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Assessment and Evaluation of the High Risk Neonate: The NICU Network Neurobehavioral Scale
Published on: August 25, 2014
Association between peak serum bilirubin and neurodevelopmental outcomes in extremely low birth weight infants
William Oh1, Jon E Tyson, Avroy A Fanaroff
1Women and Infants' Hospital of Rhode Island/Brown University, Providence, Rhode Island 02905, USA. woh@wihri.org
Insights
Peak total serum bilirubin levels in extremely low birth weight infants are linked to higher risks of death, neurodevelopmental impairment, and hearing loss. Further research is needed to clarify these associations.
Area of Science:
- Neonatalogy
- Pediatric Neurology
- Bilirubin Metabolism
Background:
- Extremely low birth weight (ELBW) infants face significant risks for adverse neurodevelopmental outcomes.
- Hyperbilirubinemia, indicated by elevated serum bilirubin levels, is common in neonates and has been historically linked to neurological damage.
Purpose of the Study:
- To investigate the association between peak total serum bilirubin (PSB) levels in the first two weeks of life and neurodevelopmental outcomes in ELBW infants.
- To determine if PSB levels predict adverse outcomes such as neurodevelopmental impairment (NDI), cerebral palsy (CP), or hearing impairment.
Main Methods:
- Retrospective analysis of a cohort of ELBW infants (401-1000g) who survived at least 14 days.
- Data collected on demographic factors, clinical variables, and PSB levels within the first 14 days.
- Neurodevelopmental outcomes assessed at 18-22 months' postmenstrual age, including Psychomotor Developmental Index (PDI), Mental Developmental Index (MDI), CP, and hearing impairment.
Main Results:
- A significant association was found between higher PSB levels and increased risk of death or NDI (OR: 1.068), PDI <70 (OR: 1.057), and hearing impairment requiring aids (OR: 1.138).
- No significant association was observed between PSB levels and cerebral palsy (CP) or MDI <70.
- The study included 2575 ELBW infants with an 81% follow-up compliance rate.
Conclusions:
- Elevated PSB levels in the first two weeks of life are correlated with adverse neurodevelopmental outcomes, including death or NDI, hearing impairment, and lower PDI scores in ELBW infants.
- The findings, based on observational data, suggest a cautious interpretation due to potential confounding factors and small effect sizes.
- A randomized controlled trial comparing aggressive and conservative phototherapy is recommended to further investigate the controversial issue of hyperbilirubinemia management in ELBW infants.
Objective:
To assess the association between peak total serum bilirubin (PSB) levels during the first 2 weeks of life and neurodevelopmental outcomes of extremely low birth weight (ELBW) infants at 18 to 22 months' postmenstrual age.
Methods:
A retrospective analysis was conducted of a cohort of ELBW infants (401-1000 g) who survived to 14 days of age in the 12 participating centers of the National Institute of Child Health and Human Development Neonatal Research Network between January 1, 1994, and December 31, 1997. Demographic and clinical risk factors and PSB levels during the first 14 days were analyzed with reference to death or adverse neurodevelopmental outcomes at 18 to 22 months' postmenstrual age. The neurodevelopmental variables considered were Psychomotor Developmental Index (PDI) <70, Mental Developmental Index (MDI) <70, moderate or severe cerebral palsy (CP), hearing impairment (needs hearing aids), and a composite category designated as neurodevelopmental impairment (NDI). The NDI is defined as infants with any 1 or more of the following: PDI <70, MDI <70, moderate to severe CP, bilateral blindness, or bilateral hearing impairment requiring amplification.
Results:
The subjects of this cohort analysis are infants who were admitted to the Network centers during calendar years 1994-1997 and survived beyond 14 days and had PSB recorded during the 14-day period. From this cohort, 3246 infants survived at discharge, 79 died after discharge, and 592 were lost to follow-up. Thus, 2575 of 3167 infants were seen in the follow-up clinics with a compliance rate of 81%. Logistic regression analysis showed that various demographic and clinical variables are associated with poor neurodevelopmental outcomes. After adjustment for these risk factor, significant association were found between PSB (mg/dL) and death or NDI (odds ratio: 1.068; 95% confidence interval [CI]: 1.03-1.11); PDI <70 (R = 1.057; 95% CI: 1.00-1.12), and hearing impairment requiring hearing aids (odds ratio: 1138; 95% CI: 1.00-1.30). There was no significant association between PSB (mg/dL) and CP, MDI <70, and NDI.
Conclusions:
PSB concentrations during the first 2 weeks of life are directly correlated with death or NDI, hearing impairment, and PDI <70 in ELBW infants. The statistical association based on retrospective analysis of observational data and relatively small effect size should be interpreted with caution. Furthermore, because of the possibility of compounding effects of variables on outcome, the potential benefits of moderate hyperbilirubinemia and the potential adverse effects of phototherapy, a randomized, controlled trial of aggressive and conservative phototherapy is needed to address this controversial issue.
