Prevalence and Clinical Correlates of HIV Viremia
Prevalence and Clinical Correlates of HIV Viremia
Objective: To examine the prevalence and clinical correlates of subsequently measurable viremia in HIV-infected patients who have achieved viral suppression below the limits of quantification (< 50 copies/ml).
Design: Non-randomized dynamic cohort study of ambulatory HIV patients in nine HIV clinics in eight cities.
Patients: Patients had two consecutive HIV-1 RNA levels < 50 copies/ml (minimum, 2 months apart) that were followed by at least two more viral level determinations while remaining on the same antiretroviral therapy (ART) between January 1997 and June 2000 (median 485 days). Transiently viremic patients were defined having a subsequently measurable viremia but again achieved suppression < 50 copies/ml.
Results: Of the 448 patients, 122 (27.2%) had transient viremia, 19 (4.2%) had lasting low-level viremia and 33 (7.4%) had lasting high-level viremia (defined as 50-400 and > 400 copies/ml, respectively). Only 16 (13.1%) of those who had transient viremia later had persistent viremia > 50 copies/ml. The occurrence of transient viremia did not vary with whether the patient was ART-naive or experienced (P = 0.31), or currently taking protease inhibitors or not (P = 0.08). On consistent ART, the median percentage increase in CD4 cell count was statistically different between subgroups of our cohort (Kruskal-Wallis, P = 0.002).
Conclusions: Transiently detectable viremia, usually 50-400 copies/ml, was frequent among patients who had two consecutive HIV-1 RNA levels below the limits of quantification. In this analysis, such viremia did not appear to affect the risk of developing lasting viremia. Caution is warranted before considering a regimen as 'failing' and changing medications.
Several studies have suggested that achieving plasma HIV-1 RNA levels below the limits of detection (as low as < 20 copies/ml) within several weeks of initiating a new regimen is predictive of long-term success of highly active antiretroviral therapy (HAART). However, many HIV-infected patients who achieve viral suppression below the limits of quantification while on HAART have measurable, but transient, viremia subsequently. It is still unclear, however, whether such transiently detectable viremia is detrimental to longer-term virologic control. On one hand, measurable viremia may be a harbinger of drug resistance and treatment failure. It has been suggested that low-levels of viremia may alter viral dynamics and change the slope of the decay curve of latently infected cells. On the other hand, transiently measurable viremia may simply reflect variability in the assay, such as that resulting from specimen processing, or could be caused by extraneous factors, such as immunization or intercurrent illness. This study further characterizes this phenomenon in the setting of clinical practice including patients both naive and experienced to antiretroviral drugs and on both protease inhibitor (PI)-based and non-PI-based regimens in terms of long-term virologic and immunologic outcomes.
Objective: To examine the prevalence and clinical correlates of subsequently measurable viremia in HIV-infected patients who have achieved viral suppression below the limits of quantification (< 50 copies/ml).
Design: Non-randomized dynamic cohort study of ambulatory HIV patients in nine HIV clinics in eight cities.
Patients: Patients had two consecutive HIV-1 RNA levels < 50 copies/ml (minimum, 2 months apart) that were followed by at least two more viral level determinations while remaining on the same antiretroviral therapy (ART) between January 1997 and June 2000 (median 485 days). Transiently viremic patients were defined having a subsequently measurable viremia but again achieved suppression < 50 copies/ml.
Results: Of the 448 patients, 122 (27.2%) had transient viremia, 19 (4.2%) had lasting low-level viremia and 33 (7.4%) had lasting high-level viremia (defined as 50-400 and > 400 copies/ml, respectively). Only 16 (13.1%) of those who had transient viremia later had persistent viremia > 50 copies/ml. The occurrence of transient viremia did not vary with whether the patient was ART-naive or experienced (P = 0.31), or currently taking protease inhibitors or not (P = 0.08). On consistent ART, the median percentage increase in CD4 cell count was statistically different between subgroups of our cohort (Kruskal-Wallis, P = 0.002).
Conclusions: Transiently detectable viremia, usually 50-400 copies/ml, was frequent among patients who had two consecutive HIV-1 RNA levels below the limits of quantification. In this analysis, such viremia did not appear to affect the risk of developing lasting viremia. Caution is warranted before considering a regimen as 'failing' and changing medications.
Several studies have suggested that achieving plasma HIV-1 RNA levels below the limits of detection (as low as < 20 copies/ml) within several weeks of initiating a new regimen is predictive of long-term success of highly active antiretroviral therapy (HAART). However, many HIV-infected patients who achieve viral suppression below the limits of quantification while on HAART have measurable, but transient, viremia subsequently. It is still unclear, however, whether such transiently detectable viremia is detrimental to longer-term virologic control. On one hand, measurable viremia may be a harbinger of drug resistance and treatment failure. It has been suggested that low-levels of viremia may alter viral dynamics and change the slope of the decay curve of latently infected cells. On the other hand, transiently measurable viremia may simply reflect variability in the assay, such as that resulting from specimen processing, or could be caused by extraneous factors, such as immunization or intercurrent illness. This study further characterizes this phenomenon in the setting of clinical practice including patients both naive and experienced to antiretroviral drugs and on both protease inhibitor (PI)-based and non-PI-based regimens in terms of long-term virologic and immunologic outcomes.
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