The influence of birth weight amongst 33-35 weeks gestational age (wGA) infants on the risk of respiratory syncytial virus (RSV) hospitalisation: a pooled analysis

OBJECTIVE: To investigate the association between birth weight and respiratory syncytial virus (RSV) hospitalisation during the first year of life in 33°-356 weeks' gestational age (wGA) infants. STUDY DESIGN: Pooled analysis of data (n = 1218) from Spain, Germany, France and Italy. RESULT: RSV hospitalised infants overall had a significantly higher birth weight than non-hospitalised infants (2.24 versus 2.14 kg; p < 0.001) for both males (2.25 versus 2.18 kg; p = 0.049) and females (2.22 versus 2.11 kg, p = 0.007). The effect was significant only in 34 wGA infants (33 wGA: hospitalised 1.95 kg versus non-hospitalised 1.95 kg, p = 0.976; 34 wGA: 2.26 versus 2.14 kg, p = 0.007; 35 wGA: 2.37 versus 2.29 kg, p = 0.070), particularly female 34 wGA infants (female: 2.24 versus 2.08 kg, p = 0.019; male: 2.27 versus 2.20, p = 0.191). Birth weight was shown to be an independent risk factor for RSV hospitalisation. CONCLUSIONS: In 33-35 wGA infants, a higher birth weight appeared independently associated with an increased risk of RSV hospitalisation.