Case-control study of the risk factors linked to respiratory syncytial virus infection requiring hospitalization in premature infants born at a gestational age of 33-35 weeks in Spain.
OBJECTIVE
The aim of this study was to identify those risk factors most likely to lead to the development of RSV-related respiratory Infection and subsequent hospital admission among premature infants born at 33-35 WGA (FLIP study)


METHODS
This was a prospective case-control study. Cases (186) hospitalized for respiratory syncytial virus (RSV) illness were recruited from 50 participating Spanish hospitals during the 2002-2003 RSV season (October 2002-April 2003). Controls (371) were selected in June 2003 but born at same time as cases.


RESULTS
Of these cases, 20.5% were admitted to the intensive care unit intensive care unit, and 7.6% required mechanical ventilation. None of the patients died. Conditional logistic regression analysis adjusted for medical center demonstrated that the risk of RSV-related respiratory infection requiring hospital admission in preterm infants 33-35 weeks of gestation (WGA) in Spain was most often associated with absolute chronologic age at start of RSV season < or =10 weeks [ie, born between July 15 and December 15; odds ratio (OR), 3.95; 95% confidence interval (CI), 2.65-5.90], breast-feeding for < or =2 months total (OR 3.26; 95% CI 1.96-5.42), presence of > or =1 school age siblings (OR 2.85; 95% CI 1.88-4.33), > or =4 residents and visitors at home (discounting school age siblings and the case/control him/herself) (OR 1.91; 95% CI 1.19-3.07) and a family history of wheezing (OR 1.90; 95% CI 1.19-3.01).


CONCLUSIONS
In premature infants born 33-35 WGA, certain underlying risk factors significantly increase the risk of RSV-related respiratory infection and hospitalization. Premature infants 33-35 WGA with additional risk factors should be considered for RSV prophylaxis with palivizumab.
Figueras-Aloy
José
J
Hospital Clínic, Unitat Integrada Pediatría, Institut d'Investigacions Biomèdiques August Pi i Sunyer, 0828 Barcelona, Spain. FIGUERAS@MEDICINA.UB.ES
Carbonell-Estrany
Xavier
X
Quero
José
J
D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D005865:Gestational Age; D006760:Hospitalization / Q000639:trends*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D000069455:Palivizumab; D011247:Pregnancy; D015995:Prevalence; D011322:Primary Prevention / Q000379:methods; D011336:Probability; D011446:Prospective Studies; D012016:Reference Values; D018357:Respiratory Syncytial Virus Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000517:prevention & control*; D018570:Risk Assessment; D012720:Severity of Illness Index; D012737:Sex Factors; D013030:Spain / Q000453:epidemiology; D016019:Survival Analysis; D016896:Treatment Outcome
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000069455:Palivizumab