Comparison of Follow-up Courses after Discharge from Neonatal Intensive Care Unit between Very Low Birth Weight Infants with and without Home Oxygen

Abstract

In order to investigate the clinical impact of home oxygen use for care of premature infants, we compared the follow-up courses after neonatal intensive care unit (NICU) discharge between very low birth weight infants (VLBWIs) with and without home oxygen. We retrospectively identified 1,232 VLBWIs born at 22 to 32 weeks of gestation, discharged from the NICU of 43 hospitals in Korea between April 2009 and March 2010, and followed them up until April 2011. Clinical outcomes, medical service uses, and readmission and death rates during follow-up after the NICU discharge were compared between VLBWIs with (HO, n = 167) and those without (CON, n = 1,056) home oxygen at discharge. The HO infants comprised 13.7% of the total VLBWIs with significant institutional variations and showed a lower gestational age (GA) and birth weight than the CON infants. The HO infants had more frequent regular pediatric outpatient clinic visits (12.7 ± 7.5 vs. 9.5 ± 6.6; P < 0.010) and emergency center visits related to respiratory problems (2.5 ± 2.2 vs. 1.8 ± 1.4; P < 0.010) than the CON infants. The HO infants also had significantly increased readmission (adjusted hazard ratio [HR], 1.60; 95% confidence interval [CI], 1.25-2.04) and death risks (adjusted HR, 7.40; 95% CI, 2.06-26.50) during up to 2 years following the NICU discharge. These increased readmission and death risks in the HO infants were not related to their prematurity degree. In conclusion, home oxygen use after discharge increases the risks for healthcare utilization, readmission, and death after NICU discharge in VLBWIs, regardless of GA, requiring more careful health care monitoring during their follow-up.

Keywords: Death; Infants, Premature; Oxygen; Prognosis; Readmission.

Fig. 1

Correlation of number of VLBWIs discharged alive with the proportion of home oxygen use. Correlation of number of VLBWIs discharged alive with the proportion of home oxygen use in each hospital, which showed no significant correlation (R² = 0.1412; P > 0.050). Fourteen hospitals showed 0% home oxygen use in VLBWIs discharged alive and 29 hospitals showed the proportion of home oxygen use ranged from 2.9% to 36.0%. VLBWIs = very low birth weight infants.

Fig. 2

Cumulative probability of readmission of enrolled infants after NICU discharge. Cumulative probability of readmission of enrolled infants depicted by time to the first readmission after NICU discharge in total (A) and according to GA subgroups (B). In total (A), the HO subgroup significantly higher probability of readmission than that of the CON subgroup in VLBWIs discharged alive from NICU. In subgroup analysis (B), whereas there were significant differences in cumulative probability or readmission among CON subgroups, no differences were found among HO subgroups. NICU = neonatal intensive care unit, GA = gestational age, HO = home oxygen use at discharge, CON = no home oxygen use at discharge, VLBWIs = very low birth weight infants, ≤ 25w GA = gestational age-subgroup of 25 weeks' gestation or less, 26–28w GA = gestational age-subgroup of 26–28 weeks' gestation, ≥ 29w GA = gestational age-subgroup of 29 weeks' gestation or more. ^*P < 0.050 by log-rank test; ^†P < 0.050 by log-rank test between the HO and the CON in ≥ 29w GA subgroup.