260 - Socioeconomic Status (SES) is an important determinant of Full Scale Intelligence Score (IQ) < 85 at Six Years in Near/Term Infants undergoing Therapeutic Hypothermia (TH)

Poster Number: 260
Publication Number: 260.224

Mary Vernov, Weill Cornell Medicine, New York, NY, United States; Gail S. Ross, Weill Cornell Medicine, NY, NY, United States; Vivien Yap, Weill Cornell Medicine, New York, NY, United States; Jeffrey Perlman, Weill Cornell Medicine, New York City, NY, United States

Background: TH has improved neurocognitive outcomes in infants presenting with early hypoxic-ischemic encephalopathy. Known markers of poor outcome include timing of TH, severe encephalopathy and basal ganglia (BG) injury on magnetic resonance imaging (MRI).

Objective: Determine factors associated with IQ < 85 at aged six years in infants undergoing TH.

Design/Methods: A retrospective study of neonates with GA ≥36 weeks admitted to the NICU between May 2007 and June 2014 who met entry criteria for TH (at least two of the following: sentinel event, cord arterial pH < 7.00, cardiopulmonary resuscitation (CPR)/intubation, 10 min Apgar score (AS) ≤ 5, postnatal pH < 7.00 within an hour of birth, abnormal aEEG tracing and neurologic exam consistent with mild, moderate or severe encephalopathy. Abnormal MRI scans included BG and hippocampus changes. The Hollingshead Scale assessed SES (highest 1, lowest 3). A Wechsler Preschool and Primary Scale of Intelligence at 6 years provided a Full-Scale Intelligence Quotient (FSIQ); mean score is 100 ± 15. Analysis included t tests and multiple logistic regression (MLR).

Results: 129 infants received TH; 13 (10%) died, 61 (52%) were evaluated at six years. Twelve (20%) were inborn and 49 (80%) outborn. Inborn vs outborn neonates were cooled at 2.8±1.3 vs 4.5±0.9 hrs (p < 0.05). FSIQ was higher in inborn vs outborn neonates i.e., 103.9±13.2 vs 83.2 ±21 (p < 0.05) (Table). FS IQ < 85 was noted in 23/49 (47%) outborn vs 0/12 inborn neonates (p=0.002); FSIQ was < 70 in 15 infants, all outborn. Neonates with BG (56±9) and hippocampus (79±17) injury had lower FSIQ vs normal MRI (97±17) (p < 0.05). For outborn neonates, severe encephalopathy was associated with FSIQ < 85. By univariate analysis, FSIQ < 85 was related to sentinel event (p=0.04), 10 min AS ≤ 5 (p=0.02) and postnatal pH < 7.00 (p=0.005). For inborn neonates, FSIQ was higher for SES 1 vs SES 2 (p=0.01). For outborn neonates, IQ was higher for SES 1 vs SES 3 (p=0.01) and SES 2 vs SES 3 groups (p < 0.05) with no difference in FSIQ for SES 1 vs SES 2 groups (p=0.14). By MLR analysis, an IQ < 85 was six fold more likely with ↓ SES status (p=0.01) and 8-fold more likely with a postnatal pH < 7.0.Conclusion(s): A FSIQ < 85 was exclusive to outborn neonates and was associated with lower SES and initial postnatal pH < 7.0. Severity of encephalopathy, BG and hippocampus injury on MRI also contributed to ↓ FSIQ. The impact of earlier onset of TH may have important neuroprotective implications.  The mechanisms contributing to lower FSIQ with ↓SES remain unclear but critical to delineate.
Table: Comparison of High Risk Markers, Severity of Encephalopathy and Socio-Economic Status on Full Scale Intelligent Quotient (FSIQ) in inborn and Outborn infants Undergoing Therapeutic Hypothermia