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Low-level viremia increased risk for virologic failure
Patients with HIV who have persistent, low-level viremia are at increased risk for virologic failure, according to data published in Clinical Infectious Diseases.
The risk for virologic failure was increased even when the viral load was as low as 50 copies/mL to 199 copies/mL for only 6 months.
“More research is needed to confirm our findings because the specific subgroup of patients with a viral load of 50 copies/mL to 200 copies/mL is a controversial group,” Claudie Laprise, PhD, a postdoctoral fellow in the division of cancer epidemiology at McGill University, told Infectious Disease News. “Low-level viremia should be considered by physicians in the clinical portrait of the patient as a possible risk factor for subsequent virologic failure.
Laprise, who was a doctoral student at the University of Montreal during the study, and colleagues evaluated a cohort of 1,860 patients who had at least one viral load measurement and received antiretroviral therapy for at least 12 months. The patients were stratified according to viral load status: undetectable viral load, viral load of 50 copies/mL to 199 copies/mL, viral load of 200 copies/mL to 499 copies/mL and viral load of 500 copies/mL to 999 copies/mL. The researchers analyzed outcome according to viral load for 6, 9 and 12 months. The patients were followed until virologic failure.
The 1-year cumulative incidence of virologic failure among patients with undetectable HIV viral load was 6.6% (95% CI, 5.3-8.2). Among those with a low-level viremia of 50 copies/mL to 199 copies/mL for 6 months, the incidence was 22.7% (95% CI, 14.9-33.6). For patients with viremia of 200 copies/mL to 499 copies/mL for 6 months, the incidence of virologic failure was 24.2%. The incidence of virologic failure was 58.9% (95% CI, 43.1-75.2) for patients with a viremia of 500 copies/mL to 999 copies/mL for 6 months. The numbers were similar for patients with these viral loads at 9 and 12 months.
“We know there are a lot of clinical factors to consider before changing ART, and persistent low-level viremia, even as low as 50 copies/mL to 200 copies/mL, should also be considered as part of the clinical decision to change ART or continue to observe viral load,” Laprise said.
Laprise said that one limitation to the study that should be addressed is that the reasons for low-level viremia were not explored. Possibilities for this, which include lack of treatment adherence or drug-resistance, should be explored.
Claudie Laprise, PhD, can be reached at: Claudie.laprise@mcgill.ca.
Disclosure: See the study for a full list of researchers’ financial disclosures.