Determinants of length of hospital stay in non-infectious neonatal jaundice: A large retrospective cohort study

Background Neonatal jaundice is a leading cause of newborn hospitalization in low- and middle-income countries (LMICs), yet factors influencing length of hospital stay (LOS) in non-infectious cases remain poorly characterized. Methods We retrospectively analyzed 1262 neonates with confirmed non-infectious jaundice admitted to a tertiary referral hospital in southern Vietnam between January 2024 and June 2025. Demographic characteristics, admission bilirubin levels, complete blood count (CBC) parameters, and derived inflammatory indices were evaluated. LOS was analyzed primarily as a continuous outcome, with prolonged hospitalization (≥3 days) assessed as a secondary outcome. Robust OLS, Poisson, and logistic regression models identified independent predictors after adjustment for age, sex, and ethnicity. Results Higher total and indirect bilirubin levels were associated with longer LOS in univariable analyses. Across all multivariable models, total bilirubin independently predicted longer hospitalization and increased odds of prolonged stay. Higher monocyte count showed a modest inverse association with LOS, although this finding should be considered exploratory. Other CBC-derived inflammatory indices (NLR, MLR, PLR, SII, and SIRI) and demographic factors, including ethnicity, were not independently associated with LOS. Conclusions Bilirubin burden was the dominant determinant of hospitalization duration in neonates with non-infectious jaundice. Routine CBC-derived inflammatory indices provided little incremental prognostic value beyond bilirubin concentration. The modest association between monocyte count and shorter LOS warrants prospective validation, while additional clinical and health-system factors not captured in this study are also likely to influence hospitalization duration.