IMPROVED OUTCOME OF RESPIRATORY SYNCYTIAL VIRUS-INFECTION IN A HIGH-RISK HOSPITALIZED POPULATION OF CANADIAN CHILDREN

Purpose: To determine the outcomes in children at high risk for death or complications from respiratory disease who are hospitalized with respiratory syncytial virus (RSV) infection. Design: Retrospective chart review. Setting: Twelve pediatric tertiary care centers. Patients: All hospitalized children with on RSV infection diagnosed by a positive antigen detection test result or viral isolation during the study period from 1988 to 1991, encompassing three winter seasons. Charts from patients in the following high-risk groups were reviewed in detail: (1) congenital heart disease, (2) chronic lung disease, (3) immunodeficiency, (4) age <6 weeks, (5) gestational age <36 weeks, and (6) hypoxia (defined as oxygen saturation <90% or arterial oxygen pressure <60 mm Hg). Measurements: The age of all children, the date of RSV identification, and the use of oxygen supplementation, intensive care, and ventilatory support. In addition, the duration of these treatments and the duration of hospitalization were noted. Left-to-right shunting and pulmonary hypertension before RSV infection were determined in those children with congenital heart disease. The nature of the chronic lung disease was noted. Death within 2 weeks of RSV identification was recorded, and the use of ribavirin, bronchodilators, and corticosteroids was determined. Results: Significant year-to-year variation in the frequency of RSV infection was confirmed, with a peak during the 1989-1990 winter noted by the majority of centers (p = 0.0001). Of the 1584 patients in the study, 260 had, underlying cardiac disease, 200 had chronic lung disease, 35 had compromised immune function, 378 had been premature, 373 were <6 weeks of age, and 338 had hypoxia. Seventeen patients died within 2 weeks (mortality rate 1%); significantly more patients with underlying cardiac disease (3.4%) or lung disease (3.5%) died. Immunocompromised patients had the longest hospital stay (median 39 days), followed by those patients with underlying cardiac or pulmonary disease (11 days); patients <6 weeks of age (5 days) and those with hypoxia (6 days) had the shortest hospital stays. Patients with underlying cardiac and pulmonary disease also required oxygen supplementation for a significantly longer period. Conclusion: The year-to-year variation in frequency of RSV infection was confirmed in this study. Morbidity and mortality rates associated with RSV infection in a high-risk population in Canada were significantly lower than previously reported.