PEDIATRIC INVESTIGATORS COLLABORATIVE NETWORK ON INFECTIONS IN CANADA(PICNIC) PROSPECTIVE-STUDY OF RISK-FACTORS AND OUTCOMES IN PATIENTS HOSPITALIZED WITH RESPIRATORY SYNCYTIAL VIRAL LOWER RESPIRATORY-TRACT INFECTION

Objective: To provide information on disease attributable to respirato ry syncytial viral lower respiratory tract infection (RSV LRI) and to quantify the morbidity associated with various risk factors. Design: P rospective cohort study. Subjects: Patients hospitalized with RSV LRIs at seven centers were eligible for study if they were younger than 2 years of age, or hospitalized patients of any age if they had underlyi ng cardiac or pulmonary disease or immunosuppression. Measurements and results: Enrolled (n = 689) and eligible but not enrolled (n = 191) p atients were similar in age, duration of illness and proportion with u nderlying illness, use of intensive care, and ventilation. Of the enro lled patients, 156 had underlying illness. The isolates from 353 patie nts were typeable: 102 isolates were subgroup A, 250 were subgroup B, and one isolated grouped with both antisera. The mean hospital stay at tributable to respiratory syncytial virus (RSV) was 7 days; 110 patien ts were admitted to intensive care units, 63 were supported by mechani cal ventilation, and 6 patients died. Regression models were developed for the prediction of three outcomes: RSV-associated hospital duratio n,intensive care unit admission, and ventilation treatment. In additio n to previously described risk factors for an increased morbidity, suc h as underlying illness, hypoxia, prematurity and young age, three oth er factors were found to be significantly associated with complicated hospitalization: aboriginal race (defined by maternal race), a history of apnea or respiratory arrest during the acute illness before hospit alization, and pulmonary consolidation as shown on the chest radiograp h obtained at admission. The RSV subgroup, family income, and day care attendance were not significantly associated with these outcomes.