Viremia copy-years and mortality among combination antiretroviral therapy-initiating HIV-positive individuals: how much viral load history is enough?

Abstract

Ongoing HIV replication while receiving combination antiretroviral therapy (cART) may reduce survival. Viremia copy-years (VCY) has shown improved mortality risk prediction over single time-point viral load measures. However, the timing of a patient's viral load history most associated with later mortality has not been studied. Here we determined the optimal duration and temporality of viral load history for predicting mortality. Survival analysis among HIV-positive men who initiated cART in the Multicenter AIDS Cohort Study (1995-2015). VCY measures were derived from area-under-the-viral load-curve. The overall VCY based upon the complete post-cART viral load history was compared with 20 VCYs derived from viral loads assessed during different shorter time periods (the most recent 1-10 years and initial 1-10 years following cART initiation) for associations with mortality. Each 10-fold increase in VCYs based on the most recent 3-8 years was significantly associated with 23-26% decrease in survival times, a magnitude of effect greater than that of the most recent viral load (16%). These associations were independent of CD4 cell count and single time-point viral loads. In addition, the degree of pre-cART immunodeficiency did not affect the mortality prognostic value of VCY based on viral loads in the most recent 3 years. Conversely, the overall VCY and VCYs based on viral loads immediately following cART initiation were not independent predictors of mortality. Among cART-treated men, VCY based upon viral loads in the recent 3 years (six viral loads) has a mortality prognostic value greater than that of the overall VCY and single time-point viral loads, making the former a more feasible measure for use.