Development and evaluation of a clinical algorithm to monitor patients on antiretrovirals in resource-limited settings using adherence, clinical and CD4 cell count criteria

Accuracy of measures for antiretroviral adherence in people living with HIV

BACKGROUND

Good patient adherence to antiretroviral (ART) medication determines effective HIV viral suppression, and thus reduces the risk of progression and transmission of HIV. With accurate methods to monitor treatment adherence, we could use simple triage to target adherence support interventions that could help in the community or at health centres in resource-limited settings.

OBJECTIVES

To determine the accuracy of simple measures of ART adherence (including patient self-report, tablet counts, pharmacy records, electronic monitoring, or composite methods) for detecting non-suppressed viral load in people living with HIV and receiving ART treatment.

SEARCH METHODS

The Cochrane Infectious Diseases Group Information Specialists searched CENTRAL, MEDLINE, Embase, LILACS, CINAHL, African-Wide information, and Web of Science up to 22 April 2021. They also searched the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov for ongoing studies. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included studies of all designs that evaluated a simple measure of adherence (index test) such as self-report, tablet counts, pharmacy records or secondary database analysis, or both, electronic monitoring or composite measures of any of those tests, in people living with HIV and receiving ART treatment. We used a viral load assay with a limit of detection ranging from 10 copies/mL to 400 copies/mL as the reference standard. We created 2 × 2 tables to calculate sensitivity and specificity.

DATA COLLECTION AND ANALYSIS

We screened studies, extracted data, and assessed risk of bias using QUADAS-2 independently and in duplicate. We assessed the certainty of evidence using the GRADE method. The results of estimated sensitivity and specificity were presented using paired forest plots and tabulated summaries. We encountered a high level of variation among studies which precluded a meaningful meta-analysis or comparison of adherence measures. We explored heterogeneity using pre-defined subgroup analysis.

MAIN RESULTS

We included 51 studies involving children and adults with HIV, mostly living in low- and middle-income settings, conducted between 2003 and 2021. Several studies assessed more than one index test, and the most common measure of adherence to ART was self-report. - Self-report questionnaires (25 studies, 9211 participants; very low-certainty): sensitivity ranged from 10% to 85% and specificity ranged from 10% to 99%. - Self-report using a visual analogue scale (VAS) (11 studies, 4235 participants; very low-certainty): sensitivity ranged from 0% to 58% and specificity ranged from 55% to 100%. - Tablet counts (12 studies, 3466 participants; very low-certainty): sensitivity ranged from 0% to 100% and specificity ranged from 5% to 99%. - Electronic monitoring devices (3 studies, 186 participants; very low-certainty): sensitivity ranged from 60% to 88% and the specificity ranged from 27% to 67%. - Pharmacy records or secondary databases (6 studies, 2254 participants; very low-certainty): sensitivity ranged from 17% to 88% and the specificity ranged from 9% to 95%. - Composite measures (9 studies, 1513 participants; very low-certainty): sensitivity ranged from 10% to 100% and specificity ranged from 49% to 100%. Across all included studies, the ability of adherence measures to detect viral non-suppression showed a large variation in both sensitivity and specificity that could not be explained by subgroup analysis. We assessed the overall certainty of the evidence as very low due to risk of bias, indirectness, inconsistency, and imprecision. The risk of bias and the applicability concerns for patient selection, index test, and reference standard domains were generally low or unclear due to unclear reporting. The main methodological issues identified were related to flow and timing due to high numbers of missing data. For all index tests, we assessed the certainty of the evidence as very low due to limitations in the design and conduct of the studies, applicability concerns and inconsistency of results.

AUTHORS' CONCLUSIONS

We encountered high variability for all index tests, and the overall certainty of evidence in all areas was very low. No measure consistently offered either a sufficiently high sensitivity or specificity to detect viral non-suppression. These concerns limit their value in triaging patients for viral load monitoring or enhanced adherence support interventions.

Interferon-γ-Inducible Protein 10 (IP-10) Kinetics after Antiretroviral Treatment Initiation in Ethiopian Adults with HIV

Interferon-γ-inducible protein 10 (IP-10) has been suggested as a marker for targeted viral load (VL) monitoring during antiretroviral treatment (ART). We aimed to determine the kinetics of IP-10 during the initial year of ART, with particular regard to the impact of tuberculosis (TB) co-infection on IP-10 secretion. Longitudinal plasma IP-10 levels were quantified in 112 treatment-naive HIV-positive adults at Ethiopian health centers, through enzyme-linked immunosorbent assay (ELISA) using samples obtained before and during the initial 12 months of ART. All participants underwent bacteriological TB investigation before starting ART. In virological responders (VRs; defined as VL < 150 copies/ml with no subsequent VL ≥ 1,000 copies/ml), IP-10 kinetics were analyzed using linear regression models. Among 91/112 (81.3%) participants classified as VRs, 17 (18.7%) had concomitant TB. Median baseline IP-10 was 650 pg/ml (interquartile range [IQR], 428-1,002) in VRs. IP-10 decline was more rapid during the first month of ART (median 306 pg/ml/month) compared with later time intervals (median 7-48 pg/ml/month, P < 0.001 in each comparison). Although VRs with TB had higher IP-10 levels at baseline (median 1106 pg/ml [IQR, 627-1,704]), compared with individuals without TB (median 628 pg/ml [IQR, 391-885]; P = 0.003), the rate of IP-10 decline during ART was similar, regardless of TB-status. During the initial year of ART, IP-10 kinetics followed a biphasic pattern in VRs, with a more rapid decline in the first month of ART compared with later time intervals. Baseline IP-10 was higher in individuals with TB versus individuals without TB, but the kinetics during ART were similar. IMPORTANCE To reach the goal of elimination of HIV as public health threat, access to antiretroviral treatment (ART) has to be further scaled up. To ensure viral suppression in individuals receiving ART, novel and robust systems for treatment monitoring are required. Targeting viral load monitoring to identify individuals at increased likelihood of treatment failure, using screening tools, could be an effective use of limited resources for viral load testing. Interferon-γ-inducible protein 10 (IP-10), a host inflammation mediator, has shown potential for this purpose. Here, we have investigated IP-10 kinetics in Ethiopian adults with HIV during the initial year after ART initiation. IP-10 levels decreased in parallel with viral load during ART, and prevalent tuberculosis at ART initiation did not influence IP-10 kinetics. This study shows satisfactory performance for IP-10 as a surrogate marker for viral load in persons starting ART, with no influence of concomitant tuberculosis.

Machine Learning Algorithms Using Routinely Collected Data Do Not Adequately Predict Viremia to Inform Targeted Services in Postpartum Women Living With HIV

BACKGROUND

Adherence to antiretroviral treatment (ART) among postpartum women with HIV is essential for optimal health and prevention of perinatal transmission. However, suboptimal adherence with subsequent viremia is common, and adherence challenges are often underreported. We aimed to predict viremia to facilitate targeted adherence support in sub-Saharan Africa during this critical period.

METHODS

Data are from PROMISE 1077BF/FF, which enrolled perinatal women between 2011 and 2014. This analysis includes postpartum women receiving ART per study randomization or country-specific criteria to continue from pregnancy. We aimed to predict viremia (single and confirmed events) after 3 months on ART at >50, >400, and >1000 copies/mL within 6-month intervals through 24 months. We built models with routine clinical and demographic data using the least absolute shrinkage and selection operator and SuperLearner (which incorporates multiple algorithms).

RESULTS

Among 1321 women included, the median age was 26 years and 96% were in WHO stage 1. Between 0 and 24 months postpartum, 42%, 31%, and 28% of women experienced viremia >50, >400, and >1000 copies/mL, respectively, at least once. Across models, the cross-validated area under the receiver operating curve ranged from 0.74 [95% confidence interval (CI): 0.72 to 0.76] to 0.78 (95% CI: 0.76 to 0.80). To achieve 90% sensitivity predicting confirmed viremia >50 copies/mL, 64% of women would be classified as high risk.

CONCLUSIONS

Using routinely collected data to predict viremia in >1300 postpartum women with HIV, we achieved moderate model discrimination, but insufficient to inform targeted adherence support. Psychosocial characteristics or objective adherence metrics may be required for improved prediction of viremia in this population.

Predictors of Virologic Failure Among a Cohort of HIV-infected Children in Southern Ethiopia

BACKGROUND

Optimal care for children with HIV infection includes timely assessment of treatment failure. Using HIV viral load to define treatment failure remains a challenge in resource-limited settings.

METHODS

Children with HIV infection who were already on or starting first-line antiretroviral therapy were enrolled and followed over time. We examined clinical and immunologic predictors of virologic failure (VF), defined as consecutive viral load measurements > 1000 copies/mL (VF). Children were followed every 6 months with clinical assessments, immunologic assays and viral load testing until treatment failure or up to 18 months.

RESULTS

Of the 484 children with complete data, we observed a prevalence of 15% who had VF at enrollment, and 18 who developed VF over 10.5 person-years of follow-up for an incidence of 4.97 [95% CI: 3.04-7.70) per 100 person-years. Lower adherence, lower CD4 T-cell count, lower white blood cells count, lower platelets and a lower glomerular filtration rate were all associated with increased VF. However, in a multivariable analysis, renal function (estimated glomerular filtration rate < 90 mL/min), odds ratio: 11.5 (95% CI: 1.5-63.7), and lower adherence, odds ratio: 3.9 (95% CI: 1.1-13.4), were the only factors associated with development of VF.

CONCLUSIONS

We identified a significant risk of VF in children with HIV infection in a prospective cohort study in southern Ethiopia and limited predictive value of clinical variables for VF. This provides further evidence that rapid and reliable viral load testing is needed to adequately address the HIV epidemic, along with implementation of adherence interventions in sub-Saharan Africa.

Super learner analysis of real-time electronically monitored adherence to antiretroviral therapy under constrained optimization and comparison to non-differentiated care approaches for persons living with HIV in rural Uganda

INTRODUCTION

Real-time electronic adherence monitoring (EAM) systems could inform on-going risk assessment for HIV viraemia and be used to personalize viral load testing schedules. We evaluated the potential of real-time EAM (transferred via cellular signal) and standard EAM (downloaded via USB cable) in rural Uganda to inform individually differentiated viral load testing strategies by applying machine learning approaches.

METHODS

We evaluated an observational cohort of persons living with HIV and treated with antiretroviral therapy (ART) who were monitored longitudinally with standard EAM from 2005 to 2011 and real-time EAM from 2011 to 2015. Super learner, an ensemble machine learning method, was used to develop a tool for targeting viral load testing to detect viraemia (>1000 copies/ml) based on clinical (CD4 count, ART regimen), viral load and demographic data, together with EAM-based adherence. Using sample-splitting (cross-validation), we evaluated area under the receiver operating characteristic curve (cvAUC), potential for EAM data to selectively defer viral load tests while minimizing delays in viraemia detection, and performance compared to WHO-recommended testing schedules.

RESULTS

In total, 443 persons (1801 person-years) and 485 persons (930 person-years) contributed to standard and real-time EAM analyses respectively. In the 2011 to 2015 dataset, addition of real-time EAM (cvAUC: 0.88; 95% CI: 0.83, 0.93) significantly improved prediction compared to clinical/demographic data alone (cvAUC: 0.78; 95% CI: 0.72, 0.86; p = 0.03). In the 2005 to 2011 dataset, addition of standard EAM (cvAUC: 0.77; 95% CI: 0.72, 0.81) did not significantly improve prediction compared to clinical/demographic data alone (cvAUC: 0.70; 95% CI: 0.64, 0.76; p = 0.08). A hypothetical testing strategy using real-time EAM to guide deferral of viral load tests would have reduced the number of tests by 32% while detecting 87% of viraemia cases without delay. By comparison, the WHO-recommended testing schedule would have reduced the number of tests by 69%, but resulted in delayed detection of viraemia a mean of 74 days for 84% of individuals with viraemia. Similar rules derived from standard EAM also resulted in potential testing frequency reductions.

CONCLUSIONS

Our machine learning approach demonstrates potential for combining EAM data with other clinical measures to develop a selective testing rule that reduces number of viral load tests ordered, while still identifying those at highest risk for viraemia.

Clinical and immunological failure among HIV-positive adults taking first-line antiretroviral therapy in Dire Dawa, eastern Ethiopia

Background

Access to antiretroviral therapy (ART) in Ethiopia has been scaled up since the introduction of the service in 2003. Free ART was launched in 2005, resulting in fewer new human immunodeficiency virus (HIV) infections and deaths from acquired immunodeficiency syndrome (AIDS). However, immunological and clinical failures for first-line ART due to poor adherence and other factors have received less attention. Thus, this study aims to determine the magnitude and associated factors of clinical and immunological failure among HIV-positive adults after six months of first-line ART in Dire Dawa, Eastern Ethiopia.

Methods

A facility-based cross-sectional study was conducted using secondary data of patients on ART in all health facilities providing ART services in Dire Dawa. A total of 949 samples were collected. The data were entered into Epidata version 3.02, and the analysis was performed using SPSS version 16.0. Univariate and multivariate analyses were performed to determine the magnitude of clinical and immunological failure and identify factors significantly associated with the outcome variable.

Results

The magnitude of clinical and immunological failure was 22.7% (n = 215). Of these, 33 (15%) patients were switched to second-line ART. CD4 count ≤100 cells/mm3 (AOR: 1.78, 95% CI: 1.18–2.69), poor adherence (AOR: 2.5, 95% CI: 1.19–5.25), restarting after interruption of ART (AOR: 1.93, 95% CI: 1.23–3.07), regimen change (AOR: 1.50, 95% CI: 1.05–2.15), ambulatory/bedridden functional status at the last visit on ART (AOR: 2.41, 95% CI: 1.22–4.75) and patients who died (AOR: 3.94, 95% CI: 1.64–9.45) had higher odds of failure.

Conclusion

The magnitude of clinical and immunological failure was high. To curb this problem, initiation of ART before the occurrence of severe immune suppression, early detection and management of failure and improved adherence support mechanisms are recommended. Restarting treatment after interruption and regimen changes-should-be-made-cautiously.

Brief Report: Assessing the Association Between Changing NRTIs When Initiating Second-Line ART and Treatment Outcomes

BACKGROUND

After first-line antiretroviral therapy failure, the importance of change in nucleoside reverse transcriptase inhibitor (NRTI) in second line is uncertain due to the high potency of protease inhibitors used in second line.

SETTING

We used clinical data from 6290 adult patients in South Africa and Zambia from the International Epidemiologic Databases to Evaluate AIDS (IeDEA) Southern Africa cohort.

METHODS

We included patients who initiated on standard first-line antiretroviral therapy and had evidence of first-line failure. We used propensity score-adjusted Cox proportional-hazards models to evaluate the impact of change in NRTI on second-line failure compared with remaining on the same NRTI in second line. In South Africa, where viral load monitoring was available, treatment failure was defined as 2 consecutive viral loads >1000 copies/mL. In Zambia, it was defined as 2 consecutive CD4 counts <100 cells/mm.

RESULTS

Among patients in South Africa initiated on zidovudine (AZT), the adjusted hazard ratio for second-line virologic failure was 0.25 (95% confidence interval: 0.11 to 0.57) for those switching to tenofovir (TDF) vs. remaining on AZT. Among patients in South Africa initiated on TDF, switching to AZT in second line was associated with reduced second-line failure (adjusted hazard ratio = 0.35 [95% confidence interval: 0.13 to 0.96]). In Zambia, where viral load monitoring was not available, results were less conclusive.

CONCLUSIONS

Changing NRTI in second line was associated with better clinical outcomes in South Africa. Additional clinical trial research regarding second-line NRTI choices for patients initiated on TDF or with contraindications to specific NRTIs is needed.

Validation of the Viral Load Testing Criteria - an algorithm for targeted viral load testing in HIV-positive adults receiving antiretroviral therapy

OBJECTIVES

Restricted capacity for viral load (VL) testing is a major obstacle for antiretroviral therapy (ART) programmes in high-burden regions. Algorithms for targeted VL testing could help allocate laboratory resources rationally. We validated the performance of the Viral Load Testing Criteria (VLTC), an algorithm with satisfactory performance in derivation (sensitivity 91%, specificity 43%).

METHODS

HIV-positive adults who had been receiving first-line ART for ≥12 months at three Ethiopian public ART clinics were included. Healthcare providers collected data on variables of the VLTC: current CD4 count, mid-upper arm circumference (MUAC) and self-reported treatment interruption. VL testing was performed in parallel. Performance of the algorithm for identification of patients with VL ≥ 1000 copies/ml was evaluated.

RESULTS

Of 562 patients (female 62%, median ART duration 92 months), 33 (6%) had VL ≥ 1000 copies/ml. Sensitivity for the VLTC was 85% (95% CI, 68-95), specificity 60% (95% CI, 55-64), positive predictive value 12% (95% CI, 10-14) and negative predictive value 98% (95% CI, 97-99). Use of the algorithm would reduce the number of VL tests required by 57%. Misclassification occurred in 5/33 (15%) of subjects with VL ≥ 1000 copies/ml.

CONCLUSION

In validation, the VLTC performed similarly well as derivation. Use of the VLTC may be considered for targeted VL testing for ART monitoring in high-burden regions.

Development of an algorithm for determination of the likelihood of virological failure in HIV-positive adults receiving antiretroviral therapy in decentralized care

Background: Early identification of virological failure (VF) limits occurrence and spread of drug-resistant viruses in patients receiving antiretroviral treatment (ART). Viral load (VL) monitoring is therefore recommended, but capacities to comply with this are insufficient in many low-income countries. Clinical algorithms might identify persons at higher likelihood of VF to allocate VL resources.

Objectives: We aimed to construct a VF algorithm (the Viral Load Testing Criteria; VLTC) and compare its performance to the 2013 WHO treatment failure criteria.

Methods: Subjects with VL results available 1 year after ART start (n = 494) were identified from a cohort of ART-naïve adults (n = 812), prospectively recruited and followed 2011–2015 at Ethiopian health centres. VF was defined as VL≥1000 copies/mL. Variables recorded at the time of sampling, with potential association with VF, were used to construct the algorithm based on multivariate logistic regression.

Results: Fifty-seven individuals (12%) had VF, which was independently associated with CD4 count <350 cells/mm³, previous ART interruption, and short mid-upper arm circumference (<24cm and <23cm, for men and women, respectively). These variables were included in the VLTC. In derivation, the VLTC identified 52/57 with VF; sensitivity 91%, specificity 43%, positive predictive value (PPV) 17%, negative predictive value (NPV) 97%. In comparison, the WHO criteria identified 38/57 with VF (sensitivity 67%, specificity 74%, PPV 25%, NPV 94%).

Conclusions: The VLTC identified subjects at greater likelihood of VF, with higher sensitivity and NPV than the WHO criteria. If external validation confirms this performance, these criteria could be used to allocate limited VL resources. Due to its limited specificity, it cannot be used to determine treatment failure in the absence of a confirmatory viral load.

Improved HIV-1 Viral Load Monitoring Capacity Using Pooled Testing With Marker-Assisted Deconvolution

OBJECTIVE

Improve pooled viral load (VL) testing to increase HIV treatment monitoring capacity, particularly relevant for resource-limited settings.

DESIGN

We developed marker-assisted mini-pooling with algorithm (mMPA), a new VL pooling deconvolution strategy that uses information from low-cost, routinely collected clinical markers to determine an efficient order of sequential individual VL testing and dictates when the sequential testing can be stopped.

METHODS

We simulated the use of pooled testing to ascertain virological failure status on 918 participants from 3 studies conducted at the Academic Model Providing Access to Healthcare in Eldoret, Kenya, and estimated the number of assays needed when using mMPA and other pooling methods. We also evaluated the impact of practical factors, such as specific markers used, prevalence of virological failure, pool size, VL measurement error, and assay detection cutoffs on mMPA, other pooling methods, and single testing.

RESULTS

Using CD4 count as a marker to assist deconvolution, mMPA significantly reduces the number of VL assays by 52% [confidence interval (CI): 48% to 57%], 40% (CI: 38% to 42%), and 19% (CI: 15% to 22%) compared with individual testing, simple mini-pooling, and mini-pooling with algorithm, respectively. mMPA has higher sensitivity and negative/positive predictive values than mini-pooling with algorithm, and comparable high specificity. Further improvement is achieved with additional clinical markers, such as age and time on therapy, with or without CD4 values. mMPA performance depends on prevalence of virological failure and pool size but is insensitive to VL measurement error and VL assay detection cutoffs.

CONCLUSIONS

mMPA can substantially increase the capacity of VL monitoring.

Assessment of WHO criteria for identifying ART treatment failure in Vietnam from 2007 to 2011

Objective

We evaluated the sensitivity and specificity of the WHO immunological criteria for detecting antiretroviral therapy (ART) treatment failure in a cohort of Vietnamese patients. We conducted a stratified analysis to determine the effects of BMI, peer support, adherence to antiretroviral (ARV) drugs, age, and gender on the sensitivity and specificity of the WHO criteria.

Methods

We conducted a retrospective cohort study of 605 HIV-infected patients using data previously collected from a cluster randomized control trial study. We compared the sensitivity and specificity of CD4⁺ counts to the gold standard of virologic testing as a diagnostic test for ART failure at different time points of 12, 18, and 24 months.

Results

The sensitivity [95% confidence interval (CI)] of the WHO immunological criteria based on a viral load ≥ 1000 copies/mL was 12% (5%-23%), 14% (2%-43%), and 12.5% (2%-38%) at 12, 18, and 24 months, respectively. In the same order, the specificity was 93% (90%-96%), 98% (96%-99%), and 98% (96%-100%). The positive predictive values (PPV) at 12, 18, and 24 months were 22% (9%-40%), 20% (3%-56%), and 29% (4%-71%); the negative predictive values (NPV) at the same time points were 87% (84%-90%), 97% (95%-98%), and 96% (93%-98%). The stratified analysis revealed similar sensitivities and specificities.

Conclusion

The sensitivity of the WHO immunological criteria is poor, but the specificity is high. Although testing costs may increase, we recommend that Vietnam and other similar settings adopt viral load testing as the principal method for determining ART failure.

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.

Positive Predictive Value of the WHO Clinical and Immunologic Criteria to Predict Viral Load Failure among Adults on First, or Second-Line Antiretroviral Therapy in Kenya

Routine HIV viral load (VL) monitoring is the standard of care for persons receiving antiretroviral therapy (ART) in developed countries. Although the World Health Organization recommends annual VL monitoring of patients on ART, recognizing difficulties in conducting routine VL testing, the WHO continues to recommend targeted VL testing to confirm treatment failure for persons who meet selected immunologic and clinical criteria. Studies have measured positive predictive value (PPV), negative predictive value, sensitivity and specificity of these criteria among patients receiving first-line ART but not specifically among those on second-line or subsequent regimens. Between 2008 and 2011, adult ART patients in Nyanza, Kenya who met national clinical or immunologic criteria for treatment failure received targeted VL testing. We calculated PPV and 95% confidence intervals (CI) of these criteria to detect virologic treatment failure among patients receiving a) first-line ART, b) second/subsequent ART, and c) any regimen. Of 12,134 patient specimens tested, 2,874 (23.7%) were virologically confirmed as treatment failures. The PPV for 2,834 first-line ART patients who met either the clinical or immunologic criteria for treatment failure was 34.4% (95% CI 33.2–35.7), 33.1% (95% CI 24.7–42.3) for the 40 patients on second-line/subsequent regimens, and 33.4% (95% CI 33.1–35.6) for any ART. PPV, regardless of criteria, for first-line ART patients was lowest among patients over 44 years old and highest for patients aged 15 to 34 years. PPV of immunological and clinical criteria for correctly identifying treatment failure was similarly low for adult patients receiving either first-line or second-line/subsequent ART regimens. Our data confirm the inadequacy of clinical and immunologic criteria to correctly identify treatment failure and support the implementation of routine VL testing.

Implementation and Operational Research: Risk Charts to Guide Targeted HIV-1 Viral Load Monitoring of ART: Development and Validation in Patients From Resource-Limited Settings

BACKGROUND

HIV-1 RNA viral load (VL) testing is recommended to monitor antiretroviral therapy (ART) but not available in many resource-limited settings. We developed and validated CD4-based risk charts to guide targeted VL testing.

METHODS

We modeled the probability of virologic failure up to 5 years of ART based on current and baseline CD4 counts, developed decision rules for targeted VL testing of 10%, 20%, or 40% of patients in 7 cohorts of patients starting ART in South Africa, and plotted cutoffs for VL testing on colour-coded risk charts. We assessed the accuracy of risk chart-guided VL testing to detect virologic failure in validation cohorts from South Africa, Zambia, and the Asia-Pacific.

RESULTS

In total, 31,450 adult patients were included in the derivation and 25,294 patients in the validation cohorts. Positive predictive values increased with the percentage of patients tested: from 79% (10% tested) to 98% (40% tested) in the South African cohort, from 64% to 93% in the Zambian cohort, and from 73% to 96% in the Asia-Pacific cohort. Corresponding increases in sensitivity were from 35% to 68% in South Africa, from 55% to 82% in Zambia, and from 37% to 71% in Asia-Pacific. The area under the receiver operating curve increased from 0.75 to 0.91 in South Africa, from 0.76 to 0.91 in Zambia, and from 0.77 to 0.92 in Asia-Pacific.

CONCLUSIONS

CD4-based risk charts with optimal cutoffs for targeted VL testing maybe useful to monitor ART in settings where VL capacity is limited.

Super Learner Analysis of Electronic Adherence Data Improves Viral Prediction and May Provide Strategies for Selective HIV RNA Monitoring

OBJECTIVE

Regular HIV RNA testing for all HIV-positive patients on antiretroviral therapy (ART) is expensive and has low yield since most tests are undetectable. Selective testing of those at higher risk of failure may improve efficiency. We investigated whether a novel analysis of adherence data could correctly classify virological failure and potentially inform a selective testing strategy.

DESIGN

Multisite prospective cohort consortium.

METHODS

We evaluated longitudinal data on 1478 adult patients treated with ART and monitored using the Medication Event Monitoring System (MEMS) in 16 US cohorts contributing to the MACH14 consortium. Because the relationship between adherence and virological failure is complex and heterogeneous, we applied a machine-learning algorithm (Super Learner) to build a model for classifying failure and evaluated its performance using cross-validation.

RESULTS

Application of the Super Learner algorithm to MEMS data, combined with data on CD4 T-cell counts and ART regimen, significantly improved classification of virological failure over a single MEMS adherence measure. Area under the receiver operating characteristic curve, evaluated on data not used in model fitting, was 0.78 (95% confidence interval: 0.75 to 0.80) and 0.79 (95% confidence interval: 0.76 to 0.81) for failure defined as single HIV RNA level >1000 copies per milliliter or >400 copies per milliliter, respectively. Our results suggest that 25%-31% of viral load tests could be avoided while maintaining sensitivity for failure detection at or above 95%, for a cost savings of $16-$29 per person-month.

CONCLUSIONS

Our findings provide initial proof of concept for the potential use of electronic medication adherence data to reduce costs through behavior-driven HIV RNA testing.

CD4 criteria improves the sensitivity of a clinical algorithm developed to identify viral failure in HIV-positive patients on antiretroviral therapy

INTRODUCTION

Several studies from resource-limited settings have demonstrated that clinical and immunologic criteria are poor predictors of virologic failure, confirming the need for viral load monitoring or at least an algorithm to target viral load testing. We used data from an electronic patient management system to develop an algorithm to identify patients at risk of viral failure using a combination of accessible and inexpensive markers.

METHODS

We analyzed data from HIV-positive adults initiated on antiretroviral therapy (ART) in Johannesburg, South Africa, between April 2004 and February 2010. Viral failure was defined as ≥ 2 consecutive HIV-RNA viral loads >400 copies/ml following suppression ≤ 400 copies/ml. We used Cox-proportional hazards models to calculate hazard ratios (HR) and 95% confidence intervals (CI). Weights for each predictor associated with virologic failure were created as the sum of the natural logarithm of the adjusted HR and dichotomized with the optimal cut-off at the point with the highest sensitivity and specificity (i.e. ≤ 4 vs. >4). We assessed the diagnostic accuracy of predictor scores cut-offs, with and without CD4 criteria (CD4 <100 cells/mm(3); CD4 < baseline; >30% drop in CD4), by calculating the proportion with the outcome and the observed sensitivity, specificity, positive and negative predictive value of the predictor score compared to the gold standard of virologic failure.

RESULTS

We matched 919 patients with virologic failure (1:3) to 2756 patients without. Our predictor score included variables at ART initiation (i.e. gender, age, CD4 count <100 cells/mm(3), WHO stage III/IV and albumin) and laboratory and clinical follow-up data (drop in haemoglobin, mean cell volume (MCV) <100 fl, CD4 count <200 cells/mm(3), new or recurrent WHO stage III/IV condition, diagnosis of new condition or symptom and regimen change). Overall, 51.4% had a score 51.4% had a score ≥ 4 and 48.6% had a score <4. A predictor score including CD4 criteria performed better than a score without CD4 criteria and better than WHO clinico-immunological criteria or WHO clinical staging to predict virologic failure (sensitivity 57.1% vs. 40.9%, 25.2% and 20.9%, respectively).

CONCLUSIONS

Predictor scores or risk categories, with CD4 criteria, could be used to identify patients at risk of virologic failure in resource-limited settings so that these patients may be targeted for focused interventions to improve HIV treatment outcomes.

Measures of viral load using Abbott RealTime HIV-1 Assay on venous and fingerstick dried blood spots from provider-collected specimens in Malawian District Hospitals

BACKGROUND

Viral suppression is a key indicator of antiretroviral therapy (ART) response among HIV-infected patients. Dried blood spots (DBS) are an appealing alternative to conventional plasma-based virologic testing, improving access to monitoring in resource-limited settings. However, validity of DBS obtained from fingerstick in field settings remains unknown.

OBJECTIVES

Investigate feasibility and accuracy of DBS vs plasma collected by healthcare workers in real-world settings of remote hospitals in Malawi. Compare venous DBS to fingerstick DBS for identifying treatment failure.

STUDY DESIGN

We recruited patients from ART clinics at two district hospitals in Malawi, collecting plasma, venous DBS (vDBS), and fingerstick DBS (fsDBS) cards for the first 149 patients, and vDBS and fsDBS only for the subsequent 398 patients. Specimens were tested using Abbott RealTime HIV-1 Assay (lower detection limit 40 copies/ml (plasma) and 550 copies/ml (DBS)).

RESULTS

21/149 (14.1%) had detectable viremia (>1.6 log copies/ml), 13 of which were detectable for plasma, vDBS, and fsDBS. Linear regression demonstrated high correlation for plasma vs. DBS (vDBS: β=1.19, R(2)=0.93 (p<0.0001); fsDBS β=1.20, R(2)=0.90 (p<0.0001)) and vDBS vs. fsDBS (β=0.88, R(2)=0.73, (p<0.0001)). Mean difference between plasma and vDBS was 1.1 log copies/ml [SD: 0.27] and plasma and fsDBS 1.1 log copies/ml [SD: 0.31]. At 5000 copies/ml, sensitivity was 100%, and specificity was 98.6% and 97.8% for vDBS and fsDBS, respectively, compared to plasma.

CONCLUSIONS

DBS from venipuncture and fingerstick perform well at the failure threshold of 5000 copies/ml. Fingerstick specimen source may improve access to virologic treatment monitoring in resource-limited settings given task-shifting in high-volume, low-resource facilities.

Simplified clinical prediction scores to target viral load testing in adults with suspected first line treatment failure in Phnom Penh, Cambodia

Background

For settings with limited laboratory capacity, 2013 World Health Organization (WHO) guidelines recommend targeted HIV-1 viral load (VL) testing to identify virological failure. We previously developed and validated a clinical prediction score (CPS) for targeted VL testing, relying on clinical, adherence and laboratory data. While outperforming the WHO failure criteria, it required substantial calculation and review of all previous laboratory tests. In response, we developed four simplified, less error-prone and broadly applicable CPS versions that can be done ‘on the spot’.

Methodology/Principal

Findings From May 2010 to June 2011, we validated the original CPS in a non-governmental hospital in Phnom Penh, Cambodia applying the CPS to adults on first-line treatment >1 year. Virological failure was defined as a single VL >1000 copies/ml. The four CPSs included CPS1 with ‘current CD4 count’ instead of %-decline-from-peak CD4; CPS2 with hemoglobin measurements removed; CPS3 having ‘decrease in CD4 count below baseline value’ removed; CPS4 was purely clinical. Score development relied on the Spiegelhalter/Knill-Jones method. Variables independently associated with virological failure with a likelihood ratio ≥1.5 or ≤0.67 were retained. CPS performance was evaluated based on the area-under-the-ROC-curve (AUROC) and 95% confidence intervals (CI). The CPSs were validated in an independent dataset. A total of 1490 individuals (56.6% female, median age: 38 years (interquartile range (IQR 33–44)); median baseline CD4 count: 94 cells/µL (IQR 28–205), median time on antiretroviral therapy 3.6 years (IQR 2.1–5.1)), were included. Forty-five 45 (3.0%) individuals had virological failure. CPS1 yielded an AUROC of 0.69 (95% CI: 0.62–0.75) in validation, CPS2 an AUROC of 0.68 (95% CI: 0.62–0.74), and CPS3, an AUROC of 0.67 (95% CI: 0.61–0.73). The purely clinical CPS4 performed poorly (AUROC-0.59; 95% CI: 0.53–0.65).

Conclusions

Simplified CPSs retained acceptable accuracy as long as current CD4 count testing was included. Ease of field application and field accuracy remains to be defined.

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.

Validation of a clinical prediction score to target viral load testing in adults with suspected first-line treatment failure in resource-constrained settings

BACKGROUND

Although routine viral load (VL) monitoring currently is too costly for poor countries, clinical failure criteria perform poorly. We previously developed an algorithm combining a clinical predictor score (CPS) with targeted VL testing in a Cambodian patient population (derivation population). We now prospectively validate the algorithm in the same clinical setting (validation population), assess its operational performance, and explore its cost-saving potential.

METHODS

We performed a cross-sectional study in a tertiary hospital in Phnom Penh, Cambodia, applying the CPS in adults on first-line antiretroviral treatment for at least 1 year. Treatment failure was defined as a VL >1000 copies per milliliter. The area under the receiver-operating characteristic (AUROC) curve of the CPS to detect treatment failure in the current study population (validation population) was compared with the AUROC of the CPS obtained in the patient population where the CPS was derived from in 2008 in the same study setting (derivation population). Costs related to VL testing and second-line regimens with the different testing strategies were compared.

RESULTS

One thousand four hundred ninety individuals {56.6% female, median age 38 years [interquartile range (IQR): 33-44]} were included, with a median baseline CD4 cell count of 94 cells per microliter (IQR: 28-205). Median time on antiretroviral treatment was 3.6 years (IQR: 2.1-5.1), 45 (3.0%) individuals had treatment failure. The AUROC of the CPS in validation was 0.75 (95% confidence interval: 0.67 to 0.83), relative to an AUROC of 0.70 in the derivation population. At the CPS cutoff ≥ 2, VL was indicated for 164 (11%) individuals, preventing inappropriate switching to second line in 143 cases. Twenty-four cases of treatment failure would be missed. When applied in routine care, the AUROC was 0.69 (95% confidence interval: 0.60 to 0.77). Overall 1-year program costs with targeted VL testing were 4-fold reduced.

CONCLUSIONS

The algorithm performed well in validation and has cost-saving potential. Further studies to assess its performance, feasibility, and impact in different settings are warranted.

Treatment outcomes of HIV-infected adolescents attending public-sector HIV clinics across Gauteng and Mpumalanga, South Africa

There is little evidence comparing treatment outcomes between adolescents and other age groups, particularly in resource-limited settings. A retrospective analysis of data from seven HIV clinics across urban Gauteng (n=5) and rural Mpumalanga (n=2), South Africa was conducted. The analysis compared HIV-positive antiretroviral treatment (ART)-naive young adolescents (10-14 years), older adolescents (15-19), and young adults (20-24 years) to adults (≥25 years) initiated onto standard first-line ART between April 2004 and August 2010. Log-binomial regression was used to estimate relative risk (RR) of failure to suppress viral load (≥400 copies/ml) or failure to achieve an adequate CD4 response at 6 or 12 months. The effect of age group on virological failure, mortality, and loss to follow-up (LTFU; ≥90 days since scheduled visit date) was estimated using Cox proportional hazards models. Of 42,427 patients initiating ART, 310 (0.7%) were young adolescents, 342 (0.8%) were older adolescents, and 1599 (3.8%) were young adults. Adolescents were similar to adults in terms of proportion male, baseline CD4 count, hemoglobin, and TB. Compared to adults, both older adolescents (6 months RR 1.75 95% CI 1.25-2.47) and young adults (6 months RR 1.33 95% CI 1.10-1.60 and 12 months RR 1.64 95% CI 1.23-2.19) were more likely to have an unsuppressed viral load and were more likely to fail virologically (HR 2.90 95% CI 1.74-4.86; HR 2.94 95% CI 1.63-5.31). Among those that died or were LTFU, the median time from ART initiation until death or LTFU was 4.7 months (IQR 1.5-13.2) and 10.9 months (IQR 5.0-22.7), respectively. There was no difference in risk of mortality by age category, compared to adults. Young adolescents were less likely to be LTFU at any time period after ART initiation (HR 0.43 95% CI 0.26-0.69) whereas older adolescents and young adults were more likely to be LTFU after ART initiation (HR 1.78 95% CI 1.34-2.36; HR 1.63 95% CI 1.41-1.89) compared to adults. HIV-infected adolescents and young adults between 15 and 24 years have poorer ART treatment outcomes in terms of virological response, LTFU, and virological failure than adults receiving ART. Interventions are needed to help improve outcomes and retention in care in this unique population.

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.

A model for reduced HIV-1 viral load monitoring in resource-limited settings

BACKGROUND

Viral load monitoring of antiretroviral therapy in low-income countries is rarely used because of high costs. Reducing the frequency of monitoring may make it financially feasible.

METHODS

We modeled three testing schemes: reduced viral load monitoring (RVLM) with CD4 count at baseline and viral load testing at 6, 36, and 60 months; United States Department of Health and Human Services (US DHHS) Treatment Guidelines; and World Health Organization (WHO) Guidelines using a cohort of 313 HIV-infected patients using Kaplan-Meier analysis.

RESULTS

Median time to detection of antiretroviral therapy (ART) failure using RVLM was 147 days; using US DHHS, it was 115 days; and using WHO guidelines, it was 1110 days. Median time for the development of first thymidine analog mutation was 594 days. The cost of RVLM was significantly lower than US DHHS.

CONCLUSIONS

RVLM detected failure significantly sooner than CD4 count monitoring alone at a lower cost than US DHHS monitoring. RVLM is a potentially effective method of monitoring ART in resource-limited settings.

Plasma drug level validates self-reported adherence but predicts limited specificity for nonadherence to antiretroviral therapy

Introduction. Adherence to antiretroviral therapy (ART) in low-income countries is mainly assessed by self-reported adherence (S-RA) without drug level determination. Nonadherence is an important factor in the emergence of resistance to ART, presenting a need for drug level determination. Objective. We set out to establish the relationship between plasma stavudine levels and S-RA and validate S-RA against the actual plasma drug concentrations. Methods. A cross-sectional investigation involving 234 patients in Uganda. Stavudine plasma levels were determined using high-performance liquid chromatography. We compared categories of plasma levels of stavudine with S-RA using multivariable logistic regression models. Results. Overall, 194/234 patients had S-RA ≥ 95% (good adherence) and 166/234 had stavudine plasma concentrations ≥ 36 nmol/L (therapeuticconcentration). Patients with good S-RA were eight times more likely to have stavudine levels within therapeutic concentration (Adjusted Odds Ratio: 7.7, 95% Confidence Interval: 3.5–7.0). However, of the 194 patients with good S-RA, 21.7% had below therapeutic concentrations. S-RA had high sensitivity for adherence (91.6%), but limited specificity for intrinsic poor adherence (38.2%). Conclusions. S-RA is a good tool for assessing adherence, but has low specificity in detecting nonadherence, which has implications for emergence of resistance.

Challenges in implementing HIV laboratory monitoring in resource-constrained settings: how to do more with less

Laboratory monitoring for HIV disease in resource-limited settings has now become one of the key challenges for antiretroviral treatment (ART) access and success, as emphasized by the 2010 revised WHO guidelines for ART in resource-limited settings. Thus, the most common method for initiating ART, and monitoring treatment response in resource-constrained environments is the measurement of CD4 T-cell count. Affordable CD4 T-cell counting has gradually been made possible by using simple, compact and robust, low-cost, new-generation cytometers, operating as single-platform volumetric instruments. Several cost-effective point-of-care CD4 T-cell testing options are also already on the market, in order to improve access to CD4 T-cell monitoring, especially for rural patients, and to reduce loss-to-follow-up of patients. In addition, HIV RNA viral load measurement is becoming increasingly important, mainly for a systematic confirmation of first-line ART failure before switching to second-line treatment to avoid belated as well as premature therapeutic decisions and their potentially negative consequences. Viral load testing should now be considered as the standard of care for therapeutic failure in all resource-limited settings. However, the measurement of HIV viral load remains a centralized marker, carried out in a limited number of reference laboratories. Finally, the costs of second-line ART regimens, rather than the laboratory test costs themselves, currently constitute the primary determinant of the total cost in ART switching. Laboratory monitoring strategies may become more attractive as price negotiations render second-line ART regimens less expensive worldwide.

A Quality Management Approach to Implementing Point-of-Care Technologies for HIV Diagnosis and Monitoring in Sub-Saharan Africa

Technology advances in rapid diagnosis and clinical monitoring of human immunodeficiency virus (HIV) infection have been made in recent years, greatly benefiting those at risk of HIV infection, those needing care and treatment, and those on antiretroviral (ART) therapy in sub-Saharan Africa. However, resource-limited, geographically remote, and harsh climate regions lack uniform access to these technologies. HIV rapid diagnostic tests (RDTs) and monitoring tools, such as those for CD4 counts, as well as tests for coinfections, are being developed and have great promise in these settings to aid in patient care. Here we explore the advances in point-of-care (POC) technology in the era where portable devices are bringing the laboratory to the patient. Quality management approaches will be imperative for the successful implementation of POC testing in endemic settings to improve patient care.

Practices to improve identification of adult antiretroviral therapy failure at the Lighthouse Trust clinic in Lilongwe, Malawi

OBJECTIVES

Evaluating treatment failure is critical when deciding to modify antiretroviral therapy (ART). Virologic Assessment Forms (VAFs) were implemented in July 2008 as a prerequisite for ordering viral load. The form requires assessment of clinical and immunologic status.

METHODS

Using the Electronic Medical Record (EMR), we retrospectively evaluated patients who met 2006 WHO guidelines for immunologic failure (≥15 years old; on ART ≥6 months; CD4 count <baseline OR CD4 count >50% drop from peak OR CD4 persistently <100 cells) at the Lighthouse Trust clinic from December 2007 to December 2009. We compared virologic screening, VAF implementation and ART modification during the same period using Fisher's exact tests and unpaired t-tests as appropriate.

RESULTS

Of 7000 enrolled ART patients ≥15 years old with at least two CD4 counts, 10% had immunologic failure with a median follow-up time on ART of 1.4 years (IQR: 0.8-2.3). Forty (6%) viral loads were ordered: 14 (35%) were detectable (>400 HIV RNA copies/mL) and one (7%) patient was switched to second-line therapy. Overall, 259 VAFs were completed: 67% for immunologic failure and 33% for WHO Stage 4 condition. Before VAF implementation, 1% of patients had viral loads drawn during routine care, whereas afterwards, 8% did (P<0.0001; 95% CI: 0.03-0.08).

CONCLUSIONS

Clinicians did not identify a large proportion of immunologic failure patients for screening. Implementation of VAFs produced little improvement in virologic screening during routine care. Better training and monitoring systems are needed.

Attitudes and practices towards HAART among people living with HIV/AIDS in a resource-limited setting in northern Burkina Faso

OBJECTIVES

To assess the perception of human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), and attitudes and practices towards highly active antiretroviral treatment (HAART) among patients living in a resource-poor region of northern Burkina Faso, where HAART has only become available in recent years.

STUDY DESIGN

A clinic-based cross-sectional survey of 306 patients taking HAART and 106 patients not yet on HAART.

METHODS

Face-to-face interview with a structured questionnaire at the clinic or at participants' homes.

RESULTS

Most patients were illiterate, but overall, they had adequate knowledge and positive attitudes towards HAART, and self-reported that their adherence was good. However, AIDS carried a psychological burden, as 27% of respondents were concerned that others might discover they were on HAART. The majority of respondents expressed concerns about transmitting HIV to others, but only 22% had disclosed their HIV status to their partners, and condom use was suboptimal. Approximately one-third of participants in the HAART group reported that they could no longer work in the same way as before they had AIDS. Multivariate logistic regression found that education and living with someone were positively associated with a favourable functioning status, and distance from clinic and lack of general support from family or friends were negatively associated with a favourable functioning status.

CONCLUSIONS

HAART was well accepted in this resource-poor region. Community education and supportive approaches may be critical for an effective preventive programme.

The Infectious Diseases Institute at Makerere University, Kampala, Uganda

The Infectious Diseases Institute (IDI) at Makerere University, Kampala, Uganda, was created in 2001. This article outlines its origins, principles, clinical programs, training activities, research programs, organizational structure, leadership, and contributions to Makerere University and its College of Health Sciences.

Development and validation of systems for rational use of viral load testing in adults receiving first-line ART in sub-Saharan Africa

BACKGROUND

World Health Organization (WHO) immunological and clinical criteria for monitoring first-line antiretroviral treatment (ART) offer low accuracy for predicting viral failure. Targeting viral load assays to those at high risk has been recommended and a system to do this has been developed in Cambodia. Systems for use in sub-Saharan African populations were evaluated.

METHODS

A new Ugandan-based scoring system for targeting viral load assays was developed from data from the first 4 years of a Ugandan cohort (N = 559) receiving first-line ART. The accuracy of this, the Cambodian system and the WHO criteria to predict viral failure, through targeting viral load assays, were compared in a separate population of 496 Ugandans.

RESULTS

The new Ugandan scoring system included CD4 cell count, mean cell volume, adherence, and HIV-associated clinical events as predictors of viral failure. In the validation population, the Ugandan system undertook viral load assays in 61 (12.3%) cases offering 20.5% sensitivity and 100% positive predictive value (PPV) to predict viral failure. The Cambodian system undertook viral load assays in 33 (6.7%) cases producing 23.1% sensitivity and 90.0% PPV. WHO criteria recommended viral load assays in 72 (14.5%) cases offering 30.8% sensitivity and 100% PPV.

CONCLUSION

Locally developed algorithms based on clinical and immunological criteria may offer little additional accuracy over WHO criteria for targeting viral load assays. When possible, confirming viral load before switching therapy is recommended. Scoring systems are more flexible than WHO criteria in allowing ART providers to choose the proportion of the population that undergo targeted viral load testing.

Monitoring of highly active antiretroviral therapy in HIV infection

PURPOSE OF REVIEW

Patients on antiretroviral therapy (ART) in high-income countries have routine laboratory tests to monitor ART efficacy/toxicity. We review studies describing the outcomes and costs of different monitoring approaches, predominantly in low-income countries.

RECENT FINDINGS

CD4 cell counts, HIV RNA viral load and clinical events are frequently discordant; viral load suppression occurs with WHO-defined CD4 failure and, as expected, viral load failure often occurs before CD4 failure. Routine CD4 monitoring provides small but significant mortality/morbidity benefits over clinical monitoring, but, at current prices, is not yet cost-effective in many sub-Saharan African countries. Viral load monitoring is less cost-effective with modelling studies reporting variable results. More research into point-of-care tests, methods for targeting monitoring and thresholds for defining failure is needed. Most laboratory monitoring for toxicity is neither effective nor cost-effective. In terms of models for delivery of care, task-shifting with nurse-led and decentralized care appear as effective as doctor-led or centralized care.

SUMMARY

Recent studies have improved the evidence base for monitoring on ART. Future research to increase cost-effectiveness by better targeting of monitoring and/or evaluating implementation of less costly point-of-care tests will contribute to long-term success of ART while continuing to increase ART coverage.

HIV Suppression among Patients on Treatment in Vietnam: A Review of HIV Viral Load Testing in a Public Urban Clinic in Ho Chi Minh City

Background. There are few reports of HIV viral load (VL) testing among patients on ART in Vietnam. Methods. From a public clinic in Ho Chi Minh City (HCMC), we reviewed cases of VL measurements from adults on ART. Results. We identified 228 cases. Median age was 30 years (27–34), 85% were male, and 77% had a history of IDU. The mean ART duration was 26 months (95% CI 25–27); d4T/3TC/NVP was the most common regimen. Viral suppression was seen in 160/228 (70%). Viremia (>1000 copies/mL) was associated with prior ART exposure (OR 5.68, P < .0001) and immunologic failure (OR 4.69, P = .0001). Targeted testing accounted for 13% of cases, only half of which yielded viremia. Conclusion. We demonstrate a high HIV suppression rate among patients on ART in HCMC, Vietnam. In this setting, routine testing detects viremia missed by targeted testing.

Cost-effectiveness of laboratory monitoring in sub-Saharan Africa: a review of the current literature

As the global community evaluates the unprecedented investment in the scale-up of human immunodeficiency virus (HIV) therapy and considers future investments in HIV care, it is crucial to identify those HIV interventions that maximize the benefit realized from each dollar spent. The use of laboratory monitoring assays--CD4 cell count and HIV RNA level--in decisions about when to initiate and switch antiretroviral therapy may offer substantial clinical benefit, but their economic value remains controversial. Cost-effectiveness analysis can be used to evaluate the value for money of strategies for HIV care, including alternative approaches to laboratory monitoring. Five published cost-effectiveness analyses address the question of CD4 cell count and HIV RNA level monitoring for HIV-infected patients in Africa, with differing conclusions. We describe the use of cost-effectiveness analysis in resource-limited settings and review the cost-effectiveness literature with regard to monitoring the CD4 cell count and HIV RNA level in Africa, highlighting some of the most critical issues in this debate.

Monitoring for treatment failure in patients on first-line antiretroviral treatment in resource-constrained settings

PURPOSE OF REVIEW

The number of people living with HIV in low-income and middle-income countries (LMICs), who will fail first-line treatment and benefit from regimen switching, will steadily increase in the coming years. The diagnosis of treatment failure in many settings is challenging because of limited access to plasma HIV RNA testing. This article summarizes recent studies in LMICs, investigating the diagnosis of treatment failure.

RECENT FINDINGS

WHO recommended clinico-immunological criteria to identify first-line treatment failure, which have a low sensitivity and positive predictive value. The addition of adherence criteria or alternative clinical and laboratory markers improves performance, but overall the results are suboptimal. This situation leads to both delayed and inappropriately premature switching to more expensive second-line agents. The cost-effectiveness of alternative monitoring strategies is debated, but there is increasing interest in the use of viral load testing to confirm virological failure before switching to second-line therapy. However, access to viral load testing in LMICs remains limited and a simple point-of-care assay is not yet available.

SUMMARY

Monitoring the efficacy of antiretroviral therapy in LMICs remains a critical challenge. Current research priorities include the development of simpler, cheaper assays and optimizing monitoring strategies based on currently available technologies.