Early postoperative red cell distribution width is associated with prolonged hospital stay and complications after non-cardiac surgery in neonates.

BACKGROUND: Red blood cell distribution width (RDW) has emerged as a potential biomarker associated with adverse outcomes in various diseases. However, its clinical significance in neonatal surgical populations remains unclear. The present study aimed to investigate the association between early postoperative RDW and postoperative outcomes in neonates undergoing non-cardiac surgery. METHODS: This retrospective cohort study included neonatal patients who underwent non-cardiac surgery at a tertiary children's hospital. Patients were stratified into quintiles based on early postoperative RDW levels: Q1 (extremely low), Q2 (low), Q3 (moderate), Q4 (high) and Q5 (extremely high). The primary outcome was postoperative length of hospital stay (LOS). Secondary outcomes included 30-day mortality, duration of postoperative mechanical ventilation and ICU stay, and postoperative complications. Multivariable regression analyses were performed to assess associations. Propensity score matching (PSM) comparing the higher-RDW group with the lower-RDW group was performed to further account for baseline confounding. RESULTS: A total of 1,014 neonates were included in this study. The RDW quintile cutoffs were defined as follows: Q1 (< 14.5%), Q2 (14.5-15.0%), Q3 (15.1-15.7%), Q4 (15.8-17.1%) and Q5 (> 17.1%). Neonates in the higher quintiles had significantly higher risks for prolonged LOS (Q4: adj. OR 2.516, [95% CI 1.217-5.204]; Q5: adj. OR 5.854, [95% CI 2.606-13.146]; p for Trend < 0.001). After PSM, the increased risk of prolonged LOS remained significant for neonates in the higher-RDW group (Q4-Q5), with an adjusted OR of 3.805 (95% CI 1.998-7.245, p < 0.001) in the matched cohort. When analyzed as a continuous variable, early postoperative RDW remained positively associated with LOS (p = 0.020). This association was consistent across subgroups and sensitivity analyses. For secondary outcomes, the association was also observed in prolonged ICU stay, acute kidney injury and acidosis (all p < 0.05) but there was no difference in 30-day mortality. CONCLUSIONS: Elevated RDW within 24 hours after non-cardiac surgery is significantly associated with prolonged LOS and increased risk of postoperative complications in neonates. RDW may serve as a clinically accessible biomarker for postoperative risk stratification in this population.