Hypoglycemia and hyperglycemia in extremely low-birth-weight infants

Abstract

Background: Glucose metabolism disorders are common in extremely low birth weight (ELBW) infants and are associated with high morbidity and mortality [1-9]. This study was conducted to evaluate the prevalence and risk factors associated with both hypo and hyperglycemia in ELBW infants. Materials and methods: All inborn ELBW neonates admitted to our NICU during a 5-year period were eligible for this retrospective analysis. Exclusion criteria were: birth weight (BW) <400 grams, major congenital malformations, death during the first 24 hours of life. Hypoglycemia was defined as blood glucose level (BGL) ≤45 mg/dL; hyperglycemia as BGL>240 mg/dL in a single determination or >180 mg/dL in two determinations at 2-hour intervals. Continuous intravenous insulin infusion was started after an ineffective glucose restriction. Results: Of 195 ELBW infants, 29 (14.8%) were excluded and 166 (GA 26.7 2.1 weeks, BW 751 152 grams) were analyzed and grouped to their BGL. Normoglycemia was observed in 79 neonates (47.6%) (N-Group); 80 neonates (52.4%) showed abnormal BGL: 21 (12.7%) were hypoglycemic (Hypo-Group), 53 (31.9%) hyperglycemic (Hyper-Group) and 13 (7.8%) showed both hypoglycemia and hyperglycemia (Hypo&Hyper-Group). Clinical characteristics of the groups are reported in Table 1. Hypo-Group respect to N-Group showed a higher rate of small for gestational age (SGA) neonates (p = 0.03). Hyper-Group in comparison to N-Group showed a tendency toward a lower GA (p = 0.05), lower BW (p < 0.001), higher sepsis rate (p < 0.001), higher rate of treatment with inotropic agents (p = 0.02), corticosteroids (p = 0.006) and nonsteroidal antiinflammatory drugs (p = 0.01). Hypo&Hyper-Group respect to N-Group showed similar GA, lower BW (p < 0.001), higher sepsis rate (p < 0.01), higher rate of inotropic treatment (p = 0.04). Insulin was administered in 35 neonates (66%) of Hyper-Group and in 8 neonates (61.5%) of Hypo&Hyper-Group. Intraventricular Hemorrhage (IVH) rate was higher in Hyper-Group and Hypo&Hyper-Group respect to N-Group (p = 0.002) as well as IVH grade3 (p = 0.001 and p = 0.02, respectively). The rate of both Retinopathy of Prematurity (ROP) and ROP ≥stage 2 in survived neonates was higher in Hyper-Group respect to N-Group (p = 0.008 and p = 0.002, respectively). Mortality was similar among the groups (Table 2). Conclusions: Among ELBW infants, hypoglycemia occurs more frequently in SGA neonates, while hyperglycemia alone or a marked variability of BGL (hypo and hyperglycaemia) is more common in sick neonates. High rate of glucose homeostasis disorders highlights the importance of carefully monitoring BGL in order to a prompt management. Continuous glucose monitoring recently used in neonates [10] might be a useful tool for monitoring glucose changes also in ELBW neonates.