title: The relation between efavirenz versus nevirapine and virologic failure in Johannesburg, South Africa.
abstract: BACKGROUND
  Previous research has raised concerns that patients given nevirapine (NVP)-based regimens experience more virologic failure than patients given efavirenz (EFV)-based regimens. We investigated this hypothesis in a cohort of HIV-positive patients at a large HIV treatment clinic in South Africa.
  
  
  METHODS
  All antiretroviral therapy (ART)-naïve non-pregnant patients, ≥ 18 years old, without tuberculosis, who initiated treatment with either NVP or EFV from April 2004 to August 2011 at the Themba Lethu Clinic in Johannesburg, South Africa, were included. Log-binomial regression and modified Poisson regression were used to estimate risk ratios (RR) with 95% confidence intervals (CI) for predictors of virologic failure, virologic suppression, and loss to follow-up (LTF), whereas a Cox proportional hazards model was used to estimate the risk of death, all within one year.
  
  
  RESULTS
  Of 12,840 included patients, 62.0% were female and the median baseline CD4 count was 98 cells/mm(3) (36-169). Of these patients, 93.2% initiated an EFV-based regimen. After adjusting for baseline characteristics, no difference in death (adjusted Hazards Ratio (aHR): 0.92; 95% CI: 0.68-1.25), LTF (adjusted Risk Ratio (aRR): 1.00; 95% CI: 0.79-1.25), nor suppression (aRR: 0.98; 95% CI: 0.95-1.00) at one year was found between regimens. Among patients with ≥ 1 viral load ≥ 4 months after ART initiation, 4% (n=350) experienced virologic failure within 12 months of initiation. Patients initiating NVP-based regimens were 60% more likely to fail than patients initiating EFV-based regimens (aRR: 1.58; 95% CI: 1.13-2.22).
  
  
  CONCLUSIONS
  In this cohort, patients initiating NVP-based regimens experienced more virologic failure than patients initiating EFV-based regimens. Future guidelines should consider the implications of different efficacy profiles when making recommendations for which drugs to prioritize.
authors.affiliation: Health Economics and Epidemiology Research Office, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; kshearer@heroza.org.
authors.forename: Kate
authors.initials: K
authors.lastname: Shearer
authors.affiliation: Center for Global Health & Development, Boston University, Boston, MA, USA.
authors.forename: Alana T
authors.initials: AT
authors.lastname: Brennan
authors.affiliation: Health Economics and Epidemiology Research Office, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: Mhairi
authors.initials: M
authors.lastname: Maskew
authors.affiliation: Health Economics and Epidemiology Research Office, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Long
authors.affiliation: Right to Care, Johannesburg, South Africa.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Berhanu
authors.affiliation: Health Economics and Epidemiology Research Office, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Center for Global Health & Development, Boston University, Boston, MA, USA; Right to Care, Johannesburg, South Africa; Clinical HIV Research Unit, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: Ian
authors.initials: I
authors.lastname: Sanne
authors.affiliation: Health Economics and Epidemiology Research Office, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Center for Global Health & Development, Boston University, Boston, MA, USA; Department of Epidemiology, School of Public Health, Boston University, Boston, MA, USA.
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Fox
mesh_terms: D000293:Adolescent; D000328:Adult; D000480:Alkynes; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D048588:Benzoxazines / Q000627:therapeutic use*; D003521:Cyclopropanes; D005260:Female; D005500:Follow-Up Studies; D006678:HIV / Q000302:isolation & purification; D015658:HIV Infections / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019829:Nevirapine / Q000627:therapeutic use*; D013019:South Africa; D017211:Treatment Failure; D014766:Viremia; D055815:Young Adult
chemical_list: D000480:Alkynes; D019380:Anti-HIV Agents; D048588:Benzoxazines; D003521:Cyclopropanes; D019829:Nevirapine; C098320:efavirenz
keywords: efavirenz; loss to follow-up; mortality; nevirapine; resource-limited settings; viral suppression; virologic failure