HIV: is 95% adherence essential for viral suppression? Not for single-pill regimens

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  • Reaching the 95% or more adherence threshold is less important for patients with HIV receiving single-tablet regimens (STRs) than for multiple-tablet regimens (MTRs).

Why this matters                                                                             

  • Poor adherence is associated with antiretroviral therapy (ART) resistance, progression to AIDS, and transmission of the virus.

Key results

  • Viral suppression was statistically similar between STR participants with 80%-94% adherence.
  • STR participants were 2.57-fold more likely to be virally suppressed with >95% adherences vs <80% adherence.
  • OR was 6.89 for MTR participants with >95% adherence vs 85%-89% adherence.
  • MTR participants were 7.61-fold as likely to be virally suppressed at >95% adherence vs 80%-84% adherence.
  • MTR participants were more than 10-fold as likely to be virally suppressed if they were >95% adherent vs <80% adherent.

Study design

  • Retrospective cohort study.
  • 1536 patients receiving STR or MTR ART were included.
  • Funding: None.


  • Only 477 participants received STR ART, limiting the power of these findings.
  • Adherence was measured by prescriptions filled.
  • Primary patient population was middle-aged and African American.