Objectives: To evaluate the relationship between incomplete antiretroviral therapy (ART) adherence and levels of residual HIV-1 viremia.
Design: Medication adherence and residual viremia less than 50 copies/ml were quantified in participants of a cohort of homeless and marginally housed individuals with HIV/AIDS.
Methods: Participants had at least 6 months of virologic suppression of less than 50 copies/ml and were in the adherence monitoring cohort with monthly unannounced pill counts. Residual viremia was measured by the single-copy assay.
Results: The median average ART adherence over the prior 1 and 2 months were 94% [interquartile range (IQR) 79–100%] and 93% (IQR 82–98%), respectively. Average ART adherence over the past 2 months was significantly associated with levels of residual HIV viremia (Spearman r = –0.25, P = 0.04). One-third of participants with 100% ART adherence over the past 2 months had detectable residual viremia. On multivariate regression analysis, ART adherence over the past 2 months, but not duration of virologic suppression, CD4+ T-cell count or ART regimen, was significantly associated with levels of residual HIV viremia. Detectable residual viremia was associated with virologic failure (>50 copies/ml) on univariate Cox proportional hazard analysis (hazard ratio 2.08, P = 0.02). However, on multivariate analysis, only ART adherence was associated with risk of virologic failure.
Conclusion: Incomplete ART adherence is associated with higher levels of residual HIV-1 viremia, but detectable residual viremia can be present despite 100% measured ART adherence.
aBrigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
bHôpital Saint Louis, Paris, France
cCenter for Biostatistics in AIDS Research, Harvard School of Public Health
dMassachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
*Jonathan Z. Li and Sebastien Gallien contributed equally to the writing of this article.
Correspondence to Jonathan Li, MD, Division of Infectious Diseases, Brigham and Women's Hospital, 65 Landsdowne Street, Rm 435, Cambridge, MA 02139, USA. Tel: +1 617 768-8381; fax: +1 617 768-8738; e-mail: email@example.com
Received 24 July, 2013
Revised 21 October, 2013
Accepted 21 October, 2013