The risks associated with low-level viremia vary depending on a person's HIV treatment experience, a U.S. study published in AIDS found. The results attempt to shed new light on a much-debated issue over the clinical relevance of viral load test results that are slightly above 50 copies/mL.
Researchers analyzed data on 2,795 participants (75% male, 50% African American) who were not currently on treatment at baseline and subsequently achieved viral suppression (VL < 50 copies/mL) after initiating or resuming antiretroviral therapy. Low-level viremia (LLV) was defined as > 51 c/mL during 2 subsequent measurements after viral suppression. Blips were defined as > 51 c/mL in a single test.
Overall, half of the study population achieved and maintained an undetectable viral load, while 10% experienced virologic failure (defined as two or more viral load test results over 500 c/mL). At least one blip or LLV was experienced by 29% of participants, with 3% of patients experiencing both:
- 20% had a blip between 51-200 c/mL
- 4% had a blip between 201-500 c/mL
- 5% had LLV between 51-200 c/mL
- 4% had LLV between 201-500 c/mL
Blips were not associated with virologic failure in the study. LLV between 51-200 c/mL roughly doubled the risk of virologic failure, while LLV between 201-500 c/mL increased failure risk approximately fourfold. Antiretroviral experience was correlated with sensitivity to LLV: In treatment-naive people, only the higher level of LLV was associated with virologic failure, while in antiretroviral-experienced people, even the lower level was linked to virologic failure.
The more often viral loads were measured, the less likely virologic failure was to occur among the study population. "This finding suggests that the patient-physician relationship and close clinical monitoring are important to successfully achieving virologic control," study authors concluded.