B V Roussanov1, J M Taylor, J V Giorgi. 1. Department of Biostatistics and Jonsson Comprehensive Cancer Center, University of California, Los Angeles, USA.
Abstract
OBJECTIVE: The pathogenesis of human disease is often multifactorial. For fatal diseases, it is common to combine survival information in relation to different aspects of pathogenesis. Here we explored a scoring system for HIV disease markers that combines measures of immunodeficiency (CD4 cell count), plasma viral burden, and immune activation (CD38 expression on CD8 T cells) DESIGN: Observational data from 252 HIV-infected individuals from the Multicenter AIDS Cohort Study (MACS) was used for model development. METHODS: A statistical model was used to develop a system that related marker values to the outcomes of clinical AIDS or death. RESULTS: Mathematical formulae were derived to calculate AIDS and death progression scores. These scores give the number of days at which there is a 50% probability that a person may develop AIDS or die. Graphs were constructed that can be used to determine the probability that a person will be AIDS-free or alive for times between 6 months and 4 years. The model was valid when tested on data from 240 additional people from the MACS cohort. CONCLUSIONS: These formulae and graphs are a convenient way for individuals and their physicians to apply existing MACS cohort data to HIV disease markers in order to estimate probabilities of progression to AIDS or death. Further investigation is needed to determine whether modifications of the formulae are required to predict outcome accurately in those patients on highly active antiretroviral therapy or in other demographic groups.
OBJECTIVE: The pathogenesis of human disease is often multifactorial. For fatal diseases, it is common to combine survival information in relation to different aspects of pathogenesis. Here we explored a scoring system for HIV disease markers that combines measures of immunodeficiency (CD4 cell count), plasma viral burden, and immune activation (CD38 expression on CD8 T cells) DESIGN: Observational data from 252 HIV-infected individuals from the Multicenter AIDS Cohort Study (MACS) was used for model development. METHODS: A statistical model was used to develop a system that related marker values to the outcomes of clinical AIDS or death. RESULTS: Mathematical formulae were derived to calculate AIDS and death progression scores. These scores give the number of days at which there is a 50% probability that a person may develop AIDS or die. Graphs were constructed that can be used to determine the probability that a person will be AIDS-free or alive for times between 6 months and 4 years. The model was valid when tested on data from 240 additional people from the MACS cohort. CONCLUSIONS: These formulae and graphs are a convenient way for individuals and their physicians to apply existing MACS cohort data to HIV disease markers in order to estimate probabilities of progression to AIDS or death. Further investigation is needed to determine whether modifications of the formulae are required to predict outcome accurately in those patients on highly active antiretroviral therapy or in other demographic groups.