XVII International AIDS Conference: From Evidence to Action - Basic science

Impact of peer support on virologic failure in HIV-infected patients on antiretroviral therapy - a cluster randomized controlled trial in Vietnam

Background

The effect of peer support on virologic and immunologic treatment outcomes among HIVinfected patients receiving antiretroviral therapy (ART) was assessed in a cluster randomized controlled trial in Vietnam.

Methods

Seventy-one clusters (communes) were randomized in intervention or control, and a total of 640 patients initiating ART were enrolled. The intervention group received peer support with weekly home-visits. Both groups received first-line ART regimens according to the National Treatment Guidelines. Viral load (VL) (ExaVir™ Load) and CD4 counts were analyzed every 6 months. The primary endpoint was virologic failure (VL >1000 copies/ml). Patients were followed up for 24 months. Intention-to-treat analysis was used. Cluster longitudinal and survival analyses were used to study time to virologic failure and CD4 trends.

Results

Of 640 patients, 71% were males, mean age 32 years, 83% started with stavudine/lamivudine/nevirapine regimen. After a mean of 20.8 months, 78% completed the study, and the median CD4 increase was 286 cells/μl. Cumulative virologic failure risk was 7.2%. There was no significant difference between intervention and control groups in risk for and time to virologic failure and in CD4 trends. Risk factors for virologic failure were ART-non-naïve status [aHR 6.9;(95% CI 3.2–14.6); p < 0.01]; baseline VL ≥100,000 copies/ml [aHR 2.3;(95% CI 1.2–4.3); p < 0.05] and incomplete adherence (self-reported missing more than one dose during 24 months) [aHR 3.1;(95% CI 1.1–8.9); p < 0.05]. Risk factors associated with slower increase of CD4 counts were: baseline VL ≥100,000 copies/ml [adj.sq.Coeff (95% CI): −0.9 (−1.5;−0.3); p < 0.01] and baseline CD4 count <100 cells/μl [adj.sq.Coeff (95% CI): −5.7 (−6.3;−5.4); p < 0.01]. Having an HIV-infected family member was also significantly associated with gain in CD4 counts [adj.sq.Coeff (95% CI): 1.3 (0.8;1.9); p < 0.01].

Conclusion

There was a low virologic failure risk during the first 2 years of ART follow-up in a rural low-income setting in Vietnam. Peer support did not show any impact on virologic and immunologic outcomes after 2 years of follow up.

Trial registration

NCT01433601.

Predicting treatment failure in adults and children on antiretroviral therapy: a systematic review of the performance characteristics of the 2010 WHO immunologic and clinical criteria for virologic failure

OBJECTIVE

We systematically reviewed the performance of 2010 WHO immunologic and clinical criteria for predicting virologic failure in HIV-infected patients on antiretroviral therapy (ART).

DESIGN

Systematic review.

METHODS

We used Cochrane Collaboration methods. We calculated unweighted sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of immunologic and clinical criteria for predicting virologic failure.

RESULTS

We identified 18 studies. Sixteen assessed immunologic criteria in adults; 12 defined virologic failure as a plasma viral load of more than 50 to more than 1000 copies/ml in adults, three as viral load at least 5000 copies/ml, and two as viral load more than 10,000 copies/ml; the sensitivity ranged from 16.8 to 54.9%, specificity from 82.9 to 95.5%, PPV from 15.0 to 38.8%, and NPV from 90.9 to 98.6%. Seven studies assessed clinical criteria to predict viral load of more than 50 to more than 1000 copies/ml; the sensitivity was 11.0%, specificity 90.5%, PPV 44.9%, and NPV 90.2%. Seven studies assessed clinical or immunologic criteria defining virologic failure as viral load of more than 50 to more than 1000 copies/ml; their sensitivity was 26.6%, specificity 85.9%, PPV 49.4%, and NPV 91.1%. Four studies assessed immunologic criteria in children; three defined virologic failure as viral load at least 5000 copies/ml and one as viral load at least 400 copies/ml. The sensitivity ranged from 4.5 to 6.3%, specificity from 97.7 to 99.3%, PPV from 20.0 to 54.9%, and NPV from 85.5 to 91.8%.

CONCLUSION

The 2010 WHO clinical and immunologic criteria are insensitive and have low PPV for predicting virologic failure. These data support the strong recommendation 2013 treatment guidelines that viral load testing be used to monitor for, diagnose, and confirm ART failure.

Optimal Allocation of Gold Standard Testing under Constrained Availability: Application to Assessment of HIV Treatment Failure

The World Health Organization (WHO) guidelines for monitoring the effectiveness of HIV treatment in resource-limited settings (RLS) are mostly based on clinical and immunological markers (e.g., CD4 cell counts). Recent research indicates that the guidelines are inadequate and can result in high error rates. Viral load (VL) is considered the "gold standard", yet its widespread use is limited by cost and infrastructure. In this paper, we propose a diagnostic algorithm that uses information from routinely-collected clinical and immunological markers to guide a selective use of VL testing for diagnosing HIV treatment failure, under the assumption that VL testing is available only at a certain portion of patient visits. Our algorithm identifies the patient sub-population, such that the use of limited VL testing on them minimizes a pre-defined risk (e.g., misdiagnosis error rate). Diagnostic properties of our proposal algorithm are assessed by simulations. For illustration, data from the Miriam Hospital Immunology Clinic (RI, USA) are analyzed.

Prediction of treatment failure using 2010 World Health Organization Guidelines is associated with high misclassification rates and drug resistance among HIV-infected Cambodian children

BACKGROUND

Antiretroviral therapy (ART) in resource-limited settings (RLSs) is monitored clinically and immunologically, according to World Health Organization (WHO) or national guidelines. Revised WHO pediatric guidelines were published in 2010, but their ability to accurately identify virological failure is unclear.

METHODS

We evaluated performance of WHO 2010 guidelines and compared them with WHO 2006 and Cambodia 2011 guidelines among children on ≥6 months of first-line ART at Angkor Hospital for Children between January 2005 and September 2010. We determined sensitivity, specificity, positive and negative predictive values, and accuracy using bootstrap resampling to account for multiple tests per child. Human immunodeficiency virus (HIV) resistance was compared between those correctly and incorrectly identified by each guideline.

RESULTS

Among 457 children with 1079 viral loads (VLs), 20% had >400 copies/mL. For children with WHO stage 1/2 HIV, misclassification as failure (met CD4 failure criteria, but VL undetectable) was 64% for WHO 2006 guidelines, 33% for WHO 2010 guidelines, and 81% for Cambodia 2011 guidelines; misclassification as success (did not meet CD4 failure, but VL detectable) was 11%, 12%, and 12%, respectively. For children with WHO stage 3/4 HIV, misclassification as failure was 35% for WHO 2006 guidelines, 40% for WHO 2010 guidelines, and 43% for Cambodia 2011 guidelines; misclassification as success was 13%, 24%, and 21%, respectively. Compared with WHO 2006 guidelines, WHO 2010 guidelines significantly increased the risk of misclassification as success in stage 3/4 HIV (P < .05). The WHO 2010 guidelines failed to identify 98% of children with extensive reverse-transcriptase resistance.

CONCLUSIONS

In our cohort, lack of virological monitoring would result in unacceptable treatment failure misclassification, leading to premature ART switch and resistance accumulation. Affordable virological monitoring suitable for use in RLSs is desperately needed.