Adherence to protease inhibitors, HIV-1 viral load, and development of drug resistance in an indigent population

David R. Bangsberg, Frederick M. Hecht, Edwin D. Charlebois, Andrew R. Zolopa, Mark Holodniy, Lewis Sheiner, Joshua D. Bamberger, Margaret A. Chesney, Andrew Moss

Research output: Contribution to journalArticlepeer-review

875 Scopus citations


Objective: To examine the relationship between adherence, viral suppression and antiretroviral resistance in HIV-infected homeless and marginally housed people on protease inhibitor (PI) therapy. Design and setting: A cross-sectional analysis of subjects in an observational prospective cohort systematically sampled from free meal lines, homeless shelters and low-income, single-room occupancy (SRO) hotels. Participants: Thirty-four HIV-infected people with a median of 12 months of PI therapy. Main outcomes: Adherence measured by periodic unannounced pill counts, electronic medication monitoring, and self-report; HIV RNA viral load; and HIV-1 genotypic changes associated with drug resistance. Results: Median adherence was 89, 73, and 67% by self-report, pill count, and electronic medication monitor, respectively. Thirty-eight per cent of the population had over 90% adherence by pill count. Depending on the measure, adherence explained 36-65% of the variation in concurrent HIV RNA levels. The three adherence measures were closely related. Of 20 genotyped patients who received a new reverse transcriptase inhibitor (RTI) when starting a PI, three had primary protease gene substitutions. Of 12 genotyped patients who received a PI without a new RTI, six had primary protease gene substitutions (P < 0.03). Conclusion: A substantial proportion of homeless and marginally housed individuals had good adherence to PI therapy. A strong relationship was found between independent methods of measuring adherence and concurrent viral suppression. PI resistance was more closely related to the failure to change RTI when starting a PI than to the level of adherence. (C) 2000 Lippincott Williams and Wilkins.

Original languageEnglish (US)
Pages (from-to)357-366
Number of pages10
Issue number4
StatePublished - 2000
Externally publishedYes


  • Access to therapy
  • Adherence
  • HIV
  • Highly active antiretroviral therapy
  • Homeless
  • Injection drug use
  • Protease inhibitor
  • Resistance
  • Viral load

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Infectious Diseases


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