Do HIV Type 1 RNA Levels Provide Additional Prognostic Value to CD4 + T Lymphocyte Counts in Patients with Advanced HIV Type 1 Infection?

Abstract

Our objective was to assess whether HIV-1 RNA levels provide additional prognostic information beyond CD4⁺ T lymphocyte counts in the prediction of subsequent HIV-1 disease progression among patients with advanced HIV-1 disease. In a nested case-control study conducted in patients with baseline CD4⁺ T lymphocyte counts < 300 cells/mm³ and receiving nucleoside reverse transcriptase inhibitors, 102 patients who progressed to an AIDS-defining event or death were matched within 10 CD4⁺ T lymphocyte cells/mm³ to patients who did not progress. The relationship between plasma HIV-1 RNA levels and HIV-1 disease progression was studied using conditional logistic regression analysis, which adjusts for the matching by baseline CD4⁺ T lymphocytes. We observed a 0.10 log₁₀ copies/ml difference in baseline HIV-1 RNA levels between cases and their matched controls (p = 0.027). The relative risk for HIV-1 disease progression increased with increasing baseline HIV-1 RNA levels (odds ratio [OR] for a 3-fold higher HIV-1 RNA level, 1.42; 95% confidence interval [CI], 1.08-1.86), and remained important when also controlling for clinical status at baseline and CD4⁺ T lymphocytes at 2 months (p = 0.038). Higher baseline HIV-1 RNA levels were associated with HIV-1 disease progression among patients with a baseline CD4⁺ T lymphocyte count of 100 cells/mm³ or greater (OR, 1.80; 95% CI, 1.15-2.81), but not among patients with a baseline CD4⁺ T lymphocyte count < 100 cells/mm³ (OR, 1.09; 95% CI, 0.73-1.63). We concluded that HIV-1 RNA levels predict subsequent HIV-1 disease progression independent of CD4⁺ T lymphocyte counts. The magnitude and importance of the prognostic information contained in the HIV-1 RNA levels appear to depend on the CD4⁺ T lymphocyte counts.