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 degrees-35(6) 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 2.14kg; p<0.001) for both males (2.25 versus 2.18kg; p=0.049) and females (2.22 versus 2.11kg, p=0.007). The effect was significant only in 34 wGA infants (33 wGA: hospitalised 1.95kg versus non-hospitalised 1.95kg, p=0.976; 34 wGA: 2.26 versus 2.14kg, p=0.007; 35 wGA: 2.37 versus 2.29kg, p=0.070), particularly female 34 wGA infants (female: 2.24 versus 2.08kg, 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.