The relation between efavirenz versus nevirapine and virologic failure in Johannesburg, South Africa

Kate Shearer, Alana T. Brennan, Mhairi Maskew, Lawrence Long, Rebecca Berhanu, Ian Sanne, Matthew P. Fox

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Introduction: 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/mm3 (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.

Original languageEnglish (US)
Article number19065
JournalJournal of the International AIDS Society
StatePublished - Oct 22 2014
Externally publishedYes


  • Efavirenz
  • Loss to follow-up
  • Mortality
  • Nevirapine
  • Resource-limited settings
  • Viral suppression
  • Virologic failure

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Infectious Diseases


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