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Author Notes:

Corresondence: s.ingle@bristol.ac.uk; Tel: +44-(0)117-928-7297

S.M.I. did statistical analyses and S.M.I. wrote the first draft of the paper, except the discussion which was drafted by H.M.C.

All authors contributed to study design, collection of data, data interpretation, writing the paper and approved the final version.

M.T.M. and S.M.I. had full access to the data and act as guarantors for the paper.

We thank all patients, doctors, cohort pharmacists and study nurses associated with the participating cohort studies.


Research Funding:

This work was supported by the UK Medical Research Council (MRC) [grant number MR/J002380/1] and the UK Department for International Development (DFID) under the MRC/DFID Concordat agreement and is also part of the EDCTP2 programme supported by the European Union.

Jonathan Sterne was supported by NIHR Senior Investigator Award NF-SI-0611-10168.

European data were supplied by COHERE which is supported by the European Union Seventh Framework Programme (FP7/2007–2013) under EuroCoord grant agreement number 260694.

The COHERE study group has received unrestricted funding from Agence Nationale de Recherches sur le SIDA et les Hépatites Virales, France; HIV Monitoring Foundation, the Netherlands; and the Augustinus Foundation, Denmark.

Dr. Lima is supported by a grant the Canadian Institutes of Health Research (CIHR; MOP-125948), by a Scholar Award from the Michael Institute for Health Research and a New Investigator award from CIHR.

Sources of funding of individual cohorts include, for ICONA the Italian Ministry of Health and unrestricted grants from Abbvie, BMS, Gilead, MSD, Janssen and ViiV Italy; for SHCS the Swiss National Science Foundation (grant 33CS30_134277); for HOMER the Pharmacare program of the British Columbia Ministry of Health; for Alberta the Alberta Government; for UW the National Institutes of Health (NIH) [UW Center for AIDS Research (CFAR) (NIH grant P30 AI027757); for UAB, UAB CFAR (NIH grant P30-AI027767); for VACS the National Institute on Alcohol Abuse and Alcoholism (U10-AA13566, U24-AA020794), for HAVACS, the US Department of Veterans Affairs.

Also the Michael Smith Foundation for Health Research, the Canadian Institutes of Health Research, the VHA Office of Research and Development and unrestricted grants from Abbott, Gilead, Tibotec-Upjohn, ViiV Healthcare, MSD, GlaxoSmithKline, Pfizer, Bristol Myers Squibb, Roche and Boehringer-Ingelheim.


  • Science & Technology
  • Life Sciences & Biomedicine
  • Medicine, General & Internal
  • General & Internal Medicine
  • HIV
  • antiretroviral therapy
  • adherence
  • viral failure
  • cohort studies

Identifying Risk of Viral Failure in Treated HIV-Infected Patients Using Different Measures of Adherence: The Antiretroviral Therapy Cohort Collaboration

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Journal Title:

Journal of Clinical Medicine


Volume 7, Number 10


Type of Work:

Article | Final Publisher PDF


Adherence to antiretroviral therapy (ART) is critical for successful treatment of Human Immunodeficiency Virus (HIV), but comparisons across settings are difficult because adherence is measured in different ways. We examined utility of different adherence measures for identification of patients at risk of viral failure (VF). Eight cohorts in the ART Cohort Collaboration contributed data from pharmacy refills or self-report questionnaires collected between 1996 and 2013 (N = 11689). For pharmacy data (N = 7156), we examined associations of percentage adherence during the 1st year of ART with VF (>500 copies/mL) at 1 year. For self-report data (N = 4533), we examined 28-day adherence with VF based on closest viral load measure within 6 months after questionnaire date. Since adherence differed markedly by measurement type, we defined different cut-off points for pharmacy (lower <45%, medium 45⁻99%, higher 100%) and self-report (lower ≤95%, medium 96⁻99%, higher 100%) data. Adjusted odds ratios (ORs) for VF in lower and medium, compared to higher adherence groups, were 23.04 (95% CI: 18.44⁻28.78) and 3.84 (3.36⁻4.39) for pharmacy data. For self-report data, they were 3.19 (2.31⁻4.40) and 1.08 (0.80⁻1.46). Both types of measure were strongly associated with VF. Although adherence measurements over longer time-frames are preferable for prediction, they are less useful for intervention.

Copyright information:

© 2018 by the authors.

This is an Open Access work distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).
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