Rehospitalization because of respiratory syncytial virus infection in premature infants younger than 33 weeks of gestation:: a prospective study

Objective, To collect data on hospitalization for respiratory syncytial virus (RSV) infections and presumptive risk factors for rehospitalization among premature infants in Spain. Design. Observational, prospective, longitudinal, multicenter study. Setting. Fourteen Spanish neonatal units with an annual birth cohort of 57 000 infants. Patients. All children (n = 680) born less than or equal to 32 weeks of gestational age between April 1, 1998, and March 31, 1999, and discharged from the hospital before March 31, 1999, were included in the study. A total of 96 were excluded because of administration of prophylactic treatment (n = 55) or were lost to follow-up (n = 41), Five children died during the study period, but death was related to RSV in only 1 case. Methods and main outcome measures. Neonatal and demographic data were recorded at the initial visit. Infants were prospectively followed at monthly intervals up to March 31, 1999, In patients rehospitalized for respiratory disorders, further data about RSV status and morbidity were collected. A comparison was made between children rehospitalized for RSV infection and those who were not. The influence of factors on the probability of rehospitalization for RSV infection was assessed by logistic regression analysis, Results. Of the 584 evaluable patients 118 (20.2%) were rehospitalized for respiratory disease during the study period. The causative pathogen was identified in 89 (75.4%) hospital admissions. Of these 59 (66.3%) were a result of RSV infection in 53 children; 6 were reinfections, In a logistic regression model significant independent prognostic variables included: lower risk of RSV hospitalization with increase gestational age [odds ratio (OR), 0.85; 95% confidence interval (CI), 0.72 to 0.99; P < 0.047]; higher risk with chronic lung disease (OR = 3.1; 95% CI 1.22 to 7.91; P < 0.016); and living with school age siblings (OR = 1.86; 95% CI 1.01 to 3.4; P < 0.048), Conclusion. This large descriptive study has enabled us to define the influence of specific risk factors that increase the risk of rehospitalization for RSV infection in preterm infants. Such studies help to define the appropriate role of available prophylactic interventions and establish treatment guidelines.