This study was conducted in accordance with the Helsinki Declaration. The requirement for informed consent was waived due to the retrospective nature of the study by the Institutional Review Board (IRB) of Yinchuan Maternal and Children's Healthcare Hospital. The study has been approved by the IRB of Yinchuan Maternal and Children's Healthcare Hospital (approval number: 2024-51).
All data generated or analysed during this study are included in this published article and its supplementary information files.
1.1 participants
This was a retrospective, multicenter, case-control study. Electronic records were used to identify participants. All infants with gestational age < 32 weeks were hospitalized in the neonatal intensive care unit (NICU) of four Hospitals from June 1, 2021, to May 31, 2023, were selected as subjects. The inclusion criteria were as follows: (1) hospitalization within 24 hours after birth; (2) hospitalization time ≥ three days; (3) Blood glucose levels were monitored ≥ three times on the first day after birth and ≥ two times on the second and third days after birth. The exclusion criteria were as follows: (1) newborns suffered from genetic and metabolic diseases; (2) malformations, including chromosome malformations. Of the 529 preterm infants with gestational age < 32 weeks were admitted, 69 cases were excluded due to death, discharge, missing or integrated blood glucose value, inherited metabolic disorders, or major malformations, including chromosome malformations (loss rate 13.0%). The final participants included 460 people. A flow diagram of the study design is shown in (Fig. 1).
The study has been approved by the Medical Ethics Committee of Yinchuan Maternal and Children Health Hospital (approval number: 2024-51). The data are anonymous, and the requirement for informed consent was therefore waived. This study was conducted in the Helsinki Declaration.
1.2 Measurements and definition:
Blood glucose levels were measured from capillary blood samples taken after the babies' heels were heated prefeed. Measured by Roche micro-blood glucose meter (ACCU-CHEKActive) and matching blood glucose test paper. Hyperglycemia was defined as a blood glucose level > 150 mg/dL on at least twice continuous measurements within three days after birth [13]. RDS was diagnosed as hard-working breathing and supplemental oxygen requirements (fraction of inspired oxygen of more than 30% to maintain oxygen saturation in the range of 88–94%)[ [14]. Intraventricular hemorrhage (IVH) was defined and graded according to et al. [15]. Hemodynamically significant patent ductus arteriosus (hs-PDA) is defined as follows: left atrium to aortic root diameter ratio(LA/Ao ≥ 1.4); left ventricular (LV enlargement, LVEF < 50%, ductal diameter ≥ 2mm or ductal diameter greater than mean pulmonary artery(MPA) diameter; PDA maximum velocity(PDA Vmax < = 2m/s); ductal left to right diastolic flow > = 0.5m/s; highly elevated mean and diastolic PA flow; severe PA dilation; anterior cerebral artery resistance index (ACA RI) > = 0.9; Holodiastolic retrograde descending aorta (DAO) flow [16]. Feeding Intolerance(FI) is defined as the inability to digest enteral feedings presented as gastric residual volume of more than 50%, abdominal distension or emesis or both, and the disruption of the patient's feeding plan [17]. An apnea is defined as a cessation of breathing for 20 seconds or longer or a shorter pause accompanied by bradycardia (< 100 bpm), cyanosis, or pallor [18].
1.3 Data collection
Demographic and perinatal characteristics of all infants and their mothers were collected from the charts. (1) Mother's information: maternal age, body mass index at delivery, total prenatal glucocorticoids, mode of delivery, multiple pregnancy, maternal hypertension, gestational diabetes mellitus(GDM), maternal hypothyroidism, assisted reproduction. (2) premature infant information: sex, gestational age(GA), birth weight(BW), age of admission (min), Apgar score 1 minute, Apgar score 5 minutes, premature rupture of membranes(PROM), fasting time, starting feeding time, PN start time, Breastfeeding, umbilical vein catheterization(UVC), umbilical artery catheterization(UAC), invasive ventilation, noninvasive ventilation, RDS, IVH, FI, apnea, hs-PDA.
1.4 Statistical analysis
For missing values, the variables with missing values ≥ 20% are eliminated directly, the missing value is dealt with by a simple filling method, the classified data is filled by mode, and a median fills the dose data. The R software Rversion4.2.0 was used for statistical analysis. Baseline description and univariate analysis: The compare-groups package was used with automatic identification, the glm package was used for multifactor Logistic regression, and the pROC package was used for discrimination analysis to calibrate function and value. Prob function in rms package was used for calibration, riskrggression package was used for the calibration curve, rmda package was used for the DCA curve, and rms package was used for nomogram. Statistical significance was set at P < 0.05.