Use of bilirubin as a marker of adherence to atazanavir-based antiretroviral therapy.

We retrospectively reviewed 134 patients to evaluate atazanavir-related bilirubin elevation as an adherence marker. Using a 2 log reduction or undetectable viral load as a marker for suppression, the median bilirubin increase at first follow-up was 1.3 (0.7-2.2), versus 0.2 (-0.05-0.65) for those not suppressed. An increase in bilirubin of more than 0.4 mg/dl correctly classified 81% of patients as having successful treatment response (sensitivity 87%, specificity 63%), suggesting that bilirubin is a good adherence marker.