Objectives: To assess the characteristics of medication regimen modification and the influence of a commercial genotypic resistance assay on the short-term (3–12 weeks) viral load response (≥ 0.5 log reduction) in HIV-1-infected patients extensively treated with antiretroviral therapy (ART).
Methods: A nested cohort study was performed in two clinics from the HIV Outpatient Study of 96 persons with a HIV-1 viral load of 104 log copies/ml or greater taking at least two antiretroviral medications.
Results: Successful modification was associated with adding at least two new medications [relative risk (RR), 1.5; 95% confidence interval (CI), 1.1–2.2], adding a drug from a previously unused class of agents (RR, 2.0; CI, 1.4–2.9), the initiation of a non-nucleoside reverse transcriptase inhibitor (NNRTI) (RR, 1.7; CI, 1.2–2.4), but not substituting a protease inhibitor or the use of a commercial genotypic resistance assay.
Conclusion: Incorporating a drug from a previously unused class or changing at least two new medications, but, within the confines of this study, not using a commercial genotypic resistance assay, was associated with the successful modification of ART as measured by a reduction in viral load.
From the aEpidemiology Branch, Division of HIV/AIDS Prevention Surveillance and Epidemiology, National Center for HIV, STD, and TB Prevention, and bEpidemic Intelligence Service, Epidemiology Program Office, Centers for Disease Control, Atlanta, GA, USA; cRose Medical Center, Denver, CO, USA; and dNorthwestern University Medical School, Chicago, IL, USA.
*The investigators participating in the HIV Outpatient Study are listed in the Appendix.
This work was presented at the Thirty-sixth Annual Meeting of the Infectious Disease Society of America, November, 1998, Denver, Colorado [abstract 445].
Sponsorship: The HIV Outpatient Study was supported by cooperative agreement UC64/CCU5096889-03 between the Centers for Disease Control and Prevention and the Health Research Network of APACHE Medical Systems, Inc., McLean, VA, USA.
Correspondence to: Paul J. Weidle, PharmD, MPH, Division of HIV/AIDS Prevention, National Center for HIV, STD, and TB Prevention, Centers for Disease Control and Prevention, 1600 Clifton Road, MS E-45, Atlanta, GA 30333, USA. Tel: +1 404 639 6155; fax: +1 404 639 6127; e-mail: email@example.com
Requests for reprints to: National Center for HIV, STD, and TB Prevention, Office of Communications, Centers for Disease Control and Prevention, Mail Stop E-06, Atlanta, GA 30333, USA.
Received: 15 October 1999; accepted: 23 December 1999.