Development of a Global Respiratory Severity Score for Respiratory Syncytial Virus Infection in Infants.

ABSTRACT

Background: Respiratory syncytial virus (RSV) infection in infants has recognizable clinical signs and symptoms. However, quantification of disease severity is difficult, and published scores remain problematic. Thus, as part of a RSV pathogenesis study, we developed a global respiratory severity score (GRSS) as a research tool for evaluating infants with primary RSV infection. Methods: Previously healthy infants <10 months of age with RSV infections representing the spectrum of disease severity were prospectively evaluated. Clinical signs and symptoms were collected at 3 time points from hospitalized infants and those seen in ambulatory settings. Data were also extracted from office, emergency department, and hospital records. An unbiased data-driven approach using factor analysis was used to develop a GRSS. Results: A total of 139 infants (84 hospitalized and 55 nonhospitalized) were enrolled. Using hospitalization status as the output variable, 9 clinical variables were identified and weighted to produce a composite GRSS. The GRSS had an area under the receiver operator curve of 0.961. Construct validity was demonstrated via a significant correlation with length of stay (r = 0.586, P < .0001). Conclusions: Using routine clinical variables, we developed a severity score for infants with RSV infection that should be useful as an end point for investigation of disease pathogenesis and as an outcome measure for therapeutic interventions.