Short communication: use of serum bilirubin levels as surrogate marker of early virological response to atazanavir-based antiretroviral therapy.

Given that atazanavir (ATV) increases bilirubin in an exposure-dependent manner, we tested whether bilirubin levels could be used as a surrogate of virological response to ATV-based regimens in 182 patients. Bilirubin increases of ≥0.7 mg/dl were independently associated with early virological response with an odds ratio of 5.2 (95% confidence interval 2.2-11.9). Total bilirubin, a nonexpensive, simple, and widely available parameter, might be used as a surrogate of virological response to ATV-based regimens, especially in areas with limited resources where HIV-RNA testing is not available.