Not All Missed Doses Are the Same: Sustained NNRTI Treatment Interruptions Predict HIV Rebound at Low-to-Moderate Adherence Levels

Background: While the relationship between average adherence to HIV potent antiretroviral therapy is well defined, the relationship between patterns of adherence within adherence strata has not been investigated. We examined medication event monitoring system (MEMS) defined adherence patterns and their relation to subsequent virologic rebound. Methods and Results: We selected subjects with at least 3-months of previous virologic suppression on a non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimen from two prospective cohorts in France and North America. We assessed the risk of virologic rebound, defined as HIV RNA of >400 copies/mL according to several MEMS adherence measurements. Seventy two subjects were studied, five of them experienced virologic rebound. Subjects with and without virologic rebound had similar baseline characteristics including treatment durations, regimen (efavirenz vs nevirapine), and dosing schedule. Each 10% increase in average adherence decreased the risk of virologic rebound (OR = 0.56; 95% confidence interval (CI) [0.37, 0.81], P<0.002). Each additional consecutive day off therapy for the longest treatment interruption (OR = 1.34; 95%CI [1.15, 1.68], P<0.0001) and each additional treatment interruption for more than 2 days (OR = 1.38; 95%CI [1.13, 1.77], P<0.002) increased the risk of virologic rebound. In those with low-to-moderate adherence (i.e. <80%), treatment interruption duration (16.2 days versus 6.1 days in the control group, P<0.02), but not average adherence (53.1% vs 55.9%, respectively, P = 0.65) was significantly associated with virologic rebound. Conclusions: Sustained treatment interruption may pose a greater risk of virologic rebound on NNRTI therapy than the same number of interspersed missed doses at low-to-moderate adherence

Decreases in Community Viral Load Are Accompanied by Reductions in New HIV Infections in San Francisco

BACKGROUND: At the individual level, higher HIV viral load predicts sexual transmission risk. We evaluated San Francisco's community viral load (CVL) as a population level marker of HIV transmission risk. We hypothesized that the decrease in CVL in San Francisco from 2004-2008, corresponding with increased rates of HIV testing, antiretroviral therapy (ART) coverage and effectiveness, and population-level virologic suppression, would be associated with a reduction in new HIV infections. METHODOLOGY/PRINCIPAL FINDINGS: We used San Francisco's HIV/AIDS surveillance system to examine the trends in CVL. Mean CVL was calculated as the mean of the most recent viral load of all reported HIV-positive individuals in a particular community. Total CVL was defined as the sum of the most recent viral loads of all HIV-positive individuals in a particular community. We used Poisson models with robust standard errors to assess the relationships between the mean and total CVL and the primary outcome: annual numbers of newly diagnosed HIV cases. Both mean and total CVL decreased from 2004-2008 and were accompanied by decreases in new HIV diagnoses from 798 (2004) to 434 (2008). The mean (p = 0.003) and total CVL (p = 0.002) were significantly associated with new HIV cases from 2004-2008. CONCLUSIONS/SIGNIFICANCE: Reductions in CVL are associated with decreased HIV infections. Results suggest that wide-scale ART could reduce HIV transmission at the population level. Because CVL is temporally upstream of new HIV infections, jurisdictions should consider adding CVL to routine HIV surveillance to track the epidemic, allocate resources, and to evaluate the effectiveness of HIV prevention and treatment efforts

Baseline characteristics by study groups.

*<p>Exact Fisher chi-square test for percentages and <i>t</i>-test for continuous variables.</p

Effect of adherence rates and patterns on the risk of virologic rebound.

*<p>OR [95% CI]: Odds Ratio [95% confidence Interval] computed by conditional exact logistic regression. OR>1 means an increased probability of viral rebound.</p>§<p>OR and 95% CI are provided for a 10% increase in adherence rate.</p>$<p>Days without dose defined as drug discontinuations for more than 24 hours and less than 48 hours.</p>&<p>TI: Treatment interruptions defined as drug discontinuations for more than 48 hours.</p

Predicted and observed risk of viral control according to the longer interval of treatment discontinuation, POSOVIR and REACH cohorts.

<p>Predicted and observed risk of viral control according to the longer interval of treatment discontinuation, POSOVIR and REACH cohorts.</p

Relationship between average adherence and longer treatment interruption among subjects with (red) and without (green and blue) virologic rebound, POSOVIR and REACH cohorts.

<p>- The red lines on the X and Y-axis correspond to mean average adherence (%) and treatment interruption duration (days), respectively, among subjects with subsequent HIV RNA≥400 copies/ml. The blue lines on the X and Y-axis correspond to mean average adherence (%) and treatment interruption duration (days), respectively, among subjects with subsequent HIV RNA<400 copies/ml and low-to-moderate adherence (<80%). The difference in treatment interruption duration, but not adherence rate, is statistically significant between those with HIV RNA≥400 copies/ml and those with HIV RNA<400 copies/ml.</p

Linkage and Retention in HIV Care among Men Who Have Sex with Men in the United States

Men who have sex with men (MSM) continue to be disproportionately affected by human immunodeficiency virus (HIV) infection. While the MSM population does better than other HIV infection risk groups with regard to linkage to and retention in care, little is known about engagement in care outcomes for important subpopulations of MSM. There is also a dearth of research on engagement in care strategies specific to the MSM population. Key MSM subpopulations in the United States on which to focus future research efforts include racial/ethnic minority, young, and substance-using MSM. Health care systems navigation may offer a promising engagement in care strategy for MSM and should be further evaluated. As is the case for HIV-infected populations in general, future research should also focus on identifying the best metrics for measuring engagement in care