[Analysis of variables associated to undetectable viral load and therapeutic failure in HIV-infected individuals]

To date, antiretroviral therapies have not led to total HIV eradication in infected individuals. The achievement of undetectable viremia levels has been regarded as essential when monitorizing the efficacy of these therapies. The objectives of our study were to assess the time needed to achieve viral load (VL) undetectable levels and subsequent VL risings, as well as to determine the clinical variables associated with both events.

Owing to a follow-up period greater than 1,000 days, 314 patients were retrospectively selected. We determined the percentages of patients with undetectable VL levels and of those with subsequent VL rising. Times needed to reach both events were calculated by Kaplan-Meier analysis.

182 individuals (58%; 95% CI, 52.3-63.5) reached undetectable VL levels with a median follow-up time of 862 days. A more regular VL quantitation was associated with such event. The VL level of 38 out of these individuals (20.9%; 95% CI, 15.2-27.5) increased subsequently (> 30,000 RNA copies/ml) with a mean time of 328 days (after the first undetectable VL determination); this event was associated with changes in the clinical centre where the patient was being cared for.

In our series, the proportion of individuals with undetectable VL levels and therapeutic failure was low. The frequency of VL determination was a determining factor in the evolution of these patients.