Background: The authors evaluated hematologic changes associated with zidovudine (ZDV) following single-drug substitution from stavudine (D4T) in HIV-infected persons in Uganda.
Methods: From May 2003 through February 2007, the authors evaluated incidence rates (IR) of hematologic abnormalities from quarterly blood draws among adults prescribed highly active antiretroviral therapy (HAART) before and after single-drug substitution of D4T to ZDV.
Results: A total of 1089 adults received D4T-containing HAART (median observation time, 35.9 months), and 290 (27%) had ZDV substituted for D4T. While taking D4T, IR for anemia was 0.35/100 person-months (PMs), leukopenia was 0.29/100 PM, and thrombocytopenia was 0.32/100 PM. While taking ZDV, IR for anemia was 0.44/100 PM, leukopenia was 1.05/100 PM, and thrombocytopenia was 0.30/100 PM.
Conclusions: Patients had a higher incidence of anemia and leukopenia after substitution from D4T to ZDV, but hematologic toxicity was not a major complication in this population. Patients on ZDV-containing HAART regimens are still at risk for anemia and need close monitoring.