CD4 and coinfection: Virological failure was not significantly associated to any of the factors analysed in the univariate or multivariate analysis (i.e., presence of blips, gender, age, HCV co-infection, CD4+ nadir, CD4+ T-cell count at baseline, CDC stage, time since HIV diagnosis, time on ART, duration of virological suppression, and number of prior PIs and antiretroviral regimens).