Effect of maintaining highly active antiretroviral therapy on AIDS events among patients with late-stage HIV infection and inadequate response to therapy

Abstract

Background: We evaluated the effect of maintaining highly active antiretroviral therapy (HAART) on the development of new acquired immunodeficiency syndrome (AIDS)-related events in patients with late-stage human immunodeficiency virus (HIV) infection who had suboptimal CD4+ cell count and viral load responses to HIV therapy.

Methods: In patients with pretreatment CD4+ cell counts of <200 cells/mm3, incidence rates of new AIDS-related events occurring during HIV treatment were calculated during period 1 (pre-HAART era, 1990-1995; 88 patients) and period 2 (HAART era, 1996-2004; 214 patients) according to CD4+ cell count responses while receiving treatment. Cox multivariate model was used to compare rates of AIDS-related events from period 2 with those from period 1 according to specific CD4+ cell count response categories and rates of AIDS-related events for various viral load ranges within CD4+ cell count categories during period 2.

Results: For period 2 patients with CD4+ cell counts <50 cells/mm3 and viral loads >100,000 copies/mL, the rate of AIDS-related events (39.3 events per 100 person-years) was significantly lower than that for period 1 patients with CD4+ cell counts <50 cells/mm3 (76.4 events per 100 person-years; P=.02). This held true for patients with CD4+ cell counts <100 cells/mm3; there were also significantly fewer AIDS-related events in period 2 (18 events per 100 person-years) than in period 1 (65.2 events per 100 person-years; P=.001), including those events occurring among period 2 patients with viral loads >100,000 copies/mL (29.5 events per 100 person-years; P=.01). Similarly, for patients with CD4+ cell counts of 100-200 cells/mm3, there were fewer AIDS-related events in period 2 (7.8 events per 100 person-years) than in period 1 (34.5 events per 100 person-years; P=.001); even for patients in period 2 with viral loads >100,000 copies/mL (15.4 events per 100 person-years; P=.04).

Conclusions: Our data suggest that, even among patients with late-stage HIV infection and inadequate CD4+ cell count and viral load responses to HIV therapy, maintaining HAART may reduce the incidence of AIDS-related events.