Prematurity at less than 24 weeks of gestation is a risk for prolonged hyperglycemia in extremely low-birth weight infants.

Hyperglycemia in extremely low-birth weight infants (ELBWIs) is frequently observed during the acute perinatal phase, (i.e., first 1-2 weeks postnatal period); however it can occasionally persists for >2 weeks, extending to the post-acute phase. Since such prolonged hyperglycemia (PH) is not typical for ELBWIs, the aim of the present study was to further understand the clinical details of PH. Twenty-five hyperglycemic ELBWIs born before 28 weeks of gestation from 2015 to 2018 were included in the study. Based on the duration of hyperglycemia, we separated the subjects into two groups: non-prolonged hyperglycemia (NPH) who achieved remission within ≤2 weeks [n = 18, median 3.0 (range, 2.0-4.0) days], and PH, whose hyperglycemia persisted for >2 weeks [n = 7, median 50.0 (range, 33.5-66.0) days]. Compared to the NPH group, glucose metabolism of the PH group was more deteriorate. The peak blood glucose level was significantly higher in the PH group [PH: median 472 mg/dL, NPH: median 275 mg/dL, p < 0.001], and a higher proportion of subjects in the PH group required insulin therapy [PH: 100% (7/7) vs. NPH: 22% (4/22)]. Multivariate analysis revealed that among perinatal factors, prematurity was the only independent risk factor for PH (glucocorticoid therapy: p = 0.884, gestational age: p = 0.006), with a cutoff of 23W4D determined by receiver operating characteristic analysis. Our data revealed distinctive clinical features of PH, suggesting a type different from the previously reported hyperglycemia in ELBWIs. Specifically, extreme prematurity, less than 24 weeks of gestation, is a risk for PH, and aggressive interventions, such as insulin would be required.