Poor postnatal weight growth is a late finding after sepsis in very preterm infants

Abstract

Objective: To characterise the association between sepsis and postnatal weight growth when accounting for the degree of growth restriction present at birth.

Design: Retrospective matched cohort study using data from the Postnatal Growth and Retinopathy of Prematurity study. Participants were born with birth weights of <1500 g or gestational ages of <32 weeks between 2006 and 2011 at 29 neonatal centres in the USA and Canada. Sepsis was defined as a culture-confirmed bacterial or fungal infection of the blood or cerebrospinal fluid before 36 weeks' postmenstrual age (PMA). Growth was assessed as the change in weight z-score between birth and 36 weeks' PMA.

Results: Of 4785 eligible infants, 813 (17%) developed sepsis and 693 (85%) were matched 1:1 to controls. Sepsis was associated with a greater decline in weight z-score (mean difference -0.09, 95% CI -0.14 to -0.03). Postnatal weight growth failure (decline in weight z- score>1) was present in 237 (34%) infants with sepsis and 179 (26%) controls (adjusted OR 1.49, 95% CI 1.12 to 1.97). Longitudinal growth trajectories showed similar initial changes in weight z-scores between infants with and without sepsis. By 3 weeks after sepsis onset, there was a greater decline in weight z-scores relative to birth values in those with sepsis than without sepsis (delta z-score -0.89 vs -0.77; mean difference -0.12, 95% CI -0.18 to -0.05). This significant difference persisted until 36 weeks or discharge.

Conclusion: Infants with sepsis had similar early weight growth trajectories as infants without sepsis but developed significant deficits in weight that were not apparent until several weeks after the onset of sepsis.

Keywords: growth; microbiology; neonatology.

Figure 1:

Patient Flow Diagram CSF (cerebrospinal fluid); GA (gestational age); PMA (postmenstrual age) Flow diagram demonstrating patients included in the analysis.

Figure 2:

Delta weight z-score comparison between infants with and without sepsis Comparison of delta weight z-score before, at, and after sepsis episode time point between matched subjects with and without sepsis. The day of the sepsis onset was assigned for each matched pair according to the day of sepsis diagnosis in the infected infant. Only days with at least 100 weight data points for each group are shown and not all data points include matched pairs, as some pairs only had weight data in one group at certain time points. The daily values for the two groups (shown as o and +) represent means of the actual measurements, and the lines for the two groups represents the estimates determined from the locally estimated scatterplot smoothing (LOESS) analysis.