Value of Patient Self-Report and Plasma Human Immunodeficiency Virus Protease Inhibitor Level as Markers of Adherence to Antiretroviral Therapy: Relationship to Virologic Response [Duong, M., et al. CID 2001;33:386] This is a report from Paris concerning 149 patients who were evaluated for adherence according to virologic response using three methods of assessment: 1) patient-reported questionnaire; 2) plasma PI levels using 0.5 as the threshold to define adherence for the measured concentration/expected PI concentration according to pharmacokinetic profiles with the last dose, and 3) MCV to assess adherence to AZT and d4T. Virologic response was defined as a decrease in VL exceeding 2 log₁₀/ml. Results indicated that 112 had a virologic response, and 122 had adequate trough PI levels. There was a significant correlation between PI levels and virologic outcome, and this was the most significant predictor of virologic response (p = 0.0003). Self-reported adherence (p = 0.01) and macrocytosis for recipients for AZT or d4T (p = 0.05) were also independently associated with virologic response.
Comment: This is a potentially important paper at a time when adherence is considered the most critical component of antiretroviral therapy, and various methods to measure adherence are being scrutinized carefully. This is one of the first studies to show the potential use of plasma PI levels as an objective measure of adherence. Macrocytosis is a relatively new observation for recipients for d4T and has not been frequently used to monitor adherence to AZT or d4T despite its simplicity. As before, responses to the patient questionnaire appeared to correlate with lab results, but not as well as other objective measurements.
posted 8/10/2001

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