Switching to second-line antiretroviral therapy in resource-limited settings: comparison of programmes with and without viral load monitoring

AIDS. 2009 Sep 10;23(14):1867-74. doi: 10.1097/QAD.0b013e32832e05b2.


Background: In high-income countries, viral load is routinely measured to detect failure of antiretroviral therapy (ART) and guide switching to second-line ART. Viral load monitoring is not generally available in resource-limited settings. We examined switching from nonnucleoside reverse transcriptase inhibitor (NNRTI)-based first-line regimens to protease inhibitor-based regimens in Africa, South America and Asia.

Design and methods: Multicohort study of 17 ART programmes. All sites monitored CD4 cell count and had access to second-line ART and 10 sites monitored viral load. We compared times to switching, CD4 cell counts at switching and obtained adjusted hazard ratios for switching (aHRs) with 95% confidence intervals (CIs) from random-effects Weibull models.

Results: A total of 20 113 patients, including 6369 (31.7%) patients from 10 programmes with access to viral load monitoring, were analysed; 576 patients (2.9%) switched. Low CD4 cell counts at ART initiation were associated with switching in all programmes. Median time to switching was 16.3 months [interquartile range (IQR) 10.1-26.6] in programmes with viral load monitoring and 21.8 months (IQR 14.0-21.8) in programmes without viral load monitoring (P < 0.001). Median CD4 cell counts at switching were 161 cells/microl (IQR 77-265) in programmes with viral load monitoring and 102 cells/microl (44-181) in programmes without viral load monitoring (P < 0.001). Switching was more common in programmes with viral load monitoring during months 7-18 after starting ART (aHR 1.38; 95% CI 0.97-1.98), similar during months 19-30 (aHR 0.97; 95% CI 0.58-1.60) and less common during months 31-42 (aHR 0.29; 95% CI 0.11-0.79).

Conclusion: In resource-limited settings, switching to second-line regimens tends to occur earlier and at higher CD4 cell counts in ART programmes with viral load monitoring compared with programmes without viral load monitoring.

Publication types

  • Multicenter Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Anti-HIV Agents / therapeutic use
  • Antiretroviral Therapy, Highly Active / adverse effects
  • Antiretroviral Therapy, Highly Active / methods*
  • CD4 Lymphocyte Count
  • Developing Countries
  • Drug Monitoring / methods
  • Female
  • HIV Infections / drug therapy*
  • HIV Infections / immunology
  • HIV Infections / virology
  • HIV Protease Inhibitors / therapeutic use
  • HIV-1 / isolation & purification*
  • Humans
  • Male
  • Medically Underserved Area*
  • Middle Aged
  • Reverse Transcriptase Inhibitors / therapeutic use
  • Time Factors
  • Treatment Failure
  • Viral Load*
  • Young Adult


  • Anti-HIV Agents
  • HIV Protease Inhibitors
  • Reverse Transcriptase Inhibitors