Severity and duration of dysglycemia and brain injury among patients with neonatal encephalopathy

Background: Evidence is needed to inform thresholds for glycemic management in neonatal encephalopathy (NE). We investigated how severity and duration of dysglycemia relate to brain injury after NE. Methods: A prospective cohort of 108 neonates ≥36 weeks gestational age with NE were enrolled between August 2014 and November 2019 at the Hospital for Sick Children, in Toronto, Canada. Participants underwent continuous glucose monitoring for 72 h, MRI at day 4 of life, and follow-up at 18 months. Receiver operating characteristic curves were used to assess the predictive value of glucose measures (minimum and maximum glucose, sequential 1 mmol/L glucose thresholds) during the first 72 h of life (HOL) for each brain injury pattern (basal ganglia, watershed, focal infarct, posterior-predominant). Linear and logistic regression analyses were used to assess the relationship between abnormal glycemia and 18-month outcomes (Bayley-III composite scores, Child Behavior Checklist [CBCL] T-scores, neuromotor score, cerebral palsy [CP], death), adjusting for brain injury severity. Findings: Of 108 neonates enrolled, 102 (94%) had an MRI. Maximum glucose during the first 48 HOL best predicted basal ganglia (AUC = 0.811) and watershed (AUC = 0.858) injury. Minimum glucose was not predictive of brain injury (AUC <0.509). Ninety-one (89%) infants underwent follow-up assessments at 19.0 ± 1.7 months. A glucose threshold of >10.1 mmol/L during the first 48 HOL was associated with 5.8-point higher CBCL Internalizing Composite T-score (P = 0.029), 0.3-point worse neuromotor score (P = 0.035), 8.6-fold higher odds for CP diagnosis (P = 0.014). While the glucose threshold of >10.1 mmol/L during the first 48 HOL was associated with higher odds of the composite outcome of severe disability or death (OR 3.0, 95% CI 1.0–8.4, P = 0.042), it was not associated with the composite outcome of moderate-to-severe disability or death (OR 0.9, 95% CI 0.4–2.2, P = 0.801). All associations with outcome lost significance after adjusting for brain injury severity. Interpretation: Maximum glucose concentration in the first 48 HOL is predictive of brain injury after NE. Further trials are needed to assess if protocols to control maximum glucose concentrations improve outcomes after NE. Funding: Canadian Institutes for Health Research, National Institutes of Health, and SickKids Foundation.