Figure 1.

The association between hospitalization status and the 2 leading factors derived from a factor analysis. Open circles represent nonhospitalized subjects, and solid circles represent hospitalized subjects. Factor 1 and factor 2 are the top 2 factors identified by principal component analysis and varimax rotation. A subsequent logistic regression analysis determined that only factor 1 was significantly associated with hospitalization; thus the global respiratory severity score is calculated on the basis of factor 1.