The consistency of adherence to antiretroviral therapy predicts biologic outcomes for human immunodeficiency virus-infected persons in clinical trials.

We prospectively studied long-term antiretroviral adherence patterns and their impact on biologic outcomes for human immunodeficiency virus (HIV)-infected participants in 2 randomized, multicenter clinical trials. For the period from baseline to month 12 of the study, participants who reported adherence levels of 100%, 80%-99%, and 0%-79% had plasma HIV RNA levels that decreased by 2.77, 2.33, and 0.67 log(10) copies/mL, respectively (P<.001), whereas their CD4 counts increased by 179, 159, and 53 cells/mm(3), respectively (P<.001). Adherence predicted nondetectable HIV RNA levels (<50 copies/mL) at 12 months of follow-up (P<.001). The HIV RNA level was nondetectable in 72% of participants who reported 100% adherence at all 4 follow-up visits, compared with 66%, 41%, 35%, and 13% of participants who reported 100% adherence at 3, 2, 1, or 0 follow-up visits, respectively (P<.001). Nonwhite race was associated with poorer adherence (P<.001), and older age was associated with better adherence (P<.001).