Objectives: We examined the significance of plasma HIV-1 RNA levels (or viral load alone) in predicting CD4 cell decline in untreated HIV-infected individuals.
Methods: Data were obtained from the British Columbia Centre for Excellence in HIV/AIDS. Participants included all residents who ever had a viral load determination in the province and who had never taken antiretroviral drugs (N = 890). We analyzed a total of 2074 viral load measurements and 2332 CD4 cell counts. Linear mixed-effects models were used to predict CD4 cell decline over time.
Results: Longitudinal viral load was strongly associated with CD4 cell decline over time; an average of 1 log(10) increase in viral load was associated with a 55-cell/mm(3) decrease in CD4 cell count.
Conclusions: Our results support the combined use of CD4 cell count and viral load as prognostic markers in HIV-infected individuals before the introduction of antiretroviral therapy.