Natural History of Patients with Low-level HIV Viremia on Antiretroviral Therapy
 
Ultrasensitive assays for HIV RNA have identified a significant number of patients with persistent low-level viremia despite antiretroviral therapy. The clinical implications of maintaining antiretroviral therapy during low-level HIV viremia remain unclear.

The primary objective of this study was to determine the rate and risk factors for virological increase in subjects with low-level HIV viremia who did not change antiretroviral therapy.

Between July 1998 and February 2002, researchers at the University of Pennsylvania School of Medicine in Philadelphia retrospectively observed 79 HIV-infected adults with low-level HIV viremia (between 50 and 500 copies per milliliter) who had been on a stable antiretroviral regimen for at least 3 months and continued that regimen for at least 3 more months.

Virologic increase, defined as HIV RNA levels greater than 1000 copies per milliliter, was observed in 29 of the 79 (37%) subjects.

The CD4 cell counts decreased by a median of 1.8 cells/mm(3) per month in this group but increased by a median of 0.5 cells/mm3 per month in the 50 subjects who did not experience virologic increase.

A Kaplan-Meier estimate showed that at 3 years of follow-up, approximately 40% of the observed cohort had not experienced virologic increase.

There was a higher rate of virologic increase per log increase in HIV viral load at entry into the cohort. Subjects of white race were also more likely to experience virological increase.

In conclusion, the authors note, “Maintenance of antiretroviral therapy despite low-level HIV viremia provided sustained immunological benefit over a 2-year period in approximately two thirds of our cohort. Higher initial HIV RNA levels and white race were predictors for virologic increase.”

Division of Infectious Diseases, Department of Internal Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.

12/06/04

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