Immunologic, virologic, and clinical consequences of episodes of transient viremia during suppressive combination antiretroviral therapy.

OBJECTIVE

To investigate immunologic, virologic, and clinical consequences of episodes of transient viremia in patients with sustained virologic suppression.

METHODS

From the AIDS Therapy Evaluation Project, Netherlands cohort, 4447 previously therapy-naive patients were selected who were on continuous combination antiretroviral therapy and had initial success (2 consecutive HIV RNA measurements <50 copies/mL). During episodes of viral suppression (RNA <50 copies/mL), low-level viremia (RNA 50 to 1000 copies/mL), or high-level viremia (RNA >1000 copies/mL) after initial success, the occurrence of therapy changes, drug resistance, and clinical events was assessed.

RESULTS

During 11,187 person-years of follow-up, 1281 (28.8%) patients had at least 1 RNA measurement >50 copies/mL. Among 8069 episodes, there were 5989 (74.2%) episodes of suppression, 1711 (21.2%) episodes of low-level viremia, and 369 (4.6%) episodes of high-level viremia. Most episodes of low-level viremia consisted of < or =2 RNA measurements (93.7%), were without clinical events or therapy changes (79.6%), and were without changes in CD4 cell counts. Therapy changes (52.3% of episodes) and resistance (23.3%) were frequently observed during high-level viremia.

CONCLUSIONS

Episodes of low-level viremia are frequent and short lasting, and the low proportion of episodes with clinical events suggests that leaving therapy unchanged is a clinically acceptable strategy. In contrast, high-level viremia is associated with resistance and is often followed by therapy changes.