CD4 Lymphocyte Percentage Predicts Disease Progression in HIV-Infected Patients Initiating Highly Active Antiretroviral Therapy with CD4 Lymphocyte Counts >350 Lymphocytes/mm3

Background. The optimal timing of highly active antiretroviral therapy (HAART) in human immunodeficiency virus (HIV)-infected patients with ≥200 absolute CD4 lymphocytes/mm 3 is unknown. CD4 lymphocyte percentage could add prognostic information. Methods. Persons who initiated HAART between 1 January 1998 and 1 January 2003, received ≥30 days of therapy, and had baseline CD4 lymphocyte data available were included in the study. The log-rank test for time to event and Cox proportional hazards models were used to determine predictors of a new acquired immunodeficiency syndrome-defining illness or death. Results. A total of 788 patients met the inclusion criteria. At baseline, subjects had a median of 225 CD4 lymphocytes/mm 3 and 17% CD4 lymphocytes. Subjects with 350 absolute CD4 lymphocytes/mm 3 at baseline (P =.03). CD4 lymphocyte percentage 350 CD4 lymphocytes/mm 3 . This information may help identify persons who will derive the greatest benefit from initiation of HAART.