Predicting the outcomes of human immunodeficiency virus infection: How well are we doing?

An important determinant of patient outcomes is illness severity, which must be classified to guide clinical decision making and evaluate the effectiveness of diagnostic and therapeutic interventions. Currently, no widely accepted framework for grading illness severity in human immunodeficiency virus-infected patients exists. The best known classification systems for human immunodeficiency virus infection (Centers for Disease Control and Prevention; Walter Reed) are not based on illness severity, and provide stages that are not all inclusive so that a large number of persons cannot be classified (Walter Reed). Although much previous research has focused on individual prognostic factors (oral thrush, CD4 cell count, serum β₂-microglobulin), little attention has been given to incorporating these factors into illness severity scales that are easy to use in clinical settings. In addition, despite the progressive functional disability of human immunodeficiency virus-infected individuals, few of the existing approaches to illness severity classification have examined the contribution of functional status. We urge investigators to develop clinically sensible severity scales that are easy to use. Such scales will considerably improve existing approaches that tend to rely solely on the CD4 cell count and do not take into account the known prognostic effects of other variables.