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 vir us (RSV) infections and presumptive risk factors for rehospitalization amon g 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 di scharged from the hospital before March 31, 1999, were included in the stud y. A total of 96 were excluded because of administration of prophylactic tr eatment (n = 55) or were lost to follow-up (n = 41), Five children died dur ing the study period, but death was related to RSV in only 1 case. Methods and main outcome measures. Neonatal and demographic data were recor ded at the initial visit. Infants were prospectively followed at monthly in tervals up to March 31, 1999, In patients rehospitalized for respiratory di sorders, further data about RSV status and morbidity were collected. A comp arison was made between children rehospitalized for RSV infection and those who were not. The influence of factors on the probability of rehospitaliza tion 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 ide ntified in 89 (75.4%) hospital admissions. Of these 59 (66.3%) were a resul t of RSV infection in 53 children; 6 were reinfections, In a logistic regre ssion model significant independent prognostic variables included: lower ri sk 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 wi th chronic lung disease (OR = 3.1; 95% CI 1.22 to 7.91; P < 0.016); and liv ing 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 influ ence of specific risk factors that increase the risk of rehospitalization f or RSV infection in preterm infants. Such studies help to define the approp riate role of available prophylactic interventions and establish treatment guidelines.