SummaryThe aim of this study was to assess the predictive value of HIV RNA levels after 1 month of therapy on the long-term virologic outcome in an unselected general population of HIV-infected patients.DesignAnalysis was conducted retrospectively on an ongoing clinical cohort of HIV-positive patients who were receiving antiretroviral treatment. Data on 575 patients were analyzed.ResultsThe HIV RNA value at 1 month was significantly correlated with the virologic outcome after 12 and 24 months of therapy (R = 0.258 and R = 0.44, respectively). The predictive value of the 1-month viral load was also statistically significant after stratification for baseline CD4 T-cell counts. Prediction was similar in highly compromised patients (CD4 ≤100 cells/&mgr;l; R = 0.426;p= .001) or in patients with a better immunologic status (R = 0.419;p< .0001). It retained validity in patients who were naive or experienced for antiretroviral therapy.ConclusionHIV RNA level after 1 month of therapy is a useful prognostic marker in HIV-infected patients. It predicts long-term virologic and immunologic outcome. A cutoff level of 5000 copies/ml identifies patients most likely to fail current therapy. In these patients, a more aggressive strategy or specific diagnostic interventions to clarify the relative influence of viral resistance and/or subtherapeutic regimens is advised.