The impact of adherence to preexposure prophylaxis on the risk of HIV infection among people who inject drugs

Michael Martin, Suphak Vanichseni, Pravan Suntharasamai, Udomsak Sangkum, Philip A. Mock, Manoj Leethochawalit, Sithisat Chiamwongpaet, Marcel E. Curlin, Supawadee Na-Pompet, Anchalee Warapronmongkholkul, Somyot Kittimunkong, Roman J. Gvetadze, Janet M. McNicholl, Lynn A. Paxton, Kachit Choopanya, Sompob Snidvongs Na Ayudhya, Kraichack Kaewnil, Praphan Kitisin, Malinee Kukavejworakit, Pitinan NatrujiroteSaengchai Simakajorn, Wonchat Subhachaturas

Research output: Contribution to journalArticle

43 Scopus citations

Abstract

Objective: To describe participant adherence to daily oral tenofovir in an HIV preexposure prophylaxis (PrEP) trial, examine factors associated with adherence, and assess the impact of adherence on the risk of HIV infection. Design: The Bangkok Tenofovir Study was a randomized, double-blind, placebo-controlled trial conducted among people who inject drugs, 2005-2012. Methods: Participants chose daily visits or monthly visits. Study nurses observed participants swallow study drug and both initialed a diary. We assessed adherence using the diary. We examined adherence by age group and sex and used logistic regression to evaluate demographics and risk behaviors as predictors of adherence and Cox regression to assess the impact of adherence on the risk of HIV infection. Results: A total of 2413 people enrolled and contributed 9665 person-years of follow-up (mean 4.0 years, maximum 6.9 years). The risk of HIV infection decreased as adherence improved, from 48.9% overall to 83.5% for those with at least 97.5% adherence. In multivariable analysis, men were less adherent than women (P = 0.006) and participants 20-29 years old (P < 0.001) and 30-39 years old (P = 0.01) were less adherent than older participants. Other factors associated with poor adherence included incarceration (P = 0.02) and injecting methamphetamine (P = 0.04). Conclusion: In this HIV PrEP trial among people who inject drugs, improved adherence to daily tenofovir was associated with a lower risk of HIV infection. This is consistent with trials among MSM and HIV-discordant heterosexual couples and suggests that HIV PrEP can provide a high level of protection from HIV infection.

Original languageEnglish (US)
Pages (from-to)819-824
Number of pages6
JournalAIDS
Volume29
Issue number7
DOIs
StatePublished - Apr 24 2015

Keywords

  • HIV
  • adherence
  • people who inject drugs
  • preexposure prophylaxis
  • tenofovir

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Infectious Diseases

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    Martin, M., Vanichseni, S., Suntharasamai, P., Sangkum, U., Mock, P. A., Leethochawalit, M., Chiamwongpaet, S., Curlin, M. E., Na-Pompet, S., Warapronmongkholkul, A., Kittimunkong, S., Gvetadze, R. J., McNicholl, J. M., Paxton, L. A., Choopanya, K., Na Ayudhya, S. S., Kaewnil, K., Kitisin, P., Kukavejworakit, M., ... Subhachaturas, W. (2015). The impact of adherence to preexposure prophylaxis on the risk of HIV infection among people who inject drugs. AIDS, 29(7), 819-824. https://doi.org/10.1097/QAD.0000000000000613