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When to Monitor CD4 Cell Count and HIV RNA to Reduce Mortality and AIDS-Defining Illness in Virologically Suppressed HIV-Positive Persons on Antiretroviral Therapy in High-Income Countries: A Prospective Observational Study.

  • Author(s): Caniglia, Ellen C
  • Sabin, Caroline
  • Robins, James M
  • Logan, Roger
  • Cain, Lauren E
  • Abgrall, Sophie
  • Mugavero, Michael J
  • Hernandez-Diaz, Sonia
  • Meyer, Laurence
  • Seng, Remonie
  • Drozd, Daniel R
  • Seage, George R
  • Bonnet, Fabrice
  • Dabis, Francois
  • Moore, Richard R
  • Reiss, Peter
  • van Sighem, Ard
  • Mathews, William C
  • Del Amo, Julia
  • Moreno, Santiago
  • Deeks, Steven G
  • Muga, Roberto
  • Boswell, Stephen L
  • Ferrer, Elena
  • Eron, Joseph J
  • Napravnik, Sonia
  • Jose, Sophie
  • Phillips, Andrew
  • Olson, Ashley
  • Justice, Amy C
  • Tate, Janet P
  • Bucher, Heiner C
  • Egger, Matthias
  • Touloumi, Giota
  • Sterne, Jonathan A
  • Costagliola, Dominique
  • Saag, Michael
  • Hernán, Miguel A
  • Center for AIDS Research Network of Integrated Clinical Systems and the HIV-CAUSAL Collaboration
  • et al.


To illustrate an approach to compare CD4 cell count and HIV-RNA monitoring strategies in HIV-positive individuals on antiretroviral therapy (ART).


Prospective studies of HIV-positive individuals in Europe and the USA in the HIV-CAUSAL Collaboration and The Center for AIDS Research Network of Integrated Clinical Systems.


Antiretroviral-naive individuals who initiated ART and became virologically suppressed within 12 months were followed from the date of suppression. We compared 3 CD4 cell count and HIV-RNA monitoring strategies: once every (1) 3 ± 1 months, (2) 6 ± 1 months, and (3) 9-12 ± 1 months. We used inverse-probability weighted models to compare these strategies with respect to clinical, immunologic, and virologic outcomes.


In 39,029 eligible individuals, there were 265 deaths and 690 AIDS-defining illnesses or deaths. Compared with the 3-month strategy, the mortality hazard ratios (95% CIs) were 0.86 (0.42 to 1.78) for the 6 months and 0.82 (0.46 to 1.47) for the 9-12 month strategy. The respective 18-month risk ratios (95% CIs) of virologic failure (RNA >200) were 0.74 (0.46 to 1.19) and 2.35 (1.56 to 3.54) and 18-month mean CD4 differences (95% CIs) were -5.3 (-18.6 to 7.9) and -31.7 (-52.0 to -11.3). The estimates for the 2-year risk of AIDS-defining illness or death were similar across strategies.


Our findings suggest that monitoring frequency of virologically suppressed individuals can be decreased from every 3 months to every 6, 9, or 12 months with respect to clinical outcomes. Because effects of different monitoring strategies could take years to materialize, longer follow-up is needed to fully evaluate this question.

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