Efficacy of and adherence to highly active antiretroviral therapy in children infected with human immunodeficiency virus type 1

BACKGROUND: Clinical trials in adults have demonstrated the efficacy of highly active antiretroviral therapy (HAART) to suppress replication of HIV-1 to nondetectable levels, but lower success rates have been observed in practice. We sought to determine the efficacy of HAART in our population of HIV-1-infected children and to identify determinants of efficacy, especially the role of adherence to prescribed antiretrovirals. METHODS: The viral load and CD4+ T cell responses of 72 children with perinatally acquired HIV-1 treated with HAART including a protease inhibitor for at least 90 days were examined retrospectively in relation to adherence, as measured by pharmacy records for the first 180 days of HAART. RESULTS: Patients were defined as adherent if > or =75% of protease inhibitors and > or =75% of all antiretroviral prescriptions were filled. Of the 42 patients (58%) who were adherent, nondetectable viral loads were achieved and maintained in 22 (52%). A Kaplan-Meier plot showed a drop-off in patients maintaining a nondetectable viral load after 200 days. Higher initial viral load was the only pretreatment factor that identified adherent patients at risk for treatment failure. Only 3 (10%) nonadherent patients maintained a viral load of <400 copies/ml. The adherent group had a prompt and sustained increase in CD4+ T cell counts. CONCLUSIONS: HAART can achieve control of viral replication in HIV-1-infected children who adhere to therapy. However, treatment failure is likely unless there is a high level of adherence. Nonadherence to therapy is common and might be the major impediment to successful treatment of children infected with HIV-1.