Impact of Low-Level Viraemia on Virological Failure in HIV-1-Infected Patients with Stable Antiretroviral Treatment

BACKGROUND: Low-level viraemia (LLV) occurs in 20-40% of patients achieving viral suppression with antiretroviral therapy (ART). The risk of virological failure (VF: confirmed HIV RNA >200 copies/ml) in these patients is still a matter of debate. METHODS: This is a prospective cohort study in HIV-infected adults attending the HIV clinic of a tertiary care hospital in Spain. Patients with HIV RNA 200 copies/ml (HR 59.6; 95% CI 15.7, 227), ritonavir-boosted protease inhibtor (PI/r)-based dual therapy (HR 10.2; 95% CI 2.1, 49.8) and PI/r monotherapy (HR 7.9; 95% CI 1.4, 43.3) were associated with VF. Persistent LLV, defined as HIV RNA 200 copies/ml was the strongest predictor of VF. Over half of patients with persistent viraemia <200 copies/ml showed VF.