Uric acid and didanosine compliance in AIDS clinical trials: an analysis of AIDS Clinical Trials Group protocols 116A and 116B/117

Measuring uric acid levels in the blood of HIV patients taking the antiretroviral drug didanosine (ddI) is an effective and inexpensive way to assess patient compliance in clinical trials. Two AIDS Clinical Trial Group (ACTG) patient cohorts consisting of 617 and 913 mostly male patients were compared. The first group had received 16 or fewer weeks of zidovudine (commonly known as AZT) therapy, and the second group had received 16 or more weeks of AZT therapy. Over 70% of patients taking ddI with and without a history of taking AZT were correctly identified by testing for serum uric acid levels. Serum uric acid rises with AZT use. Accuracy of the test varied somewhat by daily dose of ddI. The test is not considered sensitive enough to detect short-term deviations from drug protocol rules, but it can establish longer-term trends of drug compliance.