate for GA (AGA) by comparing the lowest phos and RLS outcomes between categories and by calculating relative risks of RLS for infants with vs. without the risk factors.

Results: Mean GA was 29.4 weeks (range: 22.3, 37.0) and mean birth weight 1100 grams (range: 410, 1500). 231 (35.1%) of infants were ELBW and 248 (37.7%) were SGA (Table 1). Overall, 221 (33.6%) experienced RLS and 41 (6.2%) experienced severe RLS. ELBW infants experienced RLS more frequently than infants with birth weight 1000-1499g (45.5% vs. 12.6%; RR 1.67, 95% CI: 1.35, 2.06). SGA infants also had higher RLS incidence than AGA infants (50.0% vs. 23.4%; RR 2.13, 95% CI: 1.72, 2.66) (Tables 2 & 3).

Conclusion(s): Our study affirms that RLS is common in VLBW infants, with heightened risk seen in infants who are ELBW or SGA. In contrast, extreme prematurity (gestational age < 27 weeks) was not a risk factor for RLS. Strategies to prevent RLS should focus on these higher-risk groups, and may involve modifying parenteral nutrition approaches, enhanced electrolyte monitoring, and/or targeted electrolyte repletion when low phos levels are detected.