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The risk of virologic failure decreases with duration of HIV suppression, at greater than 50% adherence to antiretroviral therapy.

Rosenblum M, Deeks SG, van der Laan M, Bangsberg DR - PLoS ONE (2009)

Bottom Line: Eligible participants were identified from the REACH cohort of marginally housed HIV infected adults in San Francisco.A total of 221 subjects were studied (median age 44.1 years; median CD4+ T cell nadir 206 cells/mm(3)).Most subjects were taking the following types of antiretroviral regimens: non-nucleoside reverse transcriptase inhibitor based (37%), ritonavir boosted protease inhibitor based (28%), or unboosted protease inhibitor based (25%).

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, University of California San Francisco, San Francisco, California, United States of America.

ABSTRACT

Background: We hypothesized that the percent adherence to antiretroviral therapy necessary to maintain HIV suppression would decrease with longer duration of viral suppression.

Methodology: Eligible participants were identified from the REACH cohort of marginally housed HIV infected adults in San Francisco. Adherence to antiretroviral therapy was measured through pill counts obtained at unannounced visits by research staff to each participant's usual place of residence. Marginal structural models and targeted maximum likelihood estimation methodologies were used to determine the effect of adherence to antiretroviral therapy on the probability of virologic failure during early and late viral suppression.

Principal findings: A total of 221 subjects were studied (median age 44.1 years; median CD4+ T cell nadir 206 cells/mm(3)). Most subjects were taking the following types of antiretroviral regimens: non-nucleoside reverse transcriptase inhibitor based (37%), ritonavir boosted protease inhibitor based (28%), or unboosted protease inhibitor based (25%). Comparing the probability of failure just after achieving suppression vs. after 12 consecutive months of suppression, there was a statistically significant decrease in the probability of virologic failure for each range of adherence proportions we considered, as long as adherence was greater than 50%. The estimated risk difference, comparing the probability of virologic failure after 1 month vs. after 12 months of continuous viral suppression was 0.47 (95% CI 0.23-0.63) at 50-74% adherence, 0.29 (CI 0.03-0.50) at 75-89% adherence, and 0.36 (CI 0.23-0.48) at 90-100% adherence.

Conclusions: The risk of virologic failure for adherence greater than 50% declines with longer duration of continuous suppression. While high adherence is required to maximize the probability of durable viral suppression, the range of adherence capable of sustaining viral suppression is wider after prolonged periods of viral suppression.

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Related in: MedlinePlus

Estimates and 95% Confidence Intervals for the Risk of Virologic Failure, at Four Ranges of Adherence, Given Duration of Continuous Viral Suppression.
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pone-0007196-g001: Estimates and 95% Confidence Intervals for the Risk of Virologic Failure, at Four Ranges of Adherence, Given Duration of Continuous Viral Suppression.

Mentions: We first estimated the causal effect of different adherence proportions on the probability of virologic failure, conditioned on duration of continuous viral suppression (Figure 1). We stratified subject-months by corresponding duration of suppression and then estimated the probability of virologic failure setting the adherence proportion to be in the ranges (0–49%, 50–74%, 75–89%, and 90–100%). Because adherence proportion cannot be randomly assigned as an intervention, we relied on a marginal structural model and targeted maximum likelihood estimation of the causal effects of adherence on viral suppression at each time point.


The risk of virologic failure decreases with duration of HIV suppression, at greater than 50% adherence to antiretroviral therapy.

Rosenblum M, Deeks SG, van der Laan M, Bangsberg DR - PLoS ONE (2009)

Estimates and 95% Confidence Intervals for the Risk of Virologic Failure, at Four Ranges of Adherence, Given Duration of Continuous Viral Suppression.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2747009&req=5

pone-0007196-g001: Estimates and 95% Confidence Intervals for the Risk of Virologic Failure, at Four Ranges of Adherence, Given Duration of Continuous Viral Suppression.
Mentions: We first estimated the causal effect of different adherence proportions on the probability of virologic failure, conditioned on duration of continuous viral suppression (Figure 1). We stratified subject-months by corresponding duration of suppression and then estimated the probability of virologic failure setting the adherence proportion to be in the ranges (0–49%, 50–74%, 75–89%, and 90–100%). Because adherence proportion cannot be randomly assigned as an intervention, we relied on a marginal structural model and targeted maximum likelihood estimation of the causal effects of adherence on viral suppression at each time point.

Bottom Line: Eligible participants were identified from the REACH cohort of marginally housed HIV infected adults in San Francisco.A total of 221 subjects were studied (median age 44.1 years; median CD4+ T cell nadir 206 cells/mm(3)).Most subjects were taking the following types of antiretroviral regimens: non-nucleoside reverse transcriptase inhibitor based (37%), ritonavir boosted protease inhibitor based (28%), or unboosted protease inhibitor based (25%).

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, University of California San Francisco, San Francisco, California, United States of America.

ABSTRACT

Background: We hypothesized that the percent adherence to antiretroviral therapy necessary to maintain HIV suppression would decrease with longer duration of viral suppression.

Methodology: Eligible participants were identified from the REACH cohort of marginally housed HIV infected adults in San Francisco. Adherence to antiretroviral therapy was measured through pill counts obtained at unannounced visits by research staff to each participant's usual place of residence. Marginal structural models and targeted maximum likelihood estimation methodologies were used to determine the effect of adherence to antiretroviral therapy on the probability of virologic failure during early and late viral suppression.

Principal findings: A total of 221 subjects were studied (median age 44.1 years; median CD4+ T cell nadir 206 cells/mm(3)). Most subjects were taking the following types of antiretroviral regimens: non-nucleoside reverse transcriptase inhibitor based (37%), ritonavir boosted protease inhibitor based (28%), or unboosted protease inhibitor based (25%). Comparing the probability of failure just after achieving suppression vs. after 12 consecutive months of suppression, there was a statistically significant decrease in the probability of virologic failure for each range of adherence proportions we considered, as long as adherence was greater than 50%. The estimated risk difference, comparing the probability of virologic failure after 1 month vs. after 12 months of continuous viral suppression was 0.47 (95% CI 0.23-0.63) at 50-74% adherence, 0.29 (CI 0.03-0.50) at 75-89% adherence, and 0.36 (CI 0.23-0.48) at 90-100% adherence.

Conclusions: The risk of virologic failure for adherence greater than 50% declines with longer duration of continuous suppression. While high adherence is required to maximize the probability of durable viral suppression, the range of adherence capable of sustaining viral suppression is wider after prolonged periods of viral suppression.

Show MeSH
Related in: MedlinePlus