The aim is to identify risk factors associated with longer length of hospital stay (LOS) in infants with respiratory syncytial virus (RSV) bronchiolitis.
Methods
We conducted an observational study in infants, under 24-month of age, hospitalized with first episode of RSV bronchiolitis between November 2014 and February 2015, retrospectively. Demographic and clinical characteristics were collected including doctor diagnosed atopic dermatitis, days of illness before hospitalization, 25-hydroxy Vitamin D (25(OH)D), modified-Tal score, RSV genomic load at presentation, and LOS by comprehensive review of medical record. Kaplan-Meier estimator, survival analysis, and Cox proportional hazard analysis were used to identify risk factors for the longer LOS.
Results
Total 112 infants were identified, and 6 of extreme premature birth and 3 of congenital heart disease were excluded. The age of months distributed from 0 to 23 month of age (median, 10.5). The median LOS was 94 hours (range 20-224 hours), and those of modified-Tal score was 2 point (range 1-9). Higher RSV genomic load (threshold cycle < 13.68) was not associated with longer LOS (P=.1). Lower 25(OH)D (< 10 mg/dL) had a higher cumulative incidence of longer LOS (≥96 hour; P=.05, ≥72 hour; P=.04): the adjusted hazard ratio for the lower 25(OH)D was 0.07 (95% CI, 0.91-15.40, P=.07). Mode of delivery, exclusive breast-milk feeding, sex, co-infection, doctor diagnosed atopic dermatitis, and modified Tal-score were not associated with longer LOS.
Conclusion
The concurrent hypovitaminosis D in infants with first episode of RSV bronchiolitis, rather than RSV viral load had a higher risk for longer LOS.