Objective: Efavirenz (EFV) along with two nucleoside reverse transcriptase inhibitors (NRTIs) is a recommended initial antiretroviral regimen. Understanding characteristics related to EFV success is clinically useful.
Design: Data from 2220 antiretroviral-naive participants randomized to EFV and two to three NRTIs in four ACTG trials as well as a long-term cohort were analysed.
Methods: Logistic regression, using inverse probability of censoring weighting to address selective-follow-up bias, was used to identify factors associated with EFV success (no treatment interruptions of >30 days, HIV RNA < 200 copies/ml) 1 year post initiation and at years 2–5 if successful at year 1.
Results: Pretreatment characteristics were median age 38 years, 82% male, 40% white, 10% history of IDU (HxIDU), median CD4+ T-lymphocyte 227 cells/μl and 33% HIV RNA more than 100 000 copies/ml. In a multivariable model, factors associated with year 1 EFV success were race [white odds ratio (OR) 1.5; P < 0.001; Hispanic OR 1.5; P = 0.003 vs. black], no pretreatment sign/symptom grade 3 or higher (OR 1.7; P = 0.008) and no HxIDU (OR 1.7; P = 0.001). Predictors of EFV success at years 2–5 were no HxIDU (years 2–5; ORs 1.9–2.2); self-reported complete (4 days prior to study visit) adherence during year 1 (years 2–4; ORs 1.6–1.9); fewer missed visits during year 1 (years 2, 4, 5; ORs 0.92–0.98/1% increase); HIV RNA less than 50 copies/ml at year 1 (years 2, 3; ORs 1.9–2.2); and older age (>50 vs. ≤30 years) (years 2–4: ORs 2.3–3.7).
Conclusion: Characteristics predictive of EFV success in the short-term and longer term differed except for HxIDU. Behaviours occurring during year 1 were associated with EFV success over 5 years.
aCenter for Biostatistics in AIDS Research, Harvard School of Public Health, Boston, Massachusetts
bFred Hutchinson Cancer Research Center, Seattle, Washington
cUniversity of Washington, Seattle, Washington
dNorthwestern University Feinberg School of Medicine, Division of Infectious Diseases, Chicago, Illinois
eBirmingham Veterans Affairs Medical Center and University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, USA.
Correspondence to Marlene Smurzynski, PhD, Department of Epidemiology and Biostatistics, School of Public Health and Health Services, George Washington University, 2100-W Pennsylvania Avenue NW, 8th floor Washington, DC 20037, USA. Tel: +1 202 578 6862; e-mail: firstname.lastname@example.org
Received 6 November, 2012
Revised 15 March, 2013
Accepted 18 March, 2013