Variable virological outcomes according to the center providing antiretroviral therapy within the PharmAdapt clinical...

Differences in virological response between HIV-infected patients at different study centers were analyzed as a substudy of PharmAdapt, a multicenter prospective randomized study to evaluate the utility of therapeutic drug monitoring after a genotypic-based treatment adaptation.

After 12 weeks, the percentage of patients participating in PharmAdapt with HIV RNA < 200 copies/mL ranged from 17% to 69% between centers providing antiretroviral care. In a multivariate analysis, independent factors predictive of viral load <200 HIV RNA copies/mL at Week 12 included: lower baseline viral load, lower nonnucleoside reverse transcriptase inhibitor resistance, lower protease inhibitor resistance, and the center providing antiretroviral therapy. To evaluate the final factor, study sites were divided into two groups based on Week 12 HIV RNA values above or below the median.

Using this definition, observed differences between centers included the use of stavudine, abacavir-, and/or efavirenz-based regimens and use of online expert advice.