To determine if differences in short-term virologic failure among commonly used ART regimens translate to differences in clinical events in antiretroviral-naïve patients initiating ART.
Observational cohort study of patients initiating ART between January 2000 and December 2005.
The Antiretroviral Therapy Cohort Collaboration (ART-CC) is a collaboration of 15 HIV cohort studies from Canada, Europe, and the United States.
A total of 13,546 antiretroviral-naïve HIV-positive patients initiating ART with efavirenz (EFV), nevirapine (NVP), lopinavir/ritonavir (LPV/r), nelfinavir (NFV), or abacavir (ABC) as third drugs in combination with a zidovudine and lamivudine NRTI backbone.
Main outcome measures
Short-term (24-week) virologic failure (>500 copies/mL) and clinical events within 2 years of ART initiation (incident AIDS-defining event, death, and a composite measure of these two outcomes).
Compared with EFV as initial third drug, short-term virologic failure was more common with all other third drugs evaluated; NVP (adjusted odds ratio=1.87, 95%CI=1.58,2.22), LPV/r (1.32, 95%CI=1.12–1.57), NFV (3.20, 95%CI=2.74,3.74), and ABC (2.13, 95%CI=1.82,2.50). However, the rate of clinical events within 2 years of ART initiation appeared higher only with NVP (adjusted hazard ratio for composite outcome measure 1.27, 95%CI=1.04,1.56) and ABC (1.22, 95%CI=1.00,1.48).
Among antiretroviral-naïve patients initiating therapy, between-ART regimen differences in short-term virologic failure do not necessarily translate to differences in clinical outcomes. Our results should be interpreted with caution because of the possibility of residual confounding by indication.