Low-level residual viremia and risk of virological failure

Results A total of 505 patients (78% males) with a mean age of 45.6 years (SD 7.6) were enrolled. At baseline the mean CD4 count was 667 cells/μl (SD 268) and VL was < 3 copies/ml in 73.9% and between 3 and 50 copies/ml in the remaining 26.1% of cases. Over the following 8 months period, patients with a baseline VL < 3 copies/ml presented a stable HIV-RNA below this threshold in 72.8% of cases, a level between 3 and 50 copies/ml in 27.2% of cases while no patient steadily rebounded above the 50 copies/ml threshold. On the contrary, patients with a baseline HIV-RNA between 3 and 50 copies/ml, in the follow-up, presented a stable VL < 3 copies/ml in 43.8% of cases, a VL between 3 and 50 copies/ml in 53.1% of cases, while 3.1% of patients steadily rebounded above the 50 copies/ml threshold (P < 0.0001). In the multivariate analysis the only variable significantly associated with viral dynamics was the third drug in the HAART regimen. A steady VL < 3 copies/ml, a VL between 3 and 50 copies/ml or a steady VL > 50 copies/ ml was detected, respectively, in 71.8%; 27.7% and 0.6% of NNRTI-treated patients, while the same figures for PItreated subjects were 56.2%; 42.9% and 1.0% (P = 0.029).